import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises'
import { tmpdir } from 'node:os'
import { join } from 'node:path'
import { afterEach, describe, expect, it } from 'vitest'
import { simpleGit } from 'simple-git'
import { buildTreeFromPaths, createProjectFile, readAll, readProjectFile, readTree, writeProjectFile } from '../src/main/fs-service'

let dir = ''
afterEach(async () => { if (dir) await rm(dir, { recursive: true, force: true }) })

async function fixture(): Promise<string> {
  const d = await mkdtemp(join(tmpdir(), 'helder-fs-'))
  await mkdir(join(d, 'src'), { recursive: true })
  await mkdir(join(d, 'node_modules/pkg'), { recursive: true })
  await mkdir(join(d, '.git'), { recursive: true })
  await writeFile(join(d, 'src', 'a.ts'), 'export const a = 1\n')
  await writeFile(join(d, 'README.md'), '# hi\n')
  await writeFile(join(d, 'node_modules', 'pkg', 'index.js'), 'module.exports = 1\n')
  await writeFile(join(d, '.git', 'HEAD'), 'ref: refs/heads/main\n')
  await writeFile(join(d, 'logo.bin'), Buffer.from([0x00, 0x01, 0x02, 0x00, 0x99]))
  return d
}

describe('readTree', () => {
  it('lists dirs before files, ignoring node_modules and .git', async () => {
    dir = await fixture()
    const tree = await readTree(dir)
    const top = (tree.children || []).map((c) => c.name)
    expect(top).not.toContain('node_modules')
    expect(top).not.toContain('.git')
    expect(top).toContain('src')
    // dirs first
    expect(top.indexOf('src')).toBeLessThan(top.indexOf('README.md'))
    expect(top.indexOf('src')).toBeLessThan(top.indexOf('logo.bin'))
  })
})

describe('readAll', () => {
  it('indexes text files, skipping ignored dirs and binary files', async () => {
    dir = await fixture()
    const files = await readAll(dir)
    const keys = Object.keys(files)
    expect(keys).toContain('src/a.ts')
    expect(keys).toContain('README.md')
    expect(keys.some((k) => k.includes('node_modules'))).toBe(false)
    expect(keys).not.toContain('logo.bin') // binary skipped
    expect(files['src/a.ts']).toContain('export const a')
  })

  it('shows .gitignored files in a repo (files.followGitignore default off)', async () => {
    dir = await mkdtemp(join(tmpdir(), 'helder-fs-'))
    await simpleGit(dir).init()
    await writeFile(join(dir, '.gitignore'), 'secret.txt\n')
    await writeFile(join(dir, 'secret.txt'), 'shh')
    await writeFile(join(dir, 'keep.txt'), 'ok')
    const keys = Object.keys(await readAll(dir))
    expect(keys).toContain('keep.txt')
    expect(keys).toContain('secret.txt') // gitignore not followed by default → shown
  })
})

describe('buildTreeFromPaths', () => {
  it('nests paths with dirs before files, alphabetical', () => {
    const t = buildTreeFromPaths('proj', ['src/b.ts', 'src/a.ts', 'README.md', 'src/util/x.ts'])
    expect((t.children || []).map((c) => c.name)).toEqual(['src', 'README.md'])
    const src = (t.children || []).find((c) => c.name === 'src')!
    expect((src.children || []).map((c) => c.name)).toEqual(['util', 'a.ts', 'b.ts'])
    expect((src.children || []).find((c) => c.name === 'util')!.path).toBe('src/util')
  })
})

describe('read/write round-trip', () => {
  it('writes then reads the same content', async () => {
    dir = await mkdtemp(join(tmpdir(), 'helder-fs-'))
    await writeProjectFile(dir, 'note.txt', 'hello world\n')
    expect(await readProjectFile(dir, 'note.txt')).toBe('hello world\n')
  })
})

describe('createProjectFile', () => {
  it('creates an empty file and makes missing parent folders', async () => {
    dir = await mkdtemp(join(tmpdir(), 'helder-fs-'))
    await createProjectFile(dir, 'src/new/fresh.ts')
    expect(await readProjectFile(dir, 'src/new/fresh.ts')).toBe('')
  })

  it('refuses to overwrite an existing file', async () => {
    dir = await mkdtemp(join(tmpdir(), 'helder-fs-'))
    await writeProjectFile(dir, 'keep.txt', 'precious\n')
    await expect(createProjectFile(dir, 'keep.txt')).rejects.toThrow()
    expect(await readProjectFile(dir, 'keep.txt')).toBe('precious\n')
  })

  it('refuses to escape the project root', async () => {
    dir = await mkdtemp(join(tmpdir(), 'helder-fs-'))
    await expect(createProjectFile(dir, '../escape.txt')).rejects.toThrow()
  })
})