import { execFileSync } from "node:child_process";
import { existsSync, mkdirSync, mkdtempSync, realpathSync, rmSync, writeFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { afterEach, describe, expect, it, vi } from "vitest";
import {
  getCheckoutDiff,
  getCheckoutShortstat,
  getCommitFileDiff,
  listCheckoutCommits,
} from "./checkout-git.js";

const repos: string[] = [];

const EDITED_TEXT_DIFF = {
  isNew: false,
  isDeleted: false,
  additions: 1,
  deletions: 1,
  hunks: [
    {
      oldStart: 1,
      oldCount: 1,
      newStart: 1,
      newCount: 1,
      lines: [
        { type: "header", content: "@@ -1 +1 @@" },
        { type: "remove", content: "before" },
        { type: "add", content: "after" },
      ],
    },
  ],
};

afterEach(() => {
  vi.unstubAllEnvs();
  for (const repo of repos.splice(0)) rmSync(repo, { recursive: true, force: true });
});

it.skipIf(process.platform === "win32")(
  "returns a quoted filename and its uncommitted diff using its actual path",
  async () => {
    const cwd = createChangedRepo("core.quotepath=false");
    const name = 'report "draft".txt';
    writeFileSync(join(cwd, "file.txt"), "before\n");
    writeFileSync(join(cwd, name), "before\n");
    git(cwd, "add", "--", name);
    git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "add quoted filename");
    writeFileSync(join(cwd, name), "after\n");

    const result = await getCheckoutDiff(cwd, { mode: "uncommitted", includeStructured: true });

    expect(result.structured).toHaveLength(1);
    expect(result.structured?.[0]).toMatchObject({
      path: name,
      status: "ok",
      ...EDITED_TEXT_DIFF,
    });
  },
);

describe.skipIf(process.platform === "win32")("quoted paths from real Git", () => {
  const names = [
    "normal.txt",
    "with spaces.txt",
    'report "draft".txt',
    "back\\slash.txt",
    "tab\tname.txt",
    "line\nname.txt",
    " leading and trailing .txt ",
    'report "old => draft".txt',
  ];

  function createQuotedPathsRepo(): string {
    const cwd = createChangedRepo("core.quotepath=false");
    writeFileSync(join(cwd, "file.txt"), "before\n");
    for (const name of names) writeFileSync(join(cwd, name), "before\n");
    git(cwd, "add", "--", ...names);
    git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "add filenames");
    git(cwd, "checkout", "-b", "feature");
    for (const name of names) writeFileSync(join(cwd, name), "after\n");
    return cwd;
  }

  it("preserves tracked and untracked paths, diff lines and summary counts", async () => {
    const cwd = createQuotedPathsRepo();
    const untrackedNames = names.map((name) => "untracked-" + name);
    for (const name of untrackedNames) writeFileSync(join(cwd, name), "new file\n");

    const result = await getCheckoutDiff(cwd, { mode: "uncommitted", includeStructured: true });

    expect(result.structured?.map((file) => file.path).sort()).toEqual(
      [...names, ...untrackedNames].sort(),
    );
    for (const name of names) {
      expect(result.structured?.find((file) => file.path === name)).toMatchObject({
        path: name,
        status: "ok",
        ...EDITED_TEXT_DIFF,
      });
    }
    for (const name of untrackedNames) {
      expect(result.structured?.find((file) => file.path === name)).toMatchObject({
        path: name,
        status: "ok",
        isNew: true,
        isDeleted: false,
        additions: 1,
        deletions: 0,
        hunks: [
          {
            oldStart: 0,
            oldCount: 0,
            newStart: 1,
            newCount: 1,
            lines: [
              { type: "header", content: "@@ -0,0 +1 @@" },
              { type: "add", content: "new file" },
            ],
          },
        ],
      });
    }
    expect(await getCheckoutShortstat(cwd)).toEqual({
      additions: names.length + untrackedNames.length,
      deletions: names.length,
    });
  });

  it("opens base and commit diffs using the actual paths from the commit list", async () => {
    const cwd = createQuotedPathsRepo();
    git(cwd, "add", "--", ...names);
    git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "edit filenames");
    const sha = git(cwd, "rev-parse", "HEAD").trim();

    const base = await getCheckoutDiff(cwd, {
      mode: "base",
      baseRef: "main",
      includeStructured: true,
    });
    expect(base.structured?.map((file) => file.path).sort()).toEqual([...names].sort());
    for (const name of names) {
      expect(base.structured?.find((file) => file.path === name)).toMatchObject({
        path: name,
        status: "ok",
        ...EDITED_TEXT_DIFF,
      });
    }

