// Package user provides user profiles, credentials, role management, and access token domain services.
package user

import (
	"context"
	"errors"
	"time"

	"github.com/Rain-kl/Wavelet/core/contracts"
	"github.com/Rain-kl/Wavelet/internal/infra/persistence"
	"github.com/Rain-kl/Wavelet/internal/infra/persistence/idgen"
	"github.com/Rain-kl/Wavelet/internal/model"
	"github.com/Rain-kl/Wavelet/internal/repository"
	pkgu "github.com/Rain-kl/Wavelet/pkg/util"
)

func toUserDTO(u *model.User) *contracts.UserDTO {
	if u == nil {
		return nil
	}
	return &contracts.UserDTO{
		ID:          u.ID,
		Username:    u.Username,
		Nickname:    u.Nickname,
		Email:       u.Email,
		AvatarURL:   u.AvatarURL,
		IsActive:    u.IsActive,
		IsAdmin:     u.IsAdmin,
		Bio:         u.Bio,
		Phone:       u.Phone,
		Gender:      u.Gender,
		Website:     u.Website,
		Location:    u.Location,
		LastLoginAt: u.LastLoginAt,
		CreatedAt:   u.CreatedAt,
		UpdatedAt:   u.UpdatedAt,
	}
}

type userServiceImpl struct{}

func newUserService() contracts.UserService {
	return &userServiceImpl{}
}

func (s *userServiceImpl) GetUserByID(ctx context.Context, id uint64) (*contracts.UserDTO, error) {
	u, err := repository.GetUserByID(ctx, id)
	if err != nil {
		return nil, err
	}
	return toUserDTO(&u), nil
}

func (s *userServiceImpl) GetUserByUsername(ctx context.Context, username string) (*contracts.UserDTO, error) {
	u, err := repository.GetUserByUsername(ctx, username)
	if err != nil {
		return nil, err
	}
	return toUserDTO(&u), nil
}

func (s *userServiceImpl) GetUserByEmail(ctx context.Context, email string) (*contracts.UserDTO, error) {
	var u model.User
	if err := db.DB(ctx).Where("email = ?", email).First(&u).Error; err != nil {
		return nil, err
	}
	return toUserDTO(&u), nil
}

func (s *userServiceImpl) CreateUser(ctx context.Context, req contracts.CreateUserRequest) (*contracts.UserDTO, error) {
	if req.Username == "" {
		return nil, errors.New("user: username cannot be empty")
	}

	user := model.User{
		ID:          idgen.NextUint64ID(),
		Username:    req.Username,
		Nickname:    req.Nickname,
		Email:       req.Email,
		IsActive:    true,
		IsAdmin:     req.IsAdmin,
		CreatedAt:   time.Now(),
		UpdatedAt:   time.Now(),
		LastLoginAt: time.Now(),
	}

	if user.Nickname == "" {
		user.Nickname = req.Username
	}

	if req.Password != "" {
		if err := user.SetEncryptedPassword(req.Password); err != nil {
			return nil, err
		}
	}

	if err := repository.CreateUser(ctx, &user); err != nil {
		return nil, err
	}

	return toUserDTO(&user), nil
}

func (s *userServiceImpl) UpdateProfile(ctx context.Context, id uint64, req contracts.UpdateUserProfileRequest) (*contracts.UserDTO, error) {
	updates := make(map[string]any)
	if req.Nickname != nil {
		updates["nickname"] = *req.Nickname
	}
	if req.Email != nil {
		updates["email"] = *req.Email
	}
	if req.AvatarURL != nil {
		updates["avatar_url"] = *req.AvatarURL
	}
	if req.Bio != nil {
		updates["bio"] = *req.Bio
	}
	if req.Phone != nil {
		updates["phone"] = *req.Phone
	}
	if req.Gender != nil {
		updates["gender"] = *req.Gender
	}
	if req.Website != nil {
		updates["website"] = *req.Website
	}
	if req.Location != nil {
		updates["location"] = *req.Location
	}
	updates["updated_at"] = time.Now()

	if err := db.DB(ctx).Model(&model.User{}).Where("id = ?", id).Updates(updates).Error; err != nil {
		return nil, err
	}

	return s.GetUserByID(ctx, id)
}

func (s *userServiceImpl) UpdatePassword(ctx context.Context, id uint64, oldPassword, newPassword string) error {
	var user model.User
	if err := db.DB(ctx).Where("id = ?", id).First(&user).Error; err != nil {
		return err
	}

	if !user.CheckPassword(oldPassword) {
		return errors.New("user: incorrect old password")
	}

	if err := user.SetEncryptedPassword(newPassword); err != nil {
		return err
	}

	return db.DB(