import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:stacked/stacked.dart';

import '../../about/external/data/RoutineChain.dart';
import '../../about/external/data/RoutineStep.dart';
import '../../about/internal/application/CommitmentClass.dart';
import '../../about/internal/application/RoutineKind.dart';
import '../../about/internal/application/TextType.dart';
import '../../configs/Navigator.dart';
import '../../designs/Component.dart';
import '../../designs/ProgressRing.dart';
import '../../designs/Responsive.dart';
import '../../designs/Shell.dart';
import '../../designs/buttons/Buttons.dart';
import '../../designs/text/Text.dart';
import '../../utils/Colors.dart';
import '../../utils/CommonUtils.dart';
import 'ConnectRoutines.dart';
import 'RoutineBuilder.dart';
import 'RoutineRunner.dart';
import 'Routines.dart';
import 'ViewRoutines.dart';

/// The routine library: what is due today up front, everything else below,
/// filtered by kind.
class RoutinesState extends State<Routines> implements ConnectRoutines {
  ViewRoutines? _model;

  List<RoutineChain> _routines = <RoutineChain>[];

  /// Null shows every kind.
  RoutineKind? _kind;

  @override
  Widget build(BuildContext context) {
    return ViewModelBuilder<ViewRoutines>.reactive(
      viewModelBuilder: () => ViewRoutines(context, this),
      onViewModelReady: (viewModel) {
        _model = viewModel;
        _initiate();
      },
      builder: (context, viewModel, child) => LayoutBuilder(
        builder: (BuildContext context, BoxConstraints constraints) {
          return Responsive(
            mobile: _mobileView(constraints),
            tablet: _mobileView(constraints),
            desktop: _mobileView(constraints),
          );
        },
      ),
    );
  }

  void _initiate() {
    _model?.loadRoutines();
  }

  // ── Derived ───────────────────────────────────────────────────────────────

  List<RoutineChain> get _filtered {
    if (_kind == null) {
      return _routines;
    }
    return _routines.where((item) => item.kind == _kind).toList();
  }

  List<RoutineChain> get _today {
    final DateTime now = DateTime.now();
    return _filtered.where((item) => item.scheduledOn(now)).toList();
  }

  List<RoutineChain> get _rest {
    final DateTime now = DateTime.now();
    return _filtered.where((item) => !item.scheduledOn(now)).toList();
  }

  /// Today's routines that are not finished, soonest first — the featured
  /// rail. Falls back to the whole library when nothing is due.
  List<RoutineChain> get _upNext {
    final List<RoutineChain> open =
        _today.where((item) => !item.complete).toList();
    final List<RoutineChain> source = open.isEmpty ? _filtered : open;
    return source.take(5).toList();
  }

  int _countFor(RoutineKind? kind) {
    if (kind == null) {
      return _routines.length;
    }
    return _routines.where((item) => item.kind == kind).length;
  }

  // ── Handlers ──────────────────────────────────────────────────────────────

  void _onBack() {
    Navigator.pop(context);
  }

  void _onSelectKind(RoutineKind? kind) {
    setState(() {
      _kind = _kind == kind ? null : kind;
    });
  }

  void _onBuild() async {
    final result = await GroundedNavigation()
        .navigateToPageWithData(RoutineBuilder(kind: _kind), context);

    if (result == true) {
      _model?.loadRoutines();
    }
  }

  void _onEdit(RoutineChain routine) async {
    final result = await GroundedNavigation()
        .navigateToPageWithData(RoutineBuilder(routine: routine), context);

    if (result == true) {
      _model?.loadRoutines();
    }
  }

  void _onStart(RoutineChain routine) async {
    if (routine.steps.isEmpty) {
      _onEdit(routine);
      return;
    }

    final result = await GroundedNavigation()
        .navigateToPageWithData(RoutineRunner(routine: routine.copy()), context);

    if (result == true) {
      _model?.loadRoutines();
    }
  }

  void _onPreview(RoutineChain routine) {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      backgroundColor: Colors.transparent,
      barrierColor: colorBlack.withValues(alpha: 0.55),
      builder: (BuildContext sheetContext) {
        return _previewSheet(sheetContext, routine);
      },
    );
  }

