import SwiftUI

// MARK: - 通用表单组件
struct FormView<Content: View>: View {
    let title: String?
    let content: Content
    let spacing: CGFloat
    let padding: EdgeInsets
    
    init(
        title: String? = nil,
        spacing: CGFloat = 16,
        padding: EdgeInsets = EdgeInsets(top: 20, leading: 20, bottom: 20, trailing: 20),
        @ViewBuilder content: () -> Content
    ) {
        self.title = title
        self.spacing = spacing
        self.padding = padding
        self.content = content()
    }
    
    var body: some View {
        ScrollView {
            VStack(spacing: spacing) {
                if let title = title {
                    HStack {
                        Text(title)
                            .font(.title2)
                            .fontWeight(.semibold)
                            .foregroundColor(.primary)
                        
                        Spacer()
                    }
                }
                
                content
            }
            .padding(padding)
        }
        .background(Color(.systemGroupedBackground))
    }
}

// MARK: - 表单分组组件
struct FormGroup<Content: View>: View {
    let title: String?
    let content: Content
    let spacing: CGFloat
    
    init(
        title: String? = nil,
        spacing: CGFloat = 12,
        @ViewBuilder content: () -> Content
    ) {
        self.title = title
        self.spacing = spacing
        self.content = content()
    }
    
    var body: some View {
        VStack(alignment: .leading, spacing: spacing) {
            if let title = title {
                HStack {
                    Text(title)
                        .font(.headline)
                        .foregroundColor(.primary)
                    
                    Spacer()
                }
            }
            
            content
        }
        .padding()
        .background(Color(.systemBackground))
        .cornerRadius(12)
        .shadow(color: .black.opacity(0.05), radius: 2, x: 0, y: 1)
    }
}

// MARK: - 表单行组件
struct FormRow<Content: View>: View {
    let title: String
    let isRequired: Bool
    let content: Content
    let icon: String?
    
    init(
        title: String,
        isRequired: Bool = false,
        icon: String? = nil,
        @ViewBuilder content: () -> Content
    ) {
        self.title = title
        self.isRequired = isRequired
        self.icon = icon
        self.content = content()
    }
    
    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            HStack {
                if let icon = icon {
                    Image(systemName: icon)
                        .font(.subheadline)
                        .foregroundColor(.blue)
                }
                
                Text(title)
                    .font(.subheadline)
                    .foregroundColor(.primary)
                
                if isRequired {
                    Text("*")
                        .foregroundColor(.red)
                        .font(.subheadline)
                }
                
                Spacer()
            }
            
            content
        }
    }
}

// MARK: - 表单操作按钮组件
struct FormActionButton: View {
    let title: String
    let action: () -> Void
    let isEnabled: Bool
    let style: ButtonStyle
    let icon: String?
    
    enum ButtonStyle {
        case primary
        case secondary
        case destructive
        case success
    }
    
    init(
        title: String,
        action: @escaping () -> Void,
        isEnabled: Bool = true,
        style: ButtonStyle = .primary,
        icon: String? = nil
    ) {
        self.title = title
        self.action = action
        self.isEnabled = isEnabled
        self.style = style
        self.icon = icon
    }
    
    var body: some View {
        Button(action: action) {
            HStack(spacing: 8) {
                if let icon = icon {
                    Image(systemName: icon)
                        .font(.system(size: 16, weight: .medium))
                }
                
                Text(title)
                    .font(.system(size: 16, weight: .semibold))
            }
            .frame(maxWidth: .infinity)
            .padding(.vertical, 16)
            .background(
                RoundedRectangle(cornerRadius: 12)
                    .fill(backgroundColor)
            )
            .foregroundColor(foregroundColor)
        }
        .disabled(!isEnabled)
        .opacity(isEnabled ? 1.0 : 0.6)
    }
    
    private var backgroundColor: Color {
        switch style {
        case .primary:
            return .blue
        case .secondary:
            return Color(.systemGray5)
        case .destructive:
            return .red
        case .success:
            return .green
        }
    }
    
    private var foregroundColor: Color {
        switch style {
        case .primary, .destructive, .success:
            return .white
        case .secondary:
            return .primary
        }
    }
}

// MARK: - 预定义的表单操作按钮
extension FormActionButton {
    static func primary(
        title: String,
        action: @escaping () -> Void,
        isEnabled: Bool = true,
        icon: String? = nil
    ) -> FormActionButton {
        FormActionButton(
            title: title,
            action: action,
            isEnabled: isEnabled,
            style: .primary,
            icon: icon
        )
    }
    
    static func secondary(
        title: String,
        action: @escaping () -> Void,
        isEnabled: Bool = true,
        icon: String? = nil
    ) -> FormActionButton {
        FormActionButton(
            title: title,
            action: action,
            isEnabled: isEnabled,
            style: .secondary,
            icon: icon
        )
    }
    
    static func destructive(
        title: String,
        action: @escaping () -> Void,
        isEnabled: Bool = true,
        icon: String? = nil
    ) -> FormActionButton {
        FormActionButton(
            title: title,
            action: action,
            isEnabled: isEnabled,
            style: .destructive,
            icon: icon
        )
    }
    
    static func success(
        title: String,
        action: @escaping () -> Void,
        isEnabled: Bool = true,
        icon: String? = nil
    ) -> FormActionButton {
        FormActionButton(
            title: title,
            action: action,
            isEnabled: isEnabled,
            style: .success,
            icon: icon
        )
    }
}

#Preview {
    FormView(title: "sample_form".localized) {
        FormGroup(title: "basic_info".localized) {
            FormRow(title: "username".localized, isRequired: true, icon: "person") {
                TextField("enter_username".localized, text: .constant(""))
                    .textFieldStyle(RoundedBorderTextFieldStyle())
            }
            
            FormRow(title: "email".localized, isRequired: true, icon: "envelope") {
                TextField("enter_email".localized, text: .constant(""))
                    .textFieldStyle(RoundedBorderTextFieldStyle())
                    .keyboardType(.emailAddress)
            }
        }
        
        FormGroup(title: "actions".localized) {
            FormActionButton.primary(title: "save".localized, action: {})
            FormActionButton.secondary(title: "cancel".localized, action: {})
        }
    }
}