/**
 * Book Texture Renderer Module
 * Draws the virtual book pages directly into texture-space canvases.
 */
import { BaseModule } from './base-module.js';

class BookTextureRendererModule extends BaseModule {
    constructor() {
        super('book-texture-renderer', 'Book Texture Renderer');
        this.dependencies = ['book-page-format', 'localization'];
        this.pageFormat = null;
        this.localization = null;
        this.metrics = null;
        this.canvases = {
            left: null,
            right: null
        };
        this.contexts = {
            left: null,
            right: null
        };
        this.hitMaps = {
            left: [],
            right: []
        };

        this.bindMethods([
            'initialize',
            'createPageCanvases',
            'drawEmptySpread',
            'drawPageBase',
            'drawDebugText',
            'publishSpread',
            'getPageCanvas',
            'getHitMap',
            'handleSceneReady'
        ]);
    }

    async initialize() {
        this.pageFormat = this.getModule('book-page-format');
        this.localization = this.getModule('localization');
        this.reportProgress(20, 'Preparing page texture canvases');
        this.createPageCanvases();
        this.drawEmptySpread();
        this.addEventListener(document, 'webgl-book:scene-ready', this.handleSceneReady);
        this.reportProgress(100, 'Book texture renderer ready');
        return true;
    }

    createPageCanvases(textureWidth = 1280) {
        this.metrics = this.pageFormat.getTextureMetrics(textureWidth);
        ['left', 'right'].forEach((side) => {
            const canvas = document.createElement('canvas');
            canvas.width = this.metrics.width;
            canvas.height = this.metrics.height;
            this.canvases[side] = canvas;
            this.contexts[side] = canvas.getContext('2d');
        });
    }

    drawEmptySpread() {
        this.drawPageBase('left');
        this.drawPageBase('right');
        this.drawDebugText('right', 'Book canvas renderer ready');
        this.publishSpread();
    }

    drawPageBase(side) {
        const canvas = this.canvases[side];
        const ctx = this.contexts[side];
        if (!canvas || !ctx) return;

        ctx.clearRect(0, 0, canvas.width, canvas.height);
        ctx.fillStyle = '#fff7dc';
        ctx.fillRect(0, 0, canvas.width, canvas.height);

        const shade = ctx.createLinearGradient(0, 0, canvas.width, 0);
        if (side === 'left') {
            shade.addColorStop(0, 'rgba(255, 255, 255, 0.10)');
            shade.addColorStop(0.78, 'rgba(255, 255, 255, 0)');
            shade.addColorStop(1, 'rgba(82, 42, 14, 0.16)');
        } else {
            shade.addColorStop(0, 'rgba(82, 42, 14, 0.16)');
            shade.addColorStop(0.22, 'rgba(255, 255, 255, 0)');
            shade.addColorStop(1, 'rgba(255, 255, 255, 0.10)');
        }
        ctx.fillStyle = shade;
        ctx.fillRect(0, 0, canvas.width, canvas.height);

        this.hitMaps[side] = [];
    }

    drawDebugText(side, text) {
        const ctx = this.contexts[side];
        const metrics = this.metrics;
        if (!ctx || !metrics) return;

        ctx.save();
        ctx.fillStyle = 'rgba(31, 19, 10, 0.82)';
        ctx.font = `${Math.round(metrics.typography.bodyFontSizePt * 1.55)}px ${metrics.typography.fontFamily}`;
        ctx.textBaseline = 'alphabetic';
        ctx.fillText(String(text || ''), metrics.content.x, metrics.content.y + 44);
        ctx.restore();
    }

    publishSpread() {
        document.dispatchEvent(new CustomEvent('webgl-book:page-canvases', {
            detail: {
                left: this.canvases.left,
                right: this.canvases.right,
                metrics: this.metrics,
                hitMaps: this.hitMaps
            }
        }));
    }

    getPageCanvas(side) {
        return this.canvases[side] || null;
    }

    getHitMap(side) {
        return this.hitMaps[side] || [];
    }

    handleSceneReady() {
        this.publishSpread();
    }
}

const bookTextureRenderer = new BookTextureRendererModule();

export { bookTextureRenderer as BookTextureRenderer };

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

window.BookTextureRenderer = bookTextureRenderer;