// server/utils/textDirectionClassifier.js
import { Tensor } from 'onnxruntime-node';
import sharp from 'sharp';

class TextDirectionClassifier {
    constructor() {
        this.clsSession = null;
        this.config = null;
    }

    initialize(clsSession, config) {
        this.clsSession = clsSession;
        this.config = config;
    }

    async classifyTextDirection(textRegionBuffer) {
        try {
            const inputTensor = await this.prepareClsInput(textRegionBuffer);
            const outputs = await this.clsSession.run({ [this.clsSession.inputNames[0]]: inputTensor });
            return this.postprocessCls(outputs);
        } catch (error) {
            console.error('文本方向分类失败:', error);
            return { clsResult: 0, clsConfidence: 1.0 };
        }
    }

    async prepareClsInput(textRegionBuffer) {
        const targetHeight = 48;
        const targetWidth = 192;

        const resizedBuffer = await sharp(textRegionBuffer)
            .resize(targetWidth, targetHeight)
            .png()
            .toBuffer();

        const imageData = await sharp(resizedBuffer)
            .ensureAlpha()
            .raw()
            .toBuffer({ resolveWithObject: true });

        const inputData = new Float32Array(3 * targetHeight * targetWidth);
        const data = imageData.data;
        const channels = imageData.info.channels;

        for (let i = 0; i < data.length; i += channels) {
            const pixelIndex = Math.floor(i / channels);
            const channel = Math.floor(pixelIndex / (targetHeight * targetWidth));
            const posInChannel = pixelIndex % (targetHeight * targetWidth);

            if (channel < 3) {
                const y = Math.floor(posInChannel / targetWidth);
                const x = posInChannel % targetWidth;
                const inputIndex = channel * targetHeight * targetWidth + y * targetWidth + x;

                if (inputIndex < inputData.length) {
                    inputData[inputIndex] = data[i] / 255.0;
                }
            }
        }

        return new Tensor('float32', inputData, [1, 3, targetHeight, targetWidth]);
    }

    postprocessCls(outputs) {
        const outputNames = this.clsSession.outputNames;
        const clsOutput = outputs[outputNames[0]];

        if (!clsOutput) return { clsResult: 0, clsConfidence: 1.0 };

        const data = clsOutput.data;

        let clsResult = 0;
        let clsConfidence = data[0];

        if (data.length >= 2 && data[1] > data[0]) {
            clsResult = 180;
            clsConfidence = data[1];
        }

        console.log(`🧭 文本方向分类: ${clsResult}°, 置信度: ${clsConfidence.toFixed(4)}`);
        return { clsResult, clsConfidence };
    }
}

export default TextDirectionClassifier;