/**
 * The class provides overreaching options for building the website.
 */
class PageBuilder {
    #cssClasses;
    #functions;

    constructor() {
        this.#cssClasses = document.createElement("style");
        this.#functions = document.createElement("script");
    }

    /**
     * Registers a function to be added later in a script tag in the head of the document.
     * @param {string} name 
     * @param {func} fun 
     */
    registerFunction(name, fun) {
        this.#functions.innerText += `const ${name} = ${fun}`;
    }

    /**
     * Adds a script tag into the head of the document. 
     */
    generate() {
        document.querySelector("head")
            .appendChild(this.#functions)
    }

}

const Page = new PageBuilder();
/**
 * Enum to access common events
 */
const CommonEvents = Object.freeze({
    ONCLICK: "onClick",
})

/**
 * A simple Color class for rgb set color values.
 */
class Color {
    #red;
    #green;
    #blue;

    constructor(red, green, blue) {
        this.#red = red
        this.#green = green
        this.#blue = blue
    }

    /**
     * 
     * @returns {string} an rgb object string
     */
    cssRGBString() {
        return `rgb(${this.#red}, ${this.#green}, ${this.#blue})`;
    }
}

/**
 * Simple Dimensions container for the height and width in pixels.
 */
class Dimensions {
    #x;
    #y;

    /**
     * Sets width (x) value of pixels
     * @param {number} pixels 
     * @returns this Dimensions Modifier
     */
    width(pixels) {
        this.x = pixels;
        return this;
    }

    /**
     * Sets height (y) value of pixels
     * @param {number} pixels 
     * @returns this Dimensions Modifier
     */
    height(pixels) {
        this.y = pixels;
        return this;
    }
}

/**
 * The Class holds values from each side/direction of an element.
 * Used for margin/padding.
 */
class Siding {
    pxLeft = 0;
    pxRight = 0;
    pxTop = 0;
    pxBottom = 0;

    /**
     * sets the pixels-value for all sides.
     * @param {number} pixels siding from all sides
     * @returns this Siding Object
     */
    all(pixels) {
        this.pxLeft = pixels;
        this.pxRight = pixels;
        this.pxTop = pixels;
        this.pxBottom = pixels;
        return this;
    }

    /**
     * sets the pixels-value for the horizontal sides (left and right).
     * @param {number} pixels siding for left and right.
     * @returns this Siding Object
     */
    horizontal(pixels) {
        this.pxLeft = pixels;
        this.pxRight = pixels;
        return this;
    }

    /**
     * sets the pixels-value for the vertical sides (left and right).
     * @param {number} pixels siding for top and bottom.
     * @returns this Siding Object
     */
    vertical(pixels) {
        this.pxTop = pixels;
        this.pxBottom = pixels;
        return this;
    }

    /**
     * sets the pixels-value for the left side.
     * @param {number} pixels siding for left
     * @returns this Siding Object
     */
    left(pixels) {
        this.pxLeft = pixels;
        return this;
    }

    /**
     * sets the pixels-value for the right side.
     * @param {number} pixels siding for right
     * @returns this Siding Object
     */
    right(pixels) {
        this.pxRight = pixels;
        return this;
    }

    /**
     * sets the pixels-value for the top side.
     * @param {number} pixels siding for top
     * @returns this Siding Object
     */
    top(pixels) {
        this.pxTop = pixels;
        return this;
    }

    /**
     * sets the pixels-value for the bottom side.
     * @param {number} pixels siding for bottom
     * @returns this Siding Object
     */
    bottom(pixels) {
        this.pxBottom = pixels;
        return this;
    }
}

/**
 * Enum providing common alignment rules
 */
const Alignment = Object.freeze({
    BEGIN_BORDER: 0,
    CENTER: 1,
    END_BORDER: 2,
})

/**
 * Enum providing common alignment rules
 */
const Arrangement = Object.freeze({
    START: 0,
    END: 1,
    CENTER: 2,
    SPACE_BETWEEN: 3,
    SPACE_EVENLY: 4,
    SPACE_AROUND: 5,
})
/**
 * A chained class that sets most of the stylings of an element.
 */
class Modifier {
    modifications = {};

    constructor() {
        this.modifications = new Object();
    }
    /**
     * Sets the modifications for widht and height to 100%. 
     * @returns this modifier object
     */
    fillMaxSize() {
        this.modifications["width"] = "100%";
        this.modifications["height"] = "100%";
        return this;
    }

    /**
     * Sets the modification for width to 100%.
     * @returns this modifier object
     */
    fillMaxWidth() {
        this.modifications["width"] = "100%";
        return this;
    }

