/*
 * AgentMail 鸿蒙客户端 — 会话列表页
 * GET /me/sessions 展示所有会话摘要
 */
import { ApiClient, ApiError } from '../api/ApiClient';
import { Theme } from '../common/Theme';
import { MailApi } from '../api/MailApi';
import { Session } from '../model/Models';

@Entry
@Component
struct SessionsPage {
  @State sessions: Session[] = [];
  @State loading: boolean = false;
  @State error: string = '';

  private client: ApiClient | null = null;
  private mailApi: MailApi | null = null;

  aboutToAppear(): void {
    const ctx = this.getUIContext().getHostContext();
    if (ctx !== undefined) {
      const client: ApiClient = ApiClient.getInstance(ctx);
      this.client = client;
      this.mailApi = new MailApi(client);
      this.loadSessions();
    }
  }

  async loadSessions(): Promise<void> {
    const m: MailApi | null = this.mailApi;
    if (m === null) {
      return;
    }
    this.loading = true;
    this.error = '';
    try {
      const resp = await m.sessions();
      this.sessions = resp.sessions;
    } catch (e) {
      const ae = e as ApiError;
      this.error = ae.code === 0 ? ae.message : '加载失败';
    } finally {
      this.loading = false;
    }
  }

  build() {
    Column() {
      // 顶栏
      Row() {
        Text('会话')
          .fontSize(20).fontWeight(FontWeight.Bold).fontColor(Theme.textPrimary)
      }
      .width('100%').height(56)
      .padding({ left: 16 })
      .backgroundColor(Theme.surface)

      if (this.loading) {
        Column() {
          LoadingProgress().width(40).height(40)
          Text('加载中…').fontSize(14).fontColor(Theme.textSubtle).margin({ top: 8 })
        }
        .width('100%').layoutWeight(1)
        .justifyContent(FlexAlign.Center)
      } else if (this.error.length > 0) {
        Column() {
          Text(this.error).fontSize(14).fontColor(Theme.danger)
          Button('重试').margin({ top: 12 }).onClick(() => { this.loadSessions(); })
        }
        .width('100%').layoutWeight(1)
        .justifyContent(FlexAlign.Center)
      } else if (this.sessions.length === 0) {
        Column() {
          Text('📭 暂无会话').fontSize(16).fontColor(Theme.textSubtle)
        }
        .width('100%').layoutWeight(1)
        .justifyContent(FlexAlign.Center)
      } else {
        List({ space: 1 }) {
          ForEach(this.sessions, (s: Session) => {
            ListItem() {
              this.SessionItem(s)
            }
            .height(90)
          }, (s: Session) => s.session_id)
        }
        .width('100%').layoutWeight(1)
        .divider({ strokeWidth: 1, color: Theme.border, startMargin: 16, endMargin: 16 })
      }

      // 底栏
      Row() {
        Text('共 ' + this.sessions.length + ' 个会话').fontSize(12).fontColor(Theme.textSubtle)
      }
      .width('100%').height(40).padding({ left: 16 })
      .backgroundColor(Theme.surface)
    }
    .width('100%').height('100%')
    .backgroundColor(Theme.pageBg)
  }

  @Builder
  SessionItem(s: Session) {
    Row() {
      Column() {
        Row() {
          Text(s.session_alias.length > 0 ? s.session_alias : s.subject)
            .fontSize(14).fontWeight(FontWeight.Bold).fontColor(Theme.textPrimary)
            .maxLines(1).textOverflow({ overflow: TextOverflow.Ellipsis })
            .layoutWeight(1)

          // 预算进度
          if (s.max_rounds > 0) {
            Text(s.used_rounds + '/' + s.max_rounds)
              .fontSize(11).fontColor(s.used_rounds >= s.max_rounds ? Theme.danger : Theme.textMuted)
              .backgroundColor(s.used_rounds >= s.max_rounds ? Theme.dangerBg : Theme.surfaceMuted)
              .borderRadius(4).padding({ left: 4, right: 4, top: 1, bottom: 1 })
          }

          // 未读
          if (s.unread_count > 0) {
            Text(s.unread_count + '')
              .fontSize(11).fontColor(Theme.surface)
              .backgroundColor(Theme.danger)
              .borderRadius(10).width(20).height(20)
              .textAlign(TextAlign.Center)
              .margin({ left: 6 })
          }
        }
        .width('100%')

        Text('对方: ' + s.from_agent).fontSize(12).fontColor(Theme.textMuted).margin({ top: 4 })

        Row() {
          Text(s.permission_mode.length > 0 ? s.permission_mode : '—')
            .fontSize(11).fontColor(Theme.textMuted)
            .backgroundColor(Theme.border).borderRadius(4)
            .padding({ left: 4, right: 4, top: 1, bottom: 1 })
          Blank()
          Text(s.mail_count + ' 封').fontSize(11).fontColor(Theme.textSubtle)
          Text(' · ' + s.status).fontSize(11).fontColor(s.status === 'active' ? Theme.approve : Theme.textSubtle)
        }
        .width('100%').margin({ top: 4 })
      }
      .layoutWeight(1).height('100%')
      .alignItems(HorizontalAlign.Start)
      .justifyContent(FlexAlign.SpaceBetween)
    }
    .width('100%').height('100%')
    .padding({ left: 16, right: 16, top: 12, bottom: 12 })
    .alignItems(VerticalAlign.Center)
  }
}