import { assert, assertEquals, assertRejects, assertStringIncludes } from "@std/assert";
import { chmod, readFile, symlink, unlink, writeFile } from "node:fs/promises";
import { join } from "node:path";
import { localEnvironment } from "@berry/api/environment.ts";
import { testExtension } from "@berry/api/testing.ts";
import diff from "./mod.ts";
import type { Reply, Shown } from "./types.ts";
import type { OpenFile, Save, Saved } from "./edit-types.ts";
import { onPath, tempDir } from "@berry/util";

const IDENTITY = {
  JJ_USER: "Test",
  JJ_EMAIL: "test@example.com",
  GIT_AUTHOR_NAME: "Test",
  GIT_AUTHOR_EMAIL: "test@example.com",
  GIT_COMMITTER_NAME: "Test",
  GIT_COMMITTER_EMAIL: "test@example.com",
  GIT_CONFIG_GLOBAL: "/dev/null",
  JJ_CONFIG: "/dev/null",
};

/** For setting repositories up; the extension reads them with whatever configuration it finds. */
async function run(cwd: string, program: string, ...args: string[]) {
  const result = await new Deno.Command(program, {
    args,
    cwd,
    env: IDENTITY,
    stdout: "piped",
    stderr: "piped",
  }).output();
  if (!result.success) throw new Error(new TextDecoder().decode(result.stderr));
  return new TextDecoder().decode(result.stdout).trim();
}

async function repository(test: (root: string) => Promise<void>) {
  await using rootDir = await tempDir({ prefix: "diff-test-" });
  const root = rootDir.path;
  await test(root);
}

/** What a view that had nothing would be shown. */
const shown = async (root: string, route = ""): Promise<Shown> => {
  const reply = await testExtension(diff, { env: localEnvironment(root) })
    .request("show", { route }) as Reply;
  return { ...reply, files: reply.files.map(({ diff }) => diff!) };
};

/** A save from the session "review" of `content` over what `opened` read. */
const saving = (opened: OpenFile, content: string, path = opened.file.path): Save => ({
  session: "review",
  id: "edit",
  working: opened.working,
  path,
  version: opened.version,
  content,
});

const summary = ({ files }: Shown) =>
  files.map(({ path, status, hunks }) => ({ path, status, lines: hunks.flatMap((h) => h.lines) }));

Deno.test({
  name:
    "jj: the working copy's changes come whole, its history is browsable, and edits show at once",
  ignore: !onPath("jj"),
  fn: () =>
    repository(async (root) => {
      await run(root, "jj", "git", "init");
      await writeFile(join(root, "a.txt"), "one\ntwo\nthree\n");
      await run(root, "jj", "commit", "-m", "first\n\nwith a body");
      await writeFile(join(root, "a.txt"), "one\n2\nthree\n");

      const working = await shown(root);
      assertEquals(working.vcs, "jj");
      assertEquals(working.root, root);
      assertEquals(working.revision.workingCopy, true);
      assertEquals(
        working.revision.change!.full,
        await run(
          root,
          "jj",
          "log",
          "--ignore-working-copy",
          "--no-graph",
          "-r",
          "@",
          "-T",
          "change_id",
        ),
      );
      assertEquals(
        working.revision.commit!.full,
        await run(
          root,
          "jj",
          "log",
          "--ignore-working-copy",
          "--no-graph",
          "-r",
          "@",
          "-T",
          "commit_id",
        ),
      );
      assertEquals(summary(working), [
        { path: "a.txt", status: "modified", lines: [" one", "-two", "+2", " three"] },
      ]);
      // the root commit, which never has changes, is left out
      assertEquals(working.log.map((r) => [r.route === "", r.description]), [
        [true, ""],
        [false, "first\n\nwith a body\n"],
      ]);

      const first = await shown(root, working.log[1].route);
      assertEquals(first.revision.description, "first\n\nwith a body\n");
      assertEquals(summary(first), [
        { path: "a.txt", status: "added", lines: ["+one", "+two", "+three"] },
      ]);

      await writeFile(join(root, "b.txt"), "new\n");
      assertEquals((await shown(root)).files.map(({ path }) => path), ["a.txt", "b.txt"]);
    }),
});

