// 模拟 WPF 相关类
class FrameworkElement {
    visibility: 'Visible' | 'Hidden' | 'Collapsed' = 'Visible';
    actualHeight: number = 0;
    actualWidth: number = 0;
    tabIndex: number = 0;

    constructor(public x: number, public y: number) { }

    translatePoint(point: { x: number, y: number }, root: FrameworkElement): { x: number, y: number } {
        return { x: this.x + point.x, y: this.y + point.y };
    }
}

class ScrollViewer extends FrameworkElement { }

// 模拟 Platform.Common 中的方法
class VisualTreeHelper {
    static getChildrenCount(element: FrameworkElement): number {
        // 模拟实现，实际需要根据具体情况实现
        return 0;
    }

    static getChild(element: FrameworkElement, index: number): FrameworkElement | null {
        // 模拟实现，实际需要根据具体情况实现
        return null;
    }
}

class FocusManager {
    static getOnlyMouseControlHandled(element: FrameworkElement): any | null {
        // 模拟实现，实际需要根据具体情况实现
        return null;
    }

    static getIsInternalKeyboardControlling(element: FrameworkElement): boolean {
        // 模拟实现，实际需要根据具体情况实现
        return true;
    }
}

// 扩展 FrameworkElement 类以模拟 FindVisualTreeAncestor 方法
interface FrameworkElement {
    findVisualTreeAncestor(handle: (element: any) => boolean): any | null;
}

FrameworkElement.prototype.findVisualTreeAncestor = function (handle: (element: any) => boolean): any | null {
    let current: any = this;
    while (current) {
        if (handle(current)) {
            return current;
        }
        // 模拟父元素，实际需要根据具体情况实现
        current = null;
    }
    return null;
};

export default class FocusList implements Iterable<FrameworkElement> {
    private _internalList: FrameworkElement[] = [];
    private _rootElement: FrameworkElement;
    private stackOperatorVisible: FrameworkElement[] = [];

    private constructor(rootElement: FrameworkElement) {
        this._rootElement = rootElement;
        this.refresh();
    }

    static create(rootElement: FrameworkElement): FocusList {
        return new FocusList(rootElement);
    }

    private compareByLocation(targetElement: FrameworkElement, currentElement: FrameworkElement): boolean {
        const handle = (x: any) => x instanceof ScrollViewer;
        const targetScrollViewer = targetElement.findVisualTreeAncestor(handle) as ScrollViewer | null;
        const currentScrollViewer = currentElement.findVisualTreeAncestor(handle) as ScrollViewer | null;

        if (targetScrollViewer && currentScrollViewer && targetScrollViewer !== currentScrollViewer) {
            if (true) {//TODD焦点的控制涉及到FrameworkElement targetScrollViewer.isAncestorOf(currentScrollViewer) 缺少方法isAncestorOf
                currentElement = currentScrollViewer;
            } else {
                targetElement = targetScrollViewer;
            }
        } else if (!targetScrollViewer || !currentScrollViewer || targetScrollViewer !== currentScrollViewer) {
            if (targetScrollViewer) targetElement = targetScrollViewer;
            if (currentScrollViewer) currentElement = currentScrollViewer;
        }

        const locationPoint = { x: 0, y: 0 };
        const targetElementOffset = targetElement.translatePoint(locationPoint, this._rootElement);
        const currentElementOffset = currentElement.translatePoint(locationPoint, this._rootElement);

        if (targetElementOffset.y + targetElement.actualHeight <= currentElementOffset.y + currentElement.actualHeight / 2) {
            return true;
        }

        return targetElementOffset.x <= currentElementOffset.x &&
            targetElementOffset.y <= currentElementOffset.y + currentElement.actualHeight / 2;
    }

    private getFocusChildren(rootElement: FrameworkElement) {
        if (!rootElement) return;

        if (rootElement.visibility === 'Collapsed') {
            this.stackOperatorVisible.push(rootElement);
            rootElement.visibility = 'Hidden';
            // 模拟 UpdateLayout 方法
            // rootElement.updateLayout();
        }

        const childrenCount = VisualTreeHelper.getChildrenCount(rootElement);
        for (let i = 0; i < childrenCount; i++) {
            const child = VisualTreeHelper.getChild(rootElement, i) as FrameworkElement | null;
            if (!child) continue;

            if (FocusManager.getOnlyMouseControlHandled(child) !== null) continue;

            if (!FocusManager.getIsInternalKeyboardControlling(child)) {
                this.getFocusChildren(child);
            } else {
                if (child.visibility === 'Collapsed') {
                    this.stackOperatorVisible.push(child);
                    child.visibility = 'Visible';
                    // 模拟 UpdateLayout 方法
                    // rootElement.updateLayout();
                }

                const insertIndex = this.getInsertIndex(child);
                this._internalList.splice(insertIndex, 0, child);
            }
        }
    }

    private getInsertIndex(targetElement: FrameworkElement): number {
        let currentIndex = this._internalList.length - 1;

        while (currentIndex > -1) {
            const currentElement = this._internalList[currentIndex];
            if (targetElement.tabIndex === currentElement.tabIndex) {
                if (!this.compareByLocation(targetElement, currentElement)) {
                    return currentIndex + 1;
                }
            } else if (targetElement.tabIndex > currentElement.tabIndex) {
                return currentIndex + 1;
            } else if (!this.compareByLocation(targetElement, currentElement)) {
                return currentIndex + 1;
            }
            currentIndex--;
        }
        return currentIndex > -1 ? currentIndex : 0;
    }

    refresh() {
        // 模拟 IsVisible 和 IsLoaded 属性
        if (true) {
            this._internalList = [];
            this.stackOperatorVisible = [];
            this.getFocusChildren(this._rootElement);

            this.stackOperatorVisible.forEach((current) => {
                current.visibility = 'Collapsed';
            });
        }
    }

    get count(): number {
        return this._internalList.length;
    }

    get(index: number): FrameworkElement {
        return this._internalList[index];
    }

    indexOf(element: FrameworkElement): number {
        return this._internalList.indexOf(element);
    }

    [Symbol.iterator](): Iterator<FrameworkElement> {
        return this._internalList[Symbol.iterator]();
    }
}

export { FocusList, FrameworkElement };
