import {
  scopeProjectRef,
  scopedThreadKey,
  scopeThreadRef,
} from "@t3tools/client-runtime/environment";
import { pullRequestDetailToVcsStatus } from "@t3tools/client-runtime/state/pull-requests";
import {
  type EnvironmentId,
  resolveEnvironmentMachineKind,
  type ThreadLinkedPullRequest,
  type VcsStatusResult,
} from "@t3tools/contracts";
import { Atom } from "effect/unstable/reactivity";
import { FolderGit2Icon, TerminalIcon } from "lucide-react";
import { useCallback, useMemo } from "react";
import { appAtomRegistry } from "../rpc/atomRegistry";
import { useEnvironment, usePrimaryEnvironmentId } from "../state/environments";
import { EnvironmentMachineIcon } from "./EnvironmentMachineIcon";
import { useProject } from "../state/entities";
import { useEnvironmentQuery } from "../state/query";
import { linkedPullRequestDetailAtom, useSharedPullRequestSummary } from "../state/pullRequests";
import { useThreadRunningTerminalIds } from "../state/terminalSessions";
import { vcsEnvironment } from "../state/vcs";
import { useUiStateStore } from "../uiStateStore";
import { resolveChangeRequestPresentation } from "../sourceControlPresentation";
import {
  resolveThreadLastVisitedAt,
  resolveThreadStatusPill,
  type ThreadStatusPill,
  useRetainedValue,
  useSidebarRowSubscriptionLease,
} from "./Sidebar.logic";
import { resolvePullRequestState } from "./pullRequest/pullRequestPresentation";
import type { SidebarThreadSummary } from "../types";
import { formatWorktreePathForDisplay } from "../worktreeCleanup";
import { Tooltip, TooltipPopup, TooltipTrigger } from "./ui/tooltip";

export interface PrStatusIndicator {
  label: string;
  colorClass: string;
  tooltip: string;
  tooltipLead: string;
  tooltipTitle: string;
  url: string;
}

export interface TerminalStatusIndicator {
  label: "Terminal process running";
  colorClass: string;
  pulse: boolean;
}

export type ThreadPr = VcsStatusResult["pr"];

export interface LinkedThreadPullRequestStatus {
  readonly pr: NonNullable<ThreadPr>;
  readonly sourceControlProvider: NonNullable<VcsStatusResult["sourceControlProvider"]>;
}

export function useLinkedThreadPullRequest(
  environmentId: EnvironmentId | null,
  linkedPullRequest: ThreadLinkedPullRequest | null | undefined,
  enabled = true,
): LinkedThreadPullRequestStatus | null {
  const queried = useEnvironmentQuery(
    !enabled || environmentId === null || linkedPullRequest == null
      ? null
      : linkedPullRequestDetailAtom({
          environmentId,
          input: {
            projectId: linkedPullRequest.projectId,
            repository: linkedPullRequest.repository,
            number: linkedPullRequest.number,
          },
        }),
  ).data;
  const detail = useSharedPullRequestSummary(environmentId, linkedPullRequest ?? null, queried);

  return useMemo(
    () =>
      detail === null
        ? null
        : {
            pr: pullRequestDetailToVcsStatus(detail),
            sourceControlProvider: {
              kind: detail.provider,
              name: detail.provider,
              baseUrl: "",
            },
          },
    [detail],
  );
}

export function settledPrHoverColorClass(
  state: NonNullable<ThreadPr>["state"],
  isDraft = false,
): string {
  switch (state) {
    case "open":
      if (isDraft) {
        return "group-hover/v2-row:text-zinc-500 dark:group-hover/v2-row:text-zinc-400/80";
      }
      return "group-hover/v2-row:text-emerald-600 dark:group-hover/v2-row:text-emerald-300/90";
    case "merged":
      return "group-hover/v2-row:text-violet-600 dark:group-hover/v2-row:text-violet-300/90";
    case "closed":
      return "group-hover/v2-row:text-red-600 dark:group-hover/v2-row:text-red-300/90";
  }
}

