import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../../models/programmer_day_sheet.model.dart';
import '../../../providers/profile_provider.dart';
import '../../../providers/programmer_day_data_provider.dart';
import '../../../providers/programmer_day_sheets_provider.dart';
import '../../../theme/app_status_colors.dart';
import '../../../utils/app_time.dart';
import '../../../utils/programmer_day_rows.dart';
import '../../../utils/programmer_task_ledger.dart';
import '../../../widgets/app_state_view.dart';
import '../../../widgets/app_status_summary.dart';
import '../../../widgets/status_pill.dart';
import '../report/accomplishment_report_dialog.dart';

/// Programmer-facing tab for managing personal day sheets.
///
/// Sections:
/// 1. **Today** — live work rows, total duration, sheet status and a
///    "Submit day" button (enabled when the sheet is missing/draft and there
///    is at least one logged row).
/// 2. **Needs your attention** — disapproved sheets waiting for justification.
/// 3. **History** — filterable list of past sheets
///    (All / Pending / Disapproved / Approved); tapping a card opens the
///    [DaySheetDetailScreen].
class DaySheetsTab extends ConsumerStatefulWidget {
  const DaySheetsTab({super.key});

  @override
  ConsumerState<DaySheetsTab> createState() => _DaySheetsTabState();
}

class _DaySheetsTabState extends ConsumerState<DaySheetsTab> {
  /// Null → show all history; or a [DaySheetStatus] constant to filter.
  String? _historyFilter;

  bool _submitting = false;

  // ---------------------------------------------------------------------------
  // Actions
  // ---------------------------------------------------------------------------

  Future<void> _submit(DateTime today) async {
    setState(() => _submitting = true);
    try {
      await ref.read(daySheetsControllerProvider).submit(today);
      if (!mounted) return;
      ScaffoldMessenger.of(context)
          .showSnackBar(const SnackBar(content: Text('Day submitted')));
    } on DaySheetActionException catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context)
          .showSnackBar(SnackBar(content: Text(e.message)));
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context)
          .showSnackBar(SnackBar(content: Text(e.toString())));
    } finally {
      if (mounted) setState(() => _submitting = false);
    }
  }

  // ---------------------------------------------------------------------------
  // Helpers
  // ---------------------------------------------------------------------------

  StatusKind _kindFor(String status) => switch (status) {
        DaySheetStatus.approved => StatusKind.success,
        DaySheetStatus.pending => StatusKind.info,
        DaySheetStatus.disapproved => StatusKind.warning,
        _ => StatusKind.neutral,
      };

  // ---------------------------------------------------------------------------
  // Build
  // ---------------------------------------------------------------------------

  @override
  Widget build(BuildContext context) {
    final userId = ref.watch(currentUserIdProvider);
    if (userId == null) {
      return const Center(child: CircularProgressIndicator());
    }

    final today = ref.watch(todayKeyProvider);
    final dayDataAsync = ref.watch(programmerDayDataProvider(today));
    final mySheetsAsync = ref.watch(myDaySheetsProvider);
    final profiles = ref.watch(profilesProvider).valueOrNull ?? const [];
    final profileNames = {for (final p in profiles) p.id: p.fullName};

    final mySheets = mySheetsAsync.valueOrNull ?? const [];

    // Today's sheet (if any) — compare UTC date keys.
    final todaySheet =
        mySheets.where((s) => s.workDate == today).firstOrNull;

    // Build live rows for today.
    final todayRows = dayDataAsync.when(
      data: (data) => buildDayRows(
        userId: userId,
        day: today,
        tasks: data.tasks,
        logsByTask: data.logsByTask,
        workLogs: data.workLogs,
        projectNames: const {},
        profileNames: profileNames,
        now: AppTime.now(),
      ),
      loading: () => const <DaySheetRow>[],
      error: (_, _) => const <DaySheetRow>[],
    );

    final todayTotal = Duration(seconds: totalSeconds(todayRows));
    final todayStatus = todaySheet?.status ?? DaySheetStatus.draft;
    final canSubmit =
        (todaySheet == null || todayStatus == DaySheetStatus.draft) &&
            todayRows.isNotEmpty;

    // Attention: disapproved sheets.
    final disapproved =
        mySheets.where((s) => s.status == DaySheetStatus.disapproved).toList();

    // History: past sheets (exclude today), optionally filtered by status.
    final history = mySheets.where((s) {
      if (s.workDate == today) return false;
      if (_historyFilter == null) return true;
      return s.status == _historyFilter;
    }).toList();

    // Counts for the history filter chips.
    final historyAll = mySheets.where((s) => s.workDate != today).toList();
    final countPending =
        historyAll.where((s) => s.status == DaySheetStatus.pending).length;
    final countDisapproved =
        historyAll.where((s) => s.status == DaySheetStatus.disapproved).length;
    final countApproved =
        historyAll.where((s) => s.status == DaySheetStatus.approved).length;

    return ListView(
      padding: const EdgeInsets.all(16),
      children: [
        // ── Report action ──────────────────────────────────────────────────
        Align(
          alignment: Alignment.centerRight,
          child: IconButton(
            icon: const Icon(Icons.description_outlined),
            tooltip: 'Accomplishment Report',
            onPressed: () => showAccomplishmentReportDialog(context, ref),
          ),
        ),

