/**
 * Lockfile deduplication (`dedupeLockfiles`) — WIN-1756.
 *
 * A workspace with one `dependencies/requirements.in` resolves the same lock for
 * every Python script, so the repo carries thousands of identical
 * `.script.lock` files: a dependency bump rewrites all of them and every open
 * branch conflicts on all of them. Dedup keeps one lockfile per dependency file,
 * named after it, and points the metadata at it.
 *
 * What these pin, per the invariants in `lock_dedup.ts`:
 *  - the name comes from the dependency file, so a bump is a one-file diff and a
 *    sync narrowed to one script reaches the same answer as a full one
 *  - a script whose lock is its own (an `extra_`/inline annotation, or several
 *    dependency files at once) keeps a `.script.lock`
 *  - the pass is idempotent, which is what keeps `sync pull`/`push` from seeing
 *    a diff on every run
 */

import { expect, test, describe } from "bun:test";
import { stringify as yamlStringify } from "yaml";
import * as path from "node:path";
import { mkdir, mkdtemp, rm, writeFile } from "node:fs/promises";
import os from "node:os";
import {
  applySharedLockPlanToMap,
  computeSharedLockPlan,
  isEmptySharedLockPlan,
  metadataLockUnreadable,
  scriptsReferencingSharedLock,
  sharedLockRefOf,
  sharedLockRefIn,
} from "../src/utils/lock_dedup.ts";
import { isSharedLockPath } from "../src/utils/script_common.ts";
import { yamlOptions } from "../src/commands/sync/sync.ts";

const PY_LOCK = "requests==2.32.0\nurllib3==2.2.1\n";
const PY_LOCK_BUMPED = "requests==2.32.3\nurllib3==2.2.1\n";
const OTHER_LOCK = "requests==2.32.0\nurllib3==2.2.1\npandas==2.2.0\n";
const PY_DEPS = "dependencies/requirements.in";
const TEAM_DEPS = "dependencies/team_a.requirements.in";
const BUN_DEPS = "dependencies/package.json";
const SHARED_PY = "locks/requirements.in.lock";
const SHARED_TEAM = "locks/team_a.requirements.in.lock";
const SHARED_BUN = "locks/package.json.lock";

/** A sync map is keyed with the platform separator — `sync.ts` walks the tree
 *  with `path.join` — while an `!inline` reference is always forward-slash.
 *  The fixtures speak both, or on Windows they would pin a map shape the CLI
 *  never builds. */
const k = (p: string) => p.replaceAll("/", path.sep);

function meta(lockRef: string, summary = ""): string {
  return yamlStringify({ summary, lock: lockRef }, yamlOptions);
}

/** A workspace holding the given dependency files. */
function workspace(...depFiles: string[]): Record<string, string> {
  const map: Record<string, string> = {};
  for (const dep of depFiles) map[k(dep)] = "requests\n";
  return map;
}

/** A script with its own lockfile, as `sync pull` writes it without dedup. */
function ownLock(
  map: Record<string, string>,
  base: string,
  ext: string,
  lock: string,
  body = "def main(): ...",
) {
  map[k(`${base}${ext}`)] = body;
  map[k(`${base}.script.yaml`)] = meta(`!inline ${base}.script.lock`);
  map[k(`${base}.script.lock`)] = lock;
}

/** A script already reading a shared lockfile. */
function sharedLock(
  map: Record<string, string>,
  base: string,
  ext: string,
  shared: string,
  body = "def main(): ...",
) {
  map[k(`${base}${ext}`)] = body;
  map[k(`${base}.script.yaml`)] = meta(`!inline ${shared}`);
}

function lockRefOf(metaContent: string): string {
  return metaContent.match(/lock: '(.*)'/)![1];
}

const plan = (map: Record<string, string>) =>
  computeSharedLockPlan(map, { defaultTs: "bun" });

describe("computeSharedLockPlan", () => {
  test("collapses the scripts of a dependency file into its lockfile", () => {
    const map = workspace(PY_DEPS, BUN_DEPS);
    ownLock(map, "f/a", ".py", PY_LOCK);
    ownLock(map, "f/b", ".py", PY_LOCK);
    ownLock(map, "f/c", ".py", PY_LOCK);
    ownLock(map, "f/ts", ".ts", "bun-lock", "export async function main() {}");
    ownLock(map, "f/ts2", ".ts", "bun-lock", "export async function main() {}");

    applySharedLockPlanToMap(map, plan(map));

