import e, { Request, Response, NextFunction } from 'express';
import { type Database as DB } from 'better-sqlite3';
import { type Statement } from 'better-sqlite3';
import Database from 'better-sqlite3';
// import sharp for images
import sharp, { FormatEnum, AvailableFormatInfo, Sharp } from 'sharp';
import * as fs from 'fs';

// Map file extensions to sharp formats
const imageFormatMap: { [key: string]: keyof FormatEnum | AvailableFormatInfo } = {
    jpg: 'jpeg',
    jpeg: 'jpeg',
    png: 'png',
    webp: 'webp',
    tiff: 'tiff',
    gif: 'gif'
};

interface HitResult {
    hits: number;
}

interface RGBColor {
    r: number;
    g: number;
    b: number;
}

export interface Type<T> extends Function { new (...args: any[]): T; }


interface HitCounterRenderer {
    render(): Promise<any>;
}

class BaseHitCounterRenderer implements HitCounterRenderer {
    protected counter: HitCounter;
    protected config: HitCounterConfig;

    constructor(counter: HitCounter, config: HitCounterConfig) {
        this.counter = counter;
        this.config = config;
    }

    async render(): Promise<any> {
        // render the counter
        throw new Error('Not implemented');
    }

}


class ImageHitCounterRenderer extends BaseHitCounterRenderer {
    private imageType: string;
    private imageFormat: keyof FormatEnum | AvailableFormatInfo;
    constructor(counter: HitCounter, config: HitCounterConfig) {
        super(counter, config);
        const fileExt = this.config.imageFile.split('.').pop();
        if (!fileExt) {
            throw new Error('Invalid file extension');
        }
        this.imageType = fileExt;
        this.imageFormat = imageFormatMap[fileExt.toLowerCase()];
        if (!this.imageFormat) {
            throw new Error('Unsupported file extension');
        }
    }

    private async cachedBackgroundImage(overWrite: boolean = false): Promise<Sharp> {
        // cache the image
        const dest = this.config.backgroundCacheFile;
        if (fs.existsSync(dest)) {
            if (overWrite) {
                fs.unlinkSync(dest);
            } else {
                return sharp(dest);
            }
        }
        
        // store the image in the cache
        const fileExt = dest.split('.').pop();
        if (!fileExt) {
            throw new Error('Invalid file extension');
        }
        
        const format = imageFormatMap[fileExt.toLowerCase()];
        if (!format) {
            throw new Error('Unsupported file extension');
        }

        const image = sharp(this.config.backgroundImageUrl).toFormat(format);
        await image.toFile(dest);
        return image;
    }



    async render(): Promise<Sharp> {
        const hits = await this.counter.getHits();
        const bgImage = await this.cachedBackgroundImage();
        const bgInfo = await bgImage.metadata();

        const text = this.config.customText;
        const secondaryText = this.config.secondaryText;
        const textColor = this.config.textColorRGB;
        const secondaryTextColor = this.config.secondaryTextColorRGB;
        const numberColor = this.config.numberColorRGB;
        const frameColor = this.config.frameColorRGB;
        const drawFrame = this.config.drawFrame;
        const textX = this.config.textPositionX;
        const textY = this.config.textPositionY;
        const numberX = this.config.numberPositionX;
        const numberY = this.config.numberPositionY;

        const svgFrame = `
            <svg width="${bgInfo.width}" height="${bgInfo.height}" xmlns="http://www.w3.org/2000/svg">
                <rect x="0" y="0" width="${bgInfo.width}" height="${bgInfo.height}" stroke="rgb(${frameColor.r},${frameColor.g},${frameColor.b})" stroke-width="2" fill="none"/>
            </svg>
        `;
        
        const svgOverlay = `
            <svg width="${bgInfo.width}" height="${bgInfo.height}" xmlns="http://www.w3.org/2000/svg">
                <text x="${textX}" y="${textY}" fill="rgb(${textColor.r},${textColor.g},${textColor.b})" font-size="12">${text}</text>
                <text x="${textX}" y="${textY + 15}" fill="rgb(${secondaryTextColor.r},${secondaryTextColor.g},${secondaryTextColor.b})" font-size="12">${secondaryText}</text>
                <text x="${numberX}" y="${numberY}" fill="rgb(${numberColor.r},${numberColor.g},${numberColor.b})" font-size="12">${hits}</text>
            </svg>
        `;



