package router

import (
	"io/fs"
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"
	"gorm.io/gorm"

	"git.sundynix.cn/Blizzard/sundynix-site/server/internal/handler"
	"git.sundynix.cn/Blizzard/sundynix-site/server/internal/middleware"
	"git.sundynix.cn/Blizzard/sundynix-site/server/internal/pkg/resp"
	"git.sundynix.cn/Blizzard/sundynix-site/server/internal/webfs"
)

func New(db *gorm.DB) (*gin.Engine, error) {
	r := gin.New()
	r.Use(gin.Logger(), gin.Recovery(), middleware.CORS())

	// ── 公开 API ──
	api := r.Group("/api")
	{
		api.GET("/healthz", func(c *gin.Context) {
			resp.OK(c, gin.H{"status": "ok"})
		})

		posts := handler.NewPostHandler(db)
		api.GET("/posts", posts.List)
		api.GET("/posts/:slug", posts.Get)
	}

	// ── 管理端 API ──
	adminAuth := handler.NewAdminAuthHandler()
	api.POST("/admin/login", adminAuth.Login)

	adminAPI := api.Group("/admin", middleware.Auth())
	{
		posts := handler.NewAdminPostHandler(db)
		adminAPI.GET("/posts", posts.List)
		adminAPI.POST("/posts", posts.Create)
		adminAPI.GET("/posts/:id", posts.Get)
		adminAPI.PUT("/posts/:id", posts.Update)
		adminAPI.DELETE("/posts/:id", posts.Delete)
	}

	// ── 静态站点：/admin → 管理端，其余 → 用户端 ──
	webDist, err := webfs.WebDist()
	if err != nil {
		return nil, err
	}
	adminDist, err := webfs.AdminDist()
	if err != nil {
		return nil, err
	}
	webServer := http.FileServer(http.FS(webDist))
	adminServer := http.StripPrefix("/admin", http.FileServer(http.FS(adminDist)))

	r.NoRoute(func(c *gin.Context) {
		path := c.Request.URL.Path
		if strings.HasPrefix(path, "/api/") {
			resp.NotFound(c, "接口不存在")
			return
		}
		if path == "/admin" || strings.HasPrefix(path, "/admin/") {
			serveSPA(c, adminDist, adminServer, strings.TrimPrefix(path, "/admin"), "/admin/")
			return
		}
		serveSPA(c, webDist, webServer, path, "/")
	})

	return r, nil
}

// serveSPA 真实文件直接吐，否则回退 index.html 交给前端路由。
func serveSPA(c *gin.Context, dist fs.FS, server http.Handler, rel, fallback string) {
	p := strings.TrimPrefix(rel, "/")
	if p != "" {
		if _, err := fs.Stat(dist, p); err == nil {
			server.ServeHTTP(c.Writer, c.Request)
			return
		}
	}
	c.Request.URL.Path = fallback
	server.ServeHTTP(c.Writer, c.Request)
}