    /**
     * Sets the modification for height to 100%.
     * @returns this modifier object
     */
    fillMaxHeight() {
        this.modifications["height"] = "100%";
        return this;
    }

    /**
     * Sets modifications according to the dimensions object.
     * @param {Dimensions} dimensions 
     * @returns this modifier object
     */
    size(dimensions) {
        this.modifications["height"] = dimensions.height + "px";
        this.modifications["width"] = dimensions.width + "px";
        return this;
    }

    /**
     * Sets the padding on all sides according to the given siding object. 
     * Currently the padding will always be set 
     * to the most recent padding/siding. 
     * @param {Siding} siding 
     * @returns this modifier object
     */
    padding(siding) {
        this.modifications["padding-right"] = siding.pxRight + "px";
        this.modifications["padding-left"] = siding.pxLeft + "px";
        this.modifications["padding-top"] = siding.pxTop + "px";
        this.modifications["padding-bottom"] = siding.pxBottom + "px";
        return this;
    }

    /**
     * Sets the margin on all sides according to the given siding object. 
     * Currently the margin will always be set 
     * to the most recent margin/siding. 
     * @param {Siding} siding 
     * @returns this modifier object
     */
    margin(siding) {
        this.modifications["margin-right"] = siding.pxRight + "px";
        this.modifications["margin-left"] = siding.pxLeft + "px";
        this.modifications["margin-top"] = siding.pxTop + "px";
        this.modifications["margin-bottom"] = siding.pxBottom + "px";
        return this;
    }

    /**
     * Sets the background-color as a rgb color.
     * @param {Color} color 
     * @returns this modifier object
     */
    background(color) {
        this.modifications["background-color"] = color.cssRGBString();
        return this;
    }

    /**
     * Sets the color as a rgb color.
     * @param {Color} color 
     * @returns this modifier object
     */
    color(color) {
        this.modifications["color"] = color.cssRGBString();
        return this;
    }

    /**
     * Adds the modifications of the given Modifier to current Modifier.
     * This is especailly used in the cases of extending existing/pre defined 
     * Components.
     * CAUTION matching existing modifications will be ignored. 
     * @param modifier The "new" Modifier
     * @returns The "old/current" Modifier, 
     * extended with the modifications of the given Modifier.
     */
    join(modifier, modifications = {}) {
        var keys = Object.keys(modifier.modifications);
        for (let i = 0; i < keys.length; i++) {
            if (!this.modifications.hasOwnProperty(keys[i]))
                this.modifications[keys[i]] = modifier.modifications[keys[i]];
        }
        return this;
    }

    /**
     * 
     * @param {string} key a css style rule
     * @param {string} value the corresponding value to the css style rule
     * @returns this modifier object
     */
    setStyleRule(key, value) {
        this.modifications[key] = value;
        return this;
    }

}
/**
 * A chainable HTMLElement builder. 
 */
class Component {
    _element;
    _modifier
    _alignment;
    _arrangement;

    constructor(element, attr = {}) {
        this._modifier = new Modifier().margin(new Siding().all(0));
        this._element = element;
        Object.keys(attr)
            .forEach(key => {
                this._element.setAttribute(key, attr[key]);
            })
    }

    /**
     * Sets the alignment (modifications) for this element or more specific for its children. 
     * @param {Alignment} alignment 
     * @returns this component object
     */
    alignment(alignment) {
        this._alignment = alignment;
        return this;
    }

    /**
     * Sets the arrangement (modifications) for this element or more specific for its children. 
     * @param {Arrangement} arrangement 
     * @returns this component object
     */
    arrangement(arrangement) {
        this._arrangement = arrangement;
        switch (arrangement) {
            case Arrangement.START:
                this._modifier.modifications["justify-content", "start"]
                break;
            case Arrangement.END:
                this._modifier.modifications["justify-content", "end"]
                break;
            case Arrangement.CENTER:
                this._modifier.modifications["justify-content", "center"]
                break;
            case Arrangement.SPACE_AROUND:
                this._modifier.modifications["justify-content", "space-around"]
                break;
            case Arrangement.SPACE_BETWEEN:
                this._modifier.modifications["justify-content", "space-between"]
                break;
            case Arrangement.SPACE_EVENLY:
                this._modifier.modifications["justify-content", "space-evenly"]
                break;
        }
        return this;
    }

    /**
     * 
     * @param {Modifier} modifier 
     * @returns this component object
     */
    modifier(modifier) {
        this._modifier = this._modifier.join(modifier)
        return this;
    }