    expect(map[k(SHARED_PY)]).toEqual(PY_LOCK);
    expect(map[k(SHARED_BUN)]).toEqual("bun-lock");
    for (const base of ["f/a", "f/b", "f/c"]) {
      expect(map[k(`${base}.script.lock`)]).toBeUndefined();
      expect(lockRefOf(map[k(`${base}.script.yaml`)])).toEqual(
        `!inline ${SHARED_PY}`,
      );
    }
    expect(lockRefOf(map[k("f/ts.script.yaml")])).toEqual(
      `!inline ${SHARED_BUN}`,
    );
  });

  test("is idempotent — a deduplicated tree yields no further changes", () => {
    const map = workspace(PY_DEPS);
    ownLock(map, "f/a", ".py", PY_LOCK);
    ownLock(map, "f/b", ".py", PY_LOCK);
    applySharedLockPlanToMap(map, plan(map));

    expect(isEmptySharedLockPlan(plan(map))).toBe(true);
  });

  test("a dependency bump moves only the shared file", () => {
    const committed = workspace(PY_DEPS);
    sharedLock(committed, "f/a", ".py", SHARED_PY);
    sharedLock(committed, "f/b", ".py", SHARED_PY);
    committed[k(SHARED_PY)] = PY_LOCK;

    // What the remote sends after the bump: one lock per script, all bumped.
    const remote = workspace(PY_DEPS);
    ownLock(remote, "f/a", ".py", PY_LOCK_BUMPED);
    ownLock(remote, "f/b", ".py", PY_LOCK_BUMPED);
    applySharedLockPlanToMap(remote, plan(remote));

    expect(
      Object.keys(remote).filter((key) => remote[key] !== committed[key]),
    ).toEqual([k(SHARED_PY)]);
  });

  test("each named dependency file gets a lockfile of its own", () => {
    const map = workspace(PY_DEPS, TEAM_DEPS);
    ownLock(map, "f/a", ".py", PY_LOCK);
    ownLock(map, "f/b", ".py", PY_LOCK);
    const team = "# requirements: team_a\ndef main(): ...";
    ownLock(map, "f/t1", ".py", OTHER_LOCK, team);
    ownLock(map, "f/t2", ".py", OTHER_LOCK, team);

    applySharedLockPlanToMap(map, plan(map));

    expect(map[k(SHARED_PY)]).toEqual(PY_LOCK);
    expect(map[k(SHARED_TEAM)]).toEqual(OTHER_LOCK);
    expect(lockRefOf(map[k("f/t1.script.yaml")])).toEqual(
      `!inline ${SHARED_TEAM}`,
    );
  });

  // The git-sync deploy callback narrows the sync to a single item, so this is
  // the normal case rather than an edge one.
  test("one script in view reaches the same answer as the whole workspace", () => {
    const full = workspace(PY_DEPS);
    for (const base of ["f/a", "f/b", "f/c"]) {
      ownLock(full, base, ".py", PY_LOCK);
    }
    applySharedLockPlanToMap(full, plan(full));

    const narrow = workspace(PY_DEPS);
    ownLock(narrow, "f/a", ".py", PY_LOCK);
    applySharedLockPlanToMap(narrow, plan(narrow));

    expect(narrow[k(SHARED_PY)]).toEqual(full[k(SHARED_PY)]);
    expect(lockRefOf(narrow[k("f/a.script.yaml")])).toEqual(
      lockRefOf(full[k("f/a.script.yaml")]),
    );
  });

  test("a script the worker locks differently keeps a private lockfile", () => {
    // The worker reads these from the leading comment block and several of them
    // change what it locks, so such a script cannot stand for the file's lock.
    const map = workspace(PY_DEPS, BUN_DEPS);
    ownLock(map, "f/pinned", ".py", OTHER_LOCK, "# py311\nimport requests");

    ownLock(map, "f/plain", ".py", PY_LOCK);
    ownLock(map, "f/plain2", ".py", PY_LOCK);
    // Only the names the worker matches count, so a documented script — or one
    // with a `# TODO:` or a `# type: ignore` — still deduplicates.
    ownLock(map, "f/doc", ".py", PY_LOCK, "# TODO: clean up\n# type: ignore\nimport requests");
    // Both annotation forms the worker accepts: a bare name and `name=value`.
    ownLock(map, "f/npm", ".ts", "npm-lock", "//npm\nexport async function main() {}");
    ownLock(map, "f/nb", ".ts", "nb-lock", "//nobundling=true\nexport async function main() {}");
    ownLock(map, "f/ts", ".ts", "bun-lock", "export async function main() {}");
    ownLock(map, "f/ts2", ".ts", "bun-lock", "export async function main() {}");

