// 自动扫描 controllers 目录并注册路由
// 兼容传统 routes 方式和自动注册 controller 方式
import fs from "fs"
import path from "path"

/**
 * 自动扫描 controllers 目录，注册所有导出的路由
 * 自动检测 routes 目录下已手动注册的 controller，避免重复注册
 * @param {Koa} app - Koa 实例
 * @param {string} controllersDir - controllers 目录路径
 * @param {string} prefix - 路由前缀
 * @param {Set<string>} [manualControllers] - 可选，手动传入已注册 controller 文件名集合，优先于自动扫描
 */
export function autoRegisterControllers(app, controllersDir = path.resolve(__dirname, "../controllers")) {
    let allRouter = []
    async function scan(dir, routePrefix = "") {
        for (const file of fs.readdirSync(dir)) {
            const fullPath = path.join(dir, file)
            const stat = fs.statSync(fullPath)
            if (stat.isDirectory()) {
                await scan(fullPath, routePrefix + "/" + file)
            } else if (file.endsWith("Controller.js")) {
                let controller
                try {
                    controller = require(fullPath)
                } catch (e) {
                    controller = (await import(fullPath)).default
                }
                const routes = controller.createRoutes || controller.default?.createRoutes || controller.default || controller
                if (typeof routes === "function") {
                    allRouter.push(routes())
                }
            }
        }
    }

    ;(async () => {
        await scan(controllersDir)
        // TODO: 存在问题：每个Controller都是有顺序的，如果其中一个Controller没有next方法，可能会导致后续的Controller无法执行
        // allRouter.forEach(router => {
        //     app.use(router.middleware())
        // })
        // 聚合中间件：只分发到匹配的router
        app.use(async (ctx, next) => {
            let matched = false
            for (const router of allRouter) {
                // router._matchRoute 只在 router.js 内部，需暴露或用 middleware 包一层
                if (typeof router._matchRoute === "function") {
                    const route = router._matchRoute(ctx.method.toLowerCase(), ctx.path)
                    if (route) {
                        matched = true
                        await router.middleware()(ctx, next)
                        break // 命中一个即停止
                    }
                } else {
                    // fallback: 直接尝试middleware，若未命中会自动next
                    const before = ctx.status
                    await router.middleware()(ctx, next)
                    if (ctx.status !== before) {
                        matched = true
                        break
                    }
                }
            }
            if (!matched) {
                await next()
            }
        })
    })()
}