Deno.test({
  name: "git: the working tree includes untracked files, and each commit shows against its parent",
  ignore: !onPath("git"),
  fn: () =>
    repository(async (root) => {
      await run(root, "git", "init", "--quiet");
      const before = await shown(root);
      assertEquals(before.vcs, "git");
      assertEquals(before.log.length, 1);
      await writeFile(join(root, "a.txt"), "one\ntwo\n");
      await writeFile(join(root, ".gitignore"), "ignored\n");
      await run(root, "git", "add", "-A");
      await run(root, "git", "commit", "--quiet", "-m", "first");
      await run(root, "git", "config", "core.abbrev", "12");
      await writeFile(join(root, "a.txt"), "one\n2\n");
      await writeFile(join(root, "new file.txt"), "hello\n");
      await writeFile(join(root, "ignored"), "secret\n");

      const working = await shown(root);
      assertEquals(summary(working), [
        { path: "a.txt", status: "modified", lines: [" one", "-two", "+2"] },
        { path: "new file.txt", status: "added", lines: ["+hello"] },
      ]);
      assertEquals(working.log.map((r) => [r.route === "", r.description.trim()]), [
        [true, ""],
        [false, "first"],
      ]);
      const first = await shown(root, working.log[1].route);
      assertEquals(first.revision.refs.some((ref) => ref.includes("HEAD")), true);
      assertEquals(first.revision.commit, {
        full: await run(root, "git", "rev-parse", "HEAD"),
        prefix: "",
        rest: await run(root, "git", "rev-parse", "--short", "HEAD"),
      });
      assertEquals(first.files.map(({ path, status }) => [path, status]), [
        [".gitignore", "added"],
        ["a.txt", "added"],
      ]);
    }),
});

Deno.test({
  name: "a view is sent only the keys of the changes it has already, until they change",
  ignore: !onPath("git"),
  fn: () =>
    repository(async (root) => {
      await run(root, "git", "init", "--quiet");
      await writeFile(join(root, "a.txt"), "one\n");
      await writeFile(join(root, "b.txt"), "two\n");
      const view = testExtension(diff, { env: localEnvironment(root) });
      const ask = async (known: string[]) =>
        (await view.request("show", { route: "", known }) as Reply).files;
      const first = await ask([]);
      assertEquals(first.map(({ diff }) => diff?.path), ["a.txt", "b.txt"]);
      const known = first.map(({ key }) => key);
      assertEquals(await ask(known), known.map((key) => ({ key, diff: null })));
      await writeFile(join(root, "b.txt"), "three\n");
      assertEquals((await ask(known)).map(({ diff }) => diff?.path ?? null), [null, "b.txt"]);
    }),
});

Deno.test("outside a repository, or given a route that names no revision, it says so", () =>
  repository(async (root) => {
    await assertRejects(() => shown(root), Error, "neither a jj nor a git repository");
    if (!onPath("git")) return;
    await run(root, "git", "init", "--quiet");
    for (const route of ["--output=/tmp/x", "HEAD~1", "main"]) {
      await assertRejects(() => shown(root, route), Error, "Not a commit id");
    }
  }));

Deno.test({
  name: "human saves report only their changes on exit, and retries do not repeat saves or reports",
  ignore: !onPath("git"),
}, () =>
  repository(async (root) => {
    await run(root, "git", "init", "--quiet");
    await writeFile(join(root, "a.txt"), "base\nshared\nend\n");
    await run(root, "git", "add", "-A");
    await run(root, "git", "commit", "--quiet", "-m", "first");
    await writeFile(join(root, "a.txt"), "agent\nshared\nend\n");
    const view = testExtension(diff, { env: localEnvironment(root) });
    const opened = await view.request("open", { root, path: "a.txt" }) as OpenFile;
    const save = saving(opened, "agent\nhuman\nend\n");
    const [saved, duplicate] = await Promise.all([
      view.request("save", save),
      view.request("save", save),
    ]) as Saved[];
    assertEquals(saved, duplicate);
    assertEquals(await view.prompt(), "");
    assertEquals(view.messages, []);
    assertEquals(await readFile(join(root, "a.txt"), "utf8"), save.content);
    await writeFile(join(root, "other.txt"), "later agent edit\n");
    await view.command(
      "diff-finish",
      JSON.stringify({ session: "review", saves: [saved] }),
    );
    const messages = view.messages;
    assertEquals(messages.length, 1);
    const report = messages[0].content;
    assert(typeof report === "string");
    assertStringIncludes(report, "+human");
    assert(
      !report.includes("-base") && !report.includes("+agent") && !report.includes("other.txt"),
    );
    assertEquals(await view.request("save", save), saved);
    await view.command("diff-finish", "review");
    assertEquals(await view.prompt(), "");
    assertEquals(view.messages, messages);