export function prStatusIndicator(
  pr: ThreadPr,
  provider: VcsStatusResult["sourceControlProvider"] | null | undefined,
): PrStatusIndicator | null {
  function formatPrState(pr: NonNullable<ThreadPr>): string {
    if (pr.state === "open" && pr.isDraft === true) return "Draft";
    return pr.state.charAt(0).toUpperCase() + pr.state.slice(1);
  }

  function formatPrStatusLead(pr: NonNullable<ThreadPr>, changeRequestShortName: string): string {
    return `${changeRequestShortName} #${pr.number} - ${formatPrState(pr)}`;
  }
  if (!pr) return null;
  const presentation = resolveChangeRequestPresentation(provider);

  const tooltipLead = formatPrStatusLead(pr, presentation.shortName);
  const tooltip = `${tooltipLead}: ${pr.title}`;

  if (pr.state === "open") {
    const isDraft = pr.isDraft === true;
    return {
      label: `${presentation.shortName} ${isDraft ? "draft" : "open"}`,
      colorClass: isDraft
        ? "text-zinc-500 dark:text-zinc-400/80"
        : "text-emerald-600 dark:text-emerald-300/90",
      tooltip,
      tooltipLead,
      tooltipTitle: pr.title,
      url: pr.url,
    };
  }
  if (pr.state === "closed") {
    return {
      label: `${presentation.shortName} closed`,
      colorClass: "text-red-600 dark:text-red-300/90",
      tooltip,
      tooltipLead,
      tooltipTitle: pr.title,
      url: pr.url,
    };
  }
  if (pr.state === "merged") {
    return {
      label: `${presentation.shortName} merged`,
      colorClass: "text-violet-600 dark:text-violet-300/90",
      tooltip,
      tooltipLead,
      tooltipTitle: pr.title,
      url: pr.url,
    };
  }
  return null;
}

export function ChangeRequestStatusIcon({
  state,
  isDraft = false,
  className,
}: Pick<NonNullable<ThreadPr>, "state"> & {
  readonly isDraft?: boolean | undefined;
  readonly className?: string | undefined;
}) {
  const presentation = resolvePullRequestState({ state, isDraft });
  return <presentation.Icon className={className} />;
}

export function PrStatusTooltipContent({ status }: { status: PrStatusIndicator }) {
  return (
    <span className="flex max-w-[min(34rem,calc(100vw-2rem))] items-stretch overflow-hidden whitespace-nowrap">
      <span className="shrink-0 pr-2 font-medium">{status.tooltipLead}</span>
      <span className="min-h-4 shrink-0 border-border/70 border-l" aria-hidden="true" />
      <span className="min-w-0 truncate pl-2">{status.tooltipTitle}</span>
    </span>
  );
}

export function resolveThreadPr(input: {
  threadBranch: string | null;
  gitStatus: VcsStatusResult | null;
}): ThreadPr | null {
  const { threadBranch, gitStatus } = input;
  if (gitStatus === null) {
    return null;
  }

  if (threadBranch === null || gitStatus.refName !== threadBranch) {
    return null;
  }

  return gitStatus.pr ?? null;
}

/**
 * Parent-held PR snapshot for Sidebar V2. Rows remount when settlement
 * partitions move them, so terminal PR metadata must live above the row.
 */
export interface ThreadChangeRequestSnapshot {
  readonly branch: string;
  readonly pr: NonNullable<ThreadPr>;
  readonly sourceControlProvider: VcsStatusResult["sourceControlProvider"] | undefined;
  readonly linkedPullRequest?: ThreadLinkedPullRequest;
}

export const threadChangeRequestSnapshotsAtom = Atom.make<
  ReadonlyMap<string, ThreadChangeRequestSnapshot>
>(new Map()).pipe(Atom.keepAlive, Atom.withLabel("sidebar:thread-change-request-snapshots"));

function isTerminalChangeRequestState(
  state: NonNullable<ThreadPr>["state"],
): state is "merged" | "closed" {
  return state === "merged" || state === "closed";
}

function sourceControlProvidersEqual(
  left: VcsStatusResult["sourceControlProvider"] | undefined,
  right: VcsStatusResult["sourceControlProvider"] | undefined,
): boolean {
  if (left === right) return true;
  if (left == null || right == null) return left == null && right == null;
  return left.kind === right.kind && left.name === right.name && left.baseUrl === right.baseUrl;
}

