import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:tm_app/core/theme/colors.dart';
import 'package:tm_app/core/utils/date_utils.dart';
import 'package:tm_app/data/services/model/tender_submission/tender_submission.dart';
import 'package:tm_app/view_models/your_tenders_view_model.dart';

class SubmissionWorkflow extends StatelessWidget {
  const SubmissionWorkflow({super.key});

  static const _stageLabels = <String, String>{
    'opportunity': 'Opportunity',
    'in_progress': 'In Progress',
    'submitted': 'Submitted',
    'not_applied': 'Not Applied',
  };

  @override
  Widget build(BuildContext context) {
    return Consumer<YourTendersViewModel>(
      builder: (context, viewModel, _) {
        final submissions = viewModel.submissionsData?.data ?? const [];
        return Column(
          children: [
            SizedBox(
              height: 54,
              child: ListView(
                scrollDirection: Axis.horizontal,
                padding: const EdgeInsets.symmetric(
                  horizontal: 16,
                  vertical: 6,
                ),
                children:
                    YourTendersViewModel.submissionStages.map((stage) {
                      final selected =
                          viewModel.selectedSubmissionStage == stage;
                      final count =
                          viewModel.submissionStats?.byStage[stage] ?? 0;
                      return Padding(
                        padding: const EdgeInsets.only(right: 8),
                        child: ChoiceChip(
                          selected: selected,
                          onSelected:
                              (_) => viewModel.selectSubmissionStage(stage),
                          label: Text('${_stageLabels[stage]} ($count)'),
                          selectedColor: AppColors.secondary20,
                          side: BorderSide(
                            color:
                                selected
                                    ? AppColors.secondary50
                                    : AppColors.grey30,
                          ),
                        ),
                      );
                    }).toList(),
              ),
            ),
            if (viewModel.submissionActionError != null)
              Container(
                width: double.infinity,
                margin: const EdgeInsets.fromLTRB(16, 4, 16, 4),
                padding: const EdgeInsets.fromLTRB(12, 8, 4, 8),
                decoration: BoxDecoration(
                  color: AppColors.red0,
                  border: Border.all(color: AppColors.red10),
                  borderRadius: BorderRadius.circular(8),
                ),
                child: Row(
                  children: [
                    Icon(Icons.error_outline, color: AppColors.error, size: 18),
                    const SizedBox(width: 8),
                    Expanded(
                      child: Text(
                        viewModel.submissionActionError!,
                        style: TextStyle(color: AppColors.error, fontSize: 12),
                      ),
                    ),
                    IconButton(
                      visualDensity: VisualDensity.compact,
                      onPressed: viewModel.dismissSubmissionActionError,
                      icon: const Icon(Icons.close, size: 18),
                    ),
                  ],
                ),
              ),
            if (viewModel.isLoading && submissions.isEmpty)
              const Expanded(
                child: Center(
                  child: CircularProgressIndicator(
                    color: AppColors.secondary50,
                  ),
                ),
              )
            else if (submissions.isEmpty)
              Expanded(
                child: Center(
                  child: Text(
                    'No ${_stageLabels[viewModel.selectedSubmissionStage]?.toLowerCase()} submissions.',
                    style: TextStyle(color: AppColors.grey60),
                  ),
                ),
              )
            else
              Expanded(
                child: RefreshIndicator(
                  onRefresh: viewModel.loadSubmissions,
                  child: ListView.builder(
                    physics: const AlwaysScrollableScrollPhysics(),
                    padding: const EdgeInsets.fromLTRB(16, 8, 16, 24),
                    itemCount: submissions.length,
                    itemBuilder:
                        (context, index) =>
                            _SubmissionCard(submission: submissions[index]),
                  ),
                ),
              ),
            if ((viewModel.submissionsData?.meta?.pages ?? 1) > 1)
              Padding(
                padding: const EdgeInsets.fromLTRB(16, 0, 16, 12),
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    IconButton(
                      tooltip: 'Previous page',
                      onPressed:
                          viewModel.currentPage > 1 && !viewModel.isLoading
                              ? () => viewModel.jumpToPage(
                                viewModel.currentPage - 1,
                              )
                              : null,
                      icon: const Icon(Icons.chevron_left),
                    ),
                    Text(
                      'Page ${viewModel.currentPage} of ${viewModel.totalPages}',
                      style: TextStyle(color: AppColors.grey60),
                    ),
                    IconButton(
                      tooltip: 'Next page',
                      onPressed:
                          viewModel.currentPage < viewModel.totalPages &&
                                  !viewModel.isLoading
                              ? () => viewModel.jumpToPage(
                                viewModel.currentPage + 1,
                              )
                              : null,
                      icon: const Icon(Icons.chevron_right),
                    ),
                  ],
                ),
              ),
          ],
        );
      },
    );
  }
}

class _SubmissionCard extends StatelessWidget {
  const _SubmissionCard({required this.submission});

  final TenderSubmission submission;

  static const _statusLabels = <String, String>{
    'opportunity': 'Opportunity',
    'validating': 'Validating',
    'partner_pending': 'Partner Pending',
    'applying': 'Applying',
    'sent_waiting': 'Sent / Waiting',
    'rejected': 'Lost',
    'contract': 'Contract Awarded',
    'not_applied': 'Not Applied',
  };

