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

import '../about/external/data/Goal.dart';
import '../about/internal/application/TextType.dart';
import '../utils/Colors.dart';
import '../utils/CommonUtils.dart';
import 'text/Text.dart';

/// The goal chooser, shared by the task form and the routine builder. Opened
/// only once the goals have been loaded — `selectField` loads on tap.
///
/// Resolves to the chosen goal, to a bare `Goal()` (no id) for "no goal", or
/// to null when dismissed without a choice.
Future<Goal?> showGoalPicker(
  BuildContext context,
  List<Goal> goals, {
  String? selectedId,
}) {
  return showModalBottomSheet<Goal>(
    context: context,
    isScrollControlled: true,
    backgroundColor: Colors.transparent,
    barrierColor: colorBlack.withValues(alpha: 0.55),
    builder: (BuildContext sheetContext) {
      final List<Goal> active = goals.where((goal) => !goal.archived).toList();

      return Container(
        constraints: BoxConstraints(
          maxHeight: MediaQuery.of(sheetContext).size.height * 0.75,
        ),
        decoration: const BoxDecoration(
          color: colorSheetBackground,
          borderRadius: BorderRadius.only(
            topLeft: Radius.circular(28),
            topRight: Radius.circular(28),
          ),
        ),
        child: ListView(
          shrinkWrap: true,
          padding: const EdgeInsets.fromLTRB(24, 24, 24, 32),
          children: [
            text("BELONGS TO", 9, TextType.Bold,
                color: colorGrey2, letterSpacing: 1.2),
            const SizedBox(height: 8),
            text("Which goal is this for?", 24, TextType.Light,
                color: colorPrimaryDark),
            const SizedBox(height: 18),
            _goalOption(
              sheetContext,
              Goal(),
              "No goal",
              "Stands on its own",
              colorGrey,
              selectedId == null,
            ),
            ...active.map((goal) => _goalOption(
                  sheetContext,
                  goal,
                  goal.title,
                  goal.targetDate == null
                      ? "${goal.remainingTasks} open"
                      : "${goal.remainingTasks} open · ${targetLabel(goal.targetDate)}",
                  goalColor(goal.colourHex),
                  goal.id == selectedId,
                )),
            if (active.isEmpty) ...[
              const SizedBox(height: 8),
              text("No goals yet. Create one from the Goals screen.", 12,
                  TextType.Regular,
                  color: colorGrey2),
            ],
          ],
        ),
      );
    },
  );
}

Widget _goalOption(
  BuildContext sheetContext,
  Goal goal,
  String title,
  String caption,
  Color accent,
  bool selected,
) {
  return GestureDetector(
    onTap: () => Navigator.pop(sheetContext, goal),
    behavior: HitTestBehavior.opaque,
    child: Container(
      margin: const EdgeInsets.only(bottom: 8),
      padding: const EdgeInsets.fromLTRB(14, 13, 14, 13),
      decoration: BoxDecoration(
        color: colorWhite,
        borderRadius: BorderRadius.circular(14),
        border: Border.all(
          color: selected ? accent.withValues(alpha: 0.5) : colorBorder,
          width: selected ? 1.5 : 1,
        ),
      ),
      child: Row(
        children: [
          Container(
            width: 12,
            height: 12,
            decoration: BoxDecoration(color: accent, shape: BoxShape.circle),
          ),
          const SizedBox(width: 14),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              mainAxisSize: MainAxisSize.min,
              children: [
                text(title, 14, TextType.Medium, color: colorPrimaryDark),
                const SizedBox(height: 3),
                text(caption, 11, TextType.Regular, color: colorGrey2),
              ],
            ),
          ),
          if (selected)
            Icon(CupertinoIcons.checkmark_alt, size: 17, color: accent),
        ],
      ),
    ),
  );
}