/**
 * Represents a line item with text, font information, and spacing options.
 * @param {String} text The contents of the line
 * @param {FontInfo} fontInfo Font details to use for the line
 * @param {Boolean} moveDownAfter Provide extra spacing after this line?
 * @returns LineItem
 */
class LineItem {
    constructor(text, fontInfo, moveDownAfter) {
        this.text = text;
        this.fontInfo = fontInfo;
        this.moveDownAfter = moveDownAfter || false;

        return this;
    }

    /**
     * Set the contents of the line
     * @param {String} text The contents of the line
     * @returns LineItem
     */
    setText(text) {
        if (typeof text !== 'string') {
            throw new Error('Text must be a string');
        }
        this.text = text;
        return this;
    }

    /**
     * Set the font information for the line
     * @param {FontInfo} fontInfo Font details to use for the line
     * @returns LineItem
     */
    setFontInfo(fontInfo) {
        if (!(fontInfo instanceof FontInfo)) {
            throw new Error('fontInfo must be an instance of FontInfo');
        }
        this.fontInfo = fontInfo;
        return this;
    }

    /**
     * Set whether to provide extra spacing after this line
     * @param {Boolean} moveDownAfter Provide extra spacing after this line?
     * @returns LineItem
     */
    setMoveDownAfter(moveDownAfter) {
        if (typeof moveDownAfter !== 'boolean') {
            throw new Error('moveDownAfter must be a boolean');
        }
        this.moveDownAfter = moveDownAfter;
        return this;
    }
}

/**
 * Represents font information including name, size, and style.
 * @param {String} name The font name
 * @param {Number} size The font size
 * @param {String} style The font style
 * @returns FontInfo
 */
class FontInfo {
    constructor(name, size, style) {
        this.name = name || 'Helvetica';
        this.style = style || '';
        this.size = size || 12;
        return this;
    }

    /**
     * Set the font name
     * @param {String} name The font name
     * @returns FontInfo
     */
    setName(name) {
        if (typeof name !== 'string') {
            throw new Error('Font name must be a string');
        }
        this.name = name;
        return this;
    }

    /**
     * Set the font size
     * @param {Number} size The font size
     * @returns FontInfo
     */
    setSize(size) {
        if (typeof size !== 'number' || size <= 0) {
            throw new Error('Font size must be a positive number');
        }
        this.size = size;
        return this;
    }

    /**
     * Set the font style
     * @param {String} style The font style
     * @returns FontInfo
     */
    setStyle(style) {
        if (typeof style !== 'string') {
            throw new Error('Font style must be a string');
        }
        this.style = style;
        return this;
    }
}