    const next = await view.request("open", { root, path: "a.txt" }) as OpenFile;
    const secondSave = await view.request("save", {
      ...saving(next, "agent\nhuman again\nend\n"),
      session: "second",
    }) as Saved;
    await view.command(
      "diff-finish",
      JSON.stringify({ session: "second", saves: [secondSave] }),
    );
    assertEquals(view.messages.slice(0, messages.length), messages);
    const second = view.messages[1].content;
    assert(typeof second === "string");
    assertStringIncludes(second, "+human again");
    assertEquals(await view.prompt(), "");

    const unchanged = await view.request("open", { root, path: "a.txt" }) as OpenFile;
    const unchangedSave = await view.request("save", {
      ...saving(unchanged, unchanged.content),
      session: "unchanged",
    }) as Saved;
    await view.command(
      "diff-finish",
      JSON.stringify({ session: "unchanged", saves: [unchangedSave] }),
    );
    assertEquals(view.messages.length, 2);
  }));

Deno.test({
  name:
    "jj edits use complete files even when the displayed patch omits lines, preserving executable CRLF text",
  ignore: !onPath("jj"),
}, () =>
  repository(async (root) => {
    await run(root, "jj", "git", "init");
    const path = "script.txt";
    const baseline = "\ufeff" + Array.from({ length: 21_000 }, (_, i) => `line ${i}`).join("\r\n");
    await writeFile(join(root, path), baseline);
    await chmod(join(root, path), 0o755);
    await run(root, "jj", "commit", "-m", "first");
    const content = baseline.replace("line 10000\r", "agent\r");
    await writeFile(join(root, path), content);
    const view = testExtension(diff, { env: localEnvironment(root) });
    const display = await view.request("show", {}) as Reply;
    assert(display.files[0].diff!.hunks.flatMap((h) => h.lines).length < 30);
    const opened = await view.request("open", { root, path }) as OpenFile;
    assertEquals(opened.original, baseline);
    assertEquals(opened.content, content);
    const edited = content.replace("line 20000\r", "human\r");
    await view.request("save", saving(opened, edited));
    assertEquals(await readFile(join(root, path), "utf8"), edited);
    assertEquals((await Deno.stat(join(root, path))).mode! & 0o777, 0o755);
  }));

Deno.test({
  name: "a stale file or a different jj working-copy change refuses a save without overwriting",
  ignore: !onPath("jj"),
}, () =>
  repository(async (root) => {
    await run(root, "jj", "git", "init");
    await writeFile(join(root, "a.txt"), "initial\n");
    const view = testExtension(diff, { env: localEnvironment(root) });
    const opened = await view.request("open", { root, path: "a.txt" }) as OpenFile;
    const save = saving(opened, "human\n");
    await writeFile(join(root, "a.txt"), "external\n");
    await assertRejects(
      () => view.request("save", save),
      Error,
      "changed on disk",
    );
    assertEquals(await readFile(join(root, "a.txt"), "utf8"), "external\n");
    await writeFile(join(root, "a.txt"), opened.content);
    await run(root, "jj", "new");
    await assertRejects(
      () => view.request("save", save),
      Error,
      "working copy changed",
    );
    assertEquals(await readFile(join(root, "a.txt"), "utf8"), opened.content);
    assertEquals(await view.prompt(), "");
  }));

