import * as Arr from "effect/Array";
import * as Cache from "effect/Cache";
import * as Context from "effect/Context";
import * as Crypto from "effect/Crypto";
import * as DateTime from "effect/DateTime";
import * as Duration from "effect/Duration";
import * as Effect from "effect/Effect";
import * as Exit from "effect/Exit";
import * as FileSystem from "effect/FileSystem";
import * as Layer from "effect/Layer";
import * as Option from "effect/Option";
import * as Order from "effect/Order";
import * as Path from "effect/Path";
import * as Ref from "effect/Ref";
import {
  GitActionProgressEvent,
  GitActionProgressPhase,
  GitCommandError,
  GitPreparePullRequestThreadInput,
  GitPreparePullRequestThreadResult,
  GitPullRequestRefInput,
  GitResolvePullRequestResult,
  GitRunStackedActionInput,
  GitRunStackedActionResult,
  GitStackedAction,
  VcsStatusInput,
  type VcsStatusLocalResult,
  type VcsStatusRemoteResult,
  VcsStatusResult,
  ModelSelection,
} from "@t3tools/contracts";
import {
  detectSourceControlProviderFromGitRemoteUrl,
  mergeGitStatusParts,
  resolveAutoFeatureBranchName,
  sanitizeBranchFragment,
  sanitizeFeatureBranchName,
} from "@t3tools/shared/git";
import {
  getChangeRequestTerminologyForKind,
  type ChangeRequestTerminology,
} from "@t3tools/shared/sourceControl";

import { GitManagerError } from "@t3tools/contracts";
import { TextGeneration } from "../textGeneration/TextGeneration.ts";
import { ProjectSetupScriptRunner } from "../project/Services/ProjectSetupScriptRunner.ts";
import { extractBranchNameFromRemoteRef } from "./remoteRefs.ts";
import { ServerSettingsService } from "../serverSettings.ts";
import type { GitManagerServiceError } from "@t3tools/contracts";
import { GitVcsDriver, type GitStatusDetails } from "../vcs/GitVcsDriver.ts";
import { SourceControlProviderRegistry } from "../sourceControl/SourceControlProviderRegistry.ts";
import type { ChangeRequest } from "@t3tools/contracts";

export interface GitActionProgressReporter {
  readonly publish: (event: GitActionProgressEvent) => Effect.Effect<void, never>;
}

export interface GitRunStackedActionOptions {
  readonly actionId?: string;
  readonly progressReporter?: GitActionProgressReporter;
}

export interface GitManagerShape {
  readonly status: (
    input: VcsStatusInput,
  ) => Effect.Effect<VcsStatusResult, GitManagerServiceError>;
  readonly localStatus: (
    input: VcsStatusInput,
  ) => Effect.Effect<VcsStatusLocalResult, GitManagerServiceError>;
  readonly remoteStatus: (
    input: VcsStatusInput,
  ) => Effect.Effect<VcsStatusRemoteResult | null, GitManagerServiceError>;
  readonly invalidateLocalStatus: (cwd: string) => Effect.Effect<void, never>;
  readonly invalidateRemoteStatus: (cwd: string) => Effect.Effect<void, never>;
  readonly invalidateStatus: (cwd: string) => Effect.Effect<void, never>;
  readonly resolvePullRequest: (
    input: GitPullRequestRefInput,
  ) => Effect.Effect<GitResolvePullRequestResult, GitManagerServiceError>;
  readonly preparePullRequestThread: (
    input: GitPreparePullRequestThreadInput,
  ) => Effect.Effect<GitPreparePullRequestThreadResult, GitManagerServiceError>;
  readonly runStackedAction: (
    input: GitRunStackedActionInput,
    options?: GitRunStackedActionOptions,
  ) => Effect.Effect<GitRunStackedActionResult, GitManagerServiceError>;
}

export class GitManager extends Context.Service<GitManager, GitManagerShape>()(
  "t3/git/GitManager",
) {}

const COMMIT_TIMEOUT_MS = 10 * 60_000;
const MAX_PROGRESS_TEXT_LENGTH = 500;
const SHORT_SHA_LENGTH = 7;
const TOAST_DESCRIPTION_MAX = 72;
const STATUS_RESULT_CACHE_TTL = Duration.seconds(1);
const STATUS_RESULT_CACHE_CAPACITY = 2_048;
type StripProgressContext<T> = T extends any ? Omit<T, "actionId" | "cwd" | "action"> : never;
type GitActionProgressPayload = StripProgressContext<GitActionProgressEvent>;
type GitActionProgressEmitter = (event: GitActionProgressPayload) => Effect.Effect<void, never>;

function isNotGitRepositoryError(error: GitCommandError): boolean {
  return error.message.toLowerCase().includes("not a git repository");
}

interface OpenPrInfo {
  number: number;
  title: string;
  url: string;
  baseRefName: string;
  headRefName: string;
}

interface PullRequestInfo extends OpenPrInfo, PullRequestHeadRemoteInfo {
  state: "open" | "closed" | "merged";
  updatedAt: Option.Option<DateTime.Utc>;
}

const pullRequestUpdatedAtDescOrder: Order.Order<PullRequestInfo> = Order.mapInput(
  Order.flip(Option.makeOrder(DateTime.Order)),
  (pullRequest) => pullRequest.updatedAt,
);

interface ResolvedPullRequest {
  number: number;
  title: string;
  url: string;
  baseBranch: string;
  headBranch: string;
  state: "open" | "closed" | "merged";
}

interface PullRequestHeadRemoteInfo {
  isCrossRepository?: boolean | undefined;
  headRepositoryNameWithOwner?: string | null | undefined;
  headRepositoryOwnerLogin?: string | null | undefined;
}

interface BranchHeadContext {
  localBranch: string;
  headBranch: string;
  headSelectors: ReadonlyArray<string>;
  preferredHeadSelector: string;
  remoteName: string | null;
  headRepositoryNameWithOwner: string | null;
  headRepositoryOwnerLogin: string | null;
  isCrossRepository: boolean;
}

function parseRepositoryNameFromPullRequestUrl(url: string): string | null {
  const trimmed = url.trim();
  const match = /^https:\/\/github\.com\/[^/]+\/([^/]+)\/pull\/\d+(?:\/.*)?$/i.exec(trimmed);
  const repositoryName = match?.[1]?.trim() ?? "";
  return repositoryName.length > 0 ? repositoryName : null;
}

function resolveHeadRepositoryNameWithOwner(
  pullRequest: ResolvedPullRequest & PullRequestHeadRemoteInfo,
): string | null {
  const explicitRepository = pullRequest.headRepositoryNameWithOwner?.trim() ?? "";
  if (explicitRepository.length > 0) {
    return explicitRepository;
  }

  if (!pullRequest.isCrossRepository) {
    return null;
  }

  const ownerLogin = pullRequest.headRepositoryOwnerLogin?.trim() ?? "";
  const repositoryName = parseRepositoryNameFromPullRequestUrl(pullRequest.url);
  if (ownerLogin.length === 0 || !repositoryName) {
    return null;
  }

  return `${ownerLogin}/${repositoryName}`;
}

function resolvePullRequestWorktreeLocalBranchName(
  pullRequest: ResolvedPullRequest & PullRequestHeadRemoteInfo,
): string {
  if (!pullRequest.isCrossRepository) {
    return pullRequest.headBranch;
  }

  const sanitizedHeadBranch = sanitizeBranchFragment(pullRequest.headBranch).trim();
  const suffix = sanitizedHeadBranch.length > 0 ? sanitizedHeadBranch : "head";
  return `t3code/pr-${pullRequest.number}/${suffix}`;
}

function parseGitHubRepositoryNameWithOwnerFromRemoteUrl(url: string | null): string | null {
  const trimmed = url?.trim() ?? "";
  if (trimmed.length === 0) {
    return null;
  }

