import crypto from 'node:crypto'

const sha256 = (value) => crypto.createHash('sha256').update(value).digest('hex')

const cleanBaseUrl = (value) => {
  const url = new URL(String(value || '').trim())
  if (url.protocol !== 'https:' && url.hostname !== '127.0.0.1' && url.hostname !== 'localhost') {
    throw new Error('通知中心地址必须使用 HTTPS')
  }
  if (url.username || url.password || url.search || url.hash) {
    throw new Error('通知中心地址不能包含凭据、查询参数或片段')
  }
  return url.toString().replace(/\/$/, '')
}

export class YouYiDianNotificationClient {
  constructor({ baseUrl, projectCode, projectSecret, fetchImpl = fetch }) {
    if (!/^[a-z0-9_-]{2,40}$/.test(String(projectCode || ''))) {
      throw new Error('projectCode 格式不正确')
    }
    if (String(projectSecret || '').length < 24) {
      throw new Error('projectSecret 未配置或长度不足')
    }
    this.baseUrl = cleanBaseUrl(baseUrl)
    this.projectCode = projectCode
    this.projectSecret = projectSecret
    this.fetchImpl = fetchImpl
  }

  createHeaders({ method, path, body = '' }) {
    const timestamp = String(Math.floor(Date.now() / 1000))
    const nonce = crypto.randomBytes(18).toString('base64url')
    const canonical = [timestamp, nonce, method.toUpperCase(), path, sha256(body)].join('\n')
    const signature = crypto.createHmac('sha256', this.projectSecret).update(canonical).digest('hex')
    return {
      'content-type': 'application/json',
      'x-yyd-project-code': this.projectCode,
      'x-yyd-timestamp': timestamp,
      'x-yyd-nonce': nonce,
      'x-yyd-signature': signature,
    }
  }

  async request({ method, path, body }) {
    const rawBody = body === undefined ? '' : JSON.stringify(body)
    const response = await this.fetchImpl(`${this.baseUrl}${path}`, {
      method,
      headers: this.createHeaders({ method, path, body: rawBody }),
      ...(rawBody ? { body: rawBody } : {}),
    })
    const payload = await response.json().catch(() => ({ error: 'INVALID_JSON_RESPONSE' }))
    if (!response.ok) {
      const error = new Error(payload.message || payload.error || `通知中心返回 HTTP ${response.status}`)
      error.status = response.status
      error.code = payload.error
      error.payload = payload
      throw error
    }
    return payload
  }

  send(input) {
    return this.request({
      method: 'POST',
      path: '/v1/notifications',
      body: input,
    })
  }

  getDelivery(id) {
    if (!id) throw new Error('投递 id 不能为空')
    return this.request({
      method: 'GET',
      path: `/v1/notifications/${encodeURIComponent(id)}`,
    })
  }
}