function linkedPullRequestsEqual(
  left: ThreadLinkedPullRequest | null | undefined,
  right: ThreadLinkedPullRequest | null | undefined,
): boolean {
  if (left == null || right == null) return left == null && right == null;
  return (
    left.projectId === right.projectId &&
    left.repository === right.repository &&
    left.number === right.number &&
    left.url === right.url
  );
}

export function threadChangeRequestSnapshotsEqual(
  left: ThreadChangeRequestSnapshot,
  right: ThreadChangeRequestSnapshot,
): boolean {
  return (
    left.branch === right.branch &&
    left.pr.number === right.pr.number &&
    left.pr.title === right.pr.title &&
    left.pr.url === right.pr.url &&
    left.pr.baseRef === right.pr.baseRef &&
    left.pr.headRef === right.pr.headRef &&
    left.pr.state === right.pr.state &&
    left.pr.isDraft === right.pr.isDraft &&
    (left.pr.updatedAt ?? null) === (right.pr.updatedAt ?? null) &&
    sourceControlProvidersEqual(left.sourceControlProvider, right.sourceControlProvider) &&
    linkedPullRequestsEqual(left.linkedPullRequest, right.linkedPullRequest)
  );
}

export function setThreadChangeRequestSnapshot(
  threadKey: string,
  snapshot: ThreadChangeRequestSnapshot | null,
): void {
  appAtomRegistry.modify(threadChangeRequestSnapshotsAtom, (current) => {
    const existing = current.get(threadKey);
    if (snapshot === null) {
      if (existing === undefined) return [false, current];
      const next = new Map(current);
      next.delete(threadKey);
      return [true, next];
    }
    if (existing !== undefined && threadChangeRequestSnapshotsEqual(existing, snapshot)) {
      return [false, current];
    }
    const next = new Map(current);
    next.set(threadKey, snapshot);
    return [true, next];
  });
}

/**
 * Authoritative snapshot update from live VCS status.
 * - `undefined`: missing status, or a local checkout retaining a terminal PR — leave the map alone
 * - `null`: no PR (without a retained terminal snapshot), a cleared branch, or a mismatch without a terminal PR — clear
 * - snapshot: matching branch reports a PR — store/replace
 */
export function nextThreadChangeRequestSnapshot(input: {
  threadBranch: string | null;
  gitStatus: VcsStatusResult | null;
  snapshot: ThreadChangeRequestSnapshot | null | undefined;
  retainTerminalOnBranchMismatch: boolean;
  linkedPullRequest?: ThreadLinkedPullRequest | null | undefined;
  linkedPullRequestStatus?: LinkedThreadPullRequestStatus | null | undefined;
}): ThreadChangeRequestSnapshot | null | undefined {
  const {
    threadBranch,
    gitStatus,
    snapshot,
    retainTerminalOnBranchMismatch,
    linkedPullRequest,
    linkedPullRequestStatus,
  } = input;
  if (linkedPullRequest != null) {
    if (linkedPullRequestStatus === null || linkedPullRequestStatus === undefined) {
      return linkedPullRequestsEqual(snapshot?.linkedPullRequest, linkedPullRequest)
        ? undefined
        : null;
    }
    return {
      branch: threadBranch ?? linkedPullRequestStatus.pr.headRef,
      pr: linkedPullRequestStatus.pr,
      sourceControlProvider: linkedPullRequestStatus.sourceControlProvider,
      linkedPullRequest,
    };
  }
  if (gitStatus === null) {
    return snapshot?.linkedPullRequest === undefined ? undefined : null;
  }
  if (threadBranch === null) {
    return null;
  }
  if (gitStatus.refName !== threadBranch) {
    return retainTerminalOnBranchMismatch &&
      snapshot != null &&
      snapshot.linkedPullRequest === undefined &&
      isTerminalChangeRequestState(snapshot.pr.state)
      ? undefined
      : null;
  }
  if (gitStatus.pr == null) {
    if (
      retainTerminalOnBranchMismatch &&
      snapshot != null &&
      snapshot.linkedPullRequest === undefined &&
      isTerminalChangeRequestState(snapshot.pr.state)
    ) {
      return undefined;
    }
    return null;
  }
  return {
    branch: threadBranch,
    pr: gitStatus.pr,
    sourceControlProvider: gitStatus.sourceControlProvider,
  };
}