Deno.test({
  name:
    "diff saves cannot escape the repository, edit metadata, or follow a replaced symbolic link",
  ignore: !onPath("git"),
}, () =>
  repository(async (root) => {
    await run(root, "git", "init", "--quiet");
    await writeFile(join(root, "a.txt"), "initial\n");
    const view = testExtension(diff, { env: localEnvironment(root) });
    const opened = await view.request("open", { root, path: "a.txt" }) as OpenFile;
    const save = saving(opened, "human\n", "../outside");
    await assertRejects(
      () => view.request("save", save),
      Error,
      "repository path",
    );
    await assertRejects(
      () => view.request("save", { ...save, path: ".git/config" }),
      Error,
      "repository path",
    );
    await using outside = await tempDir();
    const target = join(outside.path, "target.txt");
    await writeFile(target, opened.content);
    await unlink(join(root, "a.txt"));
    await symlink(target, join(root, "a.txt"));
    await assertRejects(
      () => view.request("save", { ...save, path: "a.txt" }),
      Error,
      "symbolic links",
    );
    assertEquals(await readFile(target, "utf8"), opened.content);
  }));

Deno.test({
  name: "git merge conflicts are editable, and a save resolves the markers on disk",
  ignore: !onPath("git"),
}, () =>
  repository(async (root) => {
    await run(root, "git", "init", "--initial-branch=main", "--quiet");
    await writeFile(join(root, "a.txt"), "base\n");
    await run(root, "git", "add", "-A");
    await run(root, "git", "commit", "--quiet", "-m", "base");
    await run(root, "git", "checkout", "-qb", "branch");
    await writeFile(join(root, "a.txt"), "branch\n");
    await run(root, "git", "commit", "-am", "branch", "--quiet");
    await run(root, "git", "checkout", "main", "--quiet");
    await writeFile(join(root, "a.txt"), "main\n");
    await run(root, "git", "commit", "-am", "main", "--quiet");
    await assertRejects(() => run(root, "git", "merge", "branch"));
    const view = testExtension(diff, { env: localEnvironment(root) });
    const current = await view.request("show", {}) as Reply;
    assertEquals(current.revision.conflict, true);
    const opened = await view.request("open", { root, path: "a.txt" }) as OpenFile;
    assertStringIncludes(opened.content, "<<<<<<<");
    assertEquals(opened.original, "main\n");
    await view.request("save", saving(opened, "resolved\n"));
    assertEquals(await readFile(join(root, "a.txt"), "utf8"), "resolved\n");
  }));

/** A jj repository whose commit "theirs" changes a.txt the way "ours" does, rebased onto it to conflict. */
async function conflicting(root: string) {
  await run(root, "jj", "git", "init");
  await writeFile(join(root, "a.txt"), "one\ntwo\nthree\n");
  await run(root, "jj", "describe", "-m", "base");
  await run(root, "jj", "new");
  await writeFile(join(root, "a.txt"), "ONE\ntwo\nthree\n");
  await run(root, "jj", "describe", "-m", "ours");
  const ours = await run(root, "jj", "log", "--no-graph", "-r", "@", "-T", "change_id");
  await run(root, "jj", "new", "root()");
  await writeFile(join(root, "a.txt"), "one\ntwo\nTHREE\n");
  await run(root, "jj", "describe", "-m", "theirs");
  const theirs = await run(root, "jj", "log", "--no-graph", "-r", "@", "-T", "change_id");
  await run(root, "jj", "new", ours);
  await run(root, "jj", "rebase", "-s", theirs, "-d", ours);
  return { ours, theirs };
}

