package handlers

import (
	"net/http"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"

	"github.com/breakpilot/consent-service/internal/models"
	"github.com/breakpilot/consent-service/internal/services"
)

// AuthHandler handles authentication endpoints
type AuthHandler struct {
	authService  *services.AuthService
	emailService *services.EmailService
}

// NewAuthHandler creates a new AuthHandler
func NewAuthHandler(authService *services.AuthService, emailService *services.EmailService) *AuthHandler {
	return &AuthHandler{
		authService:  authService,
		emailService: emailService,
	}
}

// Register handles user registration
// @Summary Register a new user
// @Tags auth
// @Accept json
// @Produce json
// @Param request body models.RegisterRequest true "Registration data"
// @Success 201 {object} map[string]interface{}
// @Failure 400 {object} map[string]string
// @Failure 409 {object} map[string]string
// @Router /auth/register [post]
func (h *AuthHandler) Register(c *gin.Context) {
	var req models.RegisterRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request", "details": err.Error()})
		return
	}

	user, verificationToken, err := h.authService.Register(c.Request.Context(), &req)
	if err != nil {
		if err == services.ErrUserExists {
			c.JSON(http.StatusConflict, gin.H{"error": "User with this email already exists"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to register user"})
		return
	}

	// Send verification email (async, don't block response)
	go func() {
		var name string
		if user.Name != nil {
			name = *user.Name
		}
		if err := h.emailService.SendVerificationEmail(user.Email, name, verificationToken); err != nil {
			// Log error but don't fail registration
			println("Failed to send verification email:", err.Error())
		}
	}()

	c.JSON(http.StatusCreated, gin.H{
		"message": "Registration successful. Please check your email to verify your account.",
		"user": gin.H{
			"id":    user.ID,
			"email": user.Email,
			"name":  user.Name,
		},
	})
}

// Login handles user login
// @Summary Login user
// @Tags auth
// @Accept json
// @Produce json
// @Param request body models.LoginRequest true "Login credentials"
// @Success 200 {object} models.LoginResponse
// @Failure 400 {object} map[string]string
// @Failure 401 {object} map[string]string
// @Failure 403 {object} map[string]string
// @Router /auth/login [post]
func (h *AuthHandler) Login(c *gin.Context) {
	var req models.LoginRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request", "details": err.Error()})
		return
	}

	ipAddress := c.ClientIP()
	userAgent := c.Request.UserAgent()

	response, err := h.authService.Login(c.Request.Context(), &req, ipAddress, userAgent)
	if err != nil {
		switch err {
		case services.ErrInvalidCredentials:
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid email or password"})
		case services.ErrAccountLocked:
			c.JSON(http.StatusForbidden, gin.H{"error": "Account is temporarily locked. Please try again later."})
		case services.ErrAccountSuspended:
			c.JSON(http.StatusForbidden, gin.H{
				"error":    "Account is suspended",
				"reason":   "consent_required",
				"redirect": "/consent/pending",
			})
		default:
			c.JSON(http.StatusInternalServerError, gin.H{"error": "Login failed"})
		}
		return
	}

	c.JSON(http.StatusOK, response)
}

// Logout handles user logout
// @Summary Logout user
// @Tags auth
// @Accept json
// @Produce json
// @Param Authorization header string true "Bearer token"
// @Success 200 {object} map[string]string
// @Router /auth/logout [post]
func (h *AuthHandler) Logout(c *gin.Context) {
	var req struct {
		RefreshToken string `json:"refresh_token"`
	}
	if err := c.ShouldBindJSON(&req); err == nil && req.RefreshToken != "" {
		_ = h.authService.Logout(c.Request.Context(), req.RefreshToken)
	}

	c.JSON(http.StatusOK, gin.H{"message": "Logged out successfully"})
}

// RefreshToken refreshes the access token
// @Summary Refresh access token
// @Tags auth
// @Accept json
// @Produce json
// @Param request body models.RefreshTokenRequest true "Refresh token"
// @Success 200 {object} models.LoginResponse
// @Failure 401 {object} map[string]string
// @Router /auth/refresh [post]
func (h *AuthHandler) RefreshToken(c *gin.Context) {
	var req models.RefreshTokenRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request"})
		return
	}

	response, err := h.authService.RefreshToken(c.Request.Context(), req.RefreshToken)
	if err != nil {
		if err == services.ErrAccountSuspended {
			c.JSON(http.StatusForbidden, gin.H{
				"error":    "Account is suspended",
				"reason":   "consent_required",
				"redirect": "/consent/pending",
			})
			return
		}
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid or expired refresh token"})
		return
	}

	c.JSON(http.StatusOK, response)
}

// VerifyEmail verifies user email
// @Summary Verify email address
// @Tags auth
// @Accept json
// @Produce json
// @Param request body models.VerifyEmailRequest true "Verification token"
// @Success 200 {object} map[string]string
// @Failure 400 {object} map[string]string
// @Router /auth/verify-email [post]
func (h *AuthHandler) VerifyEmail(c *gin.Context) {
	var req models.VerifyEmailRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request"})
		return
	}

	if err := h.authService.VerifyEmail(c.Request.Context(), req.Token); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid or expired verification token"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "Email verified successfully. You can now log in."})
}

// ResendVerification resends verification email
// @Summary Resend verification email
// @Tags auth
// @Accept json
// @Produce json
// @Param request body map[string]string true "Email"
// @Success 200 {object} map[string]string
// @Router /auth/resend-verification [post]
func (h *AuthHandler) ResendVerification(c *gin.Context) {
	var req struct {
		Email string `json:"email" binding:"required,email"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request"})
		return
	}

