import SwiftUI

/// 控件渲染器 — 递归将JSON schema渲染为SwiftUI视图
/// 这是SwiftBricks的核心，对应Bricks的widget实例化链
public struct ControlRenderer: View {
    let schema: ControlSchema
    @ObservedObject var engine: BricksEngine
    
    public init(schema: ControlSchema, engine: BricksEngine) {
        self.schema = schema
        self.engine = engine
    }
    
    public var body: some View {
        let pctHeight = parsePercentHeight(schema.options.height)
        renderWidget(schema)
            .frame(
                maxWidth: resolveWidth(schema.options),
                maxHeight: pctHeight != nil ? .infinity : resolveHeight(schema.options),
                alignment: resolveAlignment(schema.options)
            )
            .layoutPriority(pctHeight ?? 0)
    }
    
    // MARK: - Widget分发
    
    @ViewBuilder
    func renderWidget(_ schema: ControlSchema) -> some View {
        let type = schema.widgettype
        
        // 优先查找自定义注册的widget
        if let factory = engine.getWidgetFactory(type: type) {
            factory(schema, engine)
        } else {
        renderKnownWidget(schema, type: type)
        }
    }
    
    @ViewBuilder
    func renderKnownWidget(_ schema: ControlSchema, type: String) -> some View {
        switch type {
        // 文本类
        case "Text":
            TextControl(schema: schema, engine: engine)
        case "Title1":
            TitleControl(schema: schema, engine: engine, level: 1)
        case "Title2":
            TitleControl(schema: schema, engine: engine, level: 2)
        case "Title3":
            TitleControl(schema: schema, engine: engine, level: 3)
        case "Title4":
            TitleControl(schema: schema, engine: engine, level: 4)
        case "Title5":
            TitleControl(schema: schema, engine: engine, level: 5)
        case "Title6":
            TitleControl(schema: schema, engine: engine, level: 6)
        case "Label":
            LabelControl(schema: schema, engine: engine)
            
        // 输入类
        case "Input", "UiStr":
            InputControl(schema: schema, engine: engine)
        case "Textarea", "UiText":
            TextareaControl(schema: schema, engine: engine)
        case "UiNumber":
            NumberControl(schema: schema, engine: engine)
        case "UiDate":
            DateControl(schema: schema, engine: engine)
        case "Select", "UiCode":
            SelectControl(schema: schema, engine: engine)
            
        // 按钮
        case "Button":
            ButtonControl(schema: schema, engine: engine)
            
        // 布局
        case "VBox", "Card":
            VBoxControl(schema: schema, engine: engine)
        case "HBox":
            HBoxControl(schema: schema, engine: engine)
        case "VScrollPanel", "HScrollPanel":
            ScrollPanelControl(schema: schema, engine: engine)
        case "Filler":
            Spacer().frame(maxWidth: .infinity, maxHeight: .infinity)
        case "DynamicColumn":
            DynamicColumnControl(schema: schema, engine: engine)
            
        // 数据展示
        case "Tabular", "DataViewer":
            TabularControl(schema: schema, engine: engine)
        case "Form":
            FormControl(schema: schema, engine: engine)
        case "InlineForm":
            InlineFormControl(schema: schema, engine: engine)
            
        // 导航
        case "TabView":
            TabViewControl(schema: schema, engine: engine)
        case "Menu":
            MenuControl(schema: schema, engine: engine)
            
        // 弹窗
        case "PopupWindow":
            PopupWindowControl(schema: schema, engine: engine)
            
        // HTML
        case "Html":
            HtmlControl(schema: schema, engine: engine)
            
        // Image
        case "Image":
            ImageControl(schema: schema, engine: engine)
        
        // VideoPlayer
        case "VideoPlayer":
            VideoPlayerControl(schema: schema, engine: engine)
            
        // urlwidget（直接加载远程内容）
        case "urlwidget":
            UrlWidgetControl(schema: schema, engine: engine)
            
        default:
            // 未知widgettype — 渲染占位符
            VStack {
                Text("⚠️ Unknown: \(type)")
                    .font(.caption)
                    .foregroundColor(.secondary)
            }
        }
    }
    
    // MARK: - 尺寸解析
    
    private func resolveWidth(_ opts: ControlOptions) -> CGFloat? {
        if let w = opts.width {
            if w == "100%" { return nil } // 使用frame的maxWidth
            if let px = parsePixels(w) { return px }
        }
        return nil
    }
    
    private func resolveHeight(_ opts: ControlOptions) -> CGFloat? {
        if let h = opts.height {
            if h == "100%" { return nil }
            if let px = parsePixels(h) { return px }
        }
        return nil
    }
    
    private func resolveAlignment(_ opts: ControlOptions) -> Alignment {
        switch opts.alignItems {
        case "center": return .center
        case "flex-end", "end": return .trailing
        case "flex-start", "start": return .leading
        default: return .topLeading
        }
    }
    
    private func parsePercentHeight(_ h: String?) -> Double? {
        guard let h = h, h.hasSuffix("%"), let val = Double(h.dropLast()) else { return nil }
        return val > 0 ? val : nil
    }
    
    private func parsePixels(_ str: String) -> CGFloat? {
        let cleaned = str.replacingOccurrences(of: "px", with: "")
        return CGFloat(Double(cleaned) ?? 0)
    }
}

// MARK: - 渲染子控件列表

struct SubWidgetsView: View {
    let subwidgets: [ControlSchema]
    @ObservedObject var engine: BricksEngine
    
    var body: some View {
        ForEach(Array(subwidgets.enumerated()), id: \.offset) { _, sub in
            ControlRenderer(schema: sub, engine: engine)
        }
    }
}