/**
 * test/http/git-log.test.ts (W3 quick-wins d) — recent-commit log parsing + getGitLog.
 *
 * Two layers:
 *  1. parseGitLog fed canned NUL-record/US-field output — the deterministic core
 *     (empty → []; malformed record skipped; subject with tabs/newlines intact;
 *     subject truncated at the cap; truncated flag when records === max).
 *  2. getGitLog against a REAL throwaway git repo in os.tmpdir (newest-first,
 *     n-clamping + truncated flag). Mirrors test/http/diff.test.ts.
 */

import { describe, it, expect, beforeAll, afterAll } from 'vitest'
import os from 'node:os'
import path from 'node:path'
import fs from 'node:fs/promises'
import { execFile } from 'node:child_process'
import { promisify } from 'node:util'
import {
  parseGitLog,
  getGitLog,
  clampLogCount,
  GIT_LOG_MAX,
  GIT_LOG_DEFAULT,
} from '../../src/http/git-log.js'

const execFileAsync = promisify(execFile)
const US = '\x1f'
const NUL = '\x00'

/** Build one NUL-terminated record: hash US ct US subject. */
function rec(hash: string, ct: number, subject: string): string {
  return `${hash}${US}${ct}${US}${subject}${NUL}`
}

// ── clampLogCount ─────────────────────────────────────────────────────────────

describe('clampLogCount', () => {
  it('defaults to GIT_LOG_DEFAULT for missing / non-numeric', () => {
    expect(clampLogCount(undefined)).toBe(GIT_LOG_DEFAULT)
    expect(clampLogCount('abc')).toBe(GIT_LOG_DEFAULT)
    expect(clampLogCount(NaN)).toBe(GIT_LOG_DEFAULT)
  })

  it('clamps to [1, GIT_LOG_MAX]', () => {
    expect(clampLogCount(0)).toBe(1)
    expect(clampLogCount(-5)).toBe(1)
    expect(clampLogCount(999)).toBe(GIT_LOG_MAX)
    expect(clampLogCount(GIT_LOG_MAX)).toBe(GIT_LOG_MAX)
  })

  it('parses a numeric string and floors it', () => {
    expect(clampLogCount('3')).toBe(3)
    expect(clampLogCount(3.9)).toBe(3)
  })
})

// ── parseGitLog (pure) ────────────────────────────────────────────────────────

describe('parseGitLog', () => {
  it('returns [] for empty stdout', () => {
    expect(parseGitLog('', 20)).toEqual({ commits: [], truncated: false })
  })

  it('parses one record into hash / at(ms) / subject', () => {
    const out = parseGitLog(rec('abc1234', 1700000000, 'first commit'), 20)
    expect(out.commits).toHaveLength(1)
    expect(out.commits[0]).toEqual({
      hash: 'abc1234',
      at: 1700000000 * 1000,
      subject: 'first commit',
    })
    expect(out.truncated).toBe(false)
  })

  it('preserves subjects containing tabs and newlines (US/NUL delimiters)', () => {
    const nasty = 'fix:\ttabbed\nand newlined'
    const out = parseGitLog(rec('h1', 1700000000, nasty), 20)
    expect(out.commits[0]?.subject).toBe(nasty)
  })

  it('skips a malformed record missing a field', () => {
    const good = rec('h1', 1700000000, 'ok')
    const bad = `h2${US}onlytwo${NUL}` // only 2 fields
    const out = parseGitLog(good + bad, 20)
    expect(out.commits.map((c) => c.hash)).toEqual(['h1'])
  })

  it('skips a record with a non-numeric timestamp', () => {
    const out = parseGitLog(rec('h1', NaN as unknown as number, 'x') + rec('h2', 1700000001, 'y'), 20)
    expect(out.commits.map((c) => c.hash)).toEqual(['h2'])
  })

  it('truncates an over-long subject at the cap', () => {
    const long = 'x'.repeat(1000)
    const out = parseGitLog(rec('h1', 1700000000, long), 20)
    expect(out.commits[0]?.subject.length).toBe(500)
  })

  it('sets truncated when records === max (there may be more)', () => {
    const stdout = rec('h1', 1, 'a') + rec('h2', 2, 'b') + rec('h3', 3, 'c')
    const out = parseGitLog(stdout, 3)
    expect(out.commits).toHaveLength(3)
    expect(out.truncated).toBe(true)
  })

  it('does NOT set truncated when fewer records than max', () => {
    const stdout = rec('h1', 1, 'a') + rec('h2', 2, 'b')
    const out = parseGitLog(stdout, 3)
    expect(out.truncated).toBe(false)
  })
})

// ── getGitLog (integration against a real git repo) ──────────────────────────

async function git(cwd: string, ...args: string[]): Promise<void> {
  await execFileAsync('git', args, { cwd })
}

describe('getGitLog (real git repo)', () => {
  let repo: string

  beforeAll(async () => {
    repo = await fs.mkdtemp(path.join(os.tmpdir(), 'webterm-gitlog-'))
    await git(repo, 'init', '-q', '-b', 'main')
    await git(repo, 'config', 'user.email', 'test@example.com')
    await git(repo, 'config', 'user.name', 'Test')
    await git(repo, 'config', 'commit.gpgsign', 'false')
    for (const [file, msg] of [
      ['a.txt', 'first'],
      ['b.txt', 'second'],
      ['c.txt', 'third'],
    ]) {
      await fs.writeFile(path.join(repo, file), `${file}\n`)
      await git(repo, 'add', '.')
      await git(repo, 'commit', '-q', '-m', msg)
    }
  })

  afterAll(async () => {
    await fs.rm(repo, { recursive: true, force: true })
  })

  it('returns 3 commits newest-first', async () => {
    const out = await getGitLog(repo, { timeoutMs: 5000 })
    expect(out.commits).toHaveLength(3)
    expect(out.commits.map((c) => c.subject)).toEqual(['third', 'second', 'first'])
    expect(out.truncated).toBe(false)
    // hashes are short + non-empty; at is a plausible ms timestamp
    for (const c of out.commits) {
      expect(c.hash.length).toBeGreaterThan(0)
      expect(c.at).toBeGreaterThan(0)
    }
  })

  it('clamps n and flags truncated when asking for fewer than exist', async () => {
    const out = await getGitLog(repo, { n: 2, timeoutMs: 5000 })
    expect(out.commits).toHaveLength(2)
    expect(out.commits.map((c) => c.subject)).toEqual(['third', 'second'])
    expect(out.truncated).toBe(true)
  })

  it('returns an empty result for a non-git directory (best-effort, no throw)', async () => {
    const plain = await fs.mkdtemp(path.join(os.tmpdir(), 'webterm-nogit-'))
    const out = await getGitLog(plain, { timeoutMs: 5000 })
    expect(out).toEqual({ commits: [], truncated: false })
    await fs.rm(plain, { recursive: true, force: true })
  })
})