/**
 * Axios Mock Adapter
 * 拦截所有 API 请求并返回 mock 数据
 * 通过 URL + method 路由到对应的 mock 响应
 */
import type { AxiosAdapter, AxiosInstance, AxiosRequestConfig } from 'axios'
import {
  mockHealth,
  mockSystemInfo,
  mockModels,
  mockTrainedModels,
  mockLocalModels,
  mockDatasets,
  mockDatasetPreviews,
  mockFineTuneList,
  mockCompareList,
  mockEvalList,
  mockEvalDetails,
  mockDimensions,
  mockLogFiles,
  mockTrainingLogFiles,
  mockLogContent,
  mockTrainingLogContents,
} from './data'
import {
  activateDatasetVersion,
  appendDatasetVersion,
  createInitialVersionState,
  deleteDatasetVersion,
  DatasetVersionMutationError,
  getActiveDatasetVersion,
  normalizeDatasetVersionState,
} from './datasetVersions'
import type { StoredDatasetVersion, StoredDatasetVersionState } from './datasetVersions'
import {
  authenticateMockUser,
  createMockUser,
  deleteMockUser,
  listMockUsers,
  updateMockUserAccess,
  UserMutationError,
} from './users'

/** 模拟网络延迟 */
function delay(ms = 200): Promise<void> {
  return new Promise((resolve) => setTimeout(resolve, ms))
}

/** 构造 Axios 风格的成功响应 */
function ok(data: any, config: AxiosRequestConfig = {}) {
  return {
    data: { code: 0, message: 'ok', data },
    status: 200,
    statusText: 'OK',
    headers: {},
    config,
  }
}

/** 构造失败响应 */
function fail(message: string, code = 500, config: AxiosRequestConfig = {}) {
  return {
    data: { code, message },
    status: code,
    statusText: message,
    headers: {},
    config,
  }
}

/** 简易 URL 解析（去掉 baseURL 前缀） */
function stripBaseURL(url: string): string {
  // url 可能带查询参数
  const [path] = url.split('?')
  return path
}

function datasetFallbackContent(fileId: string) {
  const fallbackKey = fileId.endsWith('-readme') ? 'mock-readme' : 'mock-jsonl'
  return mockDatasetPreviews[fileId] ?? mockDatasetPreviews[fallbackKey] ?? ''
}

function versionStorageKey(fileId: string) {
  return `mock:dataset-versions:${fileId}`
}

function persistVersionState(fileId: string, state: StoredDatasetVersionState) {
  localStorage.setItem(versionStorageKey(fileId), JSON.stringify(state))
}

function getVersionState(fileId: string): StoredDatasetVersionState {
  const persisted = localStorage.getItem(versionStorageKey(fileId))
  if (persisted) {
    try {
      const state = JSON.parse(persisted) as StoredDatasetVersionState
      if (state.versions?.length && state.active_version_id) {
        const normalizedState = normalizeDatasetVersionState(state)
        if (state.next_version_number !== normalizedState.next_version_number) {
          persistVersionState(fileId, normalizedState)
        }
        return normalizedState
      }
    } catch {
      // 版本数据损坏时回退到初始版本
    }
  }

  const legacyContent = localStorage.getItem(`mock:dataset-file:${fileId}`)
  const state = createInitialVersionState(legacyContent ?? datasetFallbackContent(fileId))
  persistVersionState(fileId, state)
  return state
}

function versionMetadata(version: StoredDatasetVersion) {
  const { content: _content, ...metadata } = version
  return metadata
}

function versionListResponse(state: StoredDatasetVersionState) {
  return {
    versions: state.versions.map(versionMetadata).sort((a, b) => b.version - a.version),
    active_version_id: state.active_version_id,
    next_version_number: state.next_version_number,
  }
}

/** 通过路径 + method 匹配 mock 响应 */
async function handleMock(config: AxiosRequestConfig) {
  await delay(150) // 模拟网络延迟

  const url = stripBaseURL(config.url || '')
  const method = (config.method || 'get').toLowerCase()
  const params = config.params || {}
  const body = typeof config.data === 'string' ? safeJSON(config.data) : config.data || {}

