/**
 * Book Page Format Module
 * Defines the canonical page geometry used by the WebGL book renderer.
 */
import { BaseModule } from './base-module.js';

class BookPageFormatModule extends BaseModule {
    constructor() {
        super('book-page-format', 'Book Page Format');
        this.dependencies = [];
        this.format = Object.freeze({
            id: 'us-mass-market-paperback',
            trim: Object.freeze({
                widthIn: 4.25,
                heightIn: 6.87
            }),
            margins: Object.freeze({
                topIn: 0.46,
                bottomIn: 0.58,
                innerIn: 0.56,
                outerIn: 0.44
            }),
            typography: Object.freeze({
                fontFamily: '"EB Garamond", "EB Garamond 12", serif',
                linesPerPage: 25,
                bodyLineRatio: 1.5,
                headingScale: 1,
                dropCapLines: 2
            })
        });

        this.bindMethods([
            'getFormat',
            'getAspectRatio',
            'getTextureMetrics',
            'inchesToTexture'
        ]);
    }

    async initialize() {
        this.reportProgress(100, 'Book page format ready');
        return true;
    }

    getFormat() {
        return this.format;
    }

    getAspectRatio() {
        return this.format.trim.widthIn / this.format.trim.heightIn;
    }

    inchesToTexture(valueIn, textureHeight) {
        return (Number(valueIn) / this.format.trim.heightIn) * textureHeight;
    }

    getTextureMetrics(textureWidth = 1280) {
        const width = Math.max(1, Math.round(Number(textureWidth) || 1280));
        const height = Math.round(width / this.getAspectRatio());
        const margins = {
            top: this.inchesToTexture(this.format.margins.topIn, height),
            bottom: this.inchesToTexture(this.format.margins.bottomIn, height),
            inner: this.inchesToTexture(this.format.margins.innerIn, height),
            outer: this.inchesToTexture(this.format.margins.outerIn, height)
        };
        const content = {
            x: margins.outer,
            y: margins.top,
            width: Math.max(1, width - margins.outer - margins.inner),
            height: Math.max(1, height - margins.top - margins.bottom)
        };
        const contentBySide = {
            left: {
                ...content,
                x: margins.outer
            },
            right: {
                ...content,
                x: margins.inner
            }
        };
        const linesPerPage = Math.max(1, Number(this.format.typography.linesPerPage || 25));
        const typographyLineHeightPx = content.height / linesPerPage;
        const bodyFontSizePx = typographyLineHeightPx / Math.max(1, Number(this.format.typography.bodyLineRatio || 1.5));
        return {
            width,
            height,
            aspectRatio: this.getAspectRatio(),
            margins,
            content,
            contentBySide,
            linesPerPage,
            bodyFontSizePx,
            typographyLineHeightPx,
            typography: this.format.typography
        };
    }
}

const bookPageFormat = new BookPageFormatModule();

export { bookPageFormat as BookPageFormat };

if (window.moduleRegistry) {
    window.moduleRegistry.register(bookPageFormat);
}

window.BookPageFormat = bookPageFormat;