/**
 * LoginPage（F1）—— dev-token 开发登录页。
 *
 * 闭环：设备标识（随机生成一次并持久化，可改）→ AuthStore.loginByDevToken
 *   → 成功 router.replaceUrl HomePage；失败 catch ApiError 展示 message+hint。
 * 高级设置：折叠区编辑 baseUrl（AuthStore.setBaseUrl），真机连开发机靠它。
 * 已登录态进入本页：aboutToAppear 直接跳 HomePage。
 *
 * ArkTS 约束（对齐 core/AuthStore 风格）：
 *  - 泛型调用显式类型参数；未知异常统一包 ApiError（本页只展示不抛出）
 *  - async 逻辑放具名方法，build 内只留 UI 与点击回调
 */

import router from '@ohos.router'
import preferences from '@ohos.data.preferences'
import { ApiError } from '../core/ApiTypes'
import { AuthStore, DEFAULT_BASE_URL } from '../core/AuthStore'
import { ContextHolder } from '../core/ContextHolder'
import { ErrorBanner } from '../components/f1/ErrorBanner'

const PREF_NAME_LOGIN = 'meida_login'
const KEY_DEVICE_KEY = 'device_key'
const COLOR_PRIMARY = '#C2185B'

/** 随机设备标识：dev- + 16 位 hex，生成一次后随 preferences 持久化。 */
function generateDeviceKey(): string {
  const chars = '0123456789abcdef'
  let suffix = ''
  for (let i = 0; i < 16; i++) {
    suffix += chars.charAt(Math.floor(Math.random() * chars.length))
  }
  return `dev-${suffix}`
}

/** 未知异常统一包 ApiError（与 ApiClient.wrapUnknown 同一话术）。 */
function toApiError(e: Object): ApiError {
  if (e instanceof ApiError) {
    return e
  }
  return new ApiError(50000, '请求失败，请检查网络', '请稍后重试')
}

@Entry
@Component
struct LoginPage {
  @State deviceKey: string = ''
  @State baseUrlInput: string = ''
  @State showAdvanced: boolean = false
  @State logging: boolean = false
  @State savingUrl: boolean = false
  @State errMessage: string = ''
  @State errHint: string = ''
  @State savedTip: string = ''

  aboutToAppear(): void {
    this.bootstrap()
  }

  /** 具名 async 初始化：确保令牌已载入 → 已登录直跳 → 回填设备标识与地址。 */
  private async bootstrap(): Promise<void> {
    try {
      await AuthStore.init()
    } catch (_e) {
      // onCreate 里已 fire-and-forget 初始化过，这里重复 init 失败不影响
    }
    if (AuthStore.isLoggedIn()) {
      router.replaceUrl({ url: 'pages/HomePage' })
      return
    }
    try {
      const prefs = await preferences.getPreferences(ContextHolder.get(), { name: PREF_NAME_LOGIN })
      const saved = await prefs.get(KEY_DEVICE_KEY, '') as string
      if (saved !== '') {
        this.deviceKey = saved
      } else {
        this.deviceKey = generateDeviceKey()
        await prefs.put(KEY_DEVICE_KEY, this.deviceKey)
        await prefs.flush()
      }
    } catch (_e) {
      this.deviceKey = generateDeviceKey()
    }
    this.baseUrlInput = await AuthStore.getBaseUrl()
  }

  /** 登录主流程：校验 → loading → dev-token → 跳首页；失败横幅展示。 */
  private async doLogin(): Promise<void> {
    if (this.logging) {
      return
    }
    const key = this.deviceKey.trim()
    this.errMessage = ''
    this.errHint = ''
    this.savedTip = ''
    if (key === '') {
      this.errMessage = '请先填写设备标识'
      this.errHint = '可点「随机生成」重新生成一个'
      return
    }
    this.logging = true
    this.persistDeviceKey(key)
    try {
      await AuthStore.loginByDevToken(key)
      router.replaceUrl({ url: 'pages/HomePage' })
    } catch (e) {
      const err = toApiError(e)
      this.errMessage = err.message
      this.errHint = err.hint !== undefined ? err.hint : ''
    } finally {
      this.logging = false
    }
  }

  /** 设备标识持久化失败不阻塞登录。 */
  private async persistDeviceKey(key: string): Promise<void> {
    try {
      const prefs = await preferences.getPreferences(ContextHolder.get(), { name: PREF_NAME_LOGIN })
      await prefs.put(KEY_DEVICE_KEY, key)
      await prefs.flush()
    } catch (_e) {
      // 忽略：仅影响下次回填
    }
  }

  private async saveBaseUrl(): Promise<void> {
    const url = this.baseUrlInput.trim()
    this.savedTip = ''
    if (url === '') {
      this.errMessage = '服务器地址不能为空'
      this.errHint = '示例：http://192.168.1.100:8000'
      return
    }
    if (!url.startsWith('http://') && !url.startsWith('https://')) {
      this.errMessage = '地址需以 http:// 或 https:// 开头'
      this.errHint = '示例：http://192.168.1.100:8000'
      return
    }
    this.savingUrl = true
    try {
      await AuthStore.setBaseUrl(url)
      this.errMessage = ''
      this.errHint = ''
      this.savedTip = '已保存'
    } catch (_e) {
      this.errMessage = '保存失败，请重试'
      this.errHint = ''
    } finally {
      this.savingUrl = false
    }
  }

