import SwiftUI
import SwiftData

/// 「我的 · 个人资料」编辑页。Form 风格,即改即存(无显式 Save 按钮)。
/// UserProfile 是 SwiftData 单例:进入时通过 UserProfileStore.loadOrCreate 拿到。
struct ProfileEditView: View {
    @Environment(\.modelContext) private var ctx
    @Query private var profiles: [UserProfile]

    var body: some View {
        if let p = profiles.first {
            ProfileEditForm(profile: p)
        } else {
            ProgressView()
                .onAppear { _ = UserProfileStore.loadOrCreate(in: ctx) }
        }
    }
}

/// 实际表单。`@Bindable` 让 SwiftData @Model 的字段可以 `$profile.xxx` 双向绑定。
private struct ProfileEditForm: View {
    @Environment(\.modelContext) private var ctx
    @Bindable var profile: UserProfile

    @State private var newAllergy = ""
    @State private var newFamilyEntry = ""
    @State private var newMedication = ""
    @State private var newCustomCondition = ""

    private static let chronicPresets = [
        "高血压", "糖尿病", "冠心病", "高血脂",
        "甲状腺疾病", "哮喘", "慢性肾病", "抑郁/焦虑",
    ]

    var body: some View {
        Form {
            basicsSection
            chronicSection
            allergySection
            familySection
            medicationSection
        }
        .navigationTitle("个人资料")
        .navigationBarTitleDisplayMode(.inline)
        .scrollContentBackground(.hidden)
        .background(Tj.Palette.sand.ignoresSafeArea())
        .onDisappear {
            profile.updatedAt = .now
            try? ctx.save()
        }
    }

    // MARK: - 基本

    private var basicsSection: some View {
        Section {
            birthYearPicker
            sexPicker
            heightRow
            weightRow
            bloodTypePicker
        } header: {
            Text("基本")
        } footer: {
            if let bmi = profile.bmi {
                Text("BMI: \(String(format: "%.1f", bmi))  \(bmiLabel(bmi))")
                    .font(.system(size: 11))
            }
        }
    }

    private func bmiLabel(_ bmi: Double) -> String {
        switch bmi {
        case ..<18.5:  return "(偏瘦)"
        case ..<24:    return "(正常)"
        case ..<28:    return "(超重)"
        default:       return "(肥胖)"
        }
    }

    private var birthYearPicker: some View {
        Picker("出生年份", selection: Binding(
            get: { profile.birthYear ?? 0 },
            set: { profile.birthYear = $0 == 0 ? nil : $0 }
        )) {
            Text("未设置").tag(0)
            ForEach((1900...currentYear).reversed(), id: \.self) { year in
                Text(String(year)).tag(year)
            }
        }
    }

    private var sexPicker: some View {
        Picker("性别", selection: Binding(
            get: { profile.sex },
            set: { profile.sex = $0 }
        )) {
            ForEach(UserProfile.Sex.allCases, id: \.self) { s in
                Text(s.label).tag(s)
            }
        }
        .pickerStyle(.segmented)
    }

    private var heightRow: some View {
        HStack {
            Text("身高")
            Spacer()
            TextField("cm", value: $profile.heightCM, format: .number)
                .keyboardType(.numberPad)
                .multilineTextAlignment(.trailing)
                .frame(width: 80)
            Text("cm").foregroundStyle(Tj.Palette.text3)
        }
    }

    private var weightRow: some View {
        HStack {
            Text("体重")
            Spacer()
            TextField("kg", value: $profile.weightKG, format: .number.precision(.fractionLength(0...1)))
                .keyboardType(.decimalPad)
                .multilineTextAlignment(.trailing)
                .frame(width: 80)
            Text("kg").foregroundStyle(Tj.Palette.text3)
        }
    }

    private var bloodTypePicker: some View {
        Picker("血型", selection: $profile.bloodTypeRaw) {
            Text("不知道").tag("")
            Text("A 型").tag("A")
            Text("B 型").tag("B")
            Text("AB 型").tag("AB")
            Text("O 型").tag("O")
        }
    }

    // MARK: - 慢病

    private var chronicSection: some View {
        Section {
            FlexibleChipGrid {
                ForEach(Self.chronicPresets, id: \.self) { name in
                    chip(label: name,
                         selected: profile.chronicConditions.contains(name)) {
                        toggleCondition(name)
                    }
                }
                ForEach(profile.chronicConditions.filter { !Self.chronicPresets.contains($0) },
                        id: \.self) { name in
                    chip(label: name, selected: true) {
                        profile.chronicConditions.removeAll { $0 == name }
                    }
                }
            }