    applySharedLockPlanToMap(map, plan(map));

    expect(map[k(SHARED_PY)]).toEqual(PY_LOCK);
    expect(map[k("f/pinned.script.lock")]).toEqual(OTHER_LOCK);
    expect(lockRefOf(map[k("f/doc.script.yaml")])).toEqual(
      `!inline ${SHARED_PY}`,
    );
    expect(map[k(SHARED_BUN)]).toEqual("bun-lock");
    expect(map[k("f/npm.script.lock")]).toEqual("npm-lock");
    expect(map[k("f/nb.script.lock")]).toEqual("nb-lock");
  });

  test("an annotated script alone in its group creates no shared lockfile", () => {
    // Alone, so nothing outvotes it: without the gate its variant would BECOME
    // the dependency file's lock. `# py: <spec>` is the interpreter pin the
    // python import parser reads, which the annotations macro does not cover.
    for (const header of ["# py: 3.11", "#py:3.11.4", "# py311"]) {
      const map = workspace(PY_DEPS);
      ownLock(map, "f/only", ".py", OTHER_LOCK, `${header}\nimport requests`);

      applySharedLockPlanToMap(map, plan(map));

      expect(map[k(SHARED_PY)]).toBeUndefined();
      expect(map[k("f/only.script.lock")]).toEqual(OTHER_LOCK);
      expect(lockRefOf(map[k("f/only.script.yaml")])).toEqual(
        "!inline f/only.script.lock",
      );
    }
  });

  test("a script whose lock is its own keeps a private lockfile", () => {
    const map = workspace(PY_DEPS, TEAM_DEPS);
    // `extra_` folds the script's own imports into the lock…
    const extra = "# extra_requirements: default\ndef main(): ...";
    ownLock(map, "f/extra", ".py", OTHER_LOCK, extra);
    // …and naming two files makes it no single file's lock.
    const both = "# requirements: default, team_a\ndef main(): ...";
    ownLock(map, "f/both", ".py", OTHER_LOCK, both);
    ownLock(map, "f/plain", ".py", PY_LOCK);
    ownLock(map, "f/plain2", ".py", PY_LOCK);

    applySharedLockPlanToMap(map, plan(map));

    expect(map[k("f/extra.script.lock")]).toEqual(OTHER_LOCK);
    expect(map[k("f/both.script.lock")]).toEqual(OTHER_LOCK);
    expect(lockRefOf(map[k("f/extra.script.yaml")])).toEqual(
      "!inline f/extra.script.lock",
    );
    expect(map[k(SHARED_PY)]).toEqual(PY_LOCK);
  });

  test("a script with no dependency file behind it is left alone", () => {
    const map: Record<string, string> = {};
    ownLock(map, "f/a", ".py", PY_LOCK);
    ownLock(map, "f/b", ".py", PY_LOCK);

    expect(isEmptySharedLockPlan(plan(map))).toBe(true);
  });

  test("a stale committed lock is outvoted, and keeps its own", () => {
    const map = workspace(PY_DEPS);
    ownLock(map, "f/a", ".py", PY_LOCK_BUMPED);
    ownLock(map, "f/b", ".py", PY_LOCK_BUMPED);
    ownLock(map, "f/stale", ".py", PY_LOCK);

    applySharedLockPlanToMap(map, plan(map));

    expect(map[k(SHARED_PY)]).toEqual(PY_LOCK_BUMPED);
    expect(map[k("f/stale.script.lock")]).toEqual(PY_LOCK);
  });

  test("a shared lockfile outlives its scripts but not its dependency file", () => {
    // No script in view reads it — a narrowed sync must still leave it be.
    const withDep = workspace(PY_DEPS);
    withDep[k(SHARED_PY)] = PY_LOCK;
    expect(plan(withDep).deletes).not.toContain(k(SHARED_PY));

    const withoutDep: Record<string, string> = { [k(SHARED_PY)]: PY_LOCK };
    expect(plan(withoutDep).deletes).toContain(k(SHARED_PY));
  });

