// Package api exposes a REST API and serves the embedded React SPA.
package api

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

	"github.com/gin-gonic/gin"
	"moonrelay/internal/discovery"
	"moonrelay/internal/moonlight"
	tsnode "moonrelay/internal/tailscale"
)

// Server is the HTTP API + SPA server.
type Server struct {
	disc     *discovery.Discoverer
	launcher *moonlight.Launcher
	tsNode   *tsnode.Node
	router   *gin.Engine
}

// New creates and configures the server.
// staticFS should be the embedded React build (nil = API-only mode for dev).
func New(disc *discovery.Discoverer, launcher *moonlight.Launcher, ts *tsnode.Node, staticFS fs.FS) *Server {
	gin.SetMode(gin.ReleaseMode)
	r := gin.Default()

	s := &Server{
		disc:     disc,
		launcher: launcher,
		tsNode:   ts,
		router:   r,
	}

	// CORS for local dev (browser hitting :8080 from :1420 vite dev server)
	r.Use(func(c *gin.Context) {
		c.Header("Access-Control-Allow-Origin", "*")
		c.Header("Access-Control-Allow-Methods", "GET,POST,OPTIONS")
		c.Header("Access-Control-Allow-Headers", "Content-Type")
		if c.Request.Method == "OPTIONS" {
			c.AbortWithStatus(204)
			return
		}
		c.Next()
	})

	// REST API routes
	api := r.Group("/api")
	{
		api.GET("/status", s.getStatus)
		api.GET("/hosts", s.getHosts)
		api.POST("/hosts/manual", s.addManualHost)
		api.POST("/connect", s.connect)
		api.POST("/pair", s.pair)
	}

	// Serve the embedded React SPA for all non-API routes
	if staticFS != nil {
		r.NoRoute(func(c *gin.Context) {
			// Try to serve the file from the embedded FS
			path := c.Request.URL.Path
			if path == "/" || path == "" {
				path = "/index.html"
			}
			// Strip leading slash for fs.FS
			fsPath := path[1:]
			f, err := staticFS.Open(fsPath)
			if err != nil {
				// Fall back to index.html for SPA client-side routing
				c.FileFromFS("index.html", http.FS(staticFS))
				return
			}
			f.Close()
			c.FileFromFS(fsPath, http.FS(staticFS))
		})
	}

	return s
}

// Handler returns the underlying http.Handler.
func (s *Server) Handler() http.Handler {
	return s.router
}

// getStatus returns VPN and launcher status.
func (s *Server) getStatus(c *gin.Context) {
	vpnAddr := ""
	vpnConnected := false
	if s.tsNode != nil {
		vpnAddr = s.tsNode.LocalAddr()
		vpnConnected = vpnAddr != ""
	}
	c.JSON(http.StatusOK, gin.H{
		"vpn_connected":  vpnConnected,
		"vpn_address":    vpnAddr,
		"moonlight_path": s.launcher.ExecPath(),
	})
}

// getHosts returns all discovered streaming hosts.
func (s *Server) getHosts(c *gin.Context) {
	c.JSON(http.StatusOK, s.disc.Hosts())
}

// addManualHost adds a host by IP for tailnet peers that don't multicast mDNS.
func (s *Server) addManualHost(c *gin.Context) {
	var body struct {
		Name string `json:"name" binding:"required"`
		IP   string `json:"ip"   binding:"required"`
		Port int    `json:"port"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if body.Port == 0 {
		body.Port = 47984 // Apollo default
	}
	s.disc.AddManual(body.Name, body.IP, body.Port)
	c.JSON(http.StatusOK, gin.H{"ok": true})
}

// connect launches a Moonlight stream to a host.
// In Docker mode this sends back an rtsp:// URI the browser can hand off.
func (s *Server) connect(c *gin.Context) {
	var body struct {
		IP  string `json:"ip"  binding:"required"`
		App string `json:"app"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if body.App == "" {
		body.App = "Desktop"
	}
	if err := s.launcher.Stream(body.IP, body.App); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"ok": true})
}

// pair runs the Moonlight pair flow for a host.
func (s *Server) pair(c *gin.Context) {
	var body struct {
		IP string `json:"ip" binding:"required"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if err := s.launcher.Pair(body.IP); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"ok": true})
}