Deno.test({
  name: "jj: a conflicted commit's file can be edited, resolving its conflict",
  ignore: !onPath("jj"),
}, () =>
  repository(async (root) => {
    const { theirs } = await conflicting(root);
    const revision = (await shown(root, theirs)).revision;
    assertEquals([revision.route, revision.conflict], [theirs, true]);
    const view = testExtension(diff, { env: localEnvironment(root) });
    const opened = await view.request("open", {
      root,
      path: "a.txt",
      route: theirs,
    }) as OpenFile;
    assertStringIncludes(opened.content, "<<<<<<<");
    assertEquals(opened.original, "ONE\ntwo\nthree\n");
    const saved = await view.request("save", saving(opened, "ONE\ntwo\nTHREE\n")) as Saved;
    assert(saved.working.identity !== opened.working.identity);
    assertEquals(
      await run(root, "jj", "file", "show", "-r", theirs, "--", "a.txt"),
      "ONE\ntwo\nTHREE",
    );
    assertEquals(await run(root, "jj", "log", "--no-graph", "-r", "conflicts()"), "");
  }));

Deno.test({
  name: "jj: a conflicted working copy's file can be edited, resolving its conflict",
  ignore: !onPath("jj"),
}, () =>
  repository(async (root) => {
    const { theirs } = await conflicting(root);
    await run(root, "jj", "edit", theirs);
    const view = testExtension(diff, { env: localEnvironment(root) });
    const current = await shown(root);
    assertEquals([current.revision.workingCopy, current.revision.conflict], [true, true]);
    const opened = await view.request("open", { root, path: "a.txt" }) as OpenFile;
    assertStringIncludes(opened.content, "<<<<<<<");
    await view.request("save", saving(opened, "ONE\ntwo\nTHREE\n"));
    assertEquals(await readFile(join(root, "a.txt"), "utf8"), "ONE\ntwo\nTHREE\n");
    assertEquals(await run(root, "jj", "log", "--no-graph", "-r", "conflicts()"), "");
  }));

Deno.test({
  name:
    "an exit waits for an accepted save even when its receipt was not in the exit's starting state",
  ignore: !onPath("git"),
}, () =>
  repository(async (root) => {
    await run(root, "git", "init", "--quiet");
    await writeFile(join(root, "a.txt"), "initial\n");
    const env = localEnvironment(root);
    const entered = Promise.withResolvers<void>();
    const release = Promise.withResolvers<void>();
    const write = env.writeFile.bind(env);
    env.writeFile = async (...args) => {
      entered.resolve();
      await release.promise;
      return await write(...args);
    };
    const view = testExtension(diff, { env });
    const opened = await view.request("open", { root, path: "a.txt" }) as OpenFile;
    const saved = view.request("save", saving(opened, "human\n"));
    try {
      await entered.promise;
      const finishing = view.command("diff-finish", "review");
      let finished = false;
      void finishing.then(() => {
        finished = true;
      });
      await Promise.resolve();
      await Promise.resolve();
      assertEquals(finished, false);
      release.resolve();
      await saved;
      await finishing;
      const report = view.messages[0]?.content;
      assert(typeof report === "string");
      assertStringIncludes(report, "+human");
    } finally {
      release.resolve();
      await saved;
    }
  }));

Deno.test({
  name:
    "a jj commit's file can be edited, rebasing its descendants, and a save that would conflict them is undone unless forced",
  ignore: !onPath("jj"),
}, () =>
  repository(async (root) => {
    await run(root, "jj", "git", "init");
    await writeFile(join(root, "a.txt"), "one\ntwo\nthree\nfour\nfive\n");
    await run(root, "jj", "commit", "-m", "first");
    await writeFile(join(root, "a.txt"), "one\ntwo\nthree\nfour\nFIVE\n");
    await run(root, "jj", "commit", "-m", "second");
    await writeFile(join(root, "b.txt"), "working\n");
    const view = testExtension(diff, { env: localEnvironment(root) });
    const first = (await shown(root)).log.find((r) => r.description.startsWith("first"))!;
    const opened = await view.request("open", {
      root,
      path: "a.txt",
      route: first.route,
    }) as OpenFile;
    assertEquals(opened.content, "one\ntwo\nthree\nfour\nfive\n");
    const saved = await view.request(
      "save",
      saving(opened, "ONE\ntwo\nthree\nfour\nfive\n"),
    ) as Saved;
    assertEquals(await readFile(join(root, "a.txt"), "utf8"), "ONE\ntwo\nthree\nfour\nFIVE\n");
    assertEquals(await readFile(join(root, "b.txt"), "utf8"), "working\n");
    assertEquals(await run(root, "jj", "log", "--no-graph", "-r", "conflicts()"), "");
    await assertRejects(
      () => view.request("save", { ...saving(opened, "x\n"), id: "stale" }),
      Error,
      "changed since you opened it",
    );

