// Definitions.
import { View as ViewDefinition, Point, Size, Color } from ".";
import { HorizontalAlignment, VerticalAlignment, Visibility, Length, PercentLength } from "../../styling/style-properties";

// Types.
import { Source } from "../../../utils/debug";

import {
    ViewBase, Property, booleanConverter, EventData, layout,
    getEventOrGestureName, traceEnabled, traceWrite, traceCategories
} from "../view-base";

import {
    observe as gestureObserve,
    GesturesObserver,
    GestureTypes,
    GestureEventData,
    fromString as gestureFromString
} from "../../gestures";

export * from "../../styling/style-properties";
export * from "../view-base";

import * as am from "../../animation";
let animationModule: typeof am;
function ensureAnimationModule() {
    if (!animationModule) {
        animationModule = require("ui/animation");
    }
}

export function PseudoClassHandler(...pseudoClasses: string[]): MethodDecorator {
    let stateEventNames = pseudoClasses.map(s => ":" + s);
    let listeners = Symbol("listeners");
    return <T>(target: Object, propertyKey: string | symbol, descriptor: TypedPropertyDescriptor<T>) => {
        function update(change: number) {
            let prev = this[listeners] || 0;
            let next = prev + change;
            if (prev <= 0 && next > 0) {
                this[propertyKey](true);
            } else if (prev > 0 && next <= 0) {
                this[propertyKey](false);
            }
        }
        stateEventNames.forEach(s => target[s] = update);
    };
}

export abstract class ViewCommon extends ViewBase implements ViewDefinition {
    private _measuredWidth: number;
    private _measuredHeight: number;

    _currentWidthMeasureSpec: number;
    _currentHeightMeasureSpec: number;

    _minWidthNative: Length;
    _minHeightNative: Length;

    private _isLayoutValid: boolean;
    private _cssType: string;

    public _gestureObservers = {};

    observe(type: GestureTypes, callback: (args: GestureEventData) => void, thisArg?: any): void {
        if (!this._gestureObservers[type]) {
            this._gestureObservers[type] = [];
        }

        this._gestureObservers[type].push(gestureObserve(this, type, callback, thisArg));
    }

    public getGestureObservers(type: GestureTypes): Array<GesturesObserver> {
        return this._gestureObservers[type];
    }

    public addEventListener(arg: string | GestureTypes, callback: (data: EventData) => void, thisArg?: any) {
        if (typeof arg === "string") {
            arg = getEventOrGestureName(arg);

            let gesture = gestureFromString(arg);
            if (gesture && !this._isEvent(arg)) {
                this.observe(gesture, callback, thisArg);
            } else {
                let events = (arg).split(",");
                if (events.length > 0) {
                    for (let i = 0; i < events.length; i++) {
                        let evt = events[i].trim();
                        let gst = gestureFromString(evt);
                        if (gst && !this._isEvent(arg)) {
                            this.observe(gst, callback, thisArg);
                        } else {
                            super.addEventListener(evt, callback, thisArg);
                        }
                    }
                } else {
                    super.addEventListener(arg, callback, thisArg);
                }
            }
        } else if (typeof arg === "number") {
            this.observe(<GestureTypes>arg, callback, thisArg);
        }
    }

    public removeEventListener(arg: string | GestureTypes, callback?: any, thisArg?: any) {
        if (typeof arg === "string") {
            let gesture = gestureFromString(arg);
            if (gesture && !this._isEvent(arg)) {
                this._disconnectGestureObservers(gesture);
            } else {
                let events = arg.split(",");
                if (events.length > 0) {
                    for (let i = 0; i < events.length; i++) {
                        let evt = events[i].trim();
                        let gst = gestureFromString(evt);
                        if (gst && !this._isEvent(arg)) {
                            this._disconnectGestureObservers(gst);
                        } else {
                            super.removeEventListener(evt, callback, thisArg);
                        }
                    }
                } else {
                    super.removeEventListener(arg, callback, thisArg);
                }

