package service

import (
	"context"
	"fmt"

	"github.com/rs/zerolog/log"
	"golang.org/x/crypto/bcrypt"
	"tss-rocks-be/ent"
	"tss-rocks-be/ent/role"
	"tss-rocks-be/ent/user"
	"tss-rocks-be/internal/types"
)

// GetUser gets a user by ID
func (s *serviceImpl) GetUser(ctx context.Context, id int) (*ent.User, error) {
	user, err := s.client.User.Get(ctx, id)
	if err != nil {
		return nil, fmt.Errorf("failed to get user: %w", err)
	}
	return user, nil
}

// VerifyPassword verifies the user's current password
func (s *serviceImpl) VerifyPassword(ctx context.Context, userID int, password string) error {
	user, err := s.GetUser(ctx, userID)
	if err != nil {
		return err
	}

	if !s.ValidatePassword(ctx, user, password) {
		return fmt.Errorf("invalid password")
	}

	return nil
}

// UpdateUser updates user information
func (s *serviceImpl) UpdateUser(ctx context.Context, userID int, input *types.UpdateUserInput) (*ent.User, error) {
	// Start building the update
	update := s.client.User.UpdateOneID(userID)

	// Update username if provided
	if input.Username != "" {
		// Check if username is already taken
		exists, err := s.client.User.Query().
			Where(user.And(
				user.UsernameEQ(input.Username),
				user.IDNEQ(userID),
			)).
			Exist(ctx)
		if err != nil {
			log.Error().Err(err).Msg("Failed to check username availability")
			return nil, fmt.Errorf("failed to check username availability: %w", err)
		}
		if exists {
			return nil, fmt.Errorf("username already taken")
		}
		update.SetUsername(input.Username)
	}

	// Update email if provided
	if input.Email != "" {
		update.SetEmail(input.Email)
	}

	// Update display name if provided
	if input.DisplayName != "" {
		update.SetDisplayName(input.DisplayName)
	}

	// Update password if provided
	if input.Password != "" {
		hashedPassword, err := bcrypt.GenerateFromPassword([]byte(input.Password), bcrypt.DefaultCost)
		if err != nil {
			log.Error().Err(err).Msg("Failed to hash password")
			return nil, fmt.Errorf("failed to hash password: %w", err)
		}
		update.SetPasswordHash(string(hashedPassword))
	}

	// Update status if provided
	if input.Status != "" {
		update.SetStatus(user.Status(input.Status))
	}

	// Execute the update
	user, err := update.Save(ctx)
	if err != nil {
		log.Error().Err(err).Msg("Failed to update user")
		return nil, fmt.Errorf("failed to update user: %w", err)
	}

	// Update role if provided
	if input.Role != "" {
		// Clear existing roles
		_, err = user.Update().ClearRoles().Save(ctx)
		if err != nil {
			log.Error().Err(err).Msg("Failed to clear user roles")
			return nil, fmt.Errorf("failed to update user roles: %w", err)
		}

		// Add new role
		role, err := s.client.Role.Query().Where(role.NameEQ(input.Role)).Only(ctx)
		if err != nil {
			log.Error().Err(err).Msg("Failed to find role")
			return nil, fmt.Errorf("failed to find role: %w", err)
		}

		_, err = user.Update().AddRoles(role).Save(ctx)
		if err != nil {
			log.Error().Err(err).Msg("Failed to add user role")
			return nil, fmt.Errorf("failed to update user roles: %w", err)
		}
	}

	return user, nil
}

// DeleteUser deletes a user by ID
func (s *serviceImpl) DeleteUser(ctx context.Context, userID int) error {
	err := s.client.User.DeleteOneID(userID).Exec(ctx)
	if err != nil {
		return fmt.Errorf("failed to delete user: %w", err)
	}
	return nil
}

// ListUsers lists users with filters and pagination
func (s *serviceImpl) ListUsers(ctx context.Context, params *types.ListUsersParams) ([]*ent.User, error) {
	query := s.client.User.Query()

	// Apply filters
	if params.Role != "" {
		query.Where(user.HasRolesWith(role.NameEQ(params.Role)))
	}
	if params.Status != "" {
		query.Where(user.StatusEQ(user.Status(params.Status)))
	}
	if params.Email != "" {
		query.Where(user.EmailContains(params.Email))
	}

	// Apply pagination
	if params.PerPage > 0 {
		query.Limit(params.PerPage)
		if params.Page > 0 {
			query.Offset((params.Page - 1) * params.PerPage)
		}
	}

	// Apply sorting
	if params.Sort != "" {
		switch params.Sort {
		case "email_asc":
			query.Order(ent.Asc(user.FieldEmail))
		case "email_desc":
			query.Order(ent.Desc(user.FieldEmail))
		case "created_at_asc":
			query.Order(ent.Asc(user.FieldCreatedAt))
		case "created_at_desc":
			query.Order(ent.Desc(user.FieldCreatedAt))
		}
	}

	// Execute query
	users, err := query.All(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to list users: %w", err)
	}

	return users, nil
}