  // ── Views ─────────────────────────────────────────────────────────────────

  Widget _mobileView(BoxConstraints constraints) {
    return Sheet(
      eyebrow: "${_routines.length} routine${_routines.length == 1 ? "" : "s"}",
      title: "Routines",
      onBack: _onBack,
      action: chromeAction(CupertinoIcons.add, _onBuild),
      banner: _routines.isEmpty ? null : _todayBanner(),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        mainAxisSize: MainAxisSize.min,
        children: [
          text(
            "${weekdayName(DateTime.now().weekday).toUpperCase()} · ${_today.length} DUE",
            11,
            TextType.Bold,
            color: colorGrey2,
            letterSpacing: 1.2,
          ),
          const SizedBox(height: 8),
          displayTitle(_headline()),
          const SizedBox(height: 24),
          _kindRail(),
          const SizedBox(height: 28),
          if (_filtered.isEmpty)
            emptyState(
              _kind == null ? CupertinoIcons.square_stack_3d_up : kindIcon(_kind!),
              _kind == null
                  ? "No routines yet"
                  : "No ${kindLabel(_kind!).toLowerCase()} routines",
              "A routine is a chain: every step, in order. Break it and it is logged as partial, not quietly forgotten.",
            )
          else ...[
            sectionBreak(
              "Up next",
              caption: _today.isEmpty ? "from your library" : "today",
            ),
            _featuredRail(),
            const SizedBox(height: 28),
            if (_today.isNotEmpty) ...[
              sectionBreak(
                "Scheduled today",
                caption: "${_today.where((item) => item.complete).length} of ${_today.length} done",
              ),
              ..._today.map(_routineRow),
              const SizedBox(height: 20),
            ],
            if (_rest.isNotEmpty) ...[
              sectionBreak("Library", caption: "${_rest.length} more"),
              ..._rest.map(_routineRow),
            ],
          ],
          const SizedBox(height: 24),
          roundedCornerButton(
            "Build a routine",
            _onBuild,
            icon: CupertinoIcons.add,
          ),
        ],
      ),
    );
  }

  String _headline() {
    if (_routines.isEmpty) {
      return "Build the things you do every time.";
    }
    final int open = _today.where((item) => !item.complete).length;
    if (_today.isEmpty) {
      return "Nothing scheduled. Run one anyway.";
    }
    if (open == 0) {
      return "Every chain held today.";
    }
    return "Here's what to hold today.";
  }

  /// The strip in the black chrome: today's load at a glance.
  Widget _todayBanner() {
    final DateTime now = DateTime.now();
    final List<RoutineChain> due =
        _routines.where((item) => item.scheduledOn(now)).toList();

    int seconds = 0;
    for (RoutineChain item in due) {
      seconds = seconds + item.totalSeconds;
    }

    final int nowMinute = now.hour * 60 + now.minute;
    final List<RoutineChain> ahead = due
        .where((item) => !item.complete && item.startMinute >= nowMinute)
        .toList()
      ..sort((a, b) => a.startMinute.compareTo(b.startMinute));

    final Color label = colorWhite.withValues(alpha: 0.45);

    return Container(
      padding: const EdgeInsets.fromLTRB(16, 14, 16, 14),
      decoration: BoxDecoration(
        color: colorWhite.withValues(alpha: 0.08),
        borderRadius: BorderRadius.circular(16),
      ),
      child: Row(
        children: [
          Expanded(
            child: labelled("Due today", "${due.length}",
                valueSize: 22,
                valueType: TextType.Light,
                valueColor: colorWhite,
                labelColor: label),
          ),
          Expanded(
            child: labelled("Planned", formatMinutes(seconds / 60),
                valueSize: 22,
                valueType: TextType.Light,
                valueColor: colorWhite,
                labelColor: label),
          ),
          Expanded(
            child: labelled(
                "Next",
                ahead.isEmpty ? "—" : formatStartMinute(ahead.first.startMinute),
                valueSize: 22,
                valueType: TextType.Light,
                valueColor: colorWhite,
                labelColor: label),
          ),
        ],
      ),
    );
  }

  /// Round category tiles — tap to filter, tap again to clear.
  Widget _kindRail() {
    final List<RoutineKind?> options = <RoutineKind?>[null, ...RoutineKind.values];

    return SizedBox(
      height: 96,
      child: ListView.separated(
        scrollDirection: Axis.horizontal,
        itemCount: options.length,
        separatorBuilder: (context, index) => const SizedBox(width: 14),
        itemBuilder: (context, index) => _kindTile(options[index]),
      ),
    );
  }