            }
        } else if (typeof arg === "number") {
            this._disconnectGestureObservers(<GestureTypes>arg);
        }
    }

    private _isEvent(name: string): boolean {
        return this.constructor && `${name}Event` in this.constructor;
    }

    private _disconnectGestureObservers(type: GestureTypes): void {
        let observers = this.getGestureObservers(type);
        if (observers) {
            for (let i = 0; i < observers.length; i++) {
                observers[i].disconnect();
            }
        }
    }

    // START Style property shortcuts
    get borderColor(): string | Color {
        return this.style.borderColor;
    }
    set borderColor(value: string | Color) {
        this.style.borderColor = value;
    }

    get borderTopColor(): Color {
        return this.style.borderTopColor;
    }
    set borderTopColor(value: Color) {
        this.style.borderTopColor = value;
    }

    get borderRightColor(): Color {
        return this.style.borderRightColor;
    }
    set borderRightColor(value: Color) {
        this.style.borderRightColor = value;
    }

    get borderBottomColor(): Color {
        return this.style.borderBottomColor;
    }
    set borderBottomColor(value: Color) {
        this.style.borderBottomColor = value;
    }

    get borderLeftColor(): Color {
        return this.style.borderLeftColor;
    }
    set borderLeftColor(value: Color) {
        this.style.borderLeftColor = value;
    }

    get borderWidth(): string | Length {
        return this.style.borderWidth;
    }
    set borderWidth(value: string | Length) {
        this.style.borderWidth = value;
    }

    get borderTopWidth(): Length {
        return this.style.borderTopWidth;
    }
    set borderTopWidth(value: Length) {
        this.style.borderTopWidth = value;
    }

    get borderRightWidth(): Length {
        return this.style.borderRightWidth;
    }
    set borderRightWidth(value: Length) {
        this.style.borderRightWidth = value;
    }

    get borderBottomWidth(): Length {
        return this.style.borderBottomWidth;
    }
    set borderBottomWidth(value: Length) {
        this.style.borderBottomWidth = value;
    }

    get borderLeftWidth(): Length {
        return this.style.borderLeftWidth;
    }
    set borderLeftWidth(value: Length) {
        this.style.borderLeftWidth = value;
    }

    get borderRadius(): string | Length {
        return this.style.borderRadius;
    }
    set borderRadius(value: string | Length) {
        this.style.borderRadius = value;
    }

    get borderTopLeftRadius(): Length {
        return this.style.borderTopLeftRadius;
    }
    set borderTopLeftRadius(value: Length) {
        this.style.borderTopLeftRadius = value;
    }

    get borderTopRightRadius(): Length {
        return this.style.borderTopRightRadius;
    }
    set borderTopRightRadius(value: Length) {
        this.style.borderTopRightRadius = value;
    }

    get borderBottomRightRadius(): Length {
        return this.style.borderBottomRightRadius;
    }
    set borderBottomRightRadius(value: Length) {
        this.style.borderBottomRightRadius = value;
    }

    get borderBottomLeftRadius(): Length {
        return this.style.borderBottomLeftRadius;
    }
    set borderBottomLeftRadius(value: Length) {
        this.style.borderBottomLeftRadius = value;
    }

    get color(): Color {
        return this.style.color;
    }
    set color(value: Color) {
        this.style.color = value;
    }

    get backgroundColor(): Color {
        return this.style.backgroundColor;
    }
    set backgroundColor(value: Color) {
        this.style.backgroundColor = value;
    }

    get backgroundImage(): string {
        return this.style.backgroundImage;
    }
    set backgroundImage(value: string) {
        this.style.backgroundImage = value;
    }

    get minWidth(): Length {
        return this.style.minWidth;
    }
    set minWidth(value: Length) {
        this.style.minWidth = value;
    }

    get minHeight(): Length {
        return this.style.minHeight;
    }
    set minHeight(value: Length) {
        this.style.minHeight = value;
    }

    get width(): PercentLength {
        return this.style.width;
    }
    set width(value: PercentLength) {
        this.style.width = value;
    }

    get height(): PercentLength {
        return this.style.height;
    }
    set height(value: PercentLength) {
        this.style.height = value;
    }

    get margin(): string | PercentLength {
        return this.style.margin;
    }
    set margin(value: string | PercentLength) {
        this.style.margin = value;
    }