/**
 * Live PR when the checkout matches the thread branch; otherwise, for local
 * checkouts only, a cached merged/closed PR for the thread. Local thread
 * metadata follows the shared checkout, so the cached branch intentionally
 * survives that metadata changing to the newly checked-out branch. Open PRs
 * are retained only while live status is absent and the branch still matches.
 */
export function resolveDisplayedThreadPr(input: {
  threadBranch: string | null;
  gitStatus: VcsStatusResult | null;
  snapshot: ThreadChangeRequestSnapshot | null | undefined;
  retainTerminalOnBranchMismatch: boolean;
  linkedPullRequest?: ThreadLinkedPullRequest | null | undefined;
  linkedPullRequestStatus?: LinkedThreadPullRequestStatus | null | undefined;
}): ThreadPr | null {
  const {
    threadBranch,
    gitStatus,
    snapshot,
    retainTerminalOnBranchMismatch,
    linkedPullRequest,
    linkedPullRequestStatus,
  } = input;
  if (linkedPullRequest != null) {
    return (
      linkedPullRequestStatus?.pr ??
      (linkedPullRequestsEqual(snapshot?.linkedPullRequest, linkedPullRequest)
        ? (snapshot?.pr ?? null)
        : null)
    );
  }
  if (
    threadBranch !== null &&
    gitStatus !== null &&
    gitStatus.refName === threadBranch &&
    gitStatus.pr != null
  ) {
    return gitStatus.pr;
  }

  if (
    gitStatus === null &&
    threadBranch !== null &&
    snapshot?.branch === threadBranch &&
    snapshot.linkedPullRequest === undefined
  ) {
    return snapshot.pr;
  }

  if (
    threadBranch !== null &&
    retainTerminalOnBranchMismatch &&
    snapshot != null &&
    snapshot.linkedPullRequest === undefined &&
    isTerminalChangeRequestState(snapshot.pr.state)
  ) {
    return snapshot.pr;
  }

  return null;
}

export function resolveDisplayedThreadPrProvider(input: {
  threadBranch: string | null;
  gitStatus: VcsStatusResult | null;
  snapshot: ThreadChangeRequestSnapshot | null | undefined;
  retainTerminalOnBranchMismatch: boolean;
  linkedPullRequest?: ThreadLinkedPullRequest | null | undefined;
  linkedPullRequestStatus?: LinkedThreadPullRequestStatus | null | undefined;
}): VcsStatusResult["sourceControlProvider"] | undefined {
  const {
    threadBranch,
    gitStatus,
    snapshot,
    retainTerminalOnBranchMismatch,
    linkedPullRequest,
    linkedPullRequestStatus,
  } = input;
  if (linkedPullRequest != null) {
    return (
      linkedPullRequestStatus?.sourceControlProvider ??
      (linkedPullRequestsEqual(snapshot?.linkedPullRequest, linkedPullRequest)
        ? snapshot?.sourceControlProvider
        : undefined)
    );
  }
  if (
    threadBranch !== null &&
    gitStatus !== null &&
    gitStatus.refName === threadBranch &&
    gitStatus.pr != null
  ) {
    return gitStatus.sourceControlProvider;
  }

  if (
    gitStatus === null &&
    threadBranch !== null &&
    snapshot?.branch === threadBranch &&
    snapshot.linkedPullRequest === undefined
  ) {
    return snapshot.sourceControlProvider;
  }

  if (
    threadBranch !== null &&
    retainTerminalOnBranchMismatch &&
    snapshot != null &&
    snapshot.linkedPullRequest === undefined &&
    isTerminalChangeRequestState(snapshot.pr.state)
  ) {
    return snapshot.sourceControlProvider;
  }