    const history = await listCheckoutCommits({ cwd });
    const commit = history.commits[0];
    expect(commit.sha).toBe(sha);
    expect(commit.files).toEqual(
      [...names].sort().map((name) => ({
        path: name,
        additions: 1,
        deletions: 1,
        status: "modified",
      })),
    );
    for (const file of commit.files) {
      expect(await getCommitFileDiff({ cwd, sha, path: file.path })).toMatchObject({
        path: file.path,
        ...EDITED_TEXT_DIFF,
      });
    }
  });

  it("preserves quoted rename destinations and binary paths in diff and commit lists", async () => {
    const cwd = createChangedRepo("core.quotepath=false");
    const oldPath = 'old "draft".txt';
    const newPath = 'new "draft".txt';
    const binaryPath = "image\tdata.bin";
    writeFileSync(join(cwd, "file.txt"), "before\n");
    writeFileSync(join(cwd, oldPath), "unchanged\n");
    writeFileSync(join(cwd, binaryPath), Buffer.from([0, 1, 2]));
    git(cwd, "add", "--", oldPath, binaryPath);
    git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "add rename and binary files");
    git(cwd, "checkout", "-b", "feature");
    git(cwd, "mv", "--", oldPath, newPath);
    writeFileSync(join(cwd, binaryPath), Buffer.from([0, 3, 4]));

    const result = await getCheckoutDiff(cwd, { mode: "uncommitted", includeStructured: true });
    expect(
      result.structured?.map(({ path, oldPath: sourcePath, status }) => ({
        path,
        oldPath: sourcePath,
        status,
      })),
    ).toEqual([
      { path: binaryPath, oldPath: undefined, status: "binary" },
      {
        path: newPath,
        oldPath,
        status: "ok",
      },
    ]);
    expect(result.structured?.[0]).toEqual({
      path: binaryPath,
      isNew: false,
      isDeleted: false,
      additions: 0,
      deletions: 0,
      hunks: [],
      status: "binary",
    });

    git(cwd, "add", "--", binaryPath);
    git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "rename file and edit binary");
    const history = await listCheckoutCommits({ cwd });
    expect(history.commits[0].files).toEqual([
      { path: binaryPath, additions: 0, deletions: 0, status: "modified" },
      { path: newPath, additions: 0, deletions: 0, status: "renamed" },
    ]);
  });
});

it.each(["diff.mnemonicPrefix=true", "color.diff=always", "diff.noprefix=true"])(
  "preserves batched paths, spaces and literal prefix directories with %s",
  async (config) => {
    const cwd = createChangedRepo(config);
    mkdirSync(join(cwd, "a"));
    for (const name of ["a/literal.txt", "with spaces.txt"]) {
      writeFileSync(join(cwd, name), "before\n");
    }
    git(cwd, "add", "a/literal.txt", "with spaces.txt");
    git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "add files");
    for (const name of ["a/literal.txt", "with spaces.txt"]) {
      writeFileSync(join(cwd, name), "after\n");
    }

    const result = await getCheckoutDiff(cwd, { mode: "uncommitted", includeStructured: true });

    expect(result.structured?.map((file) => file.path)).toEqual([
      "a/literal.txt",
      "file.txt",
      "with spaces.txt",
    ]);
    for (const file of result.structured ?? []) {
      expect(file.hunks.flatMap((hunk) => hunk.lines)).toEqual(
        expect.arrayContaining([
          expect.objectContaining({ type: "remove", content: "before" }),
          expect.objectContaining({ type: "add", content: "after" }),
        ]),
      );
    }
    expect(git(cwd, "config", "--get", config.split("=")[0]).trim()).toBe(config.split("=")[1]);
  },
);

function git(cwd: string, ...args: string[]): string {
  return execFileSync("git", args, { cwd, encoding: "utf8" });
}

function createChangedRepo(config: string): string {
  const cwd = realpathSync.native(mkdtempSync(join(tmpdir(), "checkout-patch-format-")));
  repos.push(cwd);
  git(cwd, "init", "-b", "main");
  git(cwd, "config", "user.name", "Test");
  git(cwd, "config", "user.email", "test@example.com");
  writeFileSync(join(cwd, "file.txt"), "before\n");
  git(cwd, "add", ".");
  git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "initial");
  git(cwd, "config", ...config.split("="));
  writeFileSync(join(cwd, "file.txt"), "after\n");
  return cwd;
}

function createExternalDiffCommand() {
  const directory = realpathSync.native(mkdtempSync(join(tmpdir(), "checkout-external-diff-")));
  repos.push(directory);
  const script = join(directory, "external-diff.cjs");
  const marker = join(directory, "invoked");
  writeFileSync(
    script,
    'require("node:fs").writeFileSync(process.argv[2], "invoked");\n' +
      'process.stdout.write("CUSTOM EXTERNAL DIFF\\n");\n',
  );
  const command = [process.execPath, script, marker]
    .map((argument) => `'${argument.replaceAll("'", "'\\''")}'`)
    .join(" ");
  return { command, marker };
}