    get marginLeft(): PercentLength {
        return this.style.marginLeft;
    }
    set marginLeft(value: PercentLength) {
        this.style.marginLeft = value;
    }

    get marginTop(): PercentLength {
        return this.style.marginTop;
    }
    set marginTop(value: PercentLength) {
        this.style.marginTop = value;
    }

    get marginRight(): PercentLength {
        return this.style.marginRight;
    }
    set marginRight(value: PercentLength) {
        this.style.marginRight = value;
    }

    get marginBottom(): PercentLength {
        return this.style.marginBottom;
    }
    set marginBottom(value: PercentLength) {
        this.style.marginBottom = value;
    }

    get horizontalAlignment(): HorizontalAlignment {
        return this.style.horizontalAlignment;
    }
    set horizontalAlignment(value: HorizontalAlignment) {
        this.style.horizontalAlignment = value;
    }

    get verticalAlignment(): VerticalAlignment {
        return this.style.verticalAlignment;
    }
    set verticalAlignment(value: VerticalAlignment) {
        this.style.verticalAlignment = value;
    }

    get visibility(): Visibility {
        return this.style.visibility;
    }
    set visibility(value: Visibility) {
        this.style.visibility = value;
    }

    get opacity(): number {
        return this.style.opacity;
    }
    set opacity(value: number) {
        this.style.opacity = value;
    }

    get rotate(): number {
        return this.style.rotate;
    }
    set rotate(value: number) {
        this.style.rotate = value;
    }

    get translateX(): Length {
        return this.style.translateX;
    }
    set translateX(value: Length) {
        this.style.translateX = value;
    }

    get translateY(): Length {
        return this.style.translateY;
    }
    set translateY(value: Length) {
        this.style.translateY = value;
    }

    get scaleX(): number {
        return this.style.scaleX;
    }
    set scaleX(value: number) {
        this.style.scaleX = value;
    }

    get scaleY(): number {
        return this.style.scaleY;
    }
    set scaleY(value: number) {
        this.style.scaleY = value;
    }

    //END Style property shortcuts

    public automationText: string;
    public originX: number;
    public originY: number;
    public isEnabled: boolean;
    public isUserInteractionEnabled: boolean;

    get isLayoutValid(): boolean {
        return this._isLayoutValid;
    }

    get cssType(): string {
        if (!this._cssType) {
            this._cssType = this.typeName.toLowerCase();
        }
        return this._cssType;
    }

    get isLayoutRequired(): boolean {
        return true;
    }

    public measure(widthMeasureSpec: number, heightMeasureSpec: number): void {
        this._setCurrentMeasureSpecs(widthMeasureSpec, heightMeasureSpec);
    }

    public layout(left: number, top: number, right: number, bottom: number): void {
        this._setCurrentLayoutBounds(left, top, right, bottom);
    }

    public getMeasuredWidth(): number {
        return this._measuredWidth & layout.MEASURED_SIZE_MASK || 0;
    }

    public getMeasuredHeight(): number {
        return this._measuredHeight & layout.MEASURED_SIZE_MASK || 0;
    }

    public getMeasuredState(): number {
        return (this._measuredWidth & layout.MEASURED_STATE_MASK)
            | ((this._measuredHeight >> layout.MEASURED_HEIGHT_STATE_SHIFT)
                & (layout.MEASURED_STATE_MASK >> layout.MEASURED_HEIGHT_STATE_SHIFT));
    }

    public setMeasuredDimension(measuredWidth: number, measuredHeight: number): void {
        this._measuredWidth = measuredWidth;
        this._measuredHeight = measuredHeight;
        if (traceEnabled()) {
            traceWrite(this + " :setMeasuredDimension: " + measuredWidth + ", " + measuredHeight, traceCategories.Layout);
        }
    }

    public requestLayout(): void {
        this._isLayoutValid = false;
    }

    public abstract onMeasure(widthMeasureSpec: number, heightMeasureSpec: number): void;
    public abstract onLayout(left: number, top: number, right: number, bottom: number): void;
    public abstract layoutNativeView(left: number, top: number, right: number, bottom: number): void;

    public static resolveSizeAndState(size: number, specSize: number, specMode: number, childMeasuredState: number): number {
        let result = size;
        switch (specMode) {
            case layout.UNSPECIFIED:
                result = size;
                break;

