/**
 * FFmpeg Native Addon Adapter
 * 使用原生 Node.js Addon 实现的 FFmpeg 适配器
 */

import { platform, arch } from 'node:os';
import path from 'node:path';
import { existsSync } from 'node:fs';
import { writeFile } from 'node:fs/promises';
import type { FFmpeg } from './ffmpeg-addon';
import type { IFFmpegAdapter, VideoInfoResult } from './ffmpeg-adapter-interface';
import { dlopen } from 'node:process';

/**
 * 获取 Native Addon 路径
 * @param binaryPath 二进制文件路径(来自 pathWrapper.binaryPath)
 */
function getAddonPath(binaryPath: string): string {
    const platformName = platform();
    const archName = arch();

    let addonFileName: string = process.platform + '.' + process.arch;
    let addonPath = path.join(binaryPath, "./native/ffmpeg/", `${addonFileName}.node`);
    if (existsSync(addonPath)) {
        throw new Error(`Unsupported platform: ${platformName} ${archName}`);
    }
    return addonPath;
}

/**
 * FFmpeg Native Addon 适配器实现
 */
export class FFmpegAddonAdapter implements IFFmpegAdapter {
    public readonly name = 'FFmpegAddon';
    private addon: FFmpeg | null = null;
    private binaryPath: string;

    constructor(binaryPath: string) {
        this.binaryPath = binaryPath;
    }

    /**
     * 检查 Addon 是否可用
     */
    async isAvailable(): Promise<boolean> {
        try {
            const addonPath = getAddonPath(this.binaryPath);
            if (!existsSync(addonPath)) {
                return false;
            }
            let temp_addon = { exports: {} };
            dlopen(temp_addon, addonPath);
            this.addon = temp_addon.exports as FFmpeg;
            return this.addon !== null;
        } catch (error) {
            console.log('[FFmpegAddonAdapter] Failed to load addon:', error);
            return false;
        }
    }

    private ensureAddon(): FFmpeg {
        if (!this.addon) {
            throw new Error('FFmpeg Addon is not available');
        }
        return this.addon;
    }

    /**
     * 获取视频信息
     */
    async getVideoInfo(videoPath: string): Promise<VideoInfoResult> {
        const addon = this.ensureAddon();
        const info = await addon.getVideoInfo(videoPath, 'bmp24');

        return {
            width: info.width,
            height: info.height,
            duration: info.duration,
            format: info.format,
            thumbnail: info.image,
        };
    }

    /**
     * 获取时长
     */
    async getDuration(filePath: string): Promise<number> {
        const addon = this.ensureAddon();
        return addon.getDuration(filePath);
    }

    /**
     * 转换为 PCM
     */
    async convertToPCM(filePath: string, pcmPath: string): Promise<Buffer> {
        const addon = this.ensureAddon();
        const result = await addon.decodeAudioToPCM(filePath);

        // 写入文件
        await writeFile(pcmPath, result.pcm);

        return result.pcm;
    }

    /**
     * 转换文件
     */
    async convertFile(inputFile: string, outputFile: string, format: string): Promise<void> {
        const addon = this.ensureAddon();

        if (format === 'silk' || format === 'ntsilk') {
            // 使用 Addon 的 NTSILK 转换
            await addon.convertToNTSilkTct(inputFile, outputFile);
        } else {
            throw new Error(`Format '${format}' is not supported by FFmpeg Addon`);
        }
    }

    /**
     * 提取缩略图
     */
    async extractThumbnail(videoPath: string, thumbnailPath: string): Promise<void> {
        const addon = this.ensureAddon();
        const info = await addon.getVideoInfo(videoPath);

        // 将缩略图写入文件
        await writeFile(thumbnailPath, info.image);
    }
}