  // The git-sync deploy callback narrows to one item, so a dependency file with
  // no script in view is routine — and its lockfile is read by scripts this sync
  // cannot see.
  test("a dependency file with no script in view keeps its lockfile", () => {
    const map = workspace(PY_DEPS, BUN_DEPS);
    ownLock(map, "f/a", ".py", PY_LOCK);
    ownLock(map, "f/b", ".py", PY_LOCK);
    // `present` is forward-slashed whatever the map's separator: `sync.ts`
    // normalizes it out of the local map before handing it over.
    const present = { [SHARED_BUN]: "bun-lock" };

    const result = computeSharedLockPlan(map, { defaultTs: "bun", present });
    applySharedLockPlanToMap(map, result);

    expect(result.deletes).not.toContain(k(SHARED_BUN));
    // Carried into the map, or the diff reads it as a local-only deletion.
    expect(map[k(SHARED_BUN)]).toEqual("bun-lock");
  });

  test("dependency files absent from the map are not gone", () => {
    // `--skip-workspace-dependencies` keeps them out of both maps; taking that
    // as "deleted" would un-deduplicate the tree and sweep the lockfiles.
    const map: Record<string, string> = {};
    ownLock(map, "f/a", ".py", PY_LOCK);
    ownLock(map, "f/b", ".py", PY_LOCK);

    const result = computeSharedLockPlan(map, {
      defaultTs: "bun",
      depFiles: [PY_DEPS],
      present: { [SHARED_PY]: PY_LOCK },
    });
    applySharedLockPlanToMap(map, result);

    expect(result.deletes).not.toContain(k(SHARED_PY));
    expect(lockRefOf(map[k("f/a.script.yaml")])).toEqual(
      `!inline ${SHARED_PY}`,
    );
  });






  test("a language that needs no lock is never deduplicated", () => {
    const map = workspace("dependencies/modules.json");
    ownLock(map, "f/a", ".ps1", "some-lock", "echo hi");
    ownLock(map, "f/b", ".ps1", "some-lock", "echo hi");

    expect(isEmptySharedLockPlan(plan(map))).toBe(true);
  });

  test("module-layout scripts share too, from their folder", () => {
    const map = workspace(PY_DEPS);
    for (const base of ["f/a__mod", "f/b__mod"]) {
      map[k(`${base}/script.py`)] = "def main(): ...";
      map[k(`${base}/script.yaml`)] = meta(`!inline ${base}/script.lock`);
      map[k(`${base}/script.lock`)] = PY_LOCK;
    }

    applySharedLockPlanToMap(map, plan(map));

    expect(map[k(SHARED_PY)]).toEqual(PY_LOCK);
    expect(map[k("f/a__mod/script.lock")]).toBeUndefined();
  });

  test("a script path containing dots reads its own content file", () => {
    const map = workspace(PY_DEPS, BUN_DEPS);
    ownLock(map, "f/a.b", ".py", PY_LOCK);
    ownLock(map, "f/c.d", ".py", PY_LOCK);
    // `f/a` is a bun script whose name is a prefix of `f/a.b`: its language and
    // its annotation must come from its own file, not its neighbour's.
    ownLock(map, "f/a", ".ts", "bun-lock", "export async function main() {}");
    ownLock(map, "f/e", ".ts", "bun-lock", "export async function main() {}");

    applySharedLockPlanToMap(map, plan(map));

    expect(lockRefOf(map[k("f/a.b.script.yaml")])).toEqual(
      `!inline ${SHARED_PY}`,
    );
    expect(lockRefOf(map[k("f/a.script.yaml")])).toEqual(
      `!inline ${SHARED_BUN}`,
    );
  });

  test("only the lock line of the metadata changes", () => {
    const map = workspace(PY_DEPS);
    ownLock(map, "f/a", ".py", PY_LOCK);
    ownLock(map, "f/b", ".py", PY_LOCK);
    map[k("f/a.script.yaml")] = meta("!inline f/a.script.lock", "does a thing");
    const before = map[k("f/a.script.yaml")];

    applySharedLockPlanToMap(map, plan(map));

    expect(map[k("f/a.script.yaml")]).toEqual(
      before.replace("f/a.script.lock", SHARED_PY),
    );
  });

  test("a dependency set named with a slash shares nothing", () => {
    // `dependencies/team/python.requirements.in` has no distinct name under
    // `locks/`: flattened to `locks/python.requirements.in.lock` it names a
    // different (top-level) dependency file, and every later sweep would then
    // read the lockfile as orphaned and retire it.
    const map = workspace("dependencies/team/python.requirements.in");
    const body = "# requirements: team/python\ndef main(): ...";
    ownLock(map, "f/a", ".py", PY_LOCK, body);
    ownLock(map, "f/b", ".py", PY_LOCK, body);

    const p = plan(map);
    expect(p.writes).toEqual({});
    expect(p.deletes).toEqual([]);
  });
});

