import SwiftUI

// MARK: - 通用文本编辑器组件
struct TextEditorView: View {
    let title: String
    let isRequired: Bool
    let placeholder: String
    let text: Binding<String>
    let maxCharacters: Int
    let minHeight: CGFloat
    let icon: String?
    let isFocused: Bool
    let onFocusChange: (Bool) -> Void
    
    init(
        title: String,
        isRequired: Bool = false,
        placeholder: String,
        text: Binding<String>,
        maxCharacters: Int = 1000,
        minHeight: CGFloat = 120,
        icon: String? = nil,
        isFocused: Bool = false,
        onFocusChange: @escaping (Bool) -> Void = { _ in }
    ) {
        self.title = title
        self.isRequired = isRequired
        self.placeholder = placeholder
        self.text = text
        self.maxCharacters = maxCharacters
        self.minHeight = minHeight
        self.icon = icon
        self.isFocused = isFocused
        self.onFocusChange = onFocusChange
    }
    
    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            InputTitleView.required(title, icon: icon)
            
            ZStack {
                // 文本编辑器主体
                TextEditor(text: text)
                    .frame(minHeight: minHeight)
                    .padding(8)
                    .background(Color(.systemBackground))
                    .cornerRadius(8)
                    .overlay(
                        RoundedRectangle(cornerRadius: 8)
                            .stroke(isFocused ? Color.blue : Color(.systemGray4), lineWidth: 1)
                    )
                    .onChange(of: text.wrappedValue) { newValue in
                        // 限制最大字符数
                        if newValue.count > maxCharacters {
                            text.wrappedValue = String(newValue.prefix(maxCharacters))
                        }
                    }
                    .onTapGesture {
                        onFocusChange(true)
                    }
                
                // 占位符文本 - 左上角对齐
                if text.wrappedValue.isEmpty && !isFocused {
                    VStack {
                        HStack {
                            Text(placeholder)
                                .foregroundColor(.secondary)
                                .font(.body)
                            Spacer()
                        }
                        Spacer()
                    }
                    .padding(16)
                    .allowsHitTesting(false)
                    .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .topLeading)
                }
            }
            
            // 字符计数
            HStack {
                Spacer()
                Text("\(text.wrappedValue.count)/\(maxCharacters)")
                    .font(.caption)
                    .foregroundColor(getCharacterCountColor())
            }
        }
    }
    
    private func getCharacterCountColor() -> Color {
        let count = text.wrappedValue.count
        if count >= maxCharacters {
            return .orange
        } else if count >= Int(Double(maxCharacters) * 0.9) {
            return .blue
        } else {
            return .secondary
        }
    }
}

// MARK: - 预定义的文本编辑器样式
extension TextEditorView {
    static func description(
        title: String,
        isRequired: Bool = false,
        placeholder: String,
        text: Binding<String>,
        maxCharacters: Int = 500,
        icon: String? = nil,
        isFocused: Bool = false,
        onFocusChange: @escaping (Bool) -> Void = { _ in }
    ) -> TextEditorView {
        TextEditorView(
            title: title,
            isRequired: isRequired,
            placeholder: placeholder,
            text: text,
            maxCharacters: maxCharacters,
            minHeight: 100,
            icon: icon,
            isFocused: isFocused,
            onFocusChange: onFocusChange
        )
    }
    
    static func longText(
        title: String,
        isRequired: Bool = false,
        placeholder: String,
        text: Binding<String>,
        maxCharacters: Int = 1000,
        icon: String? = nil,
        isFocused: Bool = false,
        onFocusChange: @escaping (Bool) -> Void = { _ in }
    ) -> TextEditorView {
        TextEditorView(
            title: title,
            isRequired: isRequired,
            placeholder: placeholder,
            text: text,
            maxCharacters: maxCharacters,
            minHeight: 150,
            icon: icon,
            isFocused: isFocused,
            onFocusChange: onFocusChange
        )
    }
    
    static func emailBody(
        title: String,
        isRequired: Bool = false,
        placeholder: String,
        text: Binding<String>,
        maxCharacters: Int = 1200,
        icon: String? = nil,
        isFocused: Bool = false,
        onFocusChange: @escaping (Bool) -> Void = { _ in }
    ) -> TextEditorView {
        TextEditorView(
            title: title,
            isRequired: isRequired,
            placeholder: placeholder,
            text: text,
            maxCharacters: maxCharacters,
            minHeight: 120,
            icon: icon,
            isFocused: isFocused,
            onFocusChange: onFocusChange
        )
    }
}

#Preview {
    VStack(spacing: 16) {
        TextEditorView.description(
            title: "描述",
            isRequired: true,
            placeholder: "请输入描述内容...",
            text: .constant(""),
            icon: "text.quote"
        )
        
        TextEditorView.longText(
            title: "长文本",
            isRequired: false,
            placeholder: "请输入长文本内容...",
            text: .constant(""),
            icon: "doc.text"
        )
        
        TextEditorView.emailBody(
            title: "邮件正文",
            isRequired: true,
            placeholder: "输入邮件正文内容...",
            text: .constant(""),
            icon: "envelope"
        )
    }
    .padding()
}