import { execFileSync } from "child_process";
import { mkdirSync, mkdtempSync, realpathSync, rmSync, writeFileSync } from "fs";
import { tmpdir } from "os";
import { join } from "path";
import { afterEach, describe, expect, it } from "vitest";
import { listCheckoutCommits } from "./checkout-git.js";
import { writePaseoWorktreeMetadata } from "./worktree-metadata.js";

const tempDirs: string[] = [];

afterEach(() => {
  for (const dir of tempDirs.splice(0)) {
    rmSync(dir, { recursive: true, force: true });
  }
});

function makeTempDir(): string {
  const dir = realpathSync.native(mkdtempSync(join(tmpdir(), "checkout-commits-test-")));
  tempDirs.push(dir);
  return dir;
}

function git(args: string[], cwd?: string): void {
  execFileSync("git", args, cwd ? { cwd } : {});
}

function commit(repoDir: string, message: string): void {
  git(["-c", "commit.gpgsign=false", "commit", "-m", message], repoDir);
}

function commitFile(repoDir: string, name: string, content: string, message: string): void {
  writeFileSync(join(repoDir, name), content);
  git(["add", "."], repoDir);
  commit(repoDir, message);
}

function initRepoOnMain(): { repoDir: string; tempDir: string } {
  const tempDir = makeTempDir();
  const repoDir = join(tempDir, "repo");
  mkdirSync(repoDir, { recursive: true });
  git(["init", "-b", "main"], repoDir);
  git(["config", "user.email", "test@test.com"], repoDir);
  git(["config", "user.name", "Test User"], repoDir);
  commitFile(repoDir, "README.md", "base\n", "initial");
  return { repoDir, tempDir };
}

function addBareRemote(repoDir: string, tempDir: string): string {
  const remoteDir = join(tempDir, "remote.git");
  git(["init", "--bare", "-b", "main", remoteDir]);
  git(["remote", "add", "origin", remoteDir], repoDir);
  return remoteDir;
}

describe("listCheckoutCommits", () => {
  it("lists recent commits newest-first with on-remote flags and file stats", async () => {
    const { repoDir, tempDir } = initRepoOnMain();
    git(["checkout", "-b", "feature"], repoDir);
    commitFile(repoDir, "foo.txt", "a\nb\nc\n", "Add foo");

    // Push feature (containing only commit A) to the remote, then add B locally.
    addBareRemote(repoDir, tempDir);
    git(["push", "-u", "origin", "feature"], repoDir);
    commitFile(repoDir, "bar.txt", "x\n", "Add bar");

    const { baseRef, commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(baseRef).toBe("main");
    expect(commits).toHaveLength(3);
    expect(commits[0]?.subject).toBe("Add bar");
    expect(commits[1]?.subject).toBe("Add foo");
    expect(commits[2]?.subject).toBe("initial");

    expect(commits[0]?.isOnRemote).toBe(false);
    expect(commits[1]?.isOnRemote).toBe(true);
    expect(commits[2]?.isOnRemote).toBe(true);
    expect(commits[0]?.isOnBase).toBe(false);
    expect(commits[1]?.isOnBase).toBe(false);
    expect(commits[2]?.isOnBase).toBe(true);

    expect(commits[0]?.files).toEqual([
      { path: "bar.txt", additions: 1, deletions: 0, status: "added" },
    ]);
    expect(commits[1]?.files).toEqual([
      { path: "foo.txt", additions: 3, deletions: 0, status: "added" },
    ]);

    expect(commits[0]?.authorName).toBe("Test User");
    expect(commits[0]?.sha).toHaveLength(40);
    expect((commits[0]?.shortSha.length ?? 0) > 0).toBe(true);
    expect(Number.isNaN(new Date(commits[0]?.authorDate ?? "").getTime())).toBe(false);
  });

  it("shows recent history on the base branch", async () => {
    const { repoDir } = initRepoOnMain();
    const { baseRef, commits } = await listCheckoutCommits({ cwd: repoDir });
    expect(baseRef).toBeNull();
    expect(commits.map((entry) => entry.subject)).toEqual(["initial"]);
    expect(commits[0]?.isOnBase).toBe(true);
  });

  it("keeps recent history when the saved base branch no longer exists", async () => {
    const { repoDir, tempDir } = initRepoOnMain();
    const worktreesRoot = join(tempDir, "worktrees");
    const worktreeDir = join(worktreesRoot, "repo-hash", "feature");
    mkdirSync(join(worktreesRoot, "repo-hash"), { recursive: true });
    git(["worktree", "add", "-b", "feature", worktreeDir], repoDir);
    commitFile(worktreeDir, "feature.txt", "feature\n", "Feature work");
    writePaseoWorktreeMetadata(worktreeDir, { baseRefName: "deleted-base" });

    const { baseRef, commits } = await listCheckoutCommits({
      cwd: worktreeDir,
      context: { worktreesRoot },
    });

    expect(baseRef).toBe("main");
    expect(commits.map((entry) => entry.subject)).toEqual(["Feature work", "initial"]);
    expect(commits.map((entry) => entry.isOnBase)).toEqual([false, true]);
  });

  it("marks all commits local-only when there is no remote", async () => {
    const { repoDir } = initRepoOnMain();
    git(["checkout", "-b", "feature"], repoDir);
    commitFile(repoDir, "foo.txt", "a\n", "Add foo");
    commitFile(repoDir, "bar.txt", "b\n", "Add bar");

    const { baseRef, commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(baseRef).toBe("main");
    expect(commits).toHaveLength(3);
    expect(commits.every((c) => c.isOnRemote === false)).toBe(true);
  });