  // ==================== 认证 ====================
  if (url === '/login' && method === 'post') {
    try {
      return ok(authenticateMockUser(String(body.username || ''), String(body.password || '')))
    } catch (error) {
      if (error instanceof UserMutationError) return fail(error.message, error.status)
      return fail('登录失败', 500)
    }
  }
  if (url === '/web-log' && method === 'post') {
    return ok({ received: true })
  }

  // ==================== 系统监控 ====================
  if (url === '/health' && method === 'get') return ok(mockHealth)
  if (url === '/system-info' && method === 'get') return ok(mockSystemInfo)

  // ==================== 用户设置 ====================
  if (url === '/users' && method === 'get') return ok(listMockUsers())
  if (url === '/users' && method === 'post') {
    try {
      return ok(createMockUser(body))
    } catch (error) {
      if (error instanceof UserMutationError) return fail(error.message, error.status)
      return fail('创建用户失败', 500)
    }
  }
  let userMatch = url.match(/^\/users\/([^/]+)$/)
  if (userMatch && method === 'put') {
    try {
      return ok(updateMockUserAccess(decodeURIComponent(userMatch[1]), body))
    } catch (error) {
      if (error instanceof UserMutationError) return fail(error.message, error.status)
      return fail('更新用户失败', 500)
    }
  }
  if (userMatch && method === 'delete') {
    try {
      return ok(deleteMockUser(
        decodeURIComponent(userMatch[1]),
        String(params.current_username || ''),
      ))
    } catch (error) {
      if (error instanceof UserMutationError) return fail(error.message, error.status)
      return fail('删除用户失败', 500)
    }
  }

  // ==================== 模型管理 ====================
  if (url === '/model-manage' && method === 'get') return ok(mockModels)
  if (url === '/model-manage/local-models' && method === 'get') return ok(mockLocalModels)
  if (url === '/model-manage/trained-models' && method === 'get') return ok(mockTrainedModels)
  if (url === '/model-manage/merge' && method === 'post') {
    return ok({ merged: true, path: '/data/saves/' + body.model_name + '-merged' })
  }
  // 模型详情 / 编辑 / 删除 / 用途更新
  let m = url.match(/^\/model-manage\/([^/]+)$/)
  if (m && method === 'get') {
    const id = m[1]
    const found = mockModels.find((x) => String(x.id) === id || x.name === id)
    return found ? ok(found) : fail('模型不存在', 404)
  }
  m = url.match(/^\/model-manage\/([^/]+)$/)
  if (m && (method === 'put' || method === 'delete')) {
    return ok({ id: m[1], ...body })
  }
  m = url.match(/^\/model-manage\/name\/([^/]+)$/)
  if (m && method === 'get') {
    const name = decodeURIComponent(m[1])
    const found = mockModels.find((x) => x.name === name)
    return found ? ok(found) : fail('模型不存在', 404)
  }
  m = url.match(/^\/model-manage\/trained-models\/([^/]+)$/)
  if (m && method === 'delete') {
    return ok({ deleted: m[1] })
  }
  m = url.match(/^\/model-manage\/([^/]+)\/purpose$/)
  if (m && method === 'put') {
    return ok({ id: m[1], purpose: body.purpose })
  }

  // ==================== 数据集 ====================
  if (url === '/dataset-manage' && method === 'get') return ok(mockDatasets)
  if (url === '/dataset-manage' && method === 'post') {
    const newId = Math.max(...mockDatasets.map((d) => Number(d.id))) + 1
    return ok({ id: newId })
  }
  m = url.match(/^\/dataset-manage\/([^/]+)$/)
  if (m && method === 'get') {
    const datasetId = m[1]
    const found = mockDatasets.find((x) => String(x.id) === datasetId)
    return found ? ok(found) : fail('数据集不存在', 404)
  }
  if (m && (method === 'put' || method === 'delete')) {
    return ok({ id: m[1] })
  }
  m = url.match(/^\/dataset-manage\/upload\/([^/]+)$/)
  if (m && method === 'post') return ok({ uploaded: true })
  m = url.match(/^\/dataset-manage\/preview\/([^/]+)$/)
  if (m && method === 'get') {
    const fileId = decodeURIComponent(m[1])
    return ok({ content: getActiveDatasetVersion(getVersionState(fileId)).content })
  }
  if (m && method === 'put') return fail('历史版本不可覆盖，请创建新版本', 405)

