import 'dart:io';

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 'generate_result_screen.dart';

/// `YoZaK` 生成中 — 与 EYsUi 同款顶栏结构，标题「生成中」。
class GenerateProgressScreen extends StatefulWidget {
  const GenerateProgressScreen({
    super.key,
    required this.taskId,
    this.localPreviewPath,
  });

  final String taskId;
  final String? localPreviewPath;

  @override
  State<GenerateProgressScreen> createState() => _GenerateProgressScreenState();
}

class _GenerateProgressScreenState extends State<GenerateProgressScreen> {
  ImageProgressPollHandle? _pollHandle;
  String _status = '';
  int _progress = 0;
  String? _resultUrl;
  String? _error;
  bool _navigated = false;

  @override
  void initState() {
    super.initState();
    _pollHandle = ImageProgressPoll.start(
      app: currentBackendAppType(),
      taskId: widget.taskId,
      userId: UserState.userId.value,
      interval: const Duration(seconds: 5),
      onTick: _onProgressTick,
      onTransientNetworkFailure: (n, max) {
        if (!mounted || _navigated) return;
        setState(() {
          _status = 'Reconnecting… ($n/$max)';
        });
      },
      onFatalError: (msg) {
        if (!mounted || _navigated) return;
        setState(() => _error = msg);
      },
    );
  }

  void _onProgressTick(ProgressPollTick tick) {
    if (!mounted || _navigated) return;
    final res = tick.response;
    if (!res.isSuccess || res.data == null) {
      setState(() => _error = res.msg.isNotEmpty ? res.msg : 'Progress error');
      return;
    }
    final p = res.data!;
    setState(() {
      _status = p.status ?? '';
      _progress = p.progress ?? 0;
      _resultUrl = p.resultUrl;
    });

    final doneSuccess = ProgressPollSemantics.isSuccessTerminal(p.status) ||
        ProgressPollSemantics.hasUsableResultUrl(p.resultUrl);
    if (doneSuccess) {
      _navigated = true;
      _pollHandle?.cancel();
      Navigator.of(context).pushReplacement(
        MaterialPageRoute<void>(
          builder: (_) => GenerateResultScreen(
            taskId: widget.taskId,
            resultUrl: _resultUrl ?? '',
          ),
        ),
      );
      return;
    }

    if (ProgressPollSemantics.isTerminalStatus(p.status) &&
        ProgressPollSemantics.isFailureTerminal(p.status)) {
      setState(() => _error ??= 'Task failed (${p.status})');
    }
  }

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

  @override
  Widget build(BuildContext context) {
    return Container(
      decoration: const BoxDecoration(
        gradient: PencilTheme.yellowWhitePageGradient,
      ),
      child: Scaffold(
        backgroundColor: Colors.transparent,
        body: SafeArea(
          bottom: false,
          child: Column(
            children: [
              Padding(
                padding: const EdgeInsets.fromLTRB(2, 0, 14, 10),
                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.all(24),
                  child: Column(
                    children: [
                      if (widget.localPreviewPath != null)
                        ClipRRect(
                          borderRadius: BorderRadius.circular(12),
                          child: AspectRatio(
                            aspectRatio: 1,
                            child: Image.file(
                              File(widget.localPreviewPath!),
                              fit: BoxFit.cover,
                            ),
                          ),
                        )
                      else
                        const SizedBox(height: 48),
                      const SizedBox(height: 24),
                      if (_error != null)
                        Text(
                          _error!,
                          style: GoogleFonts.inter(color: Colors.red),
                          textAlign: TextAlign.center,
                        )
                      else ...[
                        LinearProgressIndicator(
                          value: _progress > 0 ? _progress / 100 : null,
                          color: PencilTheme.underlineGold,
                        ),
                        const SizedBox(height: 16),
                        Text(
                          _status.isEmpty ? 'Processing…' : _status,
                          style: GoogleFonts.inter(color: PencilTheme.stone600),
                        ),
                        Text(
                          '$_progress%',
                          style: GoogleFonts.inter(
                            fontSize: 28,
                            fontWeight: FontWeight.w700,
                            color: PencilTheme.stone900,
                          ),
                        ),
                      ],
                    ],
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}