        // ── Today card ─────────────────────────────────────────────────────
        _TodayCard(
          total: todayTotal,
          status: todayStatus,
          statusKind: _kindFor(todayStatus),
          canSubmit: canSubmit,
          submitting: _submitting,
          onSubmit: () => _submit(today),
          onTap: todaySheet != null
              ? () => context.pushNamed(
                    'daySheetDetail',
                    pathParameters: {'id': todaySheet.id},
                  )
              : null,
        ),

        const SizedBox(height: 20),

        // ── Needs your attention ──────────────────────────────────────────
        if (disapproved.isNotEmpty) ...[
          Text(
            'Needs your attention',
            style: Theme.of(context).textTheme.titleSmall,
          ),
          const SizedBox(height: 8),
          for (final sheet in disapproved)
            _SheetHistoryTile(
              sheet: sheet,
              statusKind: _kindFor(sheet.status),
              onTap: () => context.pushNamed(
                'daySheetDetail',
                pathParameters: {'id': sheet.id},
              ),
            ),
          const SizedBox(height: 16),
        ],

        // ── History ────────────────────────────────────────────────────────
        Text('History', style: Theme.of(context).textTheme.titleSmall),
        const SizedBox(height: 8),
        AppStatusSummaryRow(
          items: [
            AppStatusSummaryItem(
              label: 'All',
              count: historyAll.length,
              kind: StatusKind.neutral,
              selected: _historyFilter == null,
              onTap: () => setState(() => _historyFilter = null),
            ),
            AppStatusSummaryItem(
              label: 'Pending',
              count: countPending,
              kind: StatusKind.info,
              selected: _historyFilter == DaySheetStatus.pending,
              onTap: () => setState(() => _historyFilter = DaySheetStatus.pending),
            ),
            AppStatusSummaryItem(
              label: 'Disapproved',
              count: countDisapproved,
              kind: StatusKind.warning,
              selected: _historyFilter == DaySheetStatus.disapproved,
              onTap: () =>
                  setState(() => _historyFilter = DaySheetStatus.disapproved),
            ),
            AppStatusSummaryItem(
              label: 'Approved',
              count: countApproved,
              kind: StatusKind.success,
              selected: _historyFilter == DaySheetStatus.approved,
              onTap: () =>
                  setState(() => _historyFilter = DaySheetStatus.approved),
            ),
          ],
        ),
        const SizedBox(height: 8),
        if (history.isEmpty)
          const AppEmptyView(
            icon: Icons.history,
            title: 'No sheets yet',
            subtitle: 'Submit your first day sheet above.',
          )
        else
          for (final sheet in history)
            _SheetHistoryTile(
              sheet: sheet,
              statusKind: _kindFor(sheet.status),
              onTap: () => context.pushNamed(
                'daySheetDetail',
                pathParameters: {'id': sheet.id},
              ),
            ),
      ],
    );
  }
}

// ---------------------------------------------------------------------------
// Today card
// ---------------------------------------------------------------------------

class _TodayCard extends StatelessWidget {
  const _TodayCard({
    required this.total,
    required this.status,
    required this.statusKind,
    required this.canSubmit,
    required this.submitting,
    required this.onSubmit,
    this.onTap,
  });

  final Duration total;
  final String status;
  final StatusKind statusKind;
  final bool canSubmit;
  final bool submitting;
  final VoidCallback onSubmit;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    final tt = Theme.of(context).textTheme;
    final cs = Theme.of(context).colorScheme;

    return Card(
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(12),
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  Expanded(
                    child: Text('Today', style: tt.titleMedium),
                  ),
                  StatusPill.kind(
                    statusKind,
                    label: DaySheetStatus.label(status),
                  ),
                ],
              ),
              const SizedBox(height: 8),
              Text(
                formatDurationHm(total),
                style: tt.headlineSmall?.copyWith(
                  fontWeight: FontWeight.w700,
                  color: cs.primary,
                ),
              ),
              const SizedBox(height: 12),
              SizedBox(
                width: double.infinity,
                child: FilledButton.tonal(
                  onPressed: canSubmit && !submitting ? onSubmit : null,
                  child: submitting
                      ? const SizedBox(
                          width: 18,
                          height: 18,
                          child: CircularProgressIndicator(strokeWidth: 2),
                        )
                      : const Text('Submit day'),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

// ---------------------------------------------------------------------------
// History tile
// ---------------------------------------------------------------------------

class _SheetHistoryTile extends StatelessWidget {
  const _SheetHistoryTile({
    required this.sheet,
    required this.statusKind,
    required this.onTap,
  });

  final ProgrammerDaySheet sheet;
  final StatusKind statusKind;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return Card(
      margin: const EdgeInsets.only(bottom: 8),
      child: ListTile(
        title: Text(AppTime.formatDate(sheet.workDate)),
        trailing: Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            StatusPill.kind(
              statusKind,
              label: DaySheetStatus.label(sheet.status),
            ),
            const SizedBox(width: 4),
            const Icon(Icons.chevron_right),
          ],
        ),
        onTap: onTap,
      ),
    );
  }
}