        const overlay = sharp(Buffer.from(svgOverlay));
        if (drawFrame) {
            const frame = sharp(Buffer.from(svgFrame));
            const composite = bgImage.composite([
                { input: await overlay.toBuffer(), gravity: 'northwest' },
                { input: await frame.toBuffer(), gravity: 'northwest' }
            ]);
            return composite;
        }

        const composite = bgImage.composite([
            { input: await overlay.toBuffer(), gravity: 'northwest' }
        ]);

        return composite;
    }
}


interface HitCounterConfig {
    siteId: number;
    // path to the database file
    counterDB: string;
    // Background image URL for the counter display
    backgroundImageUrl: string;
    // local image path
    imageFile: string;
    backgroundCacheFile: string;
    // Text settings to be displayed on the image
    customText: string; // Main headline text
    secondaryText: string; // Secondary descriptive text
    textPositionX: number; // X position of the text
    textPositionY: number; // Y position of the text
    numberPositionX: number; // X position of the number
    numberPositionY: number; // Y position of the number
    textColorRGB: RGBColor; // Text color
    secondaryTextColorRGB: RGBColor; // Secondary text color
    numberColorRGB: RGBColor; // Number color
    frameColorRGB: RGBColor; // Frame color
    drawFrame: boolean; // Whether to draw a frame around the counter
    renderer: Type<BaseHitCounterRenderer>; // Renderer class for the counter
}



// default configuration
const defaultHitCounterConfig: HitCounterConfig = {
    siteId: 1,
    counterDB: './hits.db',
    backgroundImageUrl: 'https://datakra.sh/assets/example_counter.jpg',
    imageFile: './example_counter.png',
    backgroundCacheFile: './example_counter_bg.png',
    customText: 'Hit Counter!',
    secondaryText: 'Super cyber, super cool!',
    textPositionX: 5,
    textPositionY: 5,
    numberPositionX: 5,
    numberPositionY: 15,
    textColorRGB: { r: 253, g: 252, b: 1 },
    secondaryTextColorRGB: { r: 0, g: 255, b: 0 },
    numberColorRGB: { r: 255, g: 255, b: 255 },
    frameColorRGB: { r: 255, g: 238, b: 0 },
    drawFrame: true,
    renderer: ImageHitCounterRenderer
};

class HitCounter {
    private db: DB;
    private renderer: BaseHitCounterRenderer;
    private config: HitCounterConfig;
    private preparedGet: Statement;
    private preparedIncrement: Statement;
    private preparedReset: Statement;

    constructor(renderer: Type<BaseHitCounterRenderer>, config?: HitCounterConfig) {
        this.config = { ...defaultHitCounterConfig, ...config };
        this.renderer = new renderer(this, this.config);
        this.openDB();
        this.setupDB();
        this.setupStatements();
    }

    private openDB(): void {
        const db = new Database(this.config.counterDB, {fileMustExist: false});
        db.pragma('locking_mode = EXCLUSIVE');
        db.pragma('journal_mode = WAL');
        db.pragma('synchronous = OFF');
        this.db = db;
    }

    private setupDB(): void {
        this.db.exec(`
            CREATE TABLE IF NOT EXISTS hit_counter (
                id INTEGER PRIMARY KEY,
                hits INTEGER NOT NULL
            );
        `);
        this.db.exec(`
            INSERT OR IGNORE INTO hit_counter (id, hits)
            VALUES (?, ${this.config.siteId})
        `);
    }

    private closeDB(): void {
        this.db.close();
    }

    private setupStatements(): void {
        this.preparedGet = this.db.prepare(`
            SELECT hits
            FROM hit_counter
            WHERE id = ?
        `);
        this.preparedIncrement = this.db.prepare(`
            UPDATE hit_counter
            SET hits = hits + 1
            WHERE id = ?
        `);
        this.preparedReset = this.db.prepare(`
            UPDATE hit_counter
            SET hits = 0
            WHERE id = ?
        `);
    }

    async getHits(): Promise<number> {
        const result = this.preparedGet.get(this.config.siteId) as HitResult;
        return result.hits;
    }

    async increment(): Promise<void> {
        this.preparedIncrement.run(this.config.siteId);
    }

    async reset(): Promise<void> {
        this.preparedReset.run(this.config.siteId);
    }

    // destructor
    destroy(): void {
        this.closeDB();
    }
    
}




export {
    HitCounter,
    HitCounterConfig,
    HitCounterRenderer,
    BaseHitCounterRenderer,
    ImageHitCounterRenderer
};

export default HitCounter;