  const match =
    /^(?:git@github\.com:|ssh:\/\/git@github\.com\/|https:\/\/github\.com\/|git:\/\/github\.com\/)([^/\s]+\/[^/\s]+?)(?:\.git)?\/?$/i.exec(
      trimmed,
    );
  const repositoryNameWithOwner = match?.[1]?.trim() ?? "";
  return repositoryNameWithOwner.length > 0 ? repositoryNameWithOwner : null;
}

function parseRepositoryOwnerLogin(nameWithOwner: string | null): string | null {
  const trimmed = nameWithOwner?.trim() ?? "";
  if (trimmed.length === 0) {
    return null;
  }
  const [ownerLogin] = trimmed.split("/");
  const normalizedOwnerLogin = ownerLogin?.trim() ?? "";
  return normalizedOwnerLogin.length > 0 ? normalizedOwnerLogin : null;
}

function normalizeOptionalString(value: string | null | undefined): string | null {
  const trimmed = value?.trim() ?? "";
  return trimmed.length > 0 ? trimmed : null;
}

function normalizeOptionalRepositoryNameWithOwner(value: string | null | undefined): string | null {
  const normalized = normalizeOptionalString(value);
  return normalized ? normalized.toLowerCase() : null;
}

function normalizeOptionalOwnerLogin(value: string | null | undefined): string | null {
  const normalized = normalizeOptionalString(value);
  return normalized ? normalized.toLowerCase() : null;
}

function resolvePullRequestHeadRepositoryNameWithOwner(
  pr: PullRequestHeadRemoteInfo & { url: string },
) {
  const explicitRepository = normalizeOptionalString(pr.headRepositoryNameWithOwner);
  if (explicitRepository) {
    return explicitRepository;
  }

  if (!pr.isCrossRepository) {
    return null;
  }

  const ownerLogin = normalizeOptionalString(pr.headRepositoryOwnerLogin);
  const repositoryName = parseRepositoryNameFromPullRequestUrl(pr.url);
  if (!ownerLogin || !repositoryName) {
    return null;
  }

  return `${ownerLogin}/${repositoryName}`;
}

function matchesBranchHeadContext(
  pr: PullRequestInfo,
  headContext: Pick<
    BranchHeadContext,
    "headBranch" | "headRepositoryNameWithOwner" | "headRepositoryOwnerLogin" | "isCrossRepository"
  >,
): boolean {
  if (pr.headRefName !== headContext.headBranch) {
    return false;
  }

  const expectedHeadRepository = normalizeOptionalRepositoryNameWithOwner(
    headContext.headRepositoryNameWithOwner,
  );
  const expectedHeadOwner =
    normalizeOptionalOwnerLogin(headContext.headRepositoryOwnerLogin) ??
    parseRepositoryOwnerLogin(expectedHeadRepository);
  const prHeadRepository = normalizeOptionalRepositoryNameWithOwner(
    resolvePullRequestHeadRepositoryNameWithOwner(pr),
  );
  const prHeadOwner =
    normalizeOptionalOwnerLogin(pr.headRepositoryOwnerLogin) ??
    parseRepositoryOwnerLogin(prHeadRepository);

  if (headContext.isCrossRepository) {
    if (pr.isCrossRepository === false) {
      return false;
    }
    if ((expectedHeadRepository || expectedHeadOwner) && !prHeadRepository && !prHeadOwner) {
      return false;
    }
    if (expectedHeadRepository && prHeadRepository && expectedHeadRepository !== prHeadRepository) {
      return false;
    }
    if (expectedHeadOwner && prHeadOwner && expectedHeadOwner !== prHeadOwner) {
      return false;
    }
    return true;
  }

  if (pr.isCrossRepository === true) {
    return false;
  }
  if (expectedHeadRepository && prHeadRepository && expectedHeadRepository !== prHeadRepository) {
    return false;
  }
  if (expectedHeadOwner && prHeadOwner && expectedHeadOwner !== prHeadOwner) {
    return false;
  }
  return true;
}

function toPullRequestInfo(summary: ChangeRequest): PullRequestInfo {
  return {
    number: summary.number,
    title: summary.title,
    url: summary.url,
    baseRefName: summary.baseRefName,
    headRefName: summary.headRefName,
    state: summary.state ?? "open",
    updatedAt: summary.updatedAt,
    ...(summary.isCrossRepository !== undefined
      ? { isCrossRepository: summary.isCrossRepository }
      : {}),
    ...(summary.headRepositoryNameWithOwner !== undefined
      ? { headRepositoryNameWithOwner: summary.headRepositoryNameWithOwner }
      : {}),
    ...(summary.headRepositoryOwnerLogin !== undefined
      ? { headRepositoryOwnerLogin: summary.headRepositoryOwnerLogin }
      : {}),
  };
}

function gitManagerError(operation: string, detail: string, cause?: unknown): GitManagerError {
  return new GitManagerError({
    operation,
    detail,
    ...(cause !== undefined ? { cause } : {}),
  });
}

function limitContext(value: string, maxChars: number): string {
  if (value.length <= maxChars) return value;
  return `${value.slice(0, maxChars)}\n\n[truncated]`;
}

function shortenSha(sha: string | undefined): string | null {
  if (!sha) return null;
  return sha.slice(0, SHORT_SHA_LENGTH);
}

function truncateText(
  value: string | undefined,
  maxLength = TOAST_DESCRIPTION_MAX,
): string | undefined {
  if (!value) return undefined;
  if (value.length <= maxLength) return value;
  if (maxLength <= 3) return "...".slice(0, maxLength);
  return `${value.slice(0, Math.max(0, maxLength - 3)).trimEnd()}...`;
}

function withDescription(title: string, description: string | undefined) {
  return description ? { title, description } : { title };
}

function summarizeGitActionResult(
  result: Pick<GitRunStackedActionResult, "commit" | "push" | "pr">,
  terms: ChangeRequestTerminology,
): {
  title: string;
  description?: string;
} {
  if (result.pr.status === "created" || result.pr.status === "opened_existing") {
    const prNumber = result.pr.number ? ` #${result.pr.number}` : "";
    const title = `${result.pr.status === "created" ? "Created" : "Opened"} ${terms.shortLabel}${prNumber}`;
    return withDescription(title, truncateText(result.pr.title));
  }

  if (result.push.status === "pushed") {
    const shortSha = shortenSha(result.commit.commitSha);
    const branch = result.push.upstreamBranch ?? result.push.branch;
    const pushedCommitPart = shortSha ? ` ${shortSha}` : "";
    const branchPart = branch ? ` to ${branch}` : "";
    return withDescription(
      `Pushed${pushedCommitPart}${branchPart}`,
      truncateText(result.commit.subject),
    );
  }

  if (result.commit.status === "created") {
    const shortSha = shortenSha(result.commit.commitSha);
    const title = shortSha ? `Committed ${shortSha}` : "Committed changes";
    return withDescription(title, truncateText(result.commit.subject));
  }

  return { title: "Done" };
}

function sanitizeCommitMessage(generated: {
  subject: string;
  body: string;
  branch?: string | undefined;
}): {
  subject: string;
  body: string;
  branch?: string | undefined;
} {
  const rawSubject = generated.subject.trim().split(/\r?\n/g)[0]?.trim() ?? "";
  const subject = rawSubject.replace(/[.]+$/g, "").trim();
  const safeSubject = subject.length > 0 ? subject.slice(0, 72).trimEnd() : "Update project files";
  return {
    subject: safeSubject,
    body: generated.body.trim(),
    ...(generated.branch !== undefined ? { branch: generated.branch } : {}),
  };
}

function sanitizeProgressText(value: string): string | null {
  const trimmed = value.trim();
  if (trimmed.length === 0) {
    return null;
  }
  if (trimmed.length <= MAX_PROGRESS_TEXT_LENGTH) {
    return trimmed;
  }
  return trimmed.slice(0, MAX_PROGRESS_TEXT_LENGTH).trimEnd();
}