  return undefined;
}

export function terminalStatusFromRunningIds(
  runningTerminalIds: ReadonlyArray<string>,
): TerminalStatusIndicator | null {
  if (runningTerminalIds.length === 0) {
    return null;
  }
  return {
    label: "Terminal process running",
    colorClass: "text-teal-600 dark:text-teal-300/90",
    pulse: true,
  };
}

export function ThreadWorktreeIndicator({
  thread,
}: {
  thread: Pick<SidebarThreadSummary, "id" | "branch" | "worktreePath">;
}) {
  const worktreePath = thread.worktreePath?.trim();
  if (!worktreePath) {
    return null;
  }

  const displayPath = formatWorktreePathForDisplay(worktreePath);
  const tooltip = thread.branch
    ? `Worktree: ${displayPath} (${thread.branch})`
    : `Worktree: ${displayPath}`;

  return (
    <Tooltip>
      <TooltipTrigger
        render={
          <span
            role="img"
            aria-label={tooltip}
            data-testid={`thread-worktree-${thread.id}`}
            className="inline-flex items-center justify-center"
          />
        }
      >
        <FolderGit2Icon className="size-3 text-muted-foreground/40" />
      </TooltipTrigger>
      <TooltipPopup side="top">{tooltip}</TooltipPopup>
    </Tooltip>
  );
}

export function ThreadStatusLabel({
  status,
  compact = false,
}: {
  status: ThreadStatusPill;
  compact?: boolean;
}) {
  if (compact) {
    return (
      <Tooltip>
        <TooltipTrigger
          render={
            <span
              aria-label={status.label}
              className={`inline-flex size-3.5 shrink-0 items-center justify-center ${status.colorClass}`}
            />
          }
        >
          <span
            className={`size-[9px] rounded-full ${status.dotClass} ${
              status.pulse ? "animate-status-pulse" : ""
            }`}
          />
        </TooltipTrigger>
        <TooltipPopup side="top">{status.label}</TooltipPopup>
      </Tooltip>
    );
  }

  return (
    <Tooltip>
      <TooltipTrigger
        render={
          <span
            aria-label={status.label}
            className={`inline-flex items-center gap-1 text-[10px] ${status.colorClass}`}
          />
        }
      >
        <span
          className={`h-1.5 w-1.5 rounded-full ${status.dotClass} ${
            status.pulse ? "animate-status-pulse" : ""
          }`}
        />
        <span className="hidden md:inline">{status.label}</span>
      </TooltipTrigger>
      <TooltipPopup side="top">{status.label}</TooltipPopup>
    </Tooltip>
  );
}

/**
 * Non-interactive leading status icons for a thread row in compact contexts
 * like the command palette. Shows the change request state icon (if present) and the
 * thread status dot, matching the sidebar's leading indicators.
 */
export function ThreadRowLeadingStatus({
  thread,
  snapshot,
}: {
  thread: SidebarThreadSummary;
  snapshot?: ThreadChangeRequestSnapshot | undefined;
}) {
  const { leaseLiveStatus, rowRef } = useSidebarRowSubscriptionLease(false);
  // Observe the containing title even when this thread has no badge yet.
  const statusRef = useCallback(
    (node: HTMLSpanElement | null) => rowRef(node?.parentElement ?? null),
    [rowRef],
  );
  const threadRef = scopeThreadRef(thread.environmentId, thread.id);
  const localLastVisitedAt = useUiStateStore(
    (state) => state.threadLastVisitedAtById[scopedThreadKey(threadRef)],
  );
  const lastVisitedAt = resolveThreadLastVisitedAt(thread.lastVisitedAt, localLastVisitedAt);
  const threadProject = useProject(
    useMemo(
      () => scopeProjectRef(thread.environmentId, thread.projectId),
      [thread.environmentId, thread.projectId],
    ),
  );
  const threadProjectCwd = threadProject?.workspaceRoot ?? null;
  const gitCwd = thread.worktreePath ?? threadProjectCwd;
  const linkedPullRequest = useLinkedThreadPullRequest(
    thread.environmentId,
    thread.linkedPullRequest,
    leaseLiveStatus,
  );
  const gitStatus = useEnvironmentQuery(
    leaseLiveStatus &&
      thread.linkedPullRequest == null &&
      (thread.branch != null || thread.worktreePath !== null) &&
      gitCwd !== null
      ? vcsEnvironment.status({
          environmentId: thread.environmentId,
          input: { cwd: gitCwd },
        })
      : null,
  );
  const visibleGitStatus = useRetainedValue(
    JSON.stringify([thread.environmentId, gitCwd]),
    gitStatus.data,
  );
  const displayedPrInput = {
    threadBranch: thread.branch,
    gitStatus: visibleGitStatus,
    snapshot,
    retainTerminalOnBranchMismatch: thread.worktreePath === null,
    linkedPullRequest: thread.linkedPullRequest,
    linkedPullRequestStatus: linkedPullRequest,
  };
  const pr = resolveDisplayedThreadPr(displayedPrInput);
  const prStatus = prStatusIndicator(pr, resolveDisplayedThreadPrProvider(displayedPrInput));
  const threadStatus = resolveThreadStatusPill({
    thread: {
      ...thread,
      lastVisitedAt,
    },
  });

