import { describe, it, expect, beforeEach, afterEach } from 'vitest'
import { existsSync, mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from 'node:fs'
import { tmpdir } from 'node:os'
import { join } from 'node:path'
import { customisedWarnings, writeGeneratedFiles } from '../generated-writes.js'

let outdir: string
beforeEach(() => { outdir = mkdtempSync(join(tmpdir(), 'ss-gen-writes-')) })
afterEach(() => rmSync(outdir, { recursive: true, force: true }))

describe('writeGeneratedFiles — the guarded write loop', () => {
  it('writes new and existing generated files (unconditionally — no content comparison)', () => {
    mkdirSync(join(outdir, 'src'), { recursive: true })
    writeFileSync(join(outdir, 'src', 'A.cs'), '// @generated-by x\nold', 'utf8')
    const r = writeGeneratedFiles([{ path: 'src/A.cs', content: 'new' }, { path: 'src/deep/B.cs', content: 'b' }], { outdir })
    expect(r.written).toHaveLength(2)
    expect(r.skipped).toEqual([])
    expect(readFileSync(join(outdir, 'src', 'A.cs'), 'utf8')).toBe('new')
    expect(readFileSync(join(outdir, 'src', 'deep', 'B.cs'), 'utf8')).toBe('b')
  })

  it('NEVER overwrites a file whose head carries @customised (both comment forms), and returns it', () => {
    mkdirSync(join(outdir, 'src'), { recursive: true })
    writeFileSync(join(outdir, 'src', 'Svc.cs'), '// @customised — hand-owned\nmine', 'utf8')
    writeFileSync(join(outdir, 'src', 'Page.tsx'), '/* @customised */\nmine too', 'utf8')
    const r = writeGeneratedFiles([{ path: 'src/Svc.cs', content: 'gen' }, { path: 'src/Page.tsx', content: 'gen' }, { path: 'src/New.cs', content: 'gen' }], { outdir })
    expect(r.skipped.map((p) => p.replace(/\\/g, '/'))).toEqual([join(outdir, 'src', 'Svc.cs'), join(outdir, 'src', 'Page.tsx')].map((p) => p.replace(/\\/g, '/')))
    expect(r.written).toHaveLength(1)
    expect(readFileSync(join(outdir, 'src', 'Svc.cs'), 'utf8')).toContain('mine')
    expect(readFileSync(join(outdir, 'src', 'Page.tsx'), 'utf8')).toContain('mine too')
    const w = customisedWarnings(r)
    expect(w).toHaveLength(2)
    expect(w[0]).toMatch(/kept: marked @customised/)
  })

  it('refuses a path that escapes outdir (traversal)', () => {
    expect(() => writeGeneratedFiles([{ path: '../escape.cs', content: 'x' }], { outdir })).toThrow()
    expect(existsSync(join(outdir, '..', 'escape.cs'))).toBe(false)
  })

  it('dryRun classifies without touching the disk', () => {
    const r = writeGeneratedFiles([{ path: 'src/Dry.cs', content: 'x' }], { outdir, dryRun: true })
    expect(r.written).toHaveLength(1)
    expect(existsSync(join(outdir, 'src', 'Dry.cs'))).toBe(false)
  })
})