            case layout.AT_MOST:
                if (specSize < size) {
                    result = Math.round(specSize + 0.499) | layout.MEASURED_STATE_TOO_SMALL;
                }
                break;

            case layout.EXACTLY:
                result = specSize;
                break;
        }

        return Math.round(result + 0.499) | (childMeasuredState & layout.MEASURED_STATE_MASK);
    }

    public static combineMeasuredStates(curState: number, newState): number {
        return curState | newState;
    }

    public static layoutChild(parent: ViewDefinition, child: ViewDefinition, left: number, top: number, right: number, bottom: number): void {
        if (!child || child.isCollapsed) {
            return;
        }

        let childStyle = child.style;

        let childTop: number;
        let childLeft: number;

        let childWidth = child.getMeasuredWidth();
        let childHeight = child.getMeasuredHeight();

        let effectiveMarginTop = child.effectiveMarginTop;
        let effectiveMarginBottom = child.effectiveMarginBottom;

        let vAlignment: VerticalAlignment;
        if (child.effectiveHeight >= 0 && childStyle.verticalAlignment === "stretch") {
            vAlignment = "middle";
        }
        else {
            vAlignment = childStyle.verticalAlignment;
        }

        switch (vAlignment) {
            case "top":
                childTop = top + effectiveMarginTop;
                break;

            case "middle":
                childTop = top + (bottom - top - childHeight + (effectiveMarginTop - effectiveMarginBottom)) / 2;
                break;

            case "bottom":
                childTop = bottom - childHeight - effectiveMarginBottom;
                break;

            case "stretch":
            default:
                childTop = top + effectiveMarginTop;
                childHeight = bottom - top - (effectiveMarginTop + effectiveMarginBottom);
                break;
        }

        let effectiveMarginLeft = child.effectiveMarginLeft;
        let effectiveMarginRight = child.effectiveMarginRight;

        let hAlignment: HorizontalAlignment;
        if (child.effectiveWidth >= 0 && childStyle.horizontalAlignment === "stretch") {
            hAlignment = "center";
        }
        else {
            hAlignment = childStyle.horizontalAlignment;
        }

        switch (hAlignment) {
            case "left":
                childLeft = left + effectiveMarginLeft;
                break;

            case "center":
                childLeft = left + (right - left - childWidth + (effectiveMarginLeft - effectiveMarginRight)) / 2;
                break;

            case "right":
                childLeft = right - childWidth - effectiveMarginRight;
                break;

            case "stretch":
            default:
                childLeft = left + effectiveMarginLeft;
                childWidth = right - left - (effectiveMarginLeft + effectiveMarginRight);
                break;
        }

        let childRight = Math.round(childLeft + childWidth);
        let childBottom = Math.round(childTop + childHeight);
        childLeft = Math.round(childLeft);
        childTop = Math.round(childTop);

        if (traceEnabled()) {
            traceWrite(child.parent + " :layoutChild: " + child + " " + childLeft + ", " + childTop + ", " + childRight + ", " + childBottom, traceCategories.Layout);
        }

        child.layout(childLeft, childTop, childRight, childBottom);
    }

    public static measureChild(parent: ViewCommon, child: ViewCommon, widthMeasureSpec: number, heightMeasureSpec: number): { measuredWidth: number; measuredHeight: number } {
        let measureWidth = 0;
        let measureHeight = 0;

        if (child && !child.isCollapsed) {
            let width = layout.getMeasureSpecSize(widthMeasureSpec);
            let widthMode = layout.getMeasureSpecMode(widthMeasureSpec);

            let height = layout.getMeasureSpecSize(heightMeasureSpec);
            let heightMode = layout.getMeasureSpecMode(heightMeasureSpec);

            child._updateEffectiveLayoutValues(parent);

            let style = child.style;
            let horizontalMargins = child.effectiveMarginLeft + child.effectiveMarginRight;
            let verticalMargins = child.effectiveMarginTop + child.effectiveMarginBottom;

