package web

import (
	"fmt"
	"dhcp-dns-manager/internal/config"
	"dhcp-dns-manager/internal/db"
	"dhcp-dns-manager/internal/dhcp"
	"dhcp-dns-manager/internal/dns"
	"github.com/gin-gonic/gin"
	"net/http"
	"time"
)

type Server struct {
	config        *config.WebConfig
	db            *db.DB
	dhcpServer    *dhcp.Server
	dnsServer     *dns.Server
	router        *gin.Engine
	configManager *ConfigManager
}

type User struct {
	ID       uint   `gorm:"primaryKey"`
	Username string `gorm:"uniqueIndex"`
	Password string
	IsAdmin  bool
}

// Session represents a user session
type Session struct {
	ID        string    `gorm:"primaryKey"`
	UserID    string    // username
	ExpiresAt time.Time
	CreatedAt time.Time
}

func NewServer(cfg *config.WebConfig, database *db.DB, d *dhcp.Server, n *dns.Server, cm *ConfigManager) *Server {
	gin.SetMode(gin.ReleaseMode)
	
	s := &Server{
		config:        cfg,
		db:            database,
		dhcpServer:    d,
		dnsServer:     n,
		router:        gin.New(),
		configManager: cm,
	}
	
	// Auto-migrate Session table
	s.db.AutoMigrate(&Session{})
	
	// Wire up config reloader so DHCP server picks up web UI config changes
	d.SetConfigReloader(func() *config.DHCPConfig {
		cfg := cm.GetConfig()
		dhcpCfg := new(config.DHCPConfig)
		*dhcpCfg = cfg.DHCP // copy the value
		return dhcpCfg
	})
	
	s.setupRoutes()
	
	// Start session cleanup goroutine
	go s.cleanupSessions()
	
	return s
}

func (s *Server) cleanupSessions() {
	ticker := time.NewTicker(1 * time.Hour)
	defer ticker.Stop()
	
	for range ticker.C {
		s.db.Where("expires_at < ?", time.Now()).Delete(&Session{})
	}
}

func (s *Server) setupRoutes() {
	// Custom recovery middleware that returns JSON
	s.router.Use(gin.CustomRecovery(func(c *gin.Context, err any) {
		c.JSON(http.StatusInternalServerError, gin.H{
			"error": fmt.Sprintf("Internal server error: %v", err),
		})
		c.Abort()
	}))
	
	s.router.Use(gin.Logger())
	
	// Inject ConfigManager into context
	s.router.Use(func(c *gin.Context) {
		c.Set("configManager", s.configManager)
		c.Next()
	})
	
	// Static files
	s.router.Static("/static", "./web/static")
	
	// Public routes
	s.router.GET("/", s.handleIndex)
	s.router.POST("/api/login", s.handleLogin)
	s.router.GET("/api/health", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"status": "ok", "message": "Server is running"})
	})
	s.router.POST("/api/session/verify", s.handleVerifySession)
	
	// Protected routes
	protected := s.router.Group("/api")
	protected.Use(s.authMiddleware())
	{
		// Dashboard
		protected.GET("/dashboard", s.handleDashboard)
		
		// DHCP
		protected.GET("/dhcp/config", s.handleGetDHCPConfig)
		protected.PUT("/dhcp/config", s.handleUpdateDHCPConfig)
		protected.GET("/dhcp/leases", s.handleGetLeases)
		protected.GET("/dhcp/bindings", s.handleGetBindings)
		protected.POST("/dhcp/bindings", s.handleCreateBinding)
		protected.DELETE("/dhcp/bindings/:id", s.handleDeleteBinding)
		
		// DNS
		protected.GET("/dns/config", s.handleGetDNSConfig)
		protected.PUT("/dns/config", s.handleUpdateDNSConfig)
		protected.GET("/dns/records", s.handleGetRecords)
		protected.POST("/dns/records", s.handleCreateRecord)
		protected.DELETE("/dns/records/:id", s.handleDeleteRecord)
		protected.GET("/dns/logs", s.handleGetLogs)
		protected.GET("/dns/zones", s.handleGetZones)
		protected.POST("/dns/zones", s.handleCreateZone)
		protected.DELETE("/dns/zones/:id", s.handleDeleteZone)
		
		// Config
		protected.GET("/config", s.handleGetFullConfig)
		protected.PUT("/config", s.handleUpdateConfig)
		protected.GET("/config/export", s.handleExportConfig)
		protected.POST("/config/import", s.handleImportConfig)
		
		// Service
		protected.POST("/service/restart", s.handleRestartService)
	}
}

func (s *Server) authMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		sessionID := c.GetHeader("X-Session-ID")
		if sessionID == "" {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
			c.Abort()
			return
		}

		// Validate session from database
		var session Session
		if err := s.db.Where("id = ? AND expires_at > ?", sessionID, time.Now()).First(&session).Error; err != nil {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Session expired"})
			c.Abort()
			return
		}

		c.Next()
	}
}

func (s *Server) Start() error {
	addr := fmt.Sprintf("%s:%d", s.config.Host, s.config.Port)
	return s.router.Run(addr)
}

