import {
  defineNuxtModule,
  addComponent,
  addImports,
  createResolver,
} from '@nuxt/kit'
import { readdirSync, existsSync, readFileSync } from 'node:fs'
import { join } from 'node:path'

export interface ModuleOptions {
  /**
   * Whether to import global base styles (CSS variables / design tokens).
   * @default true
   */
  importStyles?: boolean
}

function kebabCase(str: string): string {
  return str.replace(/([A-Z])/g, '-$1').toLowerCase().replace(/^-/, '')
}

// ── 从源码中提取 export function / export const 名称 ─────────
function extractExports(filePath: string): string[] {
  try {
    const content = readFileSync(filePath, 'utf-8')
    const names: string[] = []
    const re = /export\s+(?:function|const|let|var)\s+(\w+)/g
    let m: RegExpExecArray | null
    while ((m = re.exec(content)) !== null) names.push(m[1] as any)
    return names
  } catch {
    return []
  }
}

function isComposable(name: string): boolean {
  return name.startsWith('use') || name === 'createContext'
}

// ── Vite 插件：自动注入组件样式 ────────────────────────────
function BoltUiStylePlugin(styleMap: Record<string, string>) {
  return {
    name: 'bolt-ui:style-inject',
    enforce: 'post',
    transform(code: string, id: string) {
      if (!/\.(vue|tsx?|jsx?)$/.test(id)) return null
      if (id.includes('node_modules')) return null

      const matchedStyles = Object.entries(styleMap)
        .filter(([name]) => code.includes(name))
        .map(([, style]) => style)

      if (matchedStyles.length === 0) return null

      const imports = [...new Set(matchedStyles)]
        .map(p => `import '${p}';`)
        .join('\n')

      return {
        code: imports + '\n' + code,
        map: null,
      }
    },
  }
}

export default defineNuxtModule<ModuleOptions>({
  meta: {
    name: 'bolt-ui',
    configKey: 'boltUi',
  },
  defaults: {
    importStyles: true,
  },
  setup(options, nuxt) {
    const resolver = createResolver(import.meta.url)

    // ── CSS 变量层（design tokens）────────────────────────────
    nuxt.options.css.push(resolver.resolve('./theme-chalk/src/theme/index.scss'))
    if (options.importStyles) {}

    // ── 自动扫描组件目录 ────────────────────────────────────
    const componentsDir = resolver.resolve('./components')
    const componentStyleMap: Record<string, string> = {}

    for (const entry of readdirSync(componentsDir, { withFileTypes: true })) {
      if (!entry.isDirectory()) continue

      const name = entry.name
      const indexPath = join(componentsDir, name, 'index.ts')
      if (!existsSync(indexPath)) continue

      // 注册组件
      addComponent({
        name: `Bo${name}`,
        export: `Bo${name}`,
        filePath: resolver.resolve(`./components/${name}/index.ts`),
      })

      // 构建样式映射（约定：theme-chalk/src/${kebab}.scss）
      const scssPath = join(componentsDir, '..', 'theme-chalk/src', `${kebabCase(name)}.scss`)
      if (existsSync(scssPath)) {
        componentStyleMap[`Bo${name}`] = `bolt-ui/theme-chalk/src/${kebabCase(name)}.scss`
      }
    }

    // ── Vite 插件：按需注入组件样式 ─────────────────────────
    nuxt.hook('vite:extendConfig', (config) => {
      // @ts-ignore
      config.plugins = config.plugins || []
      config.plugins.push(BoltUiStylePlugin(componentStyleMap) as any)
    })

    // ── 自动扫描 composable 目录 ──────────────────────────
    for (const scanDir of ['hooks', 'utils', 'locales']) {
      const absDir = resolver.resolve(`./${scanDir}`)
      if (!existsSync(absDir)) continue

      const walk = (dir: string) => {
        for (const entry of readdirSync(dir, { withFileTypes: true })) {
          const fullPath = join(dir, entry.name)
          if (entry.isDirectory()) {
            walk(fullPath)
          } else if (entry.name === 'index.ts') {
            const names = extractExports(fullPath).filter(isComposable)
            for (const name of names) {
              addImports({ name, as: name, from: fullPath })
            }
          }
        }
      }
      walk(absDir)
    }
  },
})