const { ccclass } = cc._decorator;

/** 按可用活动横向翻页；纵向手势继续交给商城 ScrollView。 */
@ccclass
export default class ShopActivityCarousel extends cc.Component {
    private activity: cc.Node = null;
    private progress: cc.Node = null;
    private index: number = 1;
    private centerX: number = 0;
    private touchId: number = null;
    private startX: number = 0;
    private dragX: number = 0;
    private direction: string = "";
    private cancelling: boolean = false;
    private snap: cc.Tween = null;
    private pages: cc.Node[] = [];
    private dotSpacing: number = 0;

    onLoad() {
        this.activity = cc.find("activity", this.node);
        this.progress = cc.find("progress", this.node);
        this.centerX = this.activity.x;
        const dots = this.progress.children;
        this.dotSpacing = dots.length > 1 ? dots[1].x - dots[0].x : 0;
        this.setEntries(["newbieGift", "jungle", "banre"]);
    }

    /** names 按优先级传入；三个入口保留原来的左、中、右排列。 */
    setEntries(names: string[], reset: boolean = false) {
        const available = names.map(name => this.activity.getChildByName(name)).filter(node => !!node);
        const pages = available.length === 3 ? [available[1], available[0], available[2]] : available;
        const changed = pages.length !== this.pages.length || pages.some((page, i) => page !== this.pages[i]);
        if (!changed && !reset) return;
        this.touchId = null;
        if (this.snap) this.snap.stop();
        this.pages = pages;
        this.activity.children.forEach(child => { child.active = pages.indexOf(child) >= 0; });
        pages.forEach((page, i) => page.setSiblingIndex(i));
        this.activity.active = pages.length > 0;
        this.progress.active = pages.length > 0;
        const layout = this.activity.getComponent(cc.Layout);
        if (layout && pages.length) layout.updateLayout();
        this.index = pages.length === 3 ? 1 : 0;
        this.progress.children.forEach((dot, i) => {
            dot.active = i < pages.length;
            if (dot.active) dot.x = (i - (pages.length - 1) / 2) * this.dotSpacing;
        });
        this.showPage(false);
    }

    onEnable() {
        // 让卡片之间的空隙也能接收触摸；在 ScrollView 之前判定方向。
        this.activity.on(cc.Node.EventType.TOUCH_START, this.onActivityTouch, this);
        this.node.on(cc.Node.EventType.TOUCH_START, this.onTouchStart, this, true);
        this.node.on(cc.Node.EventType.TOUCH_MOVE, this.onTouchMove, this, true);
        this.node.on(cc.Node.EventType.TOUCH_END, this.onTouchEnd, this, true);
        this.node.on(cc.Node.EventType.TOUCH_CANCEL, this.onTouchCancel, this, true);
    }

    onDisable() {
        this.activity.off(cc.Node.EventType.TOUCH_START, this.onActivityTouch, this);
        this.node.off(cc.Node.EventType.TOUCH_START, this.onTouchStart, this, true);
        this.node.off(cc.Node.EventType.TOUCH_MOVE, this.onTouchMove, this, true);
        this.node.off(cc.Node.EventType.TOUCH_END, this.onTouchEnd, this, true);
        this.node.off(cc.Node.EventType.TOUCH_CANCEL, this.onTouchCancel, this, true);
        this.touchId = null;
        this.showPage(false);
    }

    private onActivityTouch() {}

    private pageX(index: number): number {
        return this.centerX - this.pages[index].x * this.activity.scaleX;
    }

    private showPage(animated: boolean) {
        if (this.snap) this.snap.stop();
        const x = this.pages.length ? this.pageX(this.index) : this.centerX;
        if (animated) {
            this.snap = cc.tween(this.activity).to(0.2, { x }, { easing: "quadOut" }).start();
        } else {
            this.activity.x = x;
        }
        this.progress.children.forEach((dot, index) => {
            const select = dot.getChildByName("select");
            if (select) select.active = index < this.pages.length && index === this.index;
        });
    }

    private onTouchStart(event: cc.Event.EventTouch) {
        if (this.touchId !== null || this.pages.length < 2) return;
        let target: cc.Node = event.target;
        while (target && target !== this.activity) target = target.parent;
        if (!target) return;
        if (this.snap) this.snap.stop();
        this.touchId = event.getID();
        this.startX = this.activity.parent.convertToNodeSpaceAR(event.getLocation()).x;
        this.dragX = this.activity.x;
        this.direction = "";
    }

    private onTouchMove(event: cc.Event.EventTouch) {
        if (event.getID() !== this.touchId) return;
        const delta = event.getLocation().sub(event.getStartLocation());
        if (!this.direction) {
            if (Math.max(Math.abs(delta.x), Math.abs(delta.y)) < 8) {
                event.stopPropagation();
                return;
            }
            this.direction = Math.abs(delta.x) > Math.abs(delta.y) ? "horizontal" : "vertical";
            if (this.direction === "horizontal") {
                // 取消按钮按下和外层滚动的触摸，避免松手时误触购买。
                const cancel = new cc.Event.EventTouch(event.getTouches(), event.bubbles);
                cancel.type = cc.Node.EventType.TOUCH_CANCEL;
                cancel.touch = event.touch;
                this.cancelling = true;
                event.target.dispatchEvent(cancel);
                this.cancelling = false;
            }
        }
        if (this.direction !== "horizontal") return;
        event.stopPropagation();
        const offset = this.activity.parent.convertToNodeSpaceAR(event.getLocation()).x - this.startX;
        const left = this.pageX(Math.min(this.index + 1, this.pages.length - 1));
        const right = this.pageX(Math.max(this.index - 1, 0));
        this.activity.x = Math.max(left, Math.min(right, this.dragX + offset));
    }

    private onTouchEnd(event: cc.Event.EventTouch) {
        if (event.getID() !== this.touchId) return;
        if (this.direction === "horizontal") {
            event.stopPropagation();
            const offset = this.activity.parent.convertToNodeSpaceAR(event.getLocation()).x - this.startX;
            if (Math.abs(offset) >= 20) {
                this.index = Math.max(0, Math.min(this.pages.length - 1,
                    this.index + (offset > 0 ? -1 : 1)));
            }
        }
        this.touchId = null;
        this.showPage(true);
    }

    private onTouchCancel(event: cc.Event.EventTouch) {
        // ScrollView 为取消按钮点击而派发的模拟事件不是手势结束。
        if (this.cancelling || (event as any).simulate || event.getID() !== this.touchId) return;
        // Cocos 在原触摸节点外松手也派发 TOUCH_CANCEL，底层事件仍为 ENDED。
        if (event.getEventCode() === (cc.Event.EventTouch as any).ENDED) {
            this.onTouchEnd(event);
            return;
        }
        if (this.direction === "horizontal") event.stopPropagation();
        this.touchId = null;
        this.showPage(true);
    }
}