  @override
  Widget build(BuildContext context) {
    final viewModel = context.watch<YourTendersViewModel>();
    final tender = submission.tender;
    final busy = viewModel.updatingSubmissionId == submission.id;
    final deadline = tender?.submissionDeadline ?? tender?.tenderDeadline;

    return Card(
      color: AppColors.cardBackground,
      elevation: 0,
      margin: const EdgeInsets.only(bottom: 12),
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(12),
        side: BorderSide(color: AppColors.borderColor),
      ),
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Expanded(
                  child: Text(
                    tender?.title?.trim().isNotEmpty == true
                        ? tender!.title!
                        : 'Tender ${submission.tenderId}',
                    style: TextStyle(
                      color: AppColors.grey80,
                      fontSize: 16,
                      fontWeight: FontWeight.w600,
                    ),
                  ),
                ),
                const SizedBox(width: 12),
                _StatusBadge(
                  label: _statusLabels[submission.status] ?? submission.status,
                  status: submission.status,
                ),
              ],
            ),
            if (tender?.description?.trim().isNotEmpty == true) ...[
              const SizedBox(height: 8),
              Text(
                tender!.description!,
                maxLines: 2,
                overflow: TextOverflow.ellipsis,
                style: TextStyle(color: AppColors.grey70, height: 1.4),
              ),
            ],
            const SizedBox(height: 12),
            Wrap(
              spacing: 16,
              runSpacing: 6,
              children: [
                if (tender?.countryCode?.isNotEmpty == true)
                  _Meta(
                    icon: Icons.location_on_outlined,
                    text: tender!.countryCode!,
                  ),
                if (deadline != null)
                  _Meta(
                    icon: Icons.event_outlined,
                    text: 'Deadline ${timeConvertor(deadline)}',
                  ),
                if (tender?.buyerOrganization?.name?.isNotEmpty == true)
                  _Meta(
                    icon: Icons.business_outlined,
                    text: tender!.buyerOrganization!.name!,
                  ),
              ],
            ),
            if (submission.statusHistory.isNotEmpty) ...[
              const SizedBox(height: 4),
              ExpansionTile(
                tilePadding: EdgeInsets.zero,
                childrenPadding: EdgeInsets.zero,
                dense: true,
                title: Text(
                  'Activity (${submission.statusHistory.length})',
                  style: TextStyle(color: AppColors.grey60, fontSize: 13),
                ),
                children:
                    submission.statusHistory.reversed
                        .map(
                          (item) => ListTile(
                            dense: true,
                            contentPadding: EdgeInsets.zero,
                            leading: const Icon(Icons.circle, size: 8),
                            title: Text(
                              _statusLabels[item.status] ?? item.status,
                              style: TextStyle(color: AppColors.grey80),
                            ),
                            subtitle: Text(
                              [
                                timeConvertor(item.changedAt, hasTime: true),
                                if (item.description?.isNotEmpty == true)
                                  item.description!,
                                if (item.reason?.isNotEmpty == true)
                                  item.reason!,
                              ].join(' · '),
                            ),
                          ),
                        )
                        .toList(),
              ),
            ],
            if (!submission.isTerminal) ...[
              const SizedBox(height: 12),
              if (busy)
                const LinearProgressIndicator(color: AppColors.secondary50)
              else
                _Actions(submission: submission),
            ],
          ],
        ),
      ),
    );
  }
}

class _Actions extends StatelessWidget {
  const _Actions({required this.submission});

  final TenderSubmission submission;