interface CommitAndBranchSuggestion {
  subject: string;
  body: string;
  branch?: string | undefined;
  commitMessage: string;
}

function isCommitAction(
  action: GitStackedAction,
): action is "commit" | "commit_push" | "commit_push_pr" {
  return action === "commit" || action === "commit_push" || action === "commit_push_pr";
}

function formatCommitMessage(subject: string, body: string): string {
  const trimmedBody = body.trim();
  if (trimmedBody.length === 0) {
    return subject;
  }
  return `${subject}\n\n${trimmedBody}`;
}

function parseCustomCommitMessage(raw: string): { subject: string; body: string } | null {
  const normalized = raw.replace(/\r\n/g, "\n").trim();
  if (normalized.length === 0) {
    return null;
  }

  const [firstLine, ...rest] = normalized.split("\n");
  const subject = firstLine?.trim() ?? "";
  if (subject.length === 0) {
    return null;
  }

  return {
    subject,
    body: rest.join("\n").trim(),
  };
}

function appendUnique(values: string[], next: string | null | undefined): void {
  const trimmed = next?.trim() ?? "";
  if (trimmed.length === 0 || values.includes(trimmed)) {
    return;
  }
  values.push(trimmed);
}

function toStatusPr(pr: PullRequestInfo): {
  number: number;
  title: string;
  url: string;
  baseRef: string;
  headRef: string;
  state: "open" | "closed" | "merged";
} {
  return {
    number: pr.number,
    title: pr.title,
    url: pr.url,
    baseRef: pr.baseRefName,
    headRef: pr.headRefName,
    state: pr.state,
  };
}

function normalizePullRequestReference(reference: string): string {
  const trimmed = reference.trim();
  const hashNumber = /^#(\d+)$/.exec(trimmed);
  return hashNumber?.[1] ?? trimmed;
}

function toResolvedPullRequest(pr: {
  number: number;
  title: string;
  url: string;
  baseRefName: string;
  headRefName: string;
  state?: "open" | "closed" | "merged";
}): ResolvedPullRequest {
  return {
    number: pr.number,
    title: pr.title,
    url: pr.url,
    baseBranch: pr.baseRefName,
    headBranch: pr.headRefName,
    state: pr.state ?? "open",
  };
}

function shouldPreferSshRemote(url: string | null): boolean {
  if (!url) return false;
  const trimmed = url.trim();
  return trimmed.startsWith("git@") || trimmed.startsWith("ssh://");
}

function toPullRequestHeadRemoteInfo(pr: {
  isCrossRepository?: boolean | undefined;
  headRepositoryNameWithOwner?: string | null | undefined;
  headRepositoryOwnerLogin?: string | null | undefined;
}): PullRequestHeadRemoteInfo {
  return {
    ...(pr.isCrossRepository !== undefined ? { isCrossRepository: pr.isCrossRepository } : {}),
    ...(pr.headRepositoryNameWithOwner !== undefined
      ? { headRepositoryNameWithOwner: pr.headRepositoryNameWithOwner }
      : {}),
    ...(pr.headRepositoryOwnerLogin !== undefined
      ? { headRepositoryOwnerLogin: pr.headRepositoryOwnerLogin }
      : {}),
  };
}

export const makeGitManager = Effect.fn("makeGitManager")(function* () {
  const gitCore = yield* GitVcsDriver;
  const sourceControlProviders = yield* SourceControlProviderRegistry;
  const textGeneration = yield* TextGeneration;
  const projectSetupScriptRunner = yield* ProjectSetupScriptRunner;
  const crypto = yield* Crypto.Crypto;

  const sourceControlProvider = (cwd: string) => sourceControlProviders.resolve({ cwd });
  const serverSettingsService = yield* ServerSettingsService;
  const randomUUIDv4 = crypto.randomUUIDv4.pipe(
    Effect.mapError((cause) =>
      gitManagerError("randomUUIDv4", "Failed to generate Git operation identifier.", cause),
    ),
  );

  const createProgressEmitter = (
    input: { cwd: string; action: GitStackedAction },
    options?: GitRunStackedActionOptions,
  ) =>
    (options?.actionId === undefined ? randomUUIDv4 : Effect.succeed(options.actionId)).pipe(
      Effect.map((actionId) => {
        const reporter = options?.progressReporter;
        const emit = (event: GitActionProgressPayload) =>
          reporter
            ? reporter.publish({
                actionId,
                cwd: input.cwd,
                action: input.action,
                ...event,
              } as GitActionProgressEvent)
            : Effect.void;

        return {
          actionId,
          emit,
        };
      }),
    );

  const configurePullRequestHeadUpstreamBase = Effect.fn("configurePullRequestHeadUpstream")(
    function* (
      cwd: string,
      pullRequest: ResolvedPullRequest & PullRequestHeadRemoteInfo,
      localBranch = pullRequest.headBranch,
    ) {
      const repositoryNameWithOwner = resolveHeadRepositoryNameWithOwner(pullRequest) ?? "";
      if (repositoryNameWithOwner.length === 0 && pullRequest.isCrossRepository !== true) {
        const remoteName = yield* gitCore.resolvePrimaryRemoteName(cwd);
        yield* gitCore.fetchRemoteTrackingBranch({
          cwd,
          remoteName,
          remoteBranch: pullRequest.headBranch,
        });
        yield* gitCore.setBranchUpstream({
          cwd,
          branch: localBranch,
          remoteName,
          remoteBranch: pullRequest.headBranch,
        });
        return;
      }

      if (repositoryNameWithOwner.length === 0) {
        return;
      }

      const cloneUrls = yield* (yield* sourceControlProvider(cwd)).getRepositoryCloneUrls({
        cwd,
        repository: repositoryNameWithOwner,
      });
      const originRemoteUrl = yield* gitCore.readConfigValue(cwd, "remote.origin.url");
      const remoteUrl = shouldPreferSshRemote(originRemoteUrl) ? cloneUrls.sshUrl : cloneUrls.url;
      const preferredRemoteName =
        pullRequest.headRepositoryOwnerLogin?.trim() ||
        repositoryNameWithOwner.split("/")[0]?.trim() ||
        "fork";
      const remoteName = yield* gitCore.ensureRemote({
        cwd,
        preferredName: preferredRemoteName,
        url: remoteUrl,
      });

      yield* gitCore.fetchRemoteTrackingBranch({
        cwd,
        remoteName,
        remoteBranch: pullRequest.headBranch,
      });
      yield* gitCore.setBranchUpstream({
        cwd,
        branch: localBranch,
        remoteName,
        remoteBranch: pullRequest.headBranch,
      });
    },
  );

  const configurePullRequestHeadUpstream = (
    cwd: string,
    pullRequest: ResolvedPullRequest & PullRequestHeadRemoteInfo,
    localBranch = pullRequest.headBranch,
  ) =>
    configurePullRequestHeadUpstreamBase(cwd, pullRequest, localBranch).pipe(
      Effect.catch((error) =>
        Effect.logWarning(
          `GitManager.configurePullRequestHeadUpstream: failed to configure upstream for ${localBranch} -> ${pullRequest.headBranch} in ${cwd}: ${error.message}`,
        ).pipe(Effect.asVoid),
      ),
    );

  const materializePullRequestHeadBranchBase = Effect.fn("materializePullRequestHeadBranch")(
    function* (
      cwd: string,
      pullRequest: ResolvedPullRequest & PullRequestHeadRemoteInfo,
      localBranch = pullRequest.headBranch,
    ) {
      const repositoryNameWithOwner = resolveHeadRepositoryNameWithOwner(pullRequest) ?? "";