            let childWidthMeasureSpec = ViewCommon.getMeasureSpec(width, widthMode, horizontalMargins, child.effectiveWidth, style.horizontalAlignment === "stretch");
            let childHeightMeasureSpec = ViewCommon.getMeasureSpec(height, heightMode, verticalMargins, child.effectiveHeight, style.verticalAlignment === "stretch");

            if (traceEnabled()) {
                traceWrite(child.parent + " :measureChild: " + child + " " + layout.measureSpecToString(childWidthMeasureSpec) + ", " + layout.measureSpecToString(childHeightMeasureSpec), traceCategories.Layout);
            }

            child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
            measureWidth = Math.round(child.getMeasuredWidth() + horizontalMargins);
            measureHeight = Math.round(child.getMeasuredHeight() + verticalMargins);
        }

        return { measuredWidth: measureWidth, measuredHeight: measureHeight };
    }

    private static getMeasureSpec(parentLength: number, parentSpecMode: number, margins: number, childLength: number, stretched: boolean): number {
        let resultSize: number;
        let resultMode: number;

        // We want a specific size... let be it.
        if (childLength >= 0) {
            // If mode !== UNSPECIFIED we take the smaller of parentLength and childLength
            // Otherwise we will need to clip the view but this is not possible in all Android API levels.
            resultSize = parentSpecMode === layout.UNSPECIFIED ? childLength : Math.min(parentLength, childLength);
            resultMode = layout.EXACTLY;
        }
        else {
            switch (parentSpecMode) {
                // Parent has imposed an exact size on us
                case layout.EXACTLY:
                    resultSize = Math.max(0, parentLength - margins);
                    // if stretched - nativeView wants to be our size. So be it.
                    // else - nativeView wants to determine its own size. It can't be bigger than us.
                    resultMode = stretched ? layout.EXACTLY : layout.AT_MOST;
                    break;

                // Parent has imposed a maximum size on us
                case layout.AT_MOST:
                    resultSize = Math.max(0, parentLength - margins);
                    resultMode = layout.AT_MOST;
                    break;

                // Equivalent to measure with Infinity.
                case layout.UNSPECIFIED:
                    resultSize = 0;
                    resultMode = layout.UNSPECIFIED;
                    break;
            }
        }

        return layout.makeMeasureSpec(resultSize, resultMode);
    }

    _setCurrentMeasureSpecs(widthMeasureSpec: number, heightMeasureSpec: number): boolean {
        let changed: boolean = this._currentWidthMeasureSpec !== widthMeasureSpec || this._currentHeightMeasureSpec !== heightMeasureSpec;
        this._currentWidthMeasureSpec = widthMeasureSpec;
        this._currentHeightMeasureSpec = heightMeasureSpec;
        return changed;
    }

    _getCurrentLayoutBounds(): { left: number; top: number; right: number; bottom: number } {
        return { left: this._oldLeft, top: this._oldTop, right: this._oldRight, bottom: this._oldBottom };
    }

    /**
     * Returns two booleans - the first if "boundsChanged" the second is "sizeChanged".
     */
    _setCurrentLayoutBounds(left: number, top: number, right: number, bottom: number): { boundsChanged: boolean, sizeChanged: boolean } {
        this._isLayoutValid = true;
        let boundsChanged: boolean = this._oldLeft !== left || this._oldTop !== top || this._oldRight !== right || this._oldBottom !== bottom;
        let sizeChanged: boolean = (this._oldRight - this._oldLeft !== right - left) || (this._oldBottom - this._oldTop !== bottom - top);
        this._oldLeft = left;
        this._oldTop = top;
        this._oldRight = right;
        this._oldBottom = bottom;
        return { boundsChanged, sizeChanged };
    }

    public eachChild(callback: (child: ViewBase) => boolean): void {
        this.eachChildView(<any>callback);
    }

    public eachChildView(callback: (view: ViewDefinition) => boolean) {
        //
    }

    _getNativeViewsCount(): number {
        return this._isAddedToNativeVisualTree ? 1 : 0;
    }