// Handlers
func (s *Server) handleIndex(c *gin.Context) {
	c.File("./web/templates/index.html")
}

func (s *Server) handleLogin(c *gin.Context) {
	var req struct {
		Username string `json:"username"`
		Password string `json:"password"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	
	// TODO: Validate against database
	// For now, simple demo auth
	if req.Username == "admin" && req.Password == "admin" {
		sessionID := fmt.Sprintf("session-%d-%s", time.Now().UnixNano(), req.Username)
		session := Session{
			ID:        sessionID,
			UserID:    req.Username,
			ExpiresAt: time.Now().Add(30 * 24 * time.Hour), // 30 days
		}
		s.db.Create(&session)
		
		c.JSON(http.StatusOK, gin.H{
			"session_id": sessionID,
			"is_admin":   true,
		})
		return
	}
	
	c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid credentials"})
}

func (s *Server) handleVerifySession(c *gin.Context) {
	var req struct {
		SessionID string `json:"session_id"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	
	var session Session
	if err := s.db.Where("id = ? AND expires_at > ?", req.SessionID, time.Now()).First(&session).Error; err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Session expired"})
		return
	}
	
	c.JSON(http.StatusOK, gin.H{
		"valid":    true,
		"user_id":  session.UserID,
		"username": session.UserID,
	})
}

func (s *Server) handleDashboard(c *gin.Context) {
	leases := s.dhcpServer.GetLeases()
	bindings, _ := s.dhcpServer.GetStaticBindings()
	records, _ := s.dnsServer.GetDNSRecords()
	
	c.JSON(http.StatusOK, gin.H{
		"active_leases":    len(leases),
		"static_bindings":  len(bindings),
		"dns_records":      len(records),
		"leases":           leases,
		"bindings":         bindings,
		"records":          records,
	})
}

func (s *Server) handleGetLeases(c *gin.Context) {
	leases := s.dhcpServer.GetLeases()
	c.JSON(http.StatusOK, gin.H{"leases": leases})
}

func (s *Server) handleGetBindings(c *gin.Context) {
	bindings, err := s.dhcpServer.GetStaticBindings()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"bindings": bindings})
}

func (s *Server) handleCreateBinding(c *gin.Context) {
	var req struct {
		MAC         string `json:"mac"`
		IP          string `json:"ip"`
		Hostname    string `json:"hostname"`
		Description string `json:"description"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	
	if err := s.dhcpServer.CreateStaticBinding(req.MAC, req.IP, req.Hostname, req.Description); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	
	c.JSON(http.StatusOK, gin.H{"message": "Binding created"})
}

func (s *Server) handleDeleteBinding(c *gin.Context) {
	_ = c.Param("id")
	// TODO: Convert to uint and delete
	c.JSON(http.StatusOK, gin.H{"message": "Binding deleted"})
}

func (s *Server) handleGetRecords(c *gin.Context) {
	records, err := s.dnsServer.GetDNSRecords()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"records": records})
}

func (s *Server) handleCreateRecord(c *gin.Context) {
	var req struct {
		Name  string `json:"name"`
		Type  string `json:"type"`
		Value string `json:"value"`
		TTL   int    `json:"ttl"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	
	if err := s.dnsServer.CreateDNSRecord(req.Name, req.Type, req.Value, req.TTL); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	
	c.JSON(http.StatusOK, gin.H{"message": "Record created"})
}

func (s *Server) handleDeleteRecord(c *gin.Context) {
	_ = c.Param("id")
	// TODO: Convert to uint and delete
	c.JSON(http.StatusOK, gin.H{"message": "Record deleted"})
}

func (s *Server) handleGetLogs(c *gin.Context) {
	logs, err := s.dnsServer.GetQueryLogs(100)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"logs": logs})
}

func (s *Server) handleGetZones(c *gin.Context) {
	zones, err := s.dnsServer.GetDNSZones()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"zones": zones})
}

func (s *Server) handleCreateZone(c *gin.Context) {
	var req struct {
		Name string `json:"name"`
		Type string `json:"type"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	
	if err := s.dnsServer.CreateDNSZone(req.Name, req.Type); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	
	c.JSON(http.StatusOK, gin.H{"message": "Zone created"})
}

func (s *Server) handleDeleteZone(c *gin.Context) {
	_ = c.Param("id")
	// TODO: Convert to uint and delete
	c.JSON(http.StatusOK, gin.H{"message": "Zone deleted"})
}

func (s *Server) handleGetConfig(c *gin.Context) {
	// Return current config (without sensitive data)
	c.JSON(http.StatusOK, gin.H{"config": "placeholder"})
}

func (s *Server) handleUpdateConfig(c *gin.Context) {
	// Update config
	c.JSON(http.StatusOK, gin.H{"message": "Config updated"})
}