describe("isSharedLockPath", () => {
  test("claims only the names a dependency file gives", () => {
    for (const p of [SHARED_PY, SHARED_TEAM, SHARED_BUN]) {
      expect(isSharedLockPath(p)).toBe(true);
    }
    // Not a dependency file's name, so a repo that already keeps lockfiles here
    // keeps them; `modules.json` is powershell, which takes no lock.
    for (const p of [
      "locks/vendor.lock",
      "locks/Cargo.lock",
      "locks/modules.json.lock",
      "locks/sub/requirements.in.lock",
      "locks/../../escape.lock",
    ]) {
      expect(isSharedLockPath(p)).toBe(false);
    }
  });
});

describe("scriptsReferencingSharedLock", () => {
  test("finds every script on the shared lock and nothing else", () => {
    const map = workspace(PY_DEPS);
    ownLock(map, "f/a", ".py", PY_LOCK);
    ownLock(map, "f/b", ".py", PY_LOCK);
    const extra = "# extra_requirements: default\ndef main(): ...";
    ownLock(map, "f/extra", ".py", OTHER_LOCK, extra);
    applySharedLockPlanToMap(map, plan(map));

    expect(scriptsReferencingSharedLock(map, k(SHARED_PY)).sort()).toEqual([
      k("f/a.script.yaml"),
      k("f/b.script.yaml"),
    ]);
  });

  test("prose naming the file is not a reference", () => {
    const map = {
      [k("f/a.py")]: "def main(): ...",
      [k("f/a.script.yaml")]: yamlStringify(
        { summary: `see !inline ${SHARED_PY}`, lock: "!inline f/a.script.lock" },
        yamlOptions,
      ),
    };
    expect(scriptsReferencingSharedLock(map, k(SHARED_PY))).toEqual([]);
  });
});

describe("sharedLockRefIn", () => {
  test("returns a reference only when it is one, and it exists", async () => {
    const root = await mkdtemp(path.join(os.tmpdir(), "wmill-dedup-ref-"));
    try {
      await mkdir(path.join(root, "locks"), { recursive: true });
      await writeFile(path.join(root, SHARED_PY), PY_LOCK, "utf-8");

      expect(sharedLockRefIn(meta(`!inline ${SHARED_PY}`), false, root)).toEqual(
        SHARED_PY,
      );
      // Flow-style YAML starts with `{` and is not JSON: deciding the format by
      // the first character would drop the reference and repoint the script.
      expect(
        sharedLockRefIn(
          `{summary: x, lock: '!inline ${SHARED_PY}'}`,
          false,
          root,
        ),
      ).toEqual(SHARED_PY);
      // A regenerated script falls back to its own lock rather than point at a
      // shared file that is not there.
      expect(
        sharedLockRefIn(meta(`!inline ${SHARED_BUN}`), false, root),
      ).toBeUndefined();
      expect(
        sharedLockRefIn(meta("!inline f/a.script.lock"), false, root),
      ).toBeUndefined();
    } finally {
      await rm(root, { recursive: true, force: true });
    }
  });
});

describe("reading the lock field off disk", () => {
  test("a folded reference is still a reference", () => {
    // A long enough dependency-set name pushes `lock:` past the serializer's
    // 80-column default, which breaks the line at the space inside the value.
    const ref =
      "locks/" + "very_long_set_name_".repeat(4) + "requirements.in.lock";
    const folded = yamlStringify(
      { lock: `!inline ${ref}`, summary: "" },
      yamlOptions,
    );
    expect(folded).not.toContain("!inline " + ref);

    expect(sharedLockRefOf("f/a.script.yaml", folded, false)).toEqual(ref);
    expect(metadataLockUnreadable("f/a.script.yaml", folded, false)).toBe(false);
  });

  test("metadata that cannot be parsed is flagged rather than read as empty", () => {
    const conflicted = `summary: ''\n<<<<<<< HEAD\nlock: '!inline ${SHARED_PY}'\n=======\nlock: '!inline ${SHARED_BUN}'\n>>>>>>> other\n`;
    expect(sharedLockRefOf("f/a.script.yaml", conflicted, false)).toBeUndefined();
    expect(metadataLockUnreadable("f/a.script.yaml", conflicted, false)).toBe(
      true,
    );
    // Nothing to read: no reference of any kind in the file.
    expect(metadataLockUnreadable("f/a.script.yaml", "summary: ''\n", false)).toBe(
      false,
    );
  });
});