    _eachLayoutView(callback: (View) => void): void {
        return callback(this);
    }

    public _updateLayout() {
        // needed for iOS.
    }

    get _nativeView(): any {
        return undefined;
    }

    public focus(): boolean {
        return undefined;
    }

    public getLocationInWindow(): Point {
        return undefined;
    }

    public getLocationOnScreen(): Point {
        return undefined;
    }

    public getLocationRelativeTo(otherView: ViewDefinition): Point {
        return undefined;
    }

    public getActualSize(): Size {
        let currentBounds = this._getCurrentLayoutBounds();
        if (!currentBounds) {
            return undefined;
        }

        return {
            width: layout.toDeviceIndependentPixels(currentBounds.right - currentBounds.left),
            height: layout.toDeviceIndependentPixels(currentBounds.bottom - currentBounds.top),
        };
    }

    public animate(animation: any): am.AnimationPromise {
        return this.createAnimation(animation).play();
    }

    public createAnimation(animation: any): am.Animation {
        ensureAnimationModule();
        animation.target = this;
        return new animationModule.Animation([animation]);
    }

    public toString(): string {
        let str = this.typeName;
        if (this.id) {
            str += `<${this.id}>`;
        } else {
            str += `(${this._domId})`;
        }
        let source = Source.get(this);
        if (source) {
            str += `@${source};`;
        }

        return str;
    }

    public _setNativeViewFrame(nativeView: any, frame: any) {
        //
    }

    public _getValue(): never {
        throw new Error("The View._setValue is obsolete. There is a new property system.");
    }

    public _setValue(): never {
        throw new Error("The View._setValue is obsolete. There is a new property system.");
    }

    _updateEffectiveLayoutValues(parent: ViewDefinition): void {
        const style = this.style;

        let parentWidthMeasureSpec = parent._currentWidthMeasureSpec;
        let parentWidthMeasureSize = layout.getMeasureSpecSize(parentWidthMeasureSpec);
        let parentWidthMeasureMode = layout.getMeasureSpecMode(parentWidthMeasureSpec);
        let parentAvailableWidth = parentWidthMeasureMode === layout.UNSPECIFIED ? -1 : parentWidthMeasureSize;

        this.effectiveWidth = PercentLength.toDevicePixels(style.width, -2, parentAvailableWidth);
        this.effectiveMarginLeft = PercentLength.toDevicePixels(style.marginLeft, 0, parentAvailableWidth);
        this.effectiveMarginRight = PercentLength.toDevicePixels(style.marginRight, 0, parentAvailableWidth);

        let parentHeightMeasureSpec = parent._currentHeightMeasureSpec;
        let parentHeightMeasureSize = layout.getMeasureSpecSize(parentHeightMeasureSpec);
        let parentHeightMeasureMode = layout.getMeasureSpecMode(parentHeightMeasureSpec);
        let parentAvailableHeight = parentHeightMeasureMode === layout.UNSPECIFIED ? -1 : parentHeightMeasureSize;

        this.effectiveHeight = PercentLength.toDevicePixels(style.height, -2, parentAvailableHeight);
        this.effectiveMarginTop = PercentLength.toDevicePixels(style.marginTop, 0, parentAvailableHeight);
        this.effectiveMarginBottom = PercentLength.toDevicePixels(style.marginBottom, 0, parentAvailableHeight);
    }

    public _setNativeClipToBounds() {
        //
    }
}

export const automationTextProperty = new Property<ViewCommon, string>({ name: "automationText" });
automationTextProperty.register(ViewCommon);

export const originXProperty = new Property<ViewCommon, number>({ name: "originX", defaultValue: 0.5, valueConverter: (v) => parseFloat(v) });
originXProperty.register(ViewCommon);

export const originYProperty = new Property<ViewCommon, number>({ name: "originY", defaultValue: 0.5, valueConverter: (v) => parseFloat(v) });
originYProperty.register(ViewCommon);

export const isEnabledProperty = new Property<ViewCommon, boolean>({
    name: "isEnabled",
    defaultValue: true,
    valueConverter: booleanConverter,
    valueChanged(this: void, target, oldValue, newValue): void {
        target._goToVisualState(newValue ? "normal" : "disabled");
    }
});
isEnabledProperty.register(ViewCommon);

export const isUserInteractionEnabledProperty = new Property<ViewCommon, boolean>({ name: "isUserInteractionEnabled", defaultValue: true, valueConverter: booleanConverter });
isUserInteractionEnabledProperty.register(ViewCommon);