  m = url.match(/^\/dataset-manage\/versions\/([^/]+)$/)
  if (m && method === 'get') {
    const fileId = decodeURIComponent(m[1])
    const state = getVersionState(fileId)
    return ok(versionListResponse(state))
  }
  if (m && method === 'post') {
    const fileId = decodeURIComponent(m[1])
    if (typeof body.content !== 'string') return fail('文件内容格式不正确', 400)
    const currentState = getVersionState(fileId)
    if (body.expected_current_version_id !== currentState.active_version_id) {
      return fail('当前版本已被其他用户更新，请刷新后重试', 409)
    }
    if (body.base_version_id !== currentState.active_version_id) {
      return fail('只能基于当前版本创建新版本', 409)
    }
    if (body.content === getActiveDatasetVersion(currentState).content) {
      return fail('数据内容没有变化，无需创建新版本', 400)
    }
    const nextState = appendDatasetVersion(
      currentState,
      body.content,
      new Date().toISOString(),
      typeof body.description === 'string' ? body.description : '在线编辑',
    )
    try {
      persistVersionState(fileId, nextState)
    } catch {
      return fail('文件内容过大，浏览器 Mock 存储空间不足', 413)
    }
    const version = getActiveDatasetVersion(nextState)
    return ok({ version: versionMetadata(version), content: version.content })
  }

  m = url.match(/^\/dataset-manage\/versions\/([^/]+)\/active$/)
  if (m && method === 'put') {
    const fileId = decodeURIComponent(m[1])
    const currentState = getVersionState(fileId)
    if (body.expected_current_version_id !== currentState.active_version_id) {
      return fail('当前版本已被其他用户更新，请刷新后重试', 409)
    }
    let nextState: StoredDatasetVersionState
    try {
      nextState = activateDatasetVersion(currentState, String(body.version_id || ''))
    } catch (error) {
      return fail(error instanceof Error ? error.message : '版本不存在', 404)
    }
    try {
      persistVersionState(fileId, nextState)
    } catch {
      return fail('浏览器 Mock 存储空间不足', 413)
    }
    const version = getActiveDatasetVersion(nextState)
    return ok({ version: versionMetadata(version), content: version.content })
  }

  m = url.match(/^\/dataset-manage\/versions\/([^/]+)\/([^/]+)$/)
  if (m && method === 'get') {
    const fileId = decodeURIComponent(m[1])
    const versionId = decodeURIComponent(m[2])
    const version = getVersionState(fileId).versions.find((item) => item.id === versionId)
    return version
      ? ok({ version: versionMetadata(version), content: version.content })
      : fail('数据集版本不存在', 404)
  }
  if (m && method === 'delete') {
    const fileId = decodeURIComponent(m[1])
    const versionId = decodeURIComponent(m[2])
    const currentState = getVersionState(fileId)
    if (params.expected_current_version_id !== currentState.active_version_id) {
      return fail('当前版本已被其他用户更新，请刷新后重试', 409)
    }

    let nextState: StoredDatasetVersionState
    try {
      nextState = deleteDatasetVersion(currentState, versionId)
    } catch (error) {
      if (error instanceof DatasetVersionMutationError) {
        return fail(error.message, error.status)
      }
      return fail('删除版本失败', 500)
    }
    try {
      persistVersionState(fileId, nextState)
    } catch {
      return fail('浏览器 Mock 存储空间不足', 413)
    }
    return ok(versionListResponse(nextState))
  }