  @override
  Widget build(BuildContext context) {
    final primary = <({String label, String status, String description})>[];
    switch (submission.status) {
      case 'opportunity':
        primary.add((
          label: 'Start validation',
          status: 'validating',
          description: 'User accepted tender',
        ));
      case 'validating':
        if (submission.submissionMode == 'partnership') {
          primary.add((
            label: 'Wait for partner',
            status: 'partner_pending',
            description: 'Validation completed; waiting for partner documents',
          ));
        } else if (submission.submissionMode == 'self-apply') {
          primary.add((
            label: 'Start applying',
            status: 'applying',
            description: 'Validation completed',
          ));
        } else {
          primary.addAll([
            (
              label: 'Start applying',
              status: 'applying',
              description: 'Validation completed',
            ),
            (
              label: 'Wait for partner',
              status: 'partner_pending',
              description:
                  'Validation completed; waiting for partner documents',
            ),
          ]);
        }
      case 'partner_pending':
        primary.add((
          label: 'Partner docs ready',
          status: 'applying',
          description: 'Partner documents received',
        ));
      case 'applying':
        primary.add((
          label: 'Submitted to buyer',
          status: 'sent_waiting',
          description: 'Application filed with procurement authority',
        ));
      case 'sent_waiting':
        primary.addAll([
          (
            label: 'Mark won',
            status: 'contract',
            description: 'Contract awarded',
          ),
          (
            label: 'Mark lost',
            status: 'rejected',
            description: 'Buyer rejected bid',
          ),
        ]);
    }

    return Wrap(
      spacing: 8,
      runSpacing: 8,
      children: [
        for (final action in primary)
          FilledButton(
            onPressed:
                () => _confirmUpdate(
                  context,
                  status: action.status,
                  label: action.label,
                  description: action.description,
                ),
            style: FilledButton.styleFrom(
              backgroundColor: AppColors.secondary50,
            ),
            child: Text(action.label),
          ),
        if (submission.status != 'sent_waiting')
          OutlinedButton(
            onPressed: () => _reject(context),
            style: OutlinedButton.styleFrom(foregroundColor: AppColors.error),
            child: const Text('Do not apply'),
          ),
      ],
    );
  }

  Future<void> _confirmUpdate(
    BuildContext context, {
    required String status,
    required String label,
    required String description,
  }) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder:
          (dialogContext) => AlertDialog(
            title: Text(label),
            content: const Text('Update this tender submission?'),
            actions: [
              TextButton(
                onPressed: () => Navigator.pop(dialogContext, false),
                child: const Text('Cancel'),
              ),
              FilledButton(
                onPressed: () => Navigator.pop(dialogContext, true),
                child: const Text('Confirm'),
              ),
            ],
          ),
    );
    if (confirmed == true && context.mounted) {
      await context.read<YourTendersViewModel>().updateSubmissionStatus(
        submission: submission,
        status: status,
        description: description,
      );
    }
  }

  Future<void> _reject(BuildContext context) async {
    final controller = TextEditingController();
    final reason = await showDialog<String>(
      context: context,
      builder:
          (dialogContext) => AlertDialog(
            title: const Text('Do not apply'),
            content: TextField(
              controller: controller,
              maxLength: 500,
              maxLines: 3,
              decoration: const InputDecoration(
                labelText: 'Reason (optional)',
                border: OutlineInputBorder(),
              ),
            ),
            actions: [
              TextButton(
                onPressed: () => Navigator.pop(dialogContext),
                child: const Text('Cancel'),
              ),
              FilledButton(
                onPressed: () => Navigator.pop(dialogContext, controller.text),
                child: const Text('Confirm'),
              ),
            ],
          ),
    );
    controller.dispose();
    if (reason != null && context.mounted) {
      await context.read<YourTendersViewModel>().updateSubmissionStatus(
        submission: submission,
        status: 'not_applied',
        reason: reason,
      );
    }
  }
}

class _StatusBadge extends StatelessWidget {
  const _StatusBadge({required this.label, required this.status});
  final String label;
  final String status;

  @override
  Widget build(BuildContext context) {
    final terminal = status == 'rejected' || status == 'not_applied';
    final won = status == 'contract';
    final color =
        terminal
            ? AppColors.error
            : (won ? AppColors.green30 : AppColors.blue10);
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 5),
      decoration: BoxDecoration(
        color: color.withValues(alpha: .12),
        borderRadius: BorderRadius.circular(20),
      ),
      child: Text(
        label,
        style: TextStyle(
          color: color,
          fontSize: 12,
          fontWeight: FontWeight.w600,
        ),
      ),
    );
  }
}

class _Meta extends StatelessWidget {
  const _Meta({required this.icon, required this.text});
  final IconData icon;
  final String text;

  @override
  Widget build(BuildContext context) => Row(
    mainAxisSize: MainAxisSize.min,
    children: [
      Icon(icon, size: 16, color: AppColors.grey60),
      const SizedBox(width: 4),
      Text(text, style: TextStyle(color: AppColors.grey60, fontSize: 12)),
    ],
  );
}