  private async resetBaseUrl(): Promise<void> {
    this.savingUrl = true
    try {
      await AuthStore.setBaseUrl(DEFAULT_BASE_URL)
      this.baseUrlInput = DEFAULT_BASE_URL
      this.savedTip = '已恢复默认'
    } catch (_e) {
      this.errMessage = '保存失败，请重试'
      this.errHint = ''
    } finally {
      this.savingUrl = false
    }
  }

  private regenDeviceKey(): void {
    this.deviceKey = generateDeviceKey()
    this.errMessage = ''
    this.errHint = ''
  }

  build() {
    Column() {
      Scroll() {
        Column({ space: 22 }) {
          // 品牌区
          Column({ space: 10 }) {
            Text('美搭')
              .fontSize(48)
              .fontWeight(FontWeight.Bold)
              .fontColor(COLOR_PRIMARY)
              .letterSpacing(6)
            Text('AI 穿搭美学助手 · 每天三分钟，搭出好气质')
              .fontSize(14)
              .fontColor('#8A8A8A')
          }
          .margin({ top: 72, bottom: 8 })

          // 设备标识
          Column({ space: 8 }) {
            Row({ space: 8 }) {
              Text('设备标识')
                .fontSize(14)
                .fontWeight(FontWeight.Medium)
                .fontColor('#2B2B2B')
              Blank()
              Text('随机生成')
                .fontSize(13)
                .fontColor(COLOR_PRIMARY)
                .padding({ left: 8, right: 8, top: 4, bottom: 4 })
                .borderRadius(12)
                .backgroundColor('#F7E3EA')
                .onClick(() => this.regenDeviceKey())
            }
            .width('100%')

            TextInput({ text: this.deviceKey, placeholder: 'dev-xxxxxxxxxxxxxxxx' })
              .height(48)
              .fontSize(15)
              .borderRadius(12)
              .backgroundColor('#FFFFFF')
              .padding({ left: 14, right: 14 })
              .onChange((value: string) => {
                this.deviceKey = value
              })

            Text('同一标识对应同一账号与配额，换标识即换新用户')
              .fontSize(11)
              .fontColor('#B3B3B3')
          }
          .width('100%')

          // 高级设置（服务器地址，真机连开发机靠它）
          Column({ space: 10 }) {
            Row() {
              Text('高级设置 · 服务器地址')
                .fontSize(14)
                .fontWeight(FontWeight.Medium)
                .fontColor('#2B2B2B')
              Blank()
              Text(this.showAdvanced ? '收起' : '展开')
                .fontSize(13)
                .fontColor(COLOR_PRIMARY)
            }
            .width('100%')
            .onClick(() => {
              this.showAdvanced = !this.showAdvanced
              this.savedTip = ''
            })

            if (this.showAdvanced) {
              Column({ space: 8 }) {
                TextInput({ text: this.baseUrlInput, placeholder: DEFAULT_BASE_URL })
                  .height(46)
                  .fontSize(14)
                  .borderRadius(12)
                  .backgroundColor('#FFFFFF')
                  .padding({ left: 14, right: 14 })
                  .onChange((value: string) => {
                    this.baseUrlInput = value
                  })

                Row({ space: 10 }) {
                  Button(this.savingUrl ? '保存中…' : '保存地址')
                    .fontSize(14)
                    .height(38)
                    .borderRadius(19)
                    .backgroundColor(COLOR_PRIMARY)
                    .fontColor('#FFFFFF')
                    .enabled(!this.savingUrl)
                    .onClick(() => this.saveBaseUrl())

                  Button('恢复默认')
                    .fontSize(14)
                    .height(38)
                    .borderRadius(19)
                    .backgroundColor('#F0E0E6')
                    .fontColor(COLOR_PRIMARY)
                    .enabled(!this.savingUrl)
                    .onClick(() => this.resetBaseUrl())

                  if (this.savedTip !== '') {
                    Text(this.savedTip)
                      .fontSize(13)
                      .fontColor('#2E9E5B')
                  }
                }
                .width('100%')

                Text('模拟器直连本机可用默认地址；真机请填开发机局域网 IP（如 http://192.168.1.100:8000）')
                  .fontSize(11)
                  .fontColor('#B3B3B3')
              }
              .width('100%')
              .padding({ top: 4 })
            }
          }
          .width('100%')
          .padding(14)
          .borderRadius(16)
          .backgroundColor('#FFFFFF')

          // 登录按钮
          Button(this.logging ? '正在进入…' : '进入美搭')
            .width('100%')
            .height(50)
            .fontSize(17)
            .fontWeight(FontWeight.Medium)
            .borderRadius(25)
            .backgroundColor(COLOR_PRIMARY)
            .fontColor('#FFFFFF')
            .enabled(!this.logging && this.deviceKey.trim() !== '')
            .onClick(() => this.doLogin())

          // 错误横幅（登录/地址保存失败）
          ErrorBanner({
            message: this.errMessage,
            hint: this.errHint,
            onClose: () => {
              this.errMessage = ''
              this.errHint = ''
            }
          })
        }
        .width('100%')
        .padding({ left: 24, right: 24, bottom: 32 })
        .constraintSize({ minHeight: '100%' })
        .justifyContent(FlexAlign.Center)
      }
      .scrollBar(BarState.Off)
      .edgeEffect(EdgeEffect.Spring)
      .layoutWeight(1)
    }
    .width('100%')
    .height('100%')
    .backgroundColor('#F7F2F4')
  }
}