  it("recognizes base history on a remote before the feature branch is pushed", async () => {
    const { repoDir, tempDir } = initRepoOnMain();
    addBareRemote(repoDir, tempDir);
    git(["push", "-u", "origin", "main"], repoDir);
    git(["checkout", "-b", "feature"], repoDir);
    commitFile(repoDir, "feature.txt", "local\n", "Local feature");

    const { commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(commits.map(({ subject, isOnRemote }) => ({ subject, isOnRemote }))).toEqual([
      { subject: "Local feature", isOnRemote: false },
      { subject: "initial", isOnRemote: true },
    ]);
  });

  it("keeps local base commits out of workspace history when the local base is ahead", async () => {
    const { repoDir, tempDir } = initRepoOnMain();
    addBareRemote(repoDir, tempDir);
    git(["push", "-u", "origin", "main"], repoDir);
    commitFile(repoDir, "local-base.txt", "base\n", "Local base work");
    git(["checkout", "-b", "feature"], repoDir);
    commitFile(repoDir, "feature.txt", "feature\n", "Feature work");

    const { commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(commits.map(({ subject, isOnBase }) => ({ subject, isOnBase }))).toEqual([
      { subject: "Feature work", isOnBase: false },
      { subject: "Local base work", isOnBase: true },
      { subject: "initial", isOnBase: true },
    ]);
  });

  it("shows every workspace commit followed by at most 10 base commits", async () => {
    const { repoDir } = initRepoOnMain();
    for (let index = 1; index <= 14; index += 1) {
      commitFile(repoDir, "base-history.txt", `${index}\n`, `Base ${index}`);
    }
    git(["checkout", "-b", "feature"], repoDir);
    for (let index = 1; index <= 24; index += 1) {
      commitFile(repoDir, "workspace-history.txt", `${index}\n`, `Workspace ${index}`);
    }

    const { commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(commits).toHaveLength(34);
    expect(commits.every((entry) => entry.isOnRemote === false)).toBe(true);
    expect(commits.slice(0, 24).map((entry) => entry.subject)).toEqual(
      Array.from({ length: 24 }, (_, index) => `Workspace ${24 - index}`),
    );
    expect(commits.slice(0, 24).every((entry) => entry.isOnBase === false)).toBe(true);
    expect(commits.slice(24).map((entry) => entry.subject)).toEqual(
      Array.from({ length: 10 }, (_, index) => `Base ${14 - index}`),
    );
    expect(commits.slice(24).every((entry) => entry.isOnBase === true)).toBe(true);
  });

  it("starts base context at the fork point when the base branch has advanced", async () => {
    const { repoDir } = initRepoOnMain();
    commitFile(repoDir, "shared.txt", "shared\n", "Shared base");
    git(["checkout", "-b", "feature"], repoDir);
    commitFile(repoDir, "feature.txt", "feature\n", "Feature work");
    git(["checkout", "main"], repoDir);
    commitFile(repoDir, "newer-base.txt", "newer\n", "Newer base");
    git(["checkout", "feature"], repoDir);

    const { commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(commits.map(({ subject, isOnBase }) => ({ subject, isOnBase }))).toEqual([
      { subject: "Feature work", isOnBase: false },
      { subject: "Shared base", isOnBase: true },
      { subject: "initial", isOnBase: true },
    ]);
  });

  it("limits base-branch history to 10 commits", async () => {
    const { repoDir } = initRepoOnMain();
    for (let index = 1; index <= 14; index += 1) {
      commitFile(repoDir, "history.txt", `${index}\n`, `Commit ${index}`);
    }

    const { commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(commits.map((entry) => entry.subject)).toEqual(
      Array.from({ length: 10 }, (_, index) => `Commit ${14 - index}`),
    );
    expect(commits.every((entry) => entry.isOnBase === true)).toBe(true);
  });

  it("shows merged branch commits and compares the merge against its first parent", async () => {
    const { repoDir } = initRepoOnMain();
    git(["checkout", "-b", "feature"], repoDir);
    commitFile(repoDir, "feature.txt", "feature\n", "Add feature");
    git(["checkout", "main"], repoDir);
    commitFile(repoDir, "main.txt", "main\n", "Advance main");
    git(["merge", "--no-ff", "feature", "-m", "Merge feature"], repoDir);

    const { commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(commits.map((entry) => entry.subject)).toEqual([
      "Merge feature",
      "Advance main",
      "Add feature",
      "initial",
    ]);
    expect(commits[0]?.files).toEqual([
      { path: "feature.txt", additions: 1, deletions: 0, status: "added" },
    ]);
  });

  it("classifies renamed files with status renamed and correct destination path", async () => {
    const { repoDir } = initRepoOnMain();
    git(["checkout", "-b", "feature"], repoDir);
    commitFile(repoDir, "original.txt", "content\n", "Add original");
    git(["mv", "original.txt", "renamed.txt"], repoDir);
    commit(repoDir, "Rename file");

    const { commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(commits[0]?.files).toEqual([
      { path: "renamed.txt", additions: 0, deletions: 0, status: "renamed" },
    ]);
  });

  it("derives status for modified and deleted files", async () => {
    const { repoDir } = initRepoOnMain();
    git(["checkout", "-b", "feature"], repoDir);
    commitFile(repoDir, "README.md", "base\nmore\n", "Edit readme");
    git(["rm", "README.md"], repoDir);
    commit(repoDir, "Delete readme");

    const { commits } = await listCheckoutCommits({ cwd: repoDir });

    expect(commits[0]?.files).toEqual([
      { path: "README.md", additions: 0, deletions: 2, status: "deleted" },
    ]);
    expect(commits[1]?.files).toEqual([
      { path: "README.md", additions: 1, deletions: 0, status: "modified" },
    ]);
  });
});