      if (repositoryNameWithOwner.length === 0) {
        yield* gitCore.fetchPullRequestBranch({
          cwd,
          prNumber: pullRequest.number,
          branch: localBranch,
        });
        return;
      }

      const cloneUrls = yield* (yield* sourceControlProvider(cwd)).getRepositoryCloneUrls({
        cwd,
        repository: repositoryNameWithOwner,
      });
      const originRemoteUrl = yield* gitCore.readConfigValue(cwd, "remote.origin.url");
      const remoteUrl = shouldPreferSshRemote(originRemoteUrl) ? cloneUrls.sshUrl : cloneUrls.url;
      const preferredRemoteName =
        pullRequest.headRepositoryOwnerLogin?.trim() ||
        repositoryNameWithOwner.split("/")[0]?.trim() ||
        "fork";
      const remoteName = yield* gitCore.ensureRemote({
        cwd,
        preferredName: preferredRemoteName,
        url: remoteUrl,
      });

      yield* gitCore.fetchRemoteBranch({
        cwd,
        remoteName,
        remoteBranch: pullRequest.headBranch,
        localBranch,
      });
      yield* gitCore.setBranchUpstream({
        cwd,
        branch: localBranch,
        remoteName,
        remoteBranch: pullRequest.headBranch,
      });
    },
  );

  const materializePullRequestHeadBranch = (
    cwd: string,
    pullRequest: ResolvedPullRequest & PullRequestHeadRemoteInfo,
    localBranch = pullRequest.headBranch,
  ) =>
    materializePullRequestHeadBranchBase(cwd, pullRequest, localBranch).pipe(
      Effect.catch(() =>
        gitCore.fetchPullRequestBranch({
          cwd,
          prNumber: pullRequest.number,
          branch: localBranch,
        }),
      ),
    );
  const fileSystem = yield* FileSystem.FileSystem;
  const path = yield* Path.Path;

  const tempDir = process.env.TMPDIR ?? process.env.TEMP ?? process.env.TMP ?? "/tmp";
  const canonicalizeExistingPath = (value: string) =>
    fileSystem.realPath(value).pipe(Effect.catch(() => Effect.succeed(value)));
  const normalizeStatusCacheKey = canonicalizeExistingPath;
  const nonRepositoryStatusDetails = {
    isRepo: false,
    hasOriginRemote: false,
    isDefaultBranch: false,
    branch: null,
    upstreamRef: null,
    hasWorkingTreeChanges: false,
    workingTree: { files: [], insertions: 0, deletions: 0 },
    hasUpstream: false,
    aheadCount: 0,
    behindCount: 0,
    aheadOfDefaultCount: 0,
  } satisfies GitStatusDetails;
  const readLocalStatus = Effect.fn("readLocalStatus")(function* (cwd: string) {
    const details = yield* gitCore
      .statusDetailsLocal(cwd)
      .pipe(
        Effect.catchIf(isNotGitRepositoryError, () => Effect.succeed(nonRepositoryStatusDetails)),
      );
    const hostingProvider = details.isRepo
      ? yield* resolveHostingProvider(cwd, details.branch)
      : null;

    return {
      isRepo: details.isRepo,
      ...(hostingProvider ? { sourceControlProvider: hostingProvider } : {}),
      hasPrimaryRemote: details.hasOriginRemote,
      isDefaultRef: details.isDefaultBranch,
      refName: details.branch,
      hasWorkingTreeChanges: details.hasWorkingTreeChanges,
      workingTree: details.workingTree,
    } satisfies VcsStatusLocalResult;
  });
  const localStatusResultCache = yield* Cache.makeWith(readLocalStatus, {
    capacity: STATUS_RESULT_CACHE_CAPACITY,
    timeToLive: (exit) => (Exit.isSuccess(exit) ? STATUS_RESULT_CACHE_TTL : Duration.zero),
  });
  const invalidateLocalStatusResultCache = (cwd: string) =>
    normalizeStatusCacheKey(cwd).pipe(
      Effect.flatMap((cacheKey) => Cache.invalidate(localStatusResultCache, cacheKey)),
    );
  const readRemoteStatus = Effect.fn("readRemoteStatus")(function* (cwd: string) {
    const details = yield* gitCore
      .statusDetails(cwd)
      .pipe(Effect.catchIf(isNotGitRepositoryError, () => Effect.succeed(null)));
    if (details === null || !details.isRepo) {
      return null;
    }

    const pr =
      details.branch !== null
        ? yield* findLatestPr(cwd, {
            branch: details.branch,
            upstreamRef: details.upstreamRef,
          }).pipe(
            Effect.map((latest) => {
              if (!latest) return null;
              // On the default branch, only surface open PRs.
              // Merged/closed matches are usually reverse-merge history, not the thread's PR context.
              if (details.isDefaultBranch && latest.state !== "open") return null;
              return toStatusPr(latest);
            }),
            Effect.catch(() => Effect.succeed(null)),
          )
        : null;

    return {
      hasUpstream: details.hasUpstream,
      aheadCount: details.aheadCount,
      behindCount: details.behindCount,
      aheadOfDefaultCount: details.aheadOfDefaultCount,
      pr,
    } satisfies VcsStatusRemoteResult;
  });
  const remoteStatusResultCache = yield* Cache.makeWith(readRemoteStatus, {
    capacity: STATUS_RESULT_CACHE_CAPACITY,
    timeToLive: (exit) => (Exit.isSuccess(exit) ? STATUS_RESULT_CACHE_TTL : Duration.zero),
  });
  const invalidateRemoteStatusResultCache = (cwd: string) =>
    normalizeStatusCacheKey(cwd).pipe(
      Effect.flatMap((cacheKey) => Cache.invalidate(remoteStatusResultCache, cacheKey)),
    );

  const readConfigValueNullable = (cwd: string, key: string) =>
    gitCore.readConfigValue(cwd, key).pipe(Effect.catch(() => Effect.succeed(null)));

  const resolveHostingProvider = Effect.fn("resolveHostingProvider")(function* (
    cwd: string,
    branch: string | null,
  ) {
    const preferredRemoteName =
      branch === null
        ? "origin"
        : ((yield* readConfigValueNullable(cwd, `branch.${branch}.remote`)) ?? "origin");
    const remoteUrl =
      (yield* readConfigValueNullable(cwd, `remote.${preferredRemoteName}.url`)) ??
      (yield* readConfigValueNullable(cwd, "remote.origin.url"));

    return remoteUrl ? detectSourceControlProviderFromGitRemoteUrl(remoteUrl) : null;
  });

  const resolveRemoteRepositoryContext = Effect.fn("resolveRemoteRepositoryContext")(function* (
    cwd: string,
    remoteName: string | null,
  ) {
    if (!remoteName) {
      return {
        repositoryNameWithOwner: null,
        ownerLogin: null,
      };
    }

    const remoteUrl = yield* readConfigValueNullable(cwd, `remote.${remoteName}.url`);
    const repositoryNameWithOwner = parseGitHubRepositoryNameWithOwnerFromRemoteUrl(remoteUrl);
    return {
      repositoryNameWithOwner,
      ownerLogin: parseRepositoryOwnerLogin(repositoryNameWithOwner),
    };
  });

  const resolveBranchHeadContext = Effect.fn("resolveBranchHeadContext")(function* (
    cwd: string,
    details: { branch: string; upstreamRef: string | null },
  ) {
    const remoteName = yield* readConfigValueNullable(cwd, `branch.${details.branch}.remote`);
    const headBranchFromUpstream = details.upstreamRef
      ? extractBranchNameFromRemoteRef(details.upstreamRef, { remoteName })
      : "";
    const headBranch = headBranchFromUpstream.length > 0 ? headBranchFromUpstream : details.branch;
    const shouldProbeLocalBranchSelector =
      headBranchFromUpstream.length === 0 || headBranch === details.branch;