  return (
    <span
      ref={statusRef}
      className={
        prStatus || threadStatus ? "inline-flex shrink-0 items-center gap-1.5" : "contents"
      }
    >
      {prStatus && pr ? (
        <Tooltip>
          <TooltipTrigger
            render={
              <span
                aria-label={prStatus.tooltip}
                className={`inline-flex items-center justify-center ${prStatus.colorClass}`}
              />
            }
          >
            <ChangeRequestStatusIcon state={pr.state} isDraft={pr.isDraft} className="size-3" />
          </TooltipTrigger>
          <TooltipPopup side="top">
            <PrStatusTooltipContent status={prStatus} />
          </TooltipPopup>
        </Tooltip>
      ) : null}
      {threadStatus ? <ThreadStatusLabel status={threadStatus} /> : null}
    </span>
  );
}

/**
 * Non-interactive trailing status icons for a thread row in compact contexts
 * like the command palette. Shows a terminal-running indicator and a remote
 * environment indicator, matching the sidebar's trailing indicators.
 */
export function ThreadRowTrailingStatus({ thread }: { thread: SidebarThreadSummary }) {
  const runningTerminalIds = useThreadRunningTerminalIds({
    environmentId: thread.environmentId,
    threadId: thread.id,
  });
  const environment = useEnvironment(thread.environmentId);
  const primaryEnvironmentId = usePrimaryEnvironmentId();
  // No primary (the hosted app) means every thread is remote, and the machine
  // glyph is what tells the environments apart.
  const isRemoteThread = thread.environmentId !== primaryEnvironmentId;
  const remoteEnvLabel = environment?.label ?? null;
  const threadEnvironmentLabel = isRemoteThread ? (remoteEnvLabel ?? "Remote") : null;
  const remoteMachine = resolveEnvironmentMachineKind(environment?.serverConfig ?? null);
  const terminalStatus = terminalStatusFromRunningIds(runningTerminalIds);

  if (!terminalStatus && !isRemoteThread) {
    return null;
  }

  return (
    <span className="inline-flex shrink-0 items-center gap-1.5">
      {terminalStatus ? (
        <Tooltip>
          <TooltipTrigger
            render={
              <span
                role="img"
                aria-label={terminalStatus.label}
                className={`inline-flex items-center justify-center ${terminalStatus.colorClass}`}
              />
            }
          >
            <TerminalIcon
              className={`size-3 ${terminalStatus.pulse ? "animate-status-pulse" : ""}`}
            />
          </TooltipTrigger>
          <TooltipPopup side="top">{terminalStatus.label}</TooltipPopup>
        </Tooltip>
      ) : null}
      {isRemoteThread ? (
        <Tooltip>
          <TooltipTrigger
            render={
              <span
                aria-label={threadEnvironmentLabel ?? "Remote"}
                className="inline-flex items-center justify-center"
              />
            }
          >
            <EnvironmentMachineIcon
              kind={remoteMachine}
              className="size-3 text-muted-foreground/60"
            />
          </TooltipTrigger>
          <TooltipPopup side="top">{threadEnvironmentLabel}</TooltipPopup>
        </Tooltip>
      ) : null}
    </span>
  );
}