    /**
     * Sets the innerText of the element
     * @param {string} text 
     * @returns this component object
     */
    text(text) {
        this._element.innerText = text;
        return this;
    }

    /**
     * 
     * @param {string} styleClass 
     * @returns this component object
     */
    addStyleClass(styleClass) {
        this._element.classList.add(styleClass);
        return this;
    }

    /**
     * 
     * @param {string} key 
     * @param {string} value 
     * @returns this component object
     */
    setAttribute(key, value) {
        this._element.setAttribute(key, value);
        return this;
    }


    /**
     * Ends chain. 
     * Applies all modifications on the element.
     * @returns {HTMLElemment} the html element
     */
    generate() {
        var mkeys = Object.keys(this._modifier.modifications);
        for (let i = 0; i < mkeys.length; i++) {
            this._element.style[mkeys[i]] = this._modifier.modifications[mkeys[i]];
        }
        return this._element;
    }

    /**
     * 
     * @param {Component|Array<Component>} innerComponent 
     * @returns this component object
     */
    childContext(innerComponent) {
        if (innerComponent instanceof Array) {
            for (let i = 0; i < innerComponent.length; i++) {
                this._element.append(innerComponent[i].generate());
            }
        } else {
            this._element.append(innerComponent.generate());
        }
        return this;
    }

    /**
     * 
     * @param {CommonEvent} commonEvent 
     * @param {string} functionName 
     * @returns this component object
     */
    setEvent(commonEvent, functionName) {
        return this.setAttribute(commonEvent, `${functionName}(this)`)
    }

}
/**
 * Represents container Components.
 * Some predefined modifications are applied on the child components.
 */
class FlexContainerComponent extends Component {
    constructor(attr = {}) {
        super(document.createElement("div"), attr)
            .addStyleClass("flex-container-component")
    }

    /**
     * 
     * @param {Component|Array<Component>} innerComponent 
     * @returns this component object
     */
    childContext(innerComponent) {
        if (innerComponent instanceof Array) {
            innerComponent.forEach(icomp => {
                icomp.modifier(
                    new Modifier()
                        .setStyleRule("flex", "none")
                )
            })
        } else {
            innerComponent.modifier(
                new Modifier()
                    .setStyleRule("flex", "none")
            )
        }
        return super.childContext(innerComponent);
    }
}

/**
 * A FlexContainerComponent, which organizes the children in a column like manner.
 */
class Column extends FlexContainerComponent {
    constructor(attr = {}) {
        super(document.createElement("div"), attr)
            .addStyleClass("column-component")
            .modifier(
                new Modifier()
                    .setStyleRule("flex-direction", "column")
            );
    }
}

/**
 * A FlexContainerComponent, which organizes the children in a row like manner.
 */
class Row extends FlexContainerComponent {
    constructor(attr = {}) {
        super(attr)
            .addStyleClass("row-component")
            .modifier(
                new Modifier()
                    .setStyleRule("flex-direction", "row")
            )
    }
}
const builder = {
    genTag: function (tag, attr = {}) { return new Component(document.createElement(tag), attr); },

    anchor: function (attr = {}) { return builder.genTag("a", attr); },
    label: function (attr = {}) { return builder.genTag("label", attr); },
    button: function (attr = {}) { return builder.genTag("button", attr); },
    input: function (attr = {}) { return builder.genTag("input", attr); },
    div: function (attr = {}) { return builder.genTag("div", attr); },
    paragraph: function (attr = {}) { return builder.genTag("paragraph", attr); },
    header: function (sizeGroup, attr = {}) { return builder.genTag(`h${sizeGroup}`, attr); },
    checkbox: function (attr = {}) { return builder.genTag("checkbox", attr); },
    selection: function (attr = {}) { return builder.genTag("selection", attr); },
    option: function (attr = {}) { return builder.genTag("option", attr); },
    section: function (attr = {}) { return builder.genTag("section", attr); },
    radioBtn: function (attr = {}) { return builder.genTag("radioBtn", attr); },
    icon: function (attr = {}) { return builder.genTag("icon", attr); },
    img: function (attr = {}) { return builder.genTag("img", attr); },
    textarea: function (attr = {}) { return builder.genTag("textarea", attr); },

    row: function (attr = {}) { return new Row(attr) },
    column: function (attr = {}) { return new Column(attr) },
    page: function(innerComponents){
        Page.generate();
        document.querySelector('#root').appendChild(innerComponents.generate()) 
    }
}