            HStack {
                TextField("自定义慢病", text: $newCustomCondition)
                Button("加") {
                    let trimmed = newCustomCondition.trimmingCharacters(in: .whitespaces)
                    guard !trimmed.isEmpty,
                          !profile.chronicConditions.contains(trimmed) else { return }
                    profile.chronicConditions.append(trimmed)
                    newCustomCondition = ""
                }
                .disabled(newCustomCondition.trimmingCharacters(in: .whitespaces).isEmpty)
            }
        } header: {
            Text("慢病(影响参考范围与 AI 解读)")
        }
    }

    // MARK: - 过敏 / 家族史 / 用药

    private var allergySection: some View {
        listSection(title: "过敏史", placeholder: "如:青霉素",
                    items: $profile.allergies, newInput: $newAllergy)
    }

    private var familySection: some View {
        listSection(title: "家族史", placeholder: "如:母亲 高血压",
                    items: $profile.familyHistory, newInput: $newFamilyEntry)
    }

    private var medicationSection: some View {
        listSection(title: "当前用药", placeholder: "如:缬沙坦 80mg qd",
                    items: $profile.currentMedications, newInput: $newMedication)
    }

    private func listSection(title: String, placeholder: String,
                             items: Binding<[String]>,
                             newInput: Binding<String>) -> some View {
        Section(title) {
            ForEach(items.wrappedValue, id: \.self) { item in
                HStack {
                    Text(item)
                    Spacer()
                    Button(role: .destructive) {
                        items.wrappedValue.removeAll { $0 == item }
                    } label: {
                        Image(systemName: "minus.circle")
                            .foregroundStyle(Tj.Palette.brick)
                    }
                    .buttonStyle(.borderless)
                }
            }
            HStack {
                TextField(placeholder, text: newInput)
                Button("加") {
                    let trimmed = newInput.wrappedValue.trimmingCharacters(in: .whitespaces)
                    guard !trimmed.isEmpty,
                          !items.wrappedValue.contains(trimmed) else { return }
                    items.wrappedValue.append(trimmed)
                    newInput.wrappedValue = ""
                }
                .disabled(newInput.wrappedValue.trimmingCharacters(in: .whitespaces).isEmpty)
            }
        }
    }

    // MARK: - helpers

    private func chip(label: String, selected: Bool, action: @escaping () -> Void) -> some View {
        Button(action: action) {
            Text(label)
                .font(.system(size: 13, weight: selected ? .semibold : .regular))
                .foregroundStyle(selected ? Tj.Palette.paper : Tj.Palette.text)
                .padding(.horizontal, 12)
                .padding(.vertical, 6)
                .background(Capsule().fill(selected ? Tj.Palette.ink : Tj.Palette.paper))
                .overlay(Capsule().strokeBorder(Tj.Palette.line, lineWidth: selected ? 0 : 1))
        }
        .buttonStyle(.plain)
    }

    private func toggleCondition(_ name: String) {
        if profile.chronicConditions.contains(name) {
            profile.chronicConditions.removeAll { $0 == name }
        } else {
            profile.chronicConditions.append(name)
        }
    }

    private var currentYear: Int {
        Calendar.current.component(.year, from: .now)
    }
}

/// 简化版 chip 流式布局——SwiftUI 没有原生 Wrap,用 Layout 协议自实现。
struct FlexibleChipGrid<Content: View>: View {
    @ViewBuilder let content: () -> Content

    var body: some View {
        FlowLayout { content() }
    }
}

private struct FlowLayout: Layout {
    var spacing: CGFloat = 6

    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
        let maxWidth = proposal.width ?? .infinity
        var rows: [CGFloat] = [0]
        var rowMaxHeight: [CGFloat] = [0]
        var x: CGFloat = 0
        for s in subviews {
            let size = s.sizeThatFits(.unspecified)
            if x + size.width > maxWidth, x > 0 {
                rows.append(0); rowMaxHeight.append(0)
                x = 0
            }
            rows[rows.count - 1] = max(rows[rows.count - 1], x + size.width)
            rowMaxHeight[rowMaxHeight.count - 1] = max(rowMaxHeight.last ?? 0, size.height)
            x += size.width + spacing
        }
        let totalHeight = rowMaxHeight.reduce(0, +) + spacing * CGFloat(max(0, rows.count - 1))
        let totalWidth = rows.max() ?? 0
        return CGSize(width: totalWidth, height: totalHeight)
    }

    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) {
        var x: CGFloat = bounds.minX
        var y: CGFloat = bounds.minY
        var rowHeight: CGFloat = 0
        for s in subviews {
            let size = s.sizeThatFits(.unspecified)
            if x + size.width > bounds.maxX, x > bounds.minX {
                x = bounds.minX
                y += rowHeight + spacing
                rowHeight = 0
            }
            s.place(at: CGPoint(x: x, y: y), proposal: ProposedViewSize(size))
            x += size.width + spacing
            rowHeight = max(rowHeight, size.height)
        }
    }
}

#Preview {
    NavigationStack {
        ProfileEditView()
    }
    .modelContainer(for: [UserProfile.self], inMemory: true)
}