package middleware

import (
	"errors"
	"net/http"
	"strings"
	"time"

	"github.com/labstack/echo/v4"
	"github.com/golang-jwt/jwt/v5"

	"github.com/treytartt/casera-api/internal/config"
	"github.com/treytartt/casera-api/internal/models"
	"github.com/treytartt/casera-api/internal/repositories"
)

const (
	// AdminUserKey is the context key for the authenticated admin user
	AdminUserKey = "admin_user"
	// AdminClaimsKey is the context key for JWT claims
	AdminClaimsKey = "admin_claims"
)

// AdminClaims represents the JWT claims for admin authentication
type AdminClaims struct {
	AdminID uint              `json:"admin_id"`
	Email   string            `json:"email"`
	Role    models.AdminRole  `json:"role"`
	jwt.RegisteredClaims
}

// AdminAuthMiddleware creates a middleware that validates admin JWT tokens
func AdminAuthMiddleware(cfg *config.Config, adminRepo *repositories.AdminRepository) echo.MiddlewareFunc {
	return func(next echo.HandlerFunc) echo.HandlerFunc {
		return func(c echo.Context) error {
			var tokenString string

			// Get token from Authorization header only.
			// Query parameter authentication is intentionally not supported
			// because tokens in URLs leak into server logs and browser history.
			authHeader := c.Request().Header.Get("Authorization")
			if authHeader != "" {
				// Check Bearer prefix
				parts := strings.SplitN(authHeader, " ", 2)
				if len(parts) == 2 && strings.ToLower(parts[0]) == "bearer" {
					tokenString = parts[1]
				}
			}

			if tokenString == "" {
				return c.JSON(http.StatusUnauthorized, map[string]interface{}{"error": "Authorization required"})
			}

			// Parse and validate token
			claims := &AdminClaims{}
			token, err := jwt.ParseWithClaims(tokenString, claims, func(token *jwt.Token) (interface{}, error) {
				// Validate signing method
				if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
					return nil, errors.New("invalid signing method")
				}
				return []byte(cfg.Security.SecretKey), nil
			})

			if err != nil {
				return c.JSON(http.StatusUnauthorized, map[string]interface{}{"error": "Invalid token"})
			}

			if !token.Valid {
				return c.JSON(http.StatusUnauthorized, map[string]interface{}{"error": "Token is not valid"})
			}

			// Get admin user from database
			admin, err := adminRepo.FindByID(claims.AdminID)
			if err != nil {
				return c.JSON(http.StatusUnauthorized, map[string]interface{}{"error": "Admin user not found"})
			}

			// Check if admin is active
			if !admin.IsActive {
				return c.JSON(http.StatusUnauthorized, map[string]interface{}{"error": "Admin account is disabled"})
			}

			// Store admin and claims in context
			c.Set(AdminUserKey, admin)
			c.Set(AdminClaimsKey, claims)

			return next(c)
		}
	}
}

// GenerateAdminToken creates a new JWT token for an admin user
func GenerateAdminToken(admin *models.AdminUser, cfg *config.Config) (string, error) {
	// Token expires in 24 hours
	expirationTime := time.Now().Add(24 * time.Hour)

	claims := &AdminClaims{
		AdminID: admin.ID,
		Email:   admin.Email,
		Role:    admin.Role,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(expirationTime),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			Subject:   admin.Email,
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString([]byte(cfg.Security.SecretKey))
}

// RequireSuperAdmin middleware requires the admin to have super_admin role
func RequireSuperAdmin() echo.MiddlewareFunc {
	return func(next echo.HandlerFunc) echo.HandlerFunc {
		return func(c echo.Context) error {
			admin := c.Get(AdminUserKey)
			if admin == nil {
				return c.JSON(http.StatusUnauthorized, map[string]interface{}{"error": "Admin authentication required"})
			}

			adminUser, ok := admin.(*models.AdminUser)
			if !ok {
				return c.JSON(http.StatusUnauthorized, map[string]interface{}{"error": "Admin authentication required"})
			}
			if !adminUser.IsSuperAdmin() {
				return c.JSON(http.StatusForbidden, map[string]interface{}{"error": "Super admin privileges required"})
			}

			return next(c)
		}
	}
}