function createExternalDiffRepo() {
  vi.stubEnv("GIT_EXTERNAL_DIFF", undefined);
  const cwd = createChangedRepo("color.diff=always");
  const { command, marker } = createExternalDiffCommand();
  git(cwd, "config", "diff.external", command);
  expect(git(cwd, "diff", "HEAD", "--", "file.txt")).toBe("CUSTOM EXTERNAL DIFF\n");
  expect(existsSync(marker)).toBe(true);
  rmSync(marker);
  return { cwd, command, marker };
}

function expectStandardPatch(result: Awaited<ReturnType<typeof getCheckoutDiff>>) {
  expect(result.structured).toMatchObject([
    {
      path: "file.txt",
      additions: 1,
      deletions: 1,
      status: "ok",
      hunks: [
        {
          lines: [
            { type: "header", content: "@@ -1 +1 @@" },
            { type: "remove", content: "before" },
            { type: "add", content: "after" },
          ],
        },
      ],
    },
  ]);
}

it("returns Git patch hunks when a repository configures an external diff command", async () => {
  const { cwd, command, marker } = createExternalDiffRepo();

  const result = await getCheckoutDiff(cwd, { mode: "uncommitted", includeStructured: true });

  expectStandardPatch(result);
  expect(existsSync(marker)).toBe(false);
  expect(git(cwd, "config", "--get", "diff.external").trim()).toBe(command);
});

it("returns Git patch hunks against the base branch with an external diff command", async () => {
  const { cwd, command, marker } = createExternalDiffRepo();
  git(cwd, "checkout", "-b", "feature");
  git(cwd, "add", ".");
  git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "edit");

  const result = await getCheckoutDiff(cwd, {
    mode: "base",
    baseRef: "main",
    includeStructured: true,
  });

  expectStandardPatch(result);
  expect(existsSync(marker)).toBe(false);
  expect(git(cwd, "config", "--get", "diff.external").trim()).toBe(command);
});

it("returns Git patch hunks when GIT_EXTERNAL_DIFF configures the external command", async () => {
  const cwd = createChangedRepo("color.diff=always");
  const { command, marker } = createExternalDiffCommand();
  vi.stubEnv("GIT_EXTERNAL_DIFF", command);
  expect(git(cwd, "diff", "HEAD", "--", "file.txt")).toBe("CUSTOM EXTERNAL DIFF\n");
  expect(existsSync(marker)).toBe(true);
  rmSync(marker);

  const result = await getCheckoutDiff(cwd, { mode: "uncommitted", includeStructured: true });

  expectStandardPatch(result);
  expect(existsSync(marker)).toBe(false);
  expect(process.env.GIT_EXTERNAL_DIFF).toBe(command);
});

describe.each(["diff.mnemonicPrefix=true", "color.diff=always"])(
  "patch format with %s",
  (config) => {
    it("returns displayable uncommitted diff lines with their file counts", async () => {
      const cwd = createChangedRepo(config);
      const result = await getCheckoutDiff(cwd, { mode: "uncommitted", includeStructured: true });

      expect(result.structured).toHaveLength(1);
      expect(result.structured?.[0]).toMatchObject({
        path: "file.txt",
        additions: 1,
        deletions: 1,
      });
      expect(result.structured?.[0].hunks.flatMap((hunk) => hunk.lines)).toEqual(
        expect.arrayContaining([
          expect.objectContaining({ type: "remove", content: "before" }),
          expect.objectContaining({ type: "add", content: "after" }),
        ]),
      );
    });

    it("returns displayable committed changes against the base branch", async () => {
      const cwd = createChangedRepo(config);
      git(cwd, "checkout", "-b", "feature");
      git(cwd, "add", ".");
      git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "edit");
      const result = await getCheckoutDiff(cwd, {
        mode: "base",
        baseRef: "main",
        includeStructured: true,
      });

      expect(result.structured?.[0]).toMatchObject({
        path: "file.txt",
        additions: 1,
        deletions: 1,
      });
      expect(result.structured?.[0].hunks.flatMap((hunk) => hunk.lines)).toEqual(
        expect.arrayContaining([expect.objectContaining({ type: "add", content: "after" })]),
      );
    });

    it("returns displayable lines when opening an individual commit file", async () => {
      const cwd = createChangedRepo(config);
      git(cwd, "add", ".");
      git(cwd, "-c", "commit.gpgsign=false", "commit", "-m", "edit");
      const file = await getCommitFileDiff({
        cwd,
        sha: git(cwd, "rev-parse", "HEAD").trim(),
        path: "file.txt",
      });

      expect(file).toMatchObject({ path: "file.txt", additions: 1, deletions: 1 });
      expect(file?.hunks.flatMap((hunk) => hunk.lines)).toEqual(
        expect.arrayContaining([expect.objectContaining({ type: "add", content: "after" })]),
      );
    });
  },
);