    const [remoteRepository, originRepository] = yield* Effect.all(
      [
        resolveRemoteRepositoryContext(cwd, remoteName),
        resolveRemoteRepositoryContext(cwd, "origin"),
      ],
      { concurrency: "unbounded" },
    );

    const isCrossRepository =
      remoteRepository.repositoryNameWithOwner !== null &&
      originRepository.repositoryNameWithOwner !== null
        ? remoteRepository.repositoryNameWithOwner.toLowerCase() !==
          originRepository.repositoryNameWithOwner.toLowerCase()
        : remoteName !== null &&
          remoteName !== "origin" &&
          remoteRepository.repositoryNameWithOwner !== null;

    const ownerHeadSelector =
      remoteRepository.ownerLogin && headBranch.length > 0
        ? `${remoteRepository.ownerLogin}:${headBranch}`
        : null;
    const remoteAliasHeadSelector =
      remoteName && headBranch.length > 0 ? `${remoteName}:${headBranch}` : null;
    const shouldProbeRemoteOwnedSelectors =
      isCrossRepository || (remoteName !== null && remoteName !== "origin");

    const headSelectors: string[] = [];
    if (isCrossRepository && shouldProbeRemoteOwnedSelectors) {
      appendUnique(headSelectors, ownerHeadSelector);
      appendUnique(
        headSelectors,
        remoteAliasHeadSelector !== ownerHeadSelector ? remoteAliasHeadSelector : null,
      );
    }
    if (shouldProbeLocalBranchSelector) {
      appendUnique(headSelectors, details.branch);
    }
    appendUnique(headSelectors, headBranch !== details.branch ? headBranch : null);
    if (!isCrossRepository && shouldProbeRemoteOwnedSelectors) {
      appendUnique(headSelectors, ownerHeadSelector);
      appendUnique(
        headSelectors,
        remoteAliasHeadSelector !== ownerHeadSelector ? remoteAliasHeadSelector : null,
      );
    }

    return {
      localBranch: details.branch,
      headBranch,
      headSelectors,
      preferredHeadSelector:
        ownerHeadSelector && isCrossRepository ? ownerHeadSelector : headBranch,
      remoteName,
      headRepositoryNameWithOwner: remoteRepository.repositoryNameWithOwner,
      headRepositoryOwnerLogin: remoteRepository.ownerLogin,
      isCrossRepository,
    } satisfies BranchHeadContext;
  });

  const findOpenPr = Effect.fn("findOpenPr")(function* (
    cwd: string,
    headContext: Pick<
      BranchHeadContext,
      | "headBranch"
      | "headSelectors"
      | "headRepositoryNameWithOwner"
      | "headRepositoryOwnerLogin"
      | "isCrossRepository"
    >,
  ) {
    for (const headSelector of headContext.headSelectors) {
      const pullRequests = yield* (yield* sourceControlProvider(cwd)).listChangeRequests({
        cwd,
        headSelector,
        state: "open",
        limit: 1,
      });
      const normalizedPullRequests = pullRequests.map(toPullRequestInfo);

      const firstPullRequest = normalizedPullRequests.find((pullRequest) =>
        matchesBranchHeadContext(pullRequest, headContext),
      );
      if (firstPullRequest) {
        return {
          number: firstPullRequest.number,
          title: firstPullRequest.title,
          url: firstPullRequest.url,
          baseRefName: firstPullRequest.baseRefName,
          headRefName: firstPullRequest.headRefName,
          state: "open",
          updatedAt: Option.none(),
        } satisfies PullRequestInfo;
      }
    }

    return null;
  });

  const findLatestPr = Effect.fn("findLatestPr")(function* (
    cwd: string,
    details: { branch: string; upstreamRef: string | null },
  ) {
    const headContext = yield* resolveBranchHeadContext(cwd, details);
    const parsedByNumber = new Map<number, PullRequestInfo>();

    for (const headSelector of headContext.headSelectors) {
      const pullRequests = yield* (yield* sourceControlProvider(cwd)).listChangeRequests({
        cwd,
        headSelector,
        state: "all",
        limit: 20,
      });

      for (const pr of pullRequests.map(toPullRequestInfo)) {
        if (!matchesBranchHeadContext(pr, headContext)) {
          continue;
        }
        parsedByNumber.set(pr.number, pr);
      }
    }

    const parsed = Arr.sort(parsedByNumber.values(), pullRequestUpdatedAtDescOrder);

    const latestOpenPr = parsed.find((pr) => pr.state === "open");
    if (latestOpenPr) {
      return latestOpenPr;
    }
    return parsed[0] ?? null;
  });

  const buildCompletionToast = Effect.fn("buildCompletionToast")(function* (
    cwd: string,
    result: Pick<GitRunStackedActionResult, "action" | "branch" | "commit" | "push" | "pr">,
  ) {
    const terms = yield* sourceControlProvider(cwd).pipe(
      Effect.map((provider) => getChangeRequestTerminologyForKind(provider.kind)),
      Effect.catch(() => Effect.succeed(getChangeRequestTerminologyForKind("unknown"))),
    );
    const summary = summarizeGitActionResult(result, terms);
    let latestOpenPr: PullRequestInfo | null = null;
    let currentBranchIsDefault = false;
    let finalBranchContext: {
      branch: string;
      upstreamRef: string | null;
      hasUpstream: boolean;
    } | null = null;

    if (result.action !== "commit") {
      const finalStatus = yield* gitCore.statusDetails(cwd);
      if (finalStatus.branch) {
        finalBranchContext = {
          branch: finalStatus.branch,
          upstreamRef: finalStatus.upstreamRef,
          hasUpstream: finalStatus.hasUpstream,
        };
        currentBranchIsDefault = finalStatus.isDefaultBranch;
      }
    }

    const explicitResultPr =
      (result.pr.status === "created" || result.pr.status === "opened_existing") && result.pr.url
        ? {
            url: result.pr.url,
            state: "open" as const,
          }
        : null;
    const shouldLookupExistingOpenPr =
      (result.action === "commit_push" || result.action === "push") &&
      result.push.status === "pushed" &&
      result.branch.status !== "created" &&
      !currentBranchIsDefault &&
      explicitResultPr === null &&
      finalBranchContext?.hasUpstream === true;

    if (shouldLookupExistingOpenPr && finalBranchContext) {
      latestOpenPr = yield* resolveBranchHeadContext(cwd, {
        branch: finalBranchContext.branch,
        upstreamRef: finalBranchContext.upstreamRef,
      }).pipe(
        Effect.flatMap((headContext) => findOpenPr(cwd, headContext)),
        Effect.catch(() => Effect.succeed(null)),
      );
    }

    const openPr = latestOpenPr ?? explicitResultPr;

    const cta =
      result.action === "commit" && result.commit.status === "created"
        ? {
            kind: "run_action" as const,
            label: "Push",
            action: { kind: "push" as const },
          }
        : (result.action === "push" ||
              result.action === "create_pr" ||
              result.action === "commit_push" ||
              result.action === "commit_push_pr") &&
            openPr?.url &&
            (!currentBranchIsDefault ||
              result.pr.status === "created" ||
              result.pr.status === "opened_existing")
          ? {
              kind: "open_pr" as const,
              label: `View ${terms.shortLabel}`,
              url: openPr.url,
            }
          : (result.action === "push" || result.action === "commit_push") &&
              result.push.status === "pushed" &&
              !currentBranchIsDefault
            ? {
                kind: "run_action" as const,
                label: `Create ${terms.shortLabel}`,
                action: { kind: "create_pr" as const },
              }
            : {
                kind: "none" as const,
              };

    return {
      ...summary,
      cta,
    };
  });

  const resolveBaseBranch = Effect.fn("resolveBaseBranch")(function* (
    cwd: string,
    branch: string,
    upstreamRef: string | null,
    headContext: Pick<BranchHeadContext, "isCrossRepository" | "remoteName">,
  ) {
    const configured = yield* gitCore.readConfigValue(cwd, `branch.${branch}.gh-merge-base`);
    if (configured) return configured;

