import 'package:client_proxy_framework/client_proxy_framework.dart';
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';

import '../../core/app_env.dart';
import '../../core/user/user_state.dart';
import '../../design/pencil_theme.dart';
import '../../widgets/pencil_chrome.dart';
import '../../widgets/pencil_yellow_white_background.dart';
import '../generate/generate_result_screen.dart';

/// 从 My History 点「生成中」任务进入：轮询 [ImageApi.getProgress]，完成后进入 [GenerateResultScreen]。
///
/// 与 app_client [GenerateProgressScreen] 行为对齐（权威数据源为 `/v1/image/progress`）。
class HistoryTaskProgressScreen extends StatefulWidget {
  const HistoryTaskProgressScreen({super.key, required this.taskId});

  final String taskId;

  @override
  State<HistoryTaskProgressScreen> createState() =>
      _HistoryTaskProgressScreenState();
}

class _HistoryTaskProgressScreenState extends State<HistoryTaskProgressScreen> {
  ImageProgressPollHandle? _pollHandle;
  String _genStatus = '';
  int _genProgress = 0;
  String? _genResultUrl;
  String? _genError;
  bool _navigated = false;

  @override
  void initState() {
    super.initState();
    _startPoll();
  }

  void _startPoll() {
    _pollHandle?.cancel();
    _pollHandle = ImageProgressPoll.start(
      app: currentBackendAppType(),
      taskId: widget.taskId,
      userId: UserState.userId.value,
      interval: const Duration(seconds: 5),
      onTick: _onTick,
      onFatalError: (msg) {
        if (!mounted || _navigated) return;
        setState(() => _genError = msg);
      },
    );
  }

  void _onTick(ProgressPollTick tick) {
    if (!mounted || _navigated) return;
    final res = tick.response;
    if (!res.isSuccess || res.data == null) {
      setState(() => _genError = res.msg.isNotEmpty ? res.msg : 'Progress error');
      return;
    }
    final p = res.data!;
    setState(() {
      _genError = null;
      _genStatus = p.status ?? '';
      _genProgress = p.progress ?? 0;
      _genResultUrl = p.resultUrl;
    });

    if (ProgressPollSemantics.isProgressSuccess(p)) {
      _navigated = true;
      _pollHandle?.cancel();
      _pollHandle = null;
      final url = _genResultUrl ?? '';
      Navigator.of(context).pushReplacement(
        MaterialPageRoute<void>(
          builder: (_) => GenerateResultScreen(
            taskId: widget.taskId,
            resultUrl: url,
          ),
        ),
      );
      return;
    }

    if (ProgressPollSemantics.isProgressFailure(p)) {
      _pollHandle?.cancel();
      _pollHandle = null;
      setState(() {
        _genError ??= 'Task failed (${p.status})';
      });
    }
  }

  @override
  void dispose() {
    _pollHandle?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return PencilYellowWhitePageBackground(
      child: Scaffold(
        backgroundColor: Colors.transparent,
        body: SafeArea(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              Padding(
                padding: const EdgeInsets.fromLTRB(2, 0, 14, 8),
                child: SizedBox(
                  height: 56,
                  child: Row(
                    children: [
                      PencilRoundBackButton(
                        onPressed: () => Navigator.of(context).pop(),
                      ),
                      Expanded(
                        child: Center(
                          child: Text(
                            'Generating',
                            style: GoogleFonts.inter(
                              fontSize: 19,
                              fontWeight: FontWeight.w700,
                              fontStyle: FontStyle.italic,
                              color: PencilTheme.stone900,
                            ),
                          ),
                        ),
                      ),
                      const SizedBox(width: 44),
                    ],
                  ),
                ),
              ),
              Expanded(
                child: Padding(
                  padding: const EdgeInsets.symmetric(horizontal: 24),
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      if (_genError != null) ...[
                        Text(
                          _genError!,
                          style: GoogleFonts.inter(color: Colors.red),
                          textAlign: TextAlign.center,
                        ),
                      ] else ...[
                        LinearProgressIndicator(
                          value: _genProgress > 0 ? _genProgress / 100 : null,
                          color: PencilTheme.underlineGold,
                        ),
                        const SizedBox(height: 16),
                        Text(
                          _genStatus.isEmpty ? 'Processing…' : _genStatus,
                          textAlign: TextAlign.center,
                          style: GoogleFonts.inter(
                            fontSize: 14,
                            color: PencilTheme.stone600,
                          ),
                        ),
                        Text(
                          '$_genProgress%',
                          textAlign: TextAlign.center,
                          style: GoogleFonts.inter(
                            fontSize: 28,
                            fontWeight: FontWeight.w700,
                            color: PencilTheme.stone900,
                          ),
                        ),
                      ],
                    ],
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}