import type { GitCommandError } from "@t3tools/contracts";import * as Effect from "effect/Effect";import * as Option from "effect/Option"; import type * as GitVcsDriver from "../vcs/GitVcsDriver.ts"; const TEMPLATE_MAX_BYTES = 8_000;const TREE_LIST_MAX_BYTES = 100_000;const TRUNCATION_MARKER = "[truncated]"; const TEMPLATE_PATHS = [  ".github/pull_request_template.md",  ".github/PULL_REQUEST_TEMPLATE.md",  "pull_request_template.md",  "PULL_REQUEST_TEMPLATE.md",  "docs/pull_request_template.md",  "docs/PULL_REQUEST_TEMPLATE.md",] as const; const TEMPLATE_DIRECTORIES = [  ".github/PULL_REQUEST_TEMPLATE",  "PULL_REQUEST_TEMPLATE",  "docs/PULL_REQUEST_TEMPLATE",] as const; const TREE_PATHS = [...TEMPLATE_PATHS, ...TEMPLATE_DIRECTORIES] as const; type ExecuteGit = GitVcsDriver.GitVcsDriver["Service"]["execute"]; interface TemplateTreeEntry {  readonly objectId: string;  readonly path: string;} function parseTemplateTreeEntries(output: string): ReadonlyArray<TemplateTreeEntry> {  const entries: TemplateTreeEntry[] = [];  for (const record of output.split("\0")) {    if (record.length === 0) {      continue;    }     const separator = record.indexOf("\t");    if (separator < 0) {      continue;    }     const [mode, type, objectId] = record.slice(0, separator).split(" ");    if (      type !== "blob" ||      (mode !== "100644" && mode !== "100755") ||      !objectId ||      !/^[0-9a-f]{40,64}$/.test(objectId)    ) {      continue;    }     entries.push({ objectId, path: record.slice(separator + 1) });  }  return entries;} function readTemplateBlob(input: {  readonly cwd: string;  readonly executeGit: ExecuteGit;  readonly entry: TemplateTreeEntry;}): Effect.Effect<Option.Option<string>, GitCommandError> {  return input    .executeGit({      operation: "PrTemplateDetection.readTemplateBlob",      cwd: input.cwd,      args: ["cat-file", "blob", input.entry.objectId],      maxOutputBytes: TEMPLATE_MAX_BYTES,      appendTruncationMarker: true,    })    .pipe(      Effect.map((result) => {        const template = result.stdout.trim();        if (template.length === 0) {          return Option.none();        }        return Option.some(          result.stdoutTruncated && !template.endsWith(TRUNCATION_MARKER)            ? `${template}\n\n${TRUNCATION_MARKER}`            : template,        );      }),    );} type DirectoryTemplateResult =  | { readonly _tag: "None" }  | { readonly _tag: "Ambiguous" }  | { readonly _tag: "Template"; readonly template: string }; function readTemplateDirectory(input: {  readonly cwd: string;  readonly executeGit: ExecuteGit;  readonly entries: ReadonlyArray<TemplateTreeEntry>;  readonly directory: string;}): Effect.Effect<DirectoryTemplateResult, GitCommandError> {  return Effect.gen(function* () {    const prefix = `${input.directory}/`;    const candidates = input.entries.filter((entry) => {      if (!entry.path.startsWith(prefix)) {        return false;      }      const relativePath = entry.path.slice(prefix.length);      return !relativePath.includes("/") && relativePath.toLowerCase().endsWith(".md");    });     const templates: string[] = [];    for (const entry of candidates) {      const template = yield* readTemplateBlob({ ...input, entry });      if (Option.isSome(template)) {        templates.push(template.value);        if (templates.length > 1) {          return { _tag: "Ambiguous" } as const;        }      }    }     return templates[0]      ? ({ _tag: "Template", template: templates[0] } as const)      : ({ _tag: "None" } as const);  });} export const detectPrTemplate = Effect.fn("detectPrTemplate")(function* (  cwd: string,  treeish: string,  executeGit: ExecuteGit,) {  return yield* Effect.gen(function* () {    // Worktree paths can be replaced between validation and open. Read regular blobs from the    // committed base tree so repository-controlled symlinks and path races never reach the host filesystem.    const result = yield* executeGit({      operation: "PrTemplateDetection.listTemplates",      cwd,      args: ["ls-tree", "-r", "-z", "--full-tree", treeish, "--", ...TREE_PATHS],      maxOutputBytes: TREE_LIST_MAX_BYTES,      appendTruncationMarker: true,    });    if (result.stdoutTruncated) {      return Option.none();    }     const entries = parseTemplateTreeEntries(result.stdout);    const entriesByPath = new Map(entries.map((entry) => [entry.path, entry]));    for (const templatePath of TEMPLATE_PATHS) {      const entry = entriesByPath.get(templatePath);      if (!entry) {        continue;      }      const template = yield* readTemplateBlob({ cwd, executeGit, entry });      if (Option.isSome(template)) {        return template;      }    }     for (const directory of TEMPLATE_DIRECTORIES) {      const directoryTemplate = yield* readTemplateDirectory({        cwd,        executeGit,        entries,        directory,      });      if (directoryTemplate._tag === "Template") {        return Option.some(directoryTemplate.template);      }      if (directoryTemplate._tag === "Ambiguous") {        return Option.none();      }    }     return Option.none();  }).pipe(Effect.orElseSucceed(() => Option.none()));});