    if (upstreamRef && !headContext.isCrossRepository) {
      const upstreamBranch = extractBranchNameFromRemoteRef(upstreamRef, {
        remoteName: headContext.remoteName,
      });
      if (upstreamBranch.length > 0 && upstreamBranch !== branch) {
        return upstreamBranch;
      }
    }

    const defaultFromProvider = yield* sourceControlProvider(cwd).pipe(
      Effect.flatMap((provider) => provider.getDefaultBranch({ cwd })),
      Effect.catch(() => Effect.succeed(null)),
    );
    if (defaultFromProvider) {
      return defaultFromProvider;
    }

    return "main";
  });

  const resolveCommitAndBranchSuggestion = Effect.fn("resolveCommitAndBranchSuggestion")(
    function* (input: {
      cwd: string;
      branch: string | null;
      commitMessage?: string;
      /** When true, also produce a semantic feature branch name. */
      includeBranch?: boolean;
      filePaths?: readonly string[];
      modelSelection: ModelSelection;
    }) {
      const context = yield* gitCore.prepareCommitContext(input.cwd, input.filePaths);
      if (!context) {
        return null;
      }

      const customCommit = parseCustomCommitMessage(input.commitMessage ?? "");
      if (customCommit) {
        return {
          subject: customCommit.subject,
          body: customCommit.body,
          ...(input.includeBranch
            ? { branch: sanitizeFeatureBranchName(customCommit.subject) }
            : {}),
          commitMessage: formatCommitMessage(customCommit.subject, customCommit.body),
        };
      }

      const generated = yield* textGeneration
        .generateCommitMessage({
          cwd: input.cwd,
          branch: input.branch,
          stagedSummary: limitContext(context.stagedSummary, 8_000),
          stagedPatch: limitContext(context.stagedPatch, 50_000),
          ...(input.includeBranch ? { includeBranch: true } : {}),
          modelSelection: input.modelSelection,
        })
        .pipe(Effect.map((result) => sanitizeCommitMessage(result)));

      return {
        subject: generated.subject,
        body: generated.body,
        ...(generated.branch !== undefined ? { branch: generated.branch } : {}),
        commitMessage: formatCommitMessage(generated.subject, generated.body),
      };
    },
  );

  const runCommitStep = Effect.fn("runCommitStep")(function* (
    modelSelection: ModelSelection,
    cwd: string,
    action: "commit" | "commit_push" | "commit_push_pr",
    branch: string | null,
    commitMessage?: string,
    preResolvedSuggestion?: CommitAndBranchSuggestion,
    filePaths?: readonly string[],
    progressReporter?: GitActionProgressReporter,
    actionId?: string,
  ) {
    const emit = (event: GitActionProgressPayload) =>
      progressReporter && actionId
        ? progressReporter.publish({
            actionId,
            cwd,
            action,
            ...event,
          } as GitActionProgressEvent)
        : Effect.void;

    let suggestion: CommitAndBranchSuggestion | null | undefined = preResolvedSuggestion;
    if (!suggestion) {
      const needsGeneration = !commitMessage?.trim();
      if (needsGeneration) {
        yield* emit({
          kind: "phase_started",
          phase: "commit",
          label: "Generating commit message...",
        });
      }
      suggestion = yield* resolveCommitAndBranchSuggestion({
        cwd,
        branch,
        ...(commitMessage ? { commitMessage } : {}),
        ...(filePaths ? { filePaths } : {}),
        modelSelection,
      });
    }
    if (!suggestion) {
      return { status: "skipped_no_changes" as const };
    }

    yield* emit({
      kind: "phase_started",
      phase: "commit",
      label: "Committing...",
    });

    let currentHookName: string | null = null;
    const commitProgress =
      progressReporter && actionId
        ? {
            onOutputLine: ({ stream, text }: { stream: "stdout" | "stderr"; text: string }) => {
              const sanitized = sanitizeProgressText(text);
              if (!sanitized) {
                return Effect.void;
              }
              return emit({
                kind: "hook_output",
                hookName: currentHookName,
                stream,
                text: sanitized,
              });
            },
            onHookStarted: (hookName: string) => {
              currentHookName = hookName;
              return emit({
                kind: "hook_started",
                hookName,
              });
            },
            onHookFinished: ({
              hookName,
              exitCode,
              durationMs,
            }: {
              hookName: string;
              exitCode: number | null;
              durationMs: number | null;
            }) => {
              if (currentHookName === hookName) {
                currentHookName = null;
              }
              return emit({
                kind: "hook_finished",
                hookName,
                exitCode,
                durationMs,
              });
            },
          }
        : null;
    const { commitSha } = yield* gitCore.commit(cwd, suggestion.subject, suggestion.body, {
      timeoutMs: COMMIT_TIMEOUT_MS,
      ...(commitProgress ? { progress: commitProgress } : {}),
    });
    if (currentHookName !== null) {
      yield* emit({
        kind: "hook_finished",
        hookName: currentHookName,
        exitCode: 0,
        durationMs: null,
      });
      currentHookName = null;
    }
    return {
      status: "created" as const,
      commitSha,
      subject: suggestion.subject,
    };
  });

  const runPrStep = Effect.fn("runPrStep")(function* (
    modelSelection: ModelSelection,
    cwd: string,
    fallbackBranch: string | null,
    emit: GitActionProgressEmitter,
  ) {
    const provider = yield* sourceControlProvider(cwd);
    const terms = getChangeRequestTerminologyForKind(provider.kind);
    const details = yield* gitCore.statusDetails(cwd);
    const branch = details.branch ?? fallbackBranch;
    if (!branch) {
      return yield* gitManagerError(
        "runPrStep",
        "Cannot create a pull request from detached HEAD.",
      );
    }
    if (!details.hasUpstream) {
      return yield* gitManagerError(
        "runPrStep",
        "Current branch has not been pushed. Push before creating a PR.",
      );
    }

    const headContext = yield* resolveBranchHeadContext(cwd, {
      branch,
      upstreamRef: details.upstreamRef,
    });

    const existing = yield* findOpenPr(cwd, headContext);
    if (existing) {
      return {
        status: "opened_existing" as const,
        url: existing.url,
        number: existing.number,
        baseBranch: existing.baseRefName,
        headBranch: existing.headRefName,
        title: existing.title,
      };
    }

    const baseBranch = yield* resolveBaseBranch(cwd, branch, details.upstreamRef, headContext);
    yield* emit({
      kind: "phase_started",
      phase: "pr",
      label: `Generating ${terms.shortLabel} content...`,
    });
    const rangeContext = yield* gitCore.readRangeContext(cwd, baseBranch);

    const generated = yield* textGeneration.generatePrContent({
      cwd,
      baseBranch,
      headBranch: headContext.headBranch,
      commitSummary: limitContext(rangeContext.commitSummary, 20_000),
      diffSummary: limitContext(rangeContext.diffSummary, 20_000),
      diffPatch: limitContext(rangeContext.diffPatch, 60_000),
      modelSelection,
    });

    const bodyFile = path.join(tempDir, `t3code-pr-body-${process.pid}-${yield* randomUUIDv4}.md`);
    yield* fileSystem
      .writeFileString(bodyFile, generated.body)
      .pipe(
        Effect.mapError((cause) =>
          gitManagerError("runPrStep", "Failed to write pull request body temp file.", cause),
        ),
      );
    yield* emit({
      kind: "phase_started",
      phase: "pr",
      label: `Creating ${terms.singular}...`,
    });
    yield* provider
      .createChangeRequest({
        cwd,
        baseRefName: baseBranch,
        headSelector: headContext.preferredHeadSelector,
        title: generated.title,
        bodyFile,
      })
      .pipe(Effect.ensuring(fileSystem.remove(bodyFile).pipe(Effect.catch(() => Effect.void))));