  Widget _kindTile(RoutineKind? kind) {
    final bool selected = _kind == kind;
    final Color tone = kind == null ? colorPrimaryDark : kindColor(kind);

    return GestureDetector(
      onTap: () => _onSelectKind(kind),
      behavior: HitTestBehavior.opaque,
      child: SizedBox(
        width: 70,
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            AnimatedContainer(
              duration: const Duration(milliseconds: 180),
              curve: Curves.easeOut,
              width: 60,
              height: 60,
              alignment: Alignment.center,
              decoration: BoxDecoration(
                shape: BoxShape.circle,
                gradient: selected
                    ? LinearGradient(
                        begin: Alignment.topLeft,
                        end: Alignment.bottomRight,
                        colors: <Color>[
                          tone,
                          kind == null ? colorPrimaryDark2 : kindDeep(kind),
                        ],
                      )
                    : null,
                color: selected ? null : colorWhite,
                border: Border.all(
                  color: selected ? tone : colorBorder,
                  width: selected ? 2 : 1,
                ),
              ),
              child: Icon(
                kind == null ? CupertinoIcons.square_grid_2x2_fill : kindIcon(kind),
                size: 22,
                color: selected ? colorWhite : tone,
              ),
            ),
            const SizedBox(height: 8),
            text(
              kind == null ? "All" : kindLabel(kind),
              11,
              selected ? TextType.Bold : TextType.Regular,
              color: selected ? colorPrimaryDark : colorGrey2,
              maxLines: 1,
            ),
            const SizedBox(height: 2),
            text("${_countFor(kind)}", 9, TextType.Bold,
                color: colorGrey, letterSpacing: 0.6),
          ],
        ),
      ),
    );
  }

  Widget _featuredRail() {
    final List<RoutineChain> items = _upNext;

    return SizedBox(
      height: 214,
      child: ListView.separated(
        scrollDirection: Axis.horizontal,
        clipBehavior: Clip.none,
        itemCount: items.length,
        separatorBuilder: (context, index) => const SizedBox(width: 12),
        itemBuilder: (context, index) => _featuredCard(items[index]),
      ),
    );
  }

  /// The large gradient card. The kind's icon sits oversized in the corner as
  /// the card's picture — routines have no stock photography.
  Widget _featuredCard(RoutineChain routine) {
    final Color tone = kindColor(routine.kind);
    final Color label = colorWhite.withValues(alpha: 0.55);

    return GestureDetector(
      onTap: () => _onPreview(routine),
      child: Container(
        width: 248,
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(20),
          gradient: LinearGradient(
            begin: Alignment.topLeft,
            end: Alignment.bottomRight,
            colors: <Color>[tone, kindDeep(routine.kind)],
          ),
          boxShadow: const [
            BoxShadow(
              color: Color(0x08000000),
              blurRadius: 18,
              offset: Offset(0, 4),
            ),
          ],
        ),
        clipBehavior: Clip.antiAlias,
        child: Stack(
          children: [
            Positioned(
              right: -26,
              bottom: 34,
              child: Icon(
                kindIcon(routine.kind),
                size: 150,
                color: colorWhite.withValues(alpha: 0.08),
              ),
            ),
            Padding(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Row(
                    children: [
                      pill(kindLabel(routine.kind), colorWhite,
                          colorWhite.withValues(alpha: 0.14),
                          textSize: 9),
                      if (routine.commitmentClass ==
                          CommitmentClass.NonNegotiable) ...[
                        const SizedBox(width: 6),
                        pill("Must hold", colorWhite,
                            colorWhite.withValues(alpha: 0.14),
                            textSize: 9),
                      ],
                      const Spacer(),
                      Container(
                        width: 34,
                        height: 34,
                        alignment: Alignment.center,
                        decoration: BoxDecoration(
                          color: colorWhite,
                          shape: BoxShape.circle,
                        ),
                        child: Icon(CupertinoIcons.play_fill,
                            size: 14, color: kindDeep(routine.kind)),
                      ),
                    ],
                  ),
                  const Spacer(),
                  if (routine.startMinute >= 0) ...[
                    text(
                      "${formatStartMinute(routine.startMinute)} · ${formatDays(routine.days)}"
                          .toUpperCase(),
                      9,
                      TextType.Bold,
                      color: label,
                      letterSpacing: 1.0,
                    ),
                    const SizedBox(height: 6),
                  ],
                  text(routine.title, 21, TextType.Light,
                      color: colorWhite,
                      maxLines: 2,
                      overflow: TextOverflow.ellipsis,
                      height: 1.15),
                  const SizedBox(height: 14),
                  Container(
                    height: 1,
                    color: colorWhite.withValues(alpha: 0.12),
                  ),
                  const SizedBox(height: 12),
                  Row(
                    children: [
                      Expanded(
                        child: labelled(
                          "Minutes",
                          "${(routine.totalSeconds / 60).round()}",
                          valueSize: 17,
                          valueColor: colorWhite,
                          labelColor: label,
                        ),
                      ),
                      Expanded(
                        child: labelled(
                          "Steps",
                          "${routine.steps.length}",
                          valueSize: 17,
                          valueColor: colorWhite,
                          labelColor: label,
                        ),
                      ),
                      Expanded(
                        child: labelled(
                          routine.kind == RoutineKind.Workout ? "Sets" : "Starts",
                          routine.kind == RoutineKind.Workout
                              ? "${routine.totalSets}"
                              : routine.startMinute < 0
                                  ? "Any"
                                  : formatStartMinute(routine.startMinute),
                          valueSize: 17,
                          valueColor: colorWhite,
                          labelColor: label,
                        ),
                      ),
                    ],
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _routineRow(RoutineChain routine) {
    final Color tone = kindColor(routine.kind);
    final bool weighted = routine.commitmentClass != CommitmentClass.Standard;