  // ==================== 训练任务 ====================
  if (url === '/fine-tune' && method === 'get') return ok(mockFineTuneList)
  if (url === '/fine-tune' && method === 'post') {
    return ok({ id: Math.floor(Math.random() * 10000) + 100 })
  }
  if (url === '/fine-tune/start' && method === 'post') {
    return ok({ started: true })
  }
  if (url === '/fine-tune/check-name' && method === 'get') {
    return ok({ exists: false })
  }
  m = url.match(/^\/fine-tune\/progress\/([^/]+)$/)
  if (m && method === 'get') {
    const taskId = m[1]
    const task = mockFineTuneList.find((t) => String(t.id) === taskId)
    if (!task) return fail('任务不存在', 404)
    if (task.status === 'running') {
      return ok({
        status: task.status,
        progress: task.progress ?? 0,
        step: `${Math.floor((task.progress ?? 0) * 10)}/1000`,
        speed: '1.23s/it',
        eta: '00:23:45',
      })
    }
    return ok({ status: task.status, progress: task.progress ?? 0 })
  }
  m = url.match(/^\/fine-tune\/([^/]+)$/)
  if (m && method === 'get') {
    const taskId = m[1]
    const found = mockFineTuneList.find((x) => String(x.id) === taskId)
    return found ? ok(found) : fail('任务不存在', 404)
  }
  m = url.match(/^\/fine-tune\/stop\/([^/]+)$/)
  if (m && method === 'post') return ok({ stopped: true })
  m = url.match(/^\/fine-tune\/([^/]+)$/)
  if (m && (method === 'put' || method === 'delete')) {
    return ok({ id: m[1] })
  }
  if (url === '/fine-tune/tensorboard/start' && method === 'post') {
    return ok({ url: 'http://10.10.10.77:6006' })
  }

  // ==================== 模型推理/对比 ====================
  if (url === '/model-compare' && method === 'get') return ok(mockCompareList)
  if (url === '/model-compare' && method === 'post') {
    return ok({ id: Math.floor(Math.random() * 10000) + 100 })
  }
  m = url.match(/^\/model-compare\/([^/]+)$/)
  if (m && method === 'get') {
    const compareId = m[1]
    const found = mockCompareList.find((x) => String(x.id) === compareId)
    return found ? ok(found) : fail('任务不存在', 404)
  }
  if (m && method === 'delete') return ok({ deleted: m[1] })
  m = url.match(/^\/model-compare\/([^/]+)\/load-status$/)
  if (m && method === 'get') {
    return ok({ all_ready: true, loaded_models: [] })
  }
  if (m && method === 'post') return ok({ updated: true })
  m = url.match(/^\/model-compare\/([^/]+)\/load$/)
  if (m && method === 'post') return ok({ loading: true })
  m = url.match(/^\/model-compare\/([^/]+)\/unload$/)
  if (m && method === 'post') return ok({ stopped: true })
  m = url.match(/^\/model-compare\/([^/]+)\/start-model$/)
  if (m && method === 'post') {
    return ok({ pid: 12345 + Math.floor(Math.random() * 100), port: 18000 + Math.floor(Math.random() * 1000) })
  }
  if (url === '/model-compare/all/stop-all' && method === 'post') return ok({ stopped: true })
  if (url === '/model-compare/stop-by-pid' && method === 'post') return ok({ stopped: true })
  if (url === '/model-compare/chat-with-port' && method === 'post') {
    // 模拟推理回答（用于对比结果页）
    const userQ = body?.messages?.find((m: any) => m.role === 'user')?.content || '你的问题'
    const answer = `这是一个针对「${userQ.slice(0, 30)}」的模拟回答。\n\n在真实环境中，对比结果页会通过端口代理调用对应模型服务，返回该模型的真实推理结果。\n\n模型参数量、温度、Top-p 等参数都会影响输出内容。\n\n- 模型：${body?.model_name || '未知'}\n- 端口：${body?.port || '-'}\n- 参数：temperature=${body?.temperature ?? 0.7}, max_tokens=${body?.max_tokens ?? 2048}`
    return ok({ response: answer, content: answer })
  }
  if (url === '/model-compare/stream-chat' && method === 'post') {
    // 模拟流式对话（前端 useStreamChat 会按块读取）
    const userQ = body?.user_question || ''
    const sysPrompt = body?.system_prompt || ''
    const answer = `${sysPrompt ? '【系统提示】' + sysPrompt.slice(0, 50) + '\n\n' : ''}关于「${userQ}」的回答：\n\n这是一段**模拟流式输出**。在真实部署中，后端会通过 SSE/WebSocket 逐字推送 token。\n\n## 模型参数\n- 温度（temperature）：${body?.temperature ?? 0.7}\n- 最大长度（max_tokens）：${body?.max_tokens ?? 2048}\n\n## 思考过程\n让我先分析这个问题...\n- 识别用户意图\n- 检索相关知识\n- 生成回答\n\n回答已生成。以上为前端 Mock 演示内容。`
    return ok({ response: answer })
  }
  if (url === '/model-compare/test-stream' && method === 'post') {
    return ok({ response: '测试流式输出' })
  }
  if (url === '/model-chat/batch' && method === 'post') return ok({ responses: [] })
  if (url === '/model-chat/local/chat' && method === 'post') return ok({ response: '本地模型回复' })
  if (url === '/model-chat/local/preload' && method === 'post') return ok({ loaded: true })
  if (url === '/model-chat/trained/preload' && method === 'post') return ok({ loaded: true })