    const created = yield* findOpenPr(cwd, headContext);
    if (!created) {
      return {
        status: "created" as const,
        baseBranch,
        headBranch: headContext.headBranch,
        title: generated.title,
      };
    }

    return {
      status: "created" as const,
      url: created.url,
      number: created.number,
      baseBranch: created.baseRefName,
      headBranch: created.headRefName,
      title: created.title,
    };
  });

  const localStatus: GitManagerShape["localStatus"] = Effect.fn("localStatus")(function* (input) {
    const cacheKey = yield* normalizeStatusCacheKey(input.cwd);
    return yield* Cache.get(localStatusResultCache, cacheKey);
  });
  const remoteStatus: GitManagerShape["remoteStatus"] = Effect.fn("remoteStatus")(
    function* (input) {
      const cacheKey = yield* normalizeStatusCacheKey(input.cwd);
      return yield* Cache.get(remoteStatusResultCache, cacheKey);
    },
  );
  const status: GitManagerShape["status"] = Effect.fn("status")(function* (input) {
    const [local, remote] = yield* Effect.all([localStatus(input), remoteStatus(input)]);
    return mergeGitStatusParts(local, remote);
  });
  const invalidateLocalStatus: GitManagerShape["invalidateLocalStatus"] = Effect.fn(
    "invalidateLocalStatus",
  )(function* (cwd) {
    yield* invalidateLocalStatusResultCache(cwd);
  });
  const invalidateRemoteStatus: GitManagerShape["invalidateRemoteStatus"] = Effect.fn(
    "invalidateRemoteStatus",
  )(function* (cwd) {
    yield* invalidateRemoteStatusResultCache(cwd);
  });
  const invalidateStatus: GitManagerShape["invalidateStatus"] = Effect.fn("invalidateStatus")(
    function* (cwd) {
      yield* invalidateLocalStatusResultCache(cwd);
      yield* invalidateRemoteStatusResultCache(cwd);
    },
  );

  const resolvePullRequest: GitManagerShape["resolvePullRequest"] = Effect.fn("resolvePullRequest")(
    function* (input) {
      const pullRequest = yield* (yield* sourceControlProvider(input.cwd))
        .getChangeRequest({
          cwd: input.cwd,
          reference: normalizePullRequestReference(input.reference),
        })
        .pipe(Effect.map((resolved) => toResolvedPullRequest(resolved)));

      return { pullRequest };
    },
  );

  const preparePullRequestThread: GitManagerShape["preparePullRequestThread"] = Effect.fn(
    "preparePullRequestThread",
  )(function* (input) {
    const maybeRunSetupScript = (worktreePath: string) => {
      if (!input.threadId) {
        return Effect.void;
      }
      return projectSetupScriptRunner
        .runForThread({
          threadId: input.threadId,
          projectCwd: input.cwd,
          worktreePath,
        })
        .pipe(
          Effect.catch((error) =>
            Effect.logWarning(
              `GitManager.preparePullRequestThread: failed to launch worktree setup script for thread ${input.threadId} in ${worktreePath}: ${error.message}`,
            ).pipe(Effect.asVoid),
          ),
        );
    };
    return yield* Effect.gen(function* () {
      const normalizedReference = normalizePullRequestReference(input.reference);
      const rootWorktreePath = yield* canonicalizeExistingPath(input.cwd);
      const pullRequestSummary = yield* (yield* sourceControlProvider(input.cwd)).getChangeRequest({
        cwd: input.cwd,
        reference: normalizedReference,
      });
      const pullRequest = toResolvedPullRequest(pullRequestSummary);

      if (input.mode === "local") {
        yield* (yield* sourceControlProvider(input.cwd)).checkoutChangeRequest({
          cwd: input.cwd,
          reference: normalizedReference,
          force: true,
        });
        const details = yield* gitCore.statusDetails(input.cwd);
        yield* configurePullRequestHeadUpstream(
          input.cwd,
          {
            ...pullRequest,
            ...toPullRequestHeadRemoteInfo(pullRequestSummary),
          },
          details.branch ?? pullRequest.headBranch,
        );
        return {
          pullRequest,
          branch: details.branch ?? pullRequest.headBranch,
          worktreePath: null,
        };
      }

      const ensureExistingWorktreeUpstream = Effect.fn("ensureExistingWorktreeUpstream")(function* (
        worktreePath: string,
      ) {
        const details = yield* gitCore.statusDetails(worktreePath);
        yield* configurePullRequestHeadUpstream(
          worktreePath,
          {
            ...pullRequest,
            ...toPullRequestHeadRemoteInfo(pullRequestSummary),
          },
          details.branch ?? pullRequest.headBranch,
        );
      });

      const pullRequestWithRemoteInfo = {
        ...pullRequest,
        ...toPullRequestHeadRemoteInfo(pullRequestSummary),
      } as const;
      const localPullRequestBranch =
        resolvePullRequestWorktreeLocalBranchName(pullRequestWithRemoteInfo);

      const findLocalHeadBranch = Effect.fn("findLocalHeadBranch")(function* (cwd: string) {
        const result = yield* gitCore.listRefs({ cwd });
        const localBranch = result.refs.find(
          (branch) => !branch.isRemote && branch.name === localPullRequestBranch,
        );
        if (localBranch) {
          return localBranch;
        }
        if (localPullRequestBranch === pullRequest.headBranch) {
          return null;
        }

        for (const branch of result.refs) {
          if (branch.isRemote || branch.name !== pullRequest.headBranch || !branch.worktreePath) {
            continue;
          }

          const worktreePath = yield* canonicalizeExistingPath(branch.worktreePath);
          if (worktreePath !== rootWorktreePath) {
            return branch;
          }
        }

        return null;
      });

      const existingBranchBeforeFetch = yield* findLocalHeadBranch(input.cwd);
      const existingBranchBeforeFetchPath = existingBranchBeforeFetch?.worktreePath
        ? yield* canonicalizeExistingPath(existingBranchBeforeFetch.worktreePath)
        : null;
      if (
        existingBranchBeforeFetch?.worktreePath &&
        existingBranchBeforeFetchPath !== rootWorktreePath
      ) {
        yield* ensureExistingWorktreeUpstream(existingBranchBeforeFetch.worktreePath);
        return {
          pullRequest,
          branch: localPullRequestBranch,
          worktreePath: existingBranchBeforeFetch.worktreePath,
        };
      }
      if (existingBranchBeforeFetchPath === rootWorktreePath) {
        return yield* gitManagerError(
          "preparePullRequestThread",
          "This PR branch is already checked out in the main repo. Use Local, or switch the main repo off that branch before creating a worktree thread.",
        );
      }

      yield* materializePullRequestHeadBranch(
        input.cwd,
        pullRequestWithRemoteInfo,
        localPullRequestBranch,
      );

      const existingBranchAfterFetch = yield* findLocalHeadBranch(input.cwd);
      const existingBranchAfterFetchPath = existingBranchAfterFetch?.worktreePath
        ? yield* canonicalizeExistingPath(existingBranchAfterFetch.worktreePath)
        : null;
      if (
        existingBranchAfterFetch?.worktreePath &&
        existingBranchAfterFetchPath !== rootWorktreePath
      ) {
        yield* ensureExistingWorktreeUpstream(existingBranchAfterFetch.worktreePath);
        return {
          pullRequest,
          branch: localPullRequestBranch,
          worktreePath: existingBranchAfterFetch.worktreePath,
        };
      }
      if (existingBranchAfterFetchPath === rootWorktreePath) {
        return yield* gitManagerError(
          "preparePullRequestThread",
          "This PR branch is already checked out in the main repo. Use Local, or switch the main repo off that branch before creating a worktree thread.",
        );
      }