    final List<String> eyebrow = <String>[
      if (weighted) classLabel(routine.commitmentClass),
      if (routine.startMinute >= 0) formatStartMinute(routine.startMinute),
      formatDays(routine.days),
    ];

    return Container(
      margin: const EdgeInsets.only(bottom: 10),
      child: card(
        padding: const EdgeInsets.fromLTRB(10, 10, 14, 10),
        onTap: () => _onPreview(routine),
        child: Row(
          children: [
            Container(
              width: 58,
              height: 58,
              decoration: BoxDecoration(
                borderRadius: BorderRadius.circular(14),
                gradient: LinearGradient(
                  begin: Alignment.topLeft,
                  end: Alignment.bottomRight,
                  colors: <Color>[kindBackground(routine.kind), colorWhite],
                ),
                border: Border.all(color: tone.withValues(alpha: 0.15)),
              ),
              alignment: Alignment.center,
              child: Icon(kindIcon(routine.kind), size: 24, color: tone),
            ),
            const SizedBox(width: 14),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                mainAxisSize: MainAxisSize.min,
                children: [
                  text(
                    eyebrow.join(" · ").toUpperCase(),
                    9,
                    TextType.Bold,
                    color: weighted
                        ? classColor(routine.commitmentClass)
                        : colorGrey2,
                    letterSpacing: 0.9,
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                  ),
                  const SizedBox(height: 5),
                  text(routine.title, 15, TextType.Medium,
                      color: colorPrimaryDark,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis),
                  const SizedBox(height: 6),
                  Row(
                    children: [
                      _meta(CupertinoIcons.clock,
                          formatMinutes(routine.totalSeconds / 60)),
                      const SizedBox(width: 12),
                      _countMeta(routine),
                    ],
                  ),
                ],
              ),
            ),
            const SizedBox(width: 10),
            routine.complete
                ? Container(
                    width: 44,
                    height: 44,
                    alignment: Alignment.center,
                    decoration: BoxDecoration(
                      color: tone,
                      shape: BoxShape.circle,
                    ),
                    child: Icon(Icons.check_rounded,
                        size: 22, color: colorWhite),
                  )
                : ProgressRing(
                    fraction: routine.partialCompletion,
                    fill: tone,
                  ),
          ],
        ),
      ),
    );
  }

  Widget _countMeta(RoutineChain routine) {
    switch (routine.kind) {
      case RoutineKind.Workout:
        return _meta(CupertinoIcons.repeat, "${routine.totalSets} sets");
      case RoutineKind.Meditation:
        return _meta(CupertinoIcons.circle_grid_hex,
            "${routine.steps.length} steps");
      case RoutineKind.MustDo:
        return _meta(CupertinoIcons.checkmark_square,
            "${routine.steps.length} tasks");
    }
  }

  Widget _meta(IconData icon, String value) {
    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        Icon(icon, size: 12, color: colorGrey2),
        const SizedBox(width: 4),
        text(value, 11, TextType.Regular, color: colorGrey2),
      ],
    );
  }

