import SwiftUI
import SwiftData
import Combine

/// 主页「今日提醒」卡:汇总今天会触发的自由提醒(CustomReminder)+ 指标提醒(MetricReminder),
/// 按时间升序展示;已过点的行淡化(只表示「时间已过」,不代表已完成——本期不追踪打卡)。
/// 今天没有任何提醒 → 整卡隐藏(返回 EmptyView,与「持续中症状」卡同款)。
/// 卡内只读;点右上「全部 ›」打开提醒中心(RemindersListView)管理。
struct TodayRemindersCard: View {
    @Query(sort: \CustomReminder.updatedAt, order: .reverse)
    private var customReminders: [CustomReminder]
    @Query(sort: \MetricReminder.updatedAt, order: .reverse)
    private var metricReminders: [MetricReminder]

    @State private var showingCenter = false
    /// 每分钟自走一次,用于刷新「今天」判定与「已过点」淡化(与 OngoingSymptomsCard 同款)。
    @State private var tick: Date = .now
    private let timer = Timer.publish(every: 60, on: .main, in: .common).autoconnect()

    /// 今天会触发的提醒,自由提醒 + 指标提醒合并成统一行模型,按时间升序。
    private var items: [TodayItem] {
        let cal = Calendar.current
        var arr: [TodayItem] = []
        for r in customReminders where r.occurs(on: tick, calendar: cal) {
            arr.append(TodayItem(id: "c-\(r.id.uuidString)",
                                 hour: r.hour, minute: r.minute, title: r.title))
        }
        for r in metricReminders where r.occurs(on: tick, calendar: cal) {
            arr.append(TodayItem(id: "m-\(r.metricId)",
                                 hour: r.hour, minute: r.minute, title: r.displayName))
        }
        return arr.sorted { ($0.hour, $0.minute) < ($1.hour, $1.minute) }
    }

    var body: some View {
        let rows = items
        if rows.isEmpty {
            EmptyView()
        } else {
            VStack(alignment: .leading, spacing: 10) {
                header(count: rows.count)
                VStack(spacing: 8) {
                    ForEach(rows) { row($0) }
                }
            }
            .padding(.bottom, 18)
            .onReceive(timer) { now in tick = now }
            .sheet(isPresented: $showingCenter) {
                // 列表页依赖外层 NavigationStack 提供标题栏;sheet 形态补「完成」按钮。
                NavigationStack { RemindersListView(presentedAsSheet: true) }
            }
        }
    }

    private func header(count: Int) -> some View {
        HStack(spacing: 8) {
            Circle()
                .fill(Tj.Palette.amber)
                .frame(width: 7, height: 7)
            Text("今日提醒")
                .font(.tjH2())
                .foregroundStyle(Tj.Palette.text)
            Text("\(count) 项")
                .font(.system(size: 12))
                .foregroundStyle(Tj.Palette.text3)
            Spacer()
            Button { showingCenter = true } label: {
                Text("全部 ›")
                    .font(.system(size: 12))
                    .foregroundStyle(Tj.Palette.text3)
            }
            .buttonStyle(.plain)
        }
    }

    private func row(_ item: TodayItem) -> some View {
        let isPast = item.isPast(now: tick)
        return HStack(spacing: 12) {
            Text(item.timeLabel)
                .font(.system(size: 14, weight: .semibold).monospacedDigit())
                .foregroundStyle(isPast ? Tj.Palette.text3 : Tj.Palette.ink)
                .frame(width: 46, alignment: .leading)
            Image(systemName: "bell.fill")
                .font(.system(size: 12))
                .foregroundStyle(isPast ? Tj.Palette.text3 : Tj.Palette.amber)
            Text(item.title)
                .font(.system(size: 15, weight: .medium))
                .foregroundStyle(isPast ? Tj.Palette.text3 : Tj.Palette.text)
                .lineLimit(1)
            Spacer(minLength: 0)
        }
        .padding(.horizontal, 14)
        .padding(.vertical, 12)
        .background(
            RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                .fill(Tj.Palette.paper)
        )
        .shadow(color: Color(red: 0.196, green: 0.157, blue: 0.098).opacity(0.04),
                radius: 2, x: 0, y: 1)
    }
}

/// 「今日提醒」行的统一展示模型(自由提醒与指标提醒共用)。
private struct TodayItem: Identifiable {
    let id: String
    let hour: Int
    let minute: Int
    let title: String

    var timeLabel: String { String(format: "%02d:%02d", hour, minute) }

    /// 该提醒的时分是否早于此刻(同一天内「已过点」)。
    func isPast(now: Date) -> Bool {
        let c = Calendar.current.dateComponents([.hour, .minute], from: now)
        let nowMinutes = (c.hour ?? 0) * 60 + (c.minute ?? 0)
        return hour * 60 + minute < nowMinutes
    }
}