      const worktree = yield* gitCore.createWorktree({
        cwd: input.cwd,
        refName: localPullRequestBranch,
        path: null,
      });
      yield* ensureExistingWorktreeUpstream(worktree.worktree.path);
      yield* maybeRunSetupScript(worktree.worktree.path);

      return {
        pullRequest,
        branch: worktree.worktree.refName,
        worktreePath: worktree.worktree.path,
      };
    }).pipe(Effect.ensuring(invalidateStatus(input.cwd)));
  });

  const runFeatureBranchStep = Effect.fn("runFeatureBranchStep")(function* (
    modelSelection: ModelSelection,
    cwd: string,
    branch: string | null,
    commitMessage?: string,
    filePaths?: readonly string[],
  ) {
    const suggestion = yield* resolveCommitAndBranchSuggestion({
      cwd,
      branch,
      ...(commitMessage ? { commitMessage } : {}),
      ...(filePaths ? { filePaths } : {}),
      includeBranch: true,
      modelSelection,
    });
    if (!suggestion) {
      return yield* gitManagerError(
        "runFeatureBranchStep",
        "Cannot create a feature branch because there are no changes to commit.",
      );
    }

    const preferredBranch = suggestion.branch ?? sanitizeFeatureBranchName(suggestion.subject);
    const existingBranchNames = yield* gitCore.listLocalBranchNames(cwd);
    const resolvedBranch = resolveAutoFeatureBranchName(existingBranchNames, preferredBranch);

    yield* gitCore.createRef({ cwd, refName: resolvedBranch });
    yield* Effect.scoped(gitCore.switchRef({ cwd, refName: resolvedBranch }));

    return {
      branchStep: { status: "created" as const, name: resolvedBranch },
      resolvedCommitMessage: suggestion.commitMessage,
      resolvedCommitSuggestion: suggestion,
    };
  });

  const runStackedAction: GitManagerShape["runStackedAction"] = Effect.fn("runStackedAction")(
    function* (input, options) {
      const progress = yield* createProgressEmitter(input, options);
      const currentPhase = yield* Ref.make<Option.Option<GitActionProgressPhase>>(Option.none());

      const runAction = Effect.fn("runStackedAction.runAction")(function* (): Effect.fn.Return<
        GitRunStackedActionResult,
        GitManagerServiceError
      > {
        const initialStatus = yield* gitCore.statusDetails(input.cwd);
        const wantsCommit = isCommitAction(input.action);
        const wantsPush =
          input.action === "push" ||
          input.action === "commit_push" ||
          input.action === "commit_push_pr" ||
          (input.action === "create_pr" &&
            (!initialStatus.hasUpstream || initialStatus.aheadCount > 0));
        const wantsPr = input.action === "create_pr" || input.action === "commit_push_pr";

        if (input.featureBranch && !wantsCommit) {
          return yield* gitManagerError(
            "runStackedAction",
            "Feature-branch checkout is only supported for commit actions.",
          );
        }
        if (input.action === "create_pr" && initialStatus.hasWorkingTreeChanges) {
          return yield* gitManagerError(
            "runStackedAction",
            "Commit local changes before creating a PR.",
          );
        }

        const phases: GitActionProgressPhase[] = [
          ...(input.featureBranch ? (["branch"] as const) : []),
          ...(wantsCommit ? (["commit"] as const) : []),
          ...(wantsPush ? (["push"] as const) : []),
          ...(wantsPr ? (["pr"] as const) : []),
        ];

        yield* progress.emit({
          kind: "action_started",
          phases,
        });

        if (!input.featureBranch && wantsPush && !initialStatus.branch) {
          return yield* gitManagerError("runStackedAction", "Cannot push from detached HEAD.");
        }
        if (!input.featureBranch && wantsPr && !initialStatus.branch) {
          return yield* gitManagerError(
            "runStackedAction",
            "Cannot create a pull request from detached HEAD.",
          );
        }

        let branchStep: { status: "created" | "skipped_not_requested"; name?: string };
        let commitMessageForStep = input.commitMessage;
        let preResolvedCommitSuggestion: CommitAndBranchSuggestion | undefined = undefined;

        const modelSelection = yield* serverSettingsService.getSettings.pipe(
          Effect.map((settings) => settings.textGenerationModelSelection),
          Effect.mapError((cause) =>
            gitManagerError("runStackedAction", "Failed to get server settings.", cause),
          ),
        );

        if (input.featureBranch) {
          yield* Ref.set(currentPhase, Option.some("branch"));
          yield* progress.emit({
            kind: "phase_started",
            phase: "branch",
            label: "Preparing feature branch...",
          });
          const result = yield* runFeatureBranchStep(
            modelSelection,
            input.cwd,
            initialStatus.branch,
            input.commitMessage,
            input.filePaths,
          );
          branchStep = result.branchStep;
          commitMessageForStep = result.resolvedCommitMessage;
          preResolvedCommitSuggestion = result.resolvedCommitSuggestion;
        } else {
          branchStep = { status: "skipped_not_requested" as const };
        }

        const currentBranch = branchStep.name ?? initialStatus.branch;
        const commitAction = isCommitAction(input.action) ? input.action : null;
        const changeRequestTerms = wantsPr
          ? yield* sourceControlProvider(input.cwd).pipe(
              Effect.map((provider) => getChangeRequestTerminologyForKind(provider.kind)),
              Effect.catch(() => Effect.succeed(getChangeRequestTerminologyForKind("unknown"))),
            )
          : null;

        const commit = commitAction
          ? yield* Ref.set(currentPhase, Option.some("commit")).pipe(
              Effect.flatMap(() =>
                runCommitStep(
                  modelSelection,
                  input.cwd,
                  commitAction,
                  currentBranch,
                  commitMessageForStep,
                  preResolvedCommitSuggestion,
                  input.filePaths,
                  options?.progressReporter,
                  progress.actionId,
                ),
              ),
            )
          : { status: "skipped_not_requested" as const };

        const push = wantsPush
          ? yield* progress
              .emit({
                kind: "phase_started",
                phase: "push",
                label: "Pushing...",
              })
              .pipe(
                Effect.tap(() => Ref.set(currentPhase, Option.some("push"))),
                Effect.flatMap(() => gitCore.pushCurrentBranch(input.cwd, currentBranch)),
              )
          : { status: "skipped_not_requested" as const };

        const pr = wantsPr
          ? yield* progress
              .emit({
                kind: "phase_started",
                phase: "pr",
                label: `Preparing ${changeRequestTerms?.shortLabel ?? "PR"}...`,
              })
              .pipe(
                Effect.tap(() => Ref.set(currentPhase, Option.some("pr"))),
                Effect.flatMap(() =>
                  runPrStep(modelSelection, input.cwd, currentBranch, progress.emit),
                ),
              )
          : { status: "skipped_not_requested" as const };

        const toast = yield* buildCompletionToast(input.cwd, {
          action: input.action,
          branch: branchStep,
          commit,
          push,
          pr,
        });

        const result = {
          action: input.action,
          branch: branchStep,
          commit,
          push,
          pr,
          toast,
        };
        yield* progress.emit({
          kind: "action_finished",
          result,
        });
        return result;
      });

      return yield* runAction().pipe(
        Effect.ensuring(invalidateStatus(input.cwd)),
        Effect.tapError((error) =>
          Effect.flatMap(Ref.get(currentPhase), (phase) =>
            progress.emit({
              kind: "action_failed",
              phase: Option.getOrNull(phase),
              message: error.message,
            }),
          ),
        ),
      );
    },
  );

  return {
    localStatus,
    remoteStatus,
    status,
    invalidateLocalStatus,
    invalidateRemoteStatus,
    invalidateStatus,
    resolvePullRequest,
    preparePullRequestThread,
    runStackedAction,
  } satisfies GitManagerShape;
});

export const layer = Layer.effect(GitManager, makeGitManager());