import SwiftUI
import SwiftData

struct SymptomEndSheet: View {
    @Environment(\.modelContext) private var ctx
    @Environment(\.dismiss) private var dismiss

    let symptom: Symptom

    @State private var endedAt: Date = .now

    private var lowerBound: Date { symptom.startedAt }

    private var durationLabel: String {
        let interval = max(0, endedAt.timeIntervalSince(lowerBound))
        return formatDuration(interval)
    }

    var body: some View {
        VStack(spacing: 0) {
            Capsule()
                .fill(Tj.Palette.line)
                .frame(width: 40, height: 4)
                .padding(.top, 10)
                .padding(.bottom, 14)

            VStack(alignment: .leading, spacing: 18) {
                HStack {
                    VStack(alignment: .leading, spacing: 4) {
                        Text("结束症状")
                            .font(.system(size: 12, weight: .semibold))
                            .tracking(0.3)
                            .foregroundStyle(Tj.Palette.text3)
                        Text(symptom.name)
                            .font(.tjTitle(24))
                            .foregroundStyle(Tj.Palette.text)
                    }
                    Spacer()
                }

                VStack(alignment: .leading, spacing: 6) {
                    Text("开始于")
                        .font(.system(size: 12))
                        .foregroundStyle(Tj.Palette.text3)
                    Text(symptom.startedAt.formatted(date: .abbreviated, time: .shortened))
                        .font(.system(size: 14, weight: .medium))
                        .foregroundStyle(Tj.Palette.text)
                }

                VStack(alignment: .leading, spacing: 8) {
                    Text("结束时间")
                        .font(.system(size: 12, weight: .semibold))
                        .tracking(0.3)
                        .foregroundStyle(Tj.Palette.text2)
                    DatePicker("", selection: $endedAt, in: lowerBound...Date.now)
                        .datePickerStyle(.compact)
                        .labelsHidden()
                }

                HStack {
                    Text("本次持续")
                        .font(.system(size: 13))
                        .foregroundStyle(Tj.Palette.text3)
                    Spacer()
                    Text(durationLabel)
                        .font(.system(size: 15, weight: .semibold, design: .monospaced))
                        .foregroundStyle(Tj.Palette.brick)
                }
                .padding(.horizontal, 14)
                .padding(.vertical, 12)
                .background(
                    RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                        .fill(Tj.Palette.paper)
                )

                Spacer(minLength: 8)
            }
            .padding(.horizontal, 20)

            HStack(spacing: 12) {
                Button("取消") { dismiss() }
                    .buttonStyle(TjGhostButton(height: 44, fontSize: 15, horizontalPadding: 18))
                Button("结束并保存") { submit() }
                    .buttonStyle(TjPrimaryButton(height: 44, fontSize: 15, horizontalPadding: 18))
            }
            .padding(.horizontal, 20)
            .padding(.vertical, 14)
        }
        .background(
            Tj.Palette.sand
                .clipShape(RoundedRectangle(cornerRadius: Tj.Radius.xl, style: .continuous))
                .ignoresSafeArea(edges: .bottom)
        )
        .presentationDetents([.medium])
        .presentationDragIndicator(.hidden)
        .presentationBackground(Tj.Palette.sand)
        .presentationCornerRadius(Tj.Radius.xl)
    }

    private func submit() {
        symptom.endedAt = max(endedAt, symptom.startedAt)
        try? ctx.save()
        dismiss()
    }
}

func formatDuration(_ interval: TimeInterval) -> String {
    let totalMinutes = Int(interval / 60)
    let days = totalMinutes / (60 * 24)
    let hours = (totalMinutes % (60 * 24)) / 60
    let minutes = totalMinutes % 60

    if days > 0 && hours > 0 { return "\(days) 天 \(hours) 小时" }
    if days > 0 { return "\(days) 天" }
    if hours > 0 && minutes > 0 { return "\(hours) 小时 \(minutes) 分" }
    if hours > 0 { return "\(hours) 小时" }
    if minutes > 0 { return "\(minutes) 分钟" }
    return "刚刚"
}