/**
 * Worker 文件生成器
 * Worker file generator
 */

import * as fs from 'fs';
import * as path from 'path';
import type { WorkerSystemInfo, GeneratorConfig, GenerationResult, WorkerScriptMapping } from './types';

/**
 * 生成 Worker 文件
 * Generate Worker files
 */
export function generateWorkerFiles(
    systems: WorkerSystemInfo[],
    config: GeneratorConfig
): GenerationResult {
    const result: GenerationResult = {
        success: [],
        errors: [],
        skipped: [],
    };

    for (const system of systems) {
        try {
            // 优先使用用户配置的 workerScriptPath
            // Prefer user-configured workerScriptPath
            let outputPath: string;

            if (system.workerScriptPath) {
                // 用户已配置路径，使用该路径（相对于项目根目录）
                // User has configured path, use it (relative to project root)
                outputPath = path.resolve(process.cwd(), system.workerScriptPath);
                if (config.verbose) {
                    console.log(`  Using configured workerScriptPath: ${system.workerScriptPath}`);
                }
            } else {
                // 未配置，使用默认输出目录
                // Not configured, use default output directory
                // 确保输出目录存在
                if (!fs.existsSync(config.outDir)) {
                    fs.mkdirSync(config.outDir, { recursive: true });
                }
                const outputFileName = `${toKebabCase(system.className)}-worker.js`;
                outputPath = path.join(config.outDir, outputFileName);

                // 提示用户需要配置 workerScriptPath
                // Remind user to configure workerScriptPath
                result.skipped.push({
                    className: system.className,
                    suggestedPath: path.relative(process.cwd(), outputPath).replace(/\\/g, '/'),
                    reason: 'No workerScriptPath configured',
                });
            }

            // 确保输出目录存在
            // Ensure output directory exists
            const outputDir = path.dirname(outputPath);
            if (!fs.existsSync(outputDir)) {
                fs.mkdirSync(outputDir, { recursive: true });
            }

            const workerCode = config.wechat
                ? generateWeChatWorkerCode(system)
                : generateStandardWorkerCode(system);

            fs.writeFileSync(outputPath, workerCode, 'utf8');

            result.success.push({
                className: system.className,
                outputPath: outputPath,
                configuredPath: system.workerScriptPath,
            });

            if (config.verbose) {
                console.log(`  Generated: ${outputPath}`);
            }
        } catch (error) {
            result.errors.push({
                className: system.className,
                filePath: system.filePath,
                error: error instanceof Error ? error.message : String(error),
            });
        }
    }

    // 生成映射文件
    // Generate mapping file
    if (config.generateMapping && result.success.length > 0) {
        generateMappingFile(result.success, config);
    }

    return result;
}

/**
 * 生成微信小游戏 Worker 代码
 * Generate WeChat Mini Game Worker code
 */
function generateWeChatWorkerCode(system: WorkerSystemInfo): string {
    const { workerProcessBody, workerProcessParams, sharedBufferProcessBody, entityDataSize } = system;

    return `/**
 * Auto-generated Worker file for ${system.className}
 * 自动生成的 Worker 文件
 *
 * Source: ${system.filePath}
 * Generated by @esengine/worker-generator
 *
 * 使用方式 | Usage:
 * 1. 将此文件放入 workers/ 目录
 * 2. 在 game.json 中配置 "workers": "workers"
 * 3. 在 System 中配置 workerScriptPath: 'workers/${toKebabCase(system.className)}-worker.js'
 */

// 微信小游戏 Worker 环境
// WeChat Mini Game Worker environment
let sharedFloatArray = null;
const ENTITY_DATA_SIZE = ${entityDataSize || 8};

worker.onMessage(function(res) {
    // 微信小游戏 Worker 消息直接传递数据，不需要 .data
    // WeChat Mini Game Worker passes data directly, no .data wrapper
    var type = res.type;
    var id = res.id;
    var entities = res.entities;
    var deltaTime = res.deltaTime;
    var systemConfig = res.systemConfig;
    var startIndex = res.startIndex;
    var endIndex = res.endIndex;
    var sharedBuffer = res.sharedBuffer;

    try {
        // 处理 SharedArrayBuffer 初始化
        // Handle SharedArrayBuffer initialization
        if (type === 'init' && sharedBuffer) {
            sharedFloatArray = new Float32Array(sharedBuffer);
            worker.postMessage({ type: 'init', success: true });
            return;
        }

        // 处理 SharedArrayBuffer 数据
        // Handle SharedArrayBuffer data
        if (type === 'shared' && sharedFloatArray) {
            processSharedArrayBuffer(startIndex, endIndex, deltaTime, systemConfig);
            worker.postMessage({ id: id, result: null });
            return;
        }

        // 传统处理方式
        // Traditional processing
        if (entities) {
            var result = workerProcess(entities, deltaTime, systemConfig);

            // 处理 Promise 返回值
            // Handle Promise return value
            if (result && typeof result.then === 'function') {
                result.then(function(finalResult) {
                    worker.postMessage({ id: id, result: finalResult });
                }).catch(function(error) {
                    worker.postMessage({ id: id, error: error.message });
                });
            } else {
                worker.postMessage({ id: id, result: result });
            }
        }
    } catch (error) {
        worker.postMessage({ id: id, error: error.message });
    }
});