  /// The preview: the whole chain laid out before you commit to starting it.
  Widget _previewSheet(BuildContext sheetContext, RoutineChain routine) {
    final Color tone = kindColor(routine.kind);

    return Container(
      constraints: BoxConstraints(
        maxHeight: MediaQuery.of(sheetContext).size.height * 0.86,
      ),
      decoration: const BoxDecoration(
        color: colorSheetBackground,
        borderRadius: BorderRadius.only(
          topLeft: Radius.circular(28),
          topRight: Radius.circular(28),
        ),
      ),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Center(
            child: Container(
              width: 38,
              height: 4,
              margin: const EdgeInsets.only(top: 10),
              decoration: BoxDecoration(
                color: colorGrey.withValues(alpha: 0.5),
                borderRadius: BorderRadius.circular(999),
              ),
            ),
          ),
          Flexible(
            child: SingleChildScrollView(
              padding: const EdgeInsets.fromLTRB(24, 20, 24, 12),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                mainAxisSize: MainAxisSize.min,
                children: [
                  Row(
                    children: [
                      pill(kindLabel(routine.kind), tone,
                          kindBackground(routine.kind),
                          icon: kindIcon(routine.kind), textSize: 9),
                      const SizedBox(width: 6),
                      pill(classLabel(routine.commitmentClass),
                          classColor(routine.commitmentClass),
                          classBackground(routine.commitmentClass),
                          textSize: 9),
                    ],
                  ),
                  const SizedBox(height: 14),
                  displayTitle(routine.title, size: 30),
                  if (routine.note.isNotEmpty) ...[
                    const SizedBox(height: 8),
                    text(routine.note, 13, TextType.Regular,
                        color: colorGrey2, height: 1.5),
                  ],
                  const SizedBox(height: 20),
                  Row(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Expanded(
                          child: statTile("Minutes",
                              "${(routine.totalSeconds / 60).round()}")),
                      Expanded(
                          child: statTile("Steps", "${routine.steps.length}")),
                      Expanded(
                        child: statTile(
                          "When",
                          routine.startMinute < 0
                              ? "Any"
                              : formatStartMinute(routine.startMinute),
                          caption: formatDays(routine.days),
                        ),
                      ),
                    ],
                  ),
                  const SizedBox(height: 24),
                  sectionBreak("The chain",
                      caption: routine.kind == RoutineKind.Workout
                          ? "${routine.totalSets} sets, in order"
                          : "${routine.steps.length} steps, in order"),
                  ...routine.steps
                      .asMap()
                      .entries
                      .map((entry) => _previewStep(entry.key, entry.value, tone)),
                ],
              ),
            ),
          ),
          SafeArea(
            top: false,
            child: Padding(
              padding: const EdgeInsets.fromLTRB(24, 8, 24, 16),
              child: Row(
                children: [
                  Expanded(
                    child: outlinedActionButton("Edit", () {
                      Navigator.pop(sheetContext);
                      _onEdit(routine);
                    }, icon: CupertinoIcons.pencil),
                  ),
                  const SizedBox(width: 10),
                  Expanded(
                    flex: 2,
                    child: roundedCornerButton("Start", () {
                      Navigator.pop(sheetContext);
                      _onStart(routine);
                    },
                        icon: CupertinoIcons.play_fill,
                        enabled: routine.steps.isNotEmpty),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _previewStep(int index, RoutineStep step, Color tone) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 12),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Container(
            width: 28,
            height: 28,
            alignment: Alignment.center,
            decoration: BoxDecoration(
              color: tone.withValues(alpha: 0.10),
              shape: BoxShape.circle,
            ),
            child: text("${index + 1}", 11, TextType.Bold, color: tone),
          ),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              mainAxisSize: MainAxisSize.min,
              children: [
                const SizedBox(height: 4),
                text(step.title, 14, TextType.Medium, color: colorPrimaryDark),
                const SizedBox(height: 3),
                text(stepSummary(step), 11, TextType.Regular,
                    color: colorGrey2),
              ],
            ),
          ),
          Padding(
            padding: const EdgeInsets.only(top: 5),
            child: Icon(stepModeIcon(step.mode), size: 15, color: colorGrey),
          ),
        ],
      ),
    );
  }

  // ── ConnectRoutines ───────────────────────────────────────────────────────

  @override
  void onRoutinesLoaded(List<RoutineChain> routines) {
    setState(() {
      _routines = routines;
    });
  }
}