    const again = { ...saving(opened, "ONE\ntwo\nthree\nfour\nfive!\n"), id: "conflicting" };
    again.working = saved.working;
    const operation = await run(root, "jj", "op", "log", "--no-graph", "--limit=1", "-T", "id");
    await assertRejects(
      () => view.request("save", again),
      Error,
      "would cause conflicts in 2 later commits",
    );
    assertEquals(await readFile(join(root, "a.txt"), "utf8"), "ONE\ntwo\nthree\nfour\nFIVE\n");
    const restored = await run(root, "jj", "op", "log", "--no-graph", "--limit=1", "-T", "id");
    assert(restored !== operation);
    assertEquals(await run(root, "jj", "log", "--no-graph", "-r", "conflicts()"), "");
    await view.request("save", { ...again, force: true });
    assertStringIncludes(await readFile(join(root, "a.txt"), "utf8"), "<<<<<<<");

    await view.command("diff-finish", "review");
    const report = view.messages[0]?.content;
    assert(typeof report === "string");
    assertStringIncludes(report, `"commit":"${first.route}"`);
    await assertRejects(
      () =>
        view.request("open", { root, path: "a.txt", route: "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz" }),
    );
  }));

Deno.test({
  name: "jj: rewording targets the opened change and preserves its files and dirty descendants",
  ignore: !onPath("jj"),
  fn: () =>
    repository(async (root) => {
      await run(root, "jj", "git", "init");
      await writeFile(join(root, "a.txt"), "base\n");
      await run(root, "jj", "describe", "-m", "original\n\nbody");
      const opened = await shown(root);
      const view = testExtension(diff, { env: localEnvironment(root) });
      await run(root, "jj", "new", "-m", "descendant");
      await writeFile(join(root, "a.txt"), "dirty descendant\n");
      const change = opened.revision.change!.full;
      await view.request("reword", {
        root,
        change,
        before: opened.revision.description,
        description: "--new subject\n\nnew body",
      });
      const updated = await shown(root, change);
      assertEquals(updated.revision.description, "--new subject\n\nnew body\n");
      assertEquals(updated.revision.change, opened.revision.change);
      assertEquals(summary(updated), summary(opened));
      const working = await shown(root);
      assertEquals(working.revision.description, "descendant\n");
      assertEquals(working.log[1].change!.full, change);
      assertEquals(await readFile(join(root, "a.txt"), "utf8"), "dirty descendant\n");

      await view.request("reword", {
        root,
        change: working.revision.change!.full,
        before: working.revision.description,
        description: "",
      });
      assertEquals((await shown(root)).revision.description, "");
    }),
});

Deno.test({
  name: "jj: rewording rejects stale descriptions, another repository, and immutable commits",
  ignore: !onPath("jj"),
  fn: () =>
    repository(async (root) => {
      await run(root, "jj", "git", "init");
      await run(root, "jj", "describe", "-m", "original");
      const opened = await shown(root);
      const view = testExtension(diff, { env: localEnvironment(root) });
      const args = {
        root,
        change: opened.revision.change!.full,
        before: opened.revision.description,
        description: "replacement",
      };
      await assertRejects(
        () => view.request("reword", { ...args, root: `${root}/elsewhere` }),
        Error,
        "another repository",
      );
      await run(root, "jj", "describe", "-m", "someone else's edit");
      await assertRejects(() => view.request("reword", args), Error, "description changed");
      assertEquals((await shown(root)).revision.description, "someone else's edit\n");
      await run(root, "jj", "bookmark", "create", "frozen");
      await run(root, "jj", "new");
      await run(
        root,
        "jj",
        "config",
        "set",
        "--repo",
        'revset-aliases."immutable_heads()"',
        "frozen",
      );
      await assertRejects(() => view.request("reword", args), Error, "immutable");
    }),
});