package admin

import (
	"net/http"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"

	"github.com/llamalink/llamalink/internal/api/middleware"
	"github.com/llamalink/llamalink/internal/db"
)

type MeHandler struct {
	db *gorm.DB
}

func NewMeHandler(db *gorm.DB) *MeHandler {
	return &MeHandler{db: db}
}

func (h *MeHandler) Me(c *gin.Context) {
	claims := middleware.GetAdminClaims(c)
	if claims == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": gin.H{"code": "unauthorized", "message": "Not authenticated"}})
		return
	}

	var user db.AdminUser
	if err := h.db.Where("username = ?", claims.Username).First(&user).Error; err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": gin.H{"code": "unauthorized", "message": "User not found"}})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"id":           user.ID,
		"username":     user.Username,
		"is_active":   user.IsActive,
		"created_at":   user.CreatedAt,
		"last_login_at": user.LastLoginAt,
	})
}

type ChangePasswordRequest struct {
	CurrentPassword string `json:"current_password" binding:"required"`
	NewPassword     string `json:"new_password" binding:"required,min=8"`
}

func (h *MeHandler) ChangePassword(c *gin.Context) {
	claims := middleware.GetAdminClaims(c)
	if claims == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": gin.H{"code": "unauthorized", "message": "Not authenticated"}})
		return
	}

	var req ChangePasswordRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": gin.H{"code": "validation_error", "message": "current_password and new_password required (min 8 chars)"}})
		return
	}

	userID, err := uuid.Parse(claims.Subject)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": gin.H{"code": "invalid_request", "message": "Invalid token claims"}})
		return
	}

	var user db.AdminUser
	if err := h.db.Where("id = ?", userID).First(&user).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": gin.H{"code": "not_found", "message": "User not found"}})
		return
	}

	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(req.CurrentPassword)); err != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": gin.H{"code": "invalid_credentials", "message": "Current password is incorrect"}})
		return
	}

	newHash, err := bcrypt.GenerateFromPassword([]byte(req.NewPassword), bcrypt.DefaultCost)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": gin.H{"code": "internal_error", "message": "Failed to hash password"}})
		return
	}

	h.db.Model(&user).Updates(map[string]interface{}{
		"password_hash": string(newHash),
		"updated_at":    time.Now(),
	})

	c.Status(http.StatusOK)
}