/**
 * 实体处理函数 - 从 ${system.className}.workerProcess 提取
 * Entity processing function - extracted from ${system.className}.workerProcess
 */
function workerProcess(${workerProcessParams.entities}, ${workerProcessParams.deltaTime}, ${workerProcessParams.config}) {
    ${convertToES5(workerProcessBody)}
}

/**
 * SharedArrayBuffer 处理函数
 * SharedArrayBuffer processing function
 */
function processSharedArrayBuffer(startIndex, endIndex, deltaTime, systemConfig) {
    if (!sharedFloatArray) return;
    ${sharedBufferProcessBody ? convertToES5(sharedBufferProcessBody) : '// No SharedArrayBuffer processing defined'}
}
`;
}

/**
 * 生成标准 Worker 代码（用于浏览器等环境）
 * Generate standard Worker code (for browsers, etc.)
 */
function generateStandardWorkerCode(system: WorkerSystemInfo): string {
    const { workerProcessBody, workerProcessParams, sharedBufferProcessBody, entityDataSize } = system;

    return `/**
 * Auto-generated Worker file for ${system.className}
 * 自动生成的 Worker 文件
 *
 * Source: ${system.filePath}
 * Generated by @esengine/worker-generator
 */

let sharedFloatArray = null;
const ENTITY_DATA_SIZE = ${entityDataSize || 8};

self.onmessage = function(e) {
    const { type, id, entities, deltaTime, systemConfig, startIndex, endIndex, sharedBuffer } = e.data;

    try {
        // 处理 SharedArrayBuffer 初始化
        if (type === 'init' && sharedBuffer) {
            sharedFloatArray = new Float32Array(sharedBuffer);
            self.postMessage({ type: 'init', success: true });
            return;
        }

        // 处理 SharedArrayBuffer 数据
        if (type === 'shared' && sharedFloatArray) {
            processSharedArrayBuffer(startIndex, endIndex, deltaTime, systemConfig);
            self.postMessage({ id, result: null });
            return;
        }

        // 传统处理方式
        if (entities) {
            const result = workerProcess(entities, deltaTime, systemConfig);

            if (result && typeof result.then === 'function') {
                result.then(finalResult => {
                    self.postMessage({ id, result: finalResult });
                }).catch(error => {
                    self.postMessage({ id, error: error.message });
                });
            } else {
                self.postMessage({ id, result });
            }
        }
    } catch (error) {
        self.postMessage({ id, error: error.message });
    }
};

/**
 * Entity processing function - extracted from ${system.className}.workerProcess
 */
function workerProcess(${workerProcessParams.entities}, ${workerProcessParams.deltaTime}, ${workerProcessParams.config}) {
    ${workerProcessBody}
}

/**
 * SharedArrayBuffer processing function
 */
function processSharedArrayBuffer(startIndex, endIndex, deltaTime, systemConfig) {
    if (!sharedFloatArray) return;
    ${sharedBufferProcessBody || '// No SharedArrayBuffer processing defined'}
}
`;
}

/**
 * 生成映射文件
 * Generate mapping file
 */
function generateMappingFile(
    success: Array<{ className: string; outputPath: string }>,
    config: GeneratorConfig
): void {
    const mapping: WorkerScriptMapping = {
        generatedAt: new Date().toISOString(),
        mappings: {},
    };

    for (const item of success) {
        // 使用相对于输出目录的路径
        // Use path relative to output directory
        const relativePath = path.relative(config.outDir, item.outputPath).replace(/\\/g, '/');
        mapping.mappings[item.className] = relativePath;
    }

    const mappingPath = path.join(config.outDir, 'worker-mapping.json');
    fs.writeFileSync(mappingPath, JSON.stringify(mapping, null, 2), 'utf8');

    if (config.verbose) {
        console.log(`  Generated mapping: ${mappingPath}`);
    }
}

/**
 * 将 camelCase/PascalCase 转换为 kebab-case
 * Convert camelCase/PascalCase to kebab-case
 */
function toKebabCase(str: string): string {
    return str
        .replace(/([a-z])([A-Z])/g, '$1-$2')
        .replace(/([A-Z])([A-Z][a-z])/g, '$1-$2')
        .toLowerCase();
}

/**
 * ES6+ 到 ES5 转换（用于微信小游戏兼容性）
 * ES6+ to ES5 conversion (for WeChat Mini Game compatibility)
 *
 * 使用 TypeScript 编译器进行安全的代码转换
 * Uses TypeScript compiler for safe code transformation
 */
function convertToES5(code: string): string {
    // 使用 ts-morph 已有的 TypeScript 依赖进行转换
    // Use ts-morph's TypeScript dependency for transformation
    const ts = require('typescript');

    const result = ts.transpileModule(code, {
        compilerOptions: {
            target: ts.ScriptTarget.ES5,
            module: ts.ModuleKind.None,
            removeComments: false,
            // 不生成严格模式声明
            noImplicitUseStrict: true,
        }
    });

    return result.outputText;
}