import { describe, expect, it } from 'bun:test'
import { readFileSync } from 'node:fs'
import { join } from 'node:path'
import { openDocument } from '../vendor/config-editor/index.ts'
import type { ConfigObject } from '../vendor/config-editor/index.ts'
import { rewriteYaml } from '../server/config-store.ts'
import { restoreInlineCommentAlignment } from './yaml-cosmetics.ts'

const fixture = readFileSync(
  join(import.meta.dir, '__fixtures__', 'config-with-comments.yaml'),
  'utf8',
)

const clone = (v: unknown) => JSON.parse(JSON.stringify(v)) as ConfigObject

/**
 * 走**生产用的那一条**写回路径，而不是在测试里重拼一遍。
 * 自己拼的话，落盘链路里漏掉其中一步这些测试照样会绿——那就白写了。
 */
function roundtrip(source: string, mutate: (draft: ConfigObject) => void): string {
  const draft = clone(openDocument(source).data)
  mutate(draft)
  return rewriteYaml(source, draft)
}

describe('写回一份带注释的配置', () => {
  it('原样写回时逐字节不变', () => {
    expect(roundtrip(fixture, () => {})).toBe(fixture)
  })

  it('新增一个此前不存在的段落时，其余每一行都不变', () => {
    const out = roundtrip(fixture, (draft) => {
      draft.listeners = [{ name: '容器A', type: 'mixed', port: 7778, proxy: 'AUTO' }]
    })

    // 这是这个项目最核心的操作，也是取信于用户的底线：只应多出新段落，别的一行都不许动。
    const before = fixture.split('\n')
    const after = out.split('\n')
    expect(after.slice(0, before.length - 1)).toEqual(before.slice(0, before.length - 1))
    expect(out).toContain('listeners:')
    expect(out).toContain('port: 7778')
  })

  it('改动某个段落时，不碰其它段落的注释和写法', () => {
    const out = roundtrip(fixture, (draft) => {
      const rules = draft.rules as string[]
      rules[rules.length - 1] = 'MATCH,AUTO'
    })

    // rules 之外的段落必须原封不动，含对齐空格和流式数组。
    expect(out).toContain('mixed-port: 7777          # HTTP 和 SOCKS5 共用这一个端口')
    expect(out).toContain('  - name: PROXY                # 总开关，手动选；默认跟着 AUTO 走')
    expect(out).toContain('    proxies: [AUTO, DIRECT]')
    expect(out).toContain('    interval: 86400            # 每 24 小时自动拉取一次订阅')
    expect(out).toContain('MATCH,AUTO')
  })

  it('被改动的段落内部注释会丢失，这是已知缺陷（见 ADR 0002）', () => {
    const out = roundtrip(fixture, (draft) => {
      const rules = draft.rules as string[]
      rules[rules.length - 1] = 'MATCH,AUTO'
    })

    // 记录现状而非期望。将来若实现了段落内的就地修改，这条断言应当反转。
    expect(out).not.toContain('# 本机和内网地址一律直连')
  })
})

describe('restoreInlineCommentAlignment', () => {
  it('内容与注释都相同时还原原本的对齐', () => {
    const source = 'a: 1          # 说明\n'
    const output = 'a: 1 # 说明\n'
    expect(restoreInlineCommentAlignment(source, output)).toBe(source)
  })

  it('注释文字变了就不还原，避免掩盖真实改动', () => {
    const source = 'a: 1          # 旧说明\n'
    const output = 'a: 1 # 新说明\n'
    expect(restoreInlineCommentAlignment(source, output)).toBe(output)
  })

  it('值变了就不还原', () => {
    const source = 'a: 1          # 说明\n'
    const output = 'a: 2 # 说明\n'
    expect(restoreInlineCommentAlignment(source, output)).toBe(output)
  })

  it('相同的行出现多次时按顺序依次配对', () => {
    const source = 'a: 1     # 同\nb: 2\na: 1        # 同\n'
    const output = 'a: 1 # 同\nb: 2\na: 1 # 同\n'
    expect(restoreInlineCommentAlignment(source, output)).toBe(source)
  })

  it('不把字符串里的井号当成注释', () => {
    const line = 'url: "http://example.com/a#b"\n'
    expect(restoreInlineCommentAlignment(line, line)).toBe(line)
  })
})