import { resolve } from 'path'
import type { ConfigEnv, UserConfig } from 'vite'
import { loadEnv } from 'vite'
import { createVitePlugins } from './build/vite'
import { exclude, include } from "./build/vite/optimize"
import os from 'os'

// 当前执行node命令时文件夹的地址(工作目录)
const root = process.cwd()

// 路径查找
function pathResolve(dir: string) {
    return resolve(root, '.', dir)
}

// https://vitejs.dev/config/
export default ({ command, mode }: ConfigEnv): UserConfig => {
    let env = {} as any
    const isBuild = command === 'build'
    if (!isBuild) {
        env = loadEnv((process.argv[3] === '--mode' ? process.argv[4] : process.argv[3]), root)
    } else {
        env = loadEnv(mode, root)
    }

    // 获取CPU核心数
    const cpuCount = os.cpus().length
    const maxWorkers = Math.min(4, Math.max(1, Math.floor(cpuCount / 2)))

    return {
        base: env.VITE_BASE_PATH,
        root: root,
        
        // 优化开发服务器
        server: {
            port: env.VITE_PORT,
            host: "0.0.0.0",
            open: env.VITE_OPEN === 'true',
            hmr: {
                overlay: false // 禁用错误遮罩层
            }
        },

        // 项目使用的vite插件
        plugins: [
            createVitePlugins()
            // 生产环境禁用可视化分析器以节省资源
        ],

        css: {
            preprocessorOptions: {
                scss: {
                    additionalData: '@use "@/styles/variables.scss" as *;',
                    javascriptEnabled: true,
                    silenceDeprecations: ["legacy-js-api"]
                }
            }
        },

        resolve: {
            extensions: ['.mjs', '.js', '.ts', '.jsx', '.tsx', '.json', '.scss', '.css'],
            alias: [
                {
                    find: 'vue-i18n',
                    replacement: 'vue-i18n/dist/vue-i18n.cjs.js'
                },
                {
                    find: /@\//,
                    replacement: `${pathResolve('src')}/`
                }
            ]
        },

        build: {
            minify: 'terser',
            outDir: env.VITE_OUT_DIR || 'dist',
            sourcemap: false, // 禁用sourcemap节省内存
            reportCompressedSize: false, // 禁用压缩大小报告
            
            // 优化构建目标
            target: 'es2015',
            cssTarget: 'chrome61',
            
            // 优化压缩选项
            terserOptions: {
                compress: {
                    drop_debugger: true,
                    drop_console: true,
                    ecma: 2020,
                    passes: 1, // 减少压缩轮次
                    // 禁用一些耗内存的压缩选项
                    pure_funcs: [],
                    reduce_funcs: false,
                    reduce_vars: false,
                    unsafe: false,
                    unsafe_comps: false,
                    unsafe_math: false,
                    unsafe_proto: false,
                    unsafe_regexp: false
                },
                format: {
                    comments: false
                },
                maxWorkers: maxWorkers // 根据CPU核心数限制工作线程
            },

            chunkSizeWarningLimit: 3000, // 提高警告阈值
            
            rollupOptions: {
                // 优化外部依赖处理
                external: [],
                
                // 优化输出配置
                output: {
                    // 智能分包策略
                    manualChunks: (id: string) => {
                        if (id.includes('node_modules')) {
                            // 大型库单独打包
                            if (id.includes('@grapecity-software')) {
                                return 'vendor-grapecity';
                            }
                            if (id.includes('echarts')) {
                                return 'vendor-echarts';
                            }
                            if (id.includes('element-plus')) {
                                return 'vendor-element-plus';
                            }
                            if (id.includes('vue') || id.includes('@vue')) {
                                return 'vendor-vue';
                            }
                            if (id.includes('lodash')) {
                                return 'vendor-lodash';
                            }
                            // 其他第三方库统一打包
                            return 'vendor';
                        }
                    },
                    
                    // 优化文件命名和路径
                    chunkFileNames: 'assets/js/[name]-[hash:8].js',
                    entryFileNames: 'assets/js/[name]-[hash:8].js',
                    assetFileNames: 'assets/[ext]/[name]-[hash:8].[ext]',
                    
                    // 优化缓存
                    hoistTransitiveImports: false,
                    sanitizeFileName: true
                },
                
                // 优化treeshaking
                treeshake: {
                    moduleSideEffects: false,
                    preset: 'smallest'
                }
            },
            
            // 优化依赖预构建
            commonjsOptions: {
                transformMixedEsModules: true,
                ignoreDynamicRequires: true
            },
            
            // 优化动态导入
            dynamicImportVarsOptions: {
                warnOnError: true
            }
        },

        optimizeDeps: {
            include,
            exclude,
            // 优化预构建
            esbuildOptions: {
                target: 'es2015',
                minify: false // 预构建不压缩，节省内存
            }
        },

        // 优化esbuild配置
        esbuild: {
            target: 'es2015',
           /// minify: false, // 禁用esbuild压缩，使用terser
            keepNames: false,
            drop: ['debugger', 'console']
        }
    }
}