  // ==================== 模型评测 ====================
  if (url === '/model-eval' && method === 'get') return ok(mockEvalList)
  if (url === '/model-eval' && method === 'delete') return ok({ deleted: true })
  if (url === '/model-eval/start' && method === 'post') return ok({ task_id: Math.floor(Math.random() * 1000) + 1 })
  m = url.match(/^\/model-eval\/([^/]+)$/)
  const evalTaskId = m?.[1]
  if (evalTaskId && method === 'get') {
    const found = mockEvalDetails.find((item) => String(item.id) === evalTaskId)
    return found ? ok(found) : fail('评测任务不存在', 404)
  }
  if (url === '/dimension' && method === 'get') return ok(mockDimensions)
  if (url === '/dimension' && method === 'post') {
    return ok({ id: Math.floor(Math.random() * 1000) + 100 })
  }
  m = url.match(/^\/dimension\/([^/]+)$/)
  if (m && method === 'get') {
    const found = mockDimensions.find((x) => String(x.id) === m[1])
    return found ? ok(found) : fail('维度不存在', 404)
  }
  if (m && (method === 'put' || method === 'delete')) {
    return ok({ id: m[1] })
  }

  // ==================== 日志 ====================
  if (url === '/log-files' && method === 'get') return ok(mockLogFiles)
  if (url === '/log-content' && method === 'get') return ok(mockLogContent)
  if (url === '/training-log-files' && method === 'get') return ok(mockTrainingLogFiles)
  if (url === '/training-log-content' && method === 'get') {
    const file = String(params.file || '')
    return ok(mockTrainingLogContents[file] || {
      file,
      size: '0 KB',
      content: `[Mock] 未找到训练日志内容：${file}`,
    })
  }

  // 未匹配的请求 → 兜底返回空成功（避免阻断 UI）
  console.warn('[Mock] 未匹配路由:', method.toUpperCase(), url, params)
  return ok({ mocked: true, url, method, params, body })
}

function safeJSON(str: string) {
  try {
    return JSON.parse(str)
  } catch {
    return {}
  }
}

/** 给 axios instance 安装 mock adapter */
export function installMockAdapter(instance: AxiosInstance) {
  const adapter = async (config: AxiosRequestConfig) => {
    try {
      const response = await handleMock(config)
      return response
    } catch (error: unknown) {
      return fail(error instanceof Error ? error.message : 'Mock 错误', 500, config)
    }
  }
  instance.defaults.adapter = adapter as AxiosAdapter
}