	// Always return success to prevent email enumeration
	c.JSON(http.StatusOK, gin.H{"message": "If an account exists with this email, a verification email has been sent."})
}

// ForgotPassword initiates password reset
// @Summary Request password reset
// @Tags auth
// @Accept json
// @Produce json
// @Param request body models.ForgotPasswordRequest true "Email"
// @Success 200 {object} map[string]string
// @Router /auth/forgot-password [post]
func (h *AuthHandler) ForgotPassword(c *gin.Context) {
	var req models.ForgotPasswordRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request"})
		return
	}

	token, userID, err := h.authService.CreatePasswordResetToken(c.Request.Context(), req.Email, c.ClientIP())
	if err == nil && userID != nil {
		// Send email asynchronously
		go func() {
			_ = h.emailService.SendPasswordResetEmail(req.Email, "", token)
		}()
	}

	// Always return success to prevent email enumeration
	c.JSON(http.StatusOK, gin.H{"message": "If an account exists with this email, a password reset link has been sent."})
}

// ResetPassword resets password with token
// @Summary Reset password
// @Tags auth
// @Accept json
// @Produce json
// @Param request body models.ResetPasswordRequest true "Reset token and new password"
// @Success 200 {object} map[string]string
// @Failure 400 {object} map[string]string
// @Router /auth/reset-password [post]
func (h *AuthHandler) ResetPassword(c *gin.Context) {
	var req models.ResetPasswordRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request", "details": err.Error()})
		return
	}

	if err := h.authService.ResetPassword(c.Request.Context(), req.Token, req.NewPassword); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid or expired reset token"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "Password reset successfully. You can now log in with your new password."})
}

// GetProfile returns the current user's profile
// @Summary Get user profile
// @Tags profile
// @Accept json
// @Produce json
// @Security BearerAuth
// @Success 200 {object} models.User
// @Failure 401 {object} map[string]string
// @Router /profile [get]
func (h *AuthHandler) GetProfile(c *gin.Context) {
	userIDStr, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
		return
	}

	userID, err := uuid.Parse(userIDStr.(string))
	if err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid user ID"})
		return
	}

	user, err := h.authService.GetUserByID(c.Request.Context(), userID)
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "User not found"})
		return
	}

	c.JSON(http.StatusOK, user)
}

// UpdateProfile updates the current user's profile
// @Summary Update user profile
// @Tags profile
// @Accept json
// @Produce json
// @Security BearerAuth
// @Param request body models.UpdateProfileRequest true "Profile data"
// @Success 200 {object} models.User
// @Failure 400 {object} map[string]string
// @Router /profile [put]
func (h *AuthHandler) UpdateProfile(c *gin.Context) {
	userIDStr, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
		return
	}

	userID, err := uuid.Parse(userIDStr.(string))
	if err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid user ID"})
		return
	}

	var req models.UpdateProfileRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request"})
		return
	}

	user, err := h.authService.UpdateProfile(c.Request.Context(), userID, &req)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to update profile"})
		return
	}

	c.JSON(http.StatusOK, user)
}

// ChangePassword changes the current user's password
// @Summary Change password
// @Tags profile
// @Accept json
// @Produce json
// @Security BearerAuth
// @Param request body models.ChangePasswordRequest true "Password data"
// @Success 200 {object} map[string]string
// @Failure 400 {object} map[string]string
// @Router /profile/password [put]
func (h *AuthHandler) ChangePassword(c *gin.Context) {
	userIDStr, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
		return
	}

	userID, err := uuid.Parse(userIDStr.(string))
	if err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid user ID"})
		return
	}

	var req models.ChangePasswordRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request", "details": err.Error()})
		return
	}

	if err := h.authService.ChangePassword(c.Request.Context(), userID, req.CurrentPassword, req.NewPassword); err != nil {
		if err == services.ErrInvalidCredentials {
			c.JSON(http.StatusBadRequest, gin.H{"error": "Current password is incorrect"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to change password"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "Password changed successfully"})
}

// GetActiveSessions returns all active sessions for the current user
// @Summary Get active sessions
// @Tags profile
// @Accept json
// @Produce json
// @Security BearerAuth
// @Success 200 {array} models.UserSession
// @Router /profile/sessions [get]
func (h *AuthHandler) GetActiveSessions(c *gin.Context) {
	userIDStr, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
		return
	}

	userID, err := uuid.Parse(userIDStr.(string))
	if err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid user ID"})
		return
	}

	sessions, err := h.authService.GetActiveSessions(c.Request.Context(), userID)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get sessions"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"sessions": sessions})
}

// RevokeSession revokes a specific session
// @Summary Revoke session
// @Tags profile
// @Accept json
// @Produce json
// @Security BearerAuth
// @Param id path string true "Session ID"
// @Success 200 {object} map[string]string
// @Failure 404 {object} map[string]string
// @Router /profile/sessions/{id} [delete]
func (h *AuthHandler) RevokeSession(c *gin.Context) {
	userIDStr, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
		return
	}

	userID, err := uuid.Parse(userIDStr.(string))
	if err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid user ID"})
		return
	}

	sessionID, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid session ID"})
		return
	}

	if err := h.authService.RevokeSession(c.Request.Context(), userID, sessionID); err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "Session not found"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "Session revoked successfully"})
}