// server/utils/imagePreprocessor.js
import sharp from 'sharp';

class ImagePreprocessor {
    constructor() {
        this.tempDir = './temp/processed';
        this.logger = {
            info: (msg, ...args) => console.log(`🖼️ [预处理] ${msg}`, ...args),
            error: (msg, ...args) => console.error(`❌ [预处理] ${msg}`, ...args),
            debug: (msg, ...args) => console.debug(`❌ [预处理] ${msg}`, ...args)
        };
    }

    async preprocessWithPadding(imagePath, config) {
        const startTime = Date.now();
        this.logger.info(`开始预处理: ${imagePath}`);

        try {
            const metadata = await sharp(imagePath).metadata();
            this.logger.info(`原始尺寸: ${metadata.width}x${metadata.height}`);

            // 智能填充策略
            const { paddingX, paddingY } = this.calculateSmartPadding(metadata);
            const paddedWidth = metadata.width + paddingX * 2;
            const paddedHeight = metadata.height + paddingY * 2;

            this.logger.debug(`添加填充: ${paddingX}x${paddingY}, 新尺寸: ${paddedWidth}x${paddedHeight}`);

            const paddedBuffer = await sharp(imagePath)
                .extend({
                    top: paddingY,
                    bottom: paddingY,
                    left: paddingX,
                    right: paddingX,
                    background: { r: 255, g: 255, b: 255 }
                })
                .png()
                .toBuffer();

            const { width, height } = this.resizeForDetection({
                width: paddedWidth,
                height: paddedHeight
            }, config);

            const resizedBuffer = await sharp(paddedBuffer)
                .resize(width, height)
                .png()
                .toBuffer();

            const processingTime = Date.now() - startTime;
            this.logger.info(`预处理完成: ${width}x${height}, 耗时${processingTime}ms`);

            return {
                processedImage: {
                    buffer: resizedBuffer,
                    width, height,
                    originalWidth: metadata.width,
                    originalHeight: metadata.height,
                    paddedWidth, paddedHeight,
                    paddingX, paddingY,
                    scaleX: paddedWidth / width,
                    scaleY: paddedHeight / height
                }
            };

        } catch (error) {
            this.logger.error('预处理错误', error);
            throw error;
        }
    }

    calculateSmartPadding(metadata) {
        const basePadding = 20;
        const minPadding = 15;

        // 根据图像尺寸动态调整填充
        const widthRatio = Math.max(0.02, Math.min(0.08, 100 / metadata.width));
        const heightRatio = Math.max(0.02, Math.min(0.08, 100 / metadata.height));

        return {
            paddingX: Math.max(minPadding, Math.floor(metadata.width * widthRatio)),
            paddingY: Math.max(minPadding, Math.floor(metadata.height * heightRatio))
        };
    }

    resizeForDetection(metadata, config) {
        const { width, height } = metadata;
        const limitSideLen = config.detLimitSideLen || 960;

        let ratio = 1;
        if (Math.max(width, height) > limitSideLen) {
            ratio = limitSideLen / Math.max(width, height);
            this.logger.debug(`缩放比例: ${ratio.toFixed(4)}`);
        }

        const newWidth = Math.floor(width * ratio);
        const newHeight = Math.floor(height * ratio);

        // 确保尺寸是32的倍数
        const finalWidth = Math.max(32, Math.floor(newWidth / 32) * 32);
        const finalHeight = Math.max(32, Math.floor(newHeight / 32) * 32);

        this.logger.debug(`调整后尺寸: ${finalWidth}x${finalHeight}`);
        return { width: finalWidth, height: finalHeight };
    }

    async getImageInfo(imagePath) {
        try {
            const metadata = await sharp(imagePath).metadata();
            return {
                width: metadata.width || 0,
                height: metadata.height || 0,
                format: metadata.format || 'unknown',
                processed: false
            };
        } catch (error) {
            this.logger.error('获取图像信息失败', error);
            return {
                width: 0, height: 0, format: 'unknown', processed: false
            };
        }
    }
}

export default ImagePreprocessor;