package middleware

import (
	"net/http"
	"slices"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/nutcas3/telecom-platform/apps/api-server/internal/models"
	"github.com/nutcas3/telecom-platform/apps/api-server/internal/rbac"
	"github.com/nutcas3/telecom-platform/apps/api-server/internal/services"
	"gorm.io/gorm"
)

// AuthMiddleware creates a JWT authentication middleware
func AuthMiddleware(authService *services.AuthService) gin.HandlerFunc {
	return func(c *gin.Context) {
		// Get token from Authorization header
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Authorization header required"})
			c.Abort()
			return
		}

		// Extract token from "Bearer <token>" format
		tokenParts := strings.Split(authHeader, " ")
		if len(tokenParts) != 2 || tokenParts[0] != "Bearer" {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid authorization header format"})
			c.Abort()
			return
		}

		token := tokenParts[1]

		// Validate token
		claims, err := authService.GetJWTService().ValidateToken(token)
		if err != nil {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
			c.Abort()
			return
		}

		// Get user from database
		user, err := authService.GetUserByID(claims.UserID)
		if err != nil {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "User not found"})
			c.Abort()
			return
		}

		// Store user and claims in context
		c.Set("user", user)
		c.Set("user_id", claims.UserID)
		c.Set("username", claims.Username)
		c.Set("role", claims.Role)

		c.Next()
	}
}

// RequirePermission creates a middleware that checks for specific permissions
func RequirePermission(resource, action string) gin.HandlerFunc {
	return func(c *gin.Context) {
		user, exists := c.Get("user")
		if !exists {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "User not authenticated"})
			c.Abort()
			return
		}

		// Get database from context (should be set by the main server)
		db, exists := c.Get("db")
		if !exists {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "Database not available"})
			c.Abort()
			return
		}

		// Check permission
		if !user.(*models.User).HasPermission(db.(*gorm.DB), resource, action) {
			c.JSON(http.StatusForbidden, gin.H{"error": "Insufficient permissions"})
			c.Abort()
			return
		}

		c.Next()
	}
}

// RequireCasbinPermission creates a middleware that checks for specific permissions using Casbin
func RequireCasbinPermission(casbinService *rbac.CasbinService, resource, action string) gin.HandlerFunc {
	return func(c *gin.Context) {
		userID, exists := c.Get("user_id")
		if !exists {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "User not authenticated"})
			c.Abort()
			return
		}

		allowed, err := casbinService.CheckPermission(c.Request.Context(), userID.(uint), resource, action)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to check permissions"})
			c.Abort()
			return
		}

		if !allowed {
			c.JSON(http.StatusForbidden, gin.H{"error": "Insufficient permissions"})
			c.Abort()
			return
		}

		c.Next()
	}
}

// RequireRole creates a middleware that checks for specific roles (legacy, use RequireCasbinPermission for new features)
func RequireRole(allowedRoles ...string) gin.HandlerFunc {
	return func(c *gin.Context) {
		role, exists := c.Get("role")
		if !exists {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "User not authenticated"})
			c.Abort()
			return
		}

		userRole := role.(string)
		if slices.Contains(allowedRoles, userRole) {
			c.Next()
			return
		}

		c.JSON(http.StatusForbidden, gin.H{"error": "Insufficient role permissions"})
		c.Abort()
	}
}

// OptionalAuthMiddleware creates an optional authentication middleware
func OptionalAuthMiddleware(authService *services.AuthService) gin.HandlerFunc {
	return func(c *gin.Context) {
		// Get token from Authorization header
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			c.Next()
			return
		}

		// Extract token from "Bearer <token>" format
		tokenParts := strings.Split(authHeader, " ")
		if len(tokenParts) != 2 || tokenParts[0] != "Bearer" {
			c.Next()
			return
		}

		token := tokenParts[1]

		// Validate token
		claims, err := authService.GetJWTService().ValidateToken(token)
		if err != nil {
			c.Next()
			return
		}

		// Get user from database
		user, err := authService.GetUserByID(claims.UserID)
		if err != nil {
			c.Next()
			return
		}

		// Store user and claims in context
		c.Set("user", user)
		c.Set("user_id", claims.UserID)
		c.Set("username", claims.Username)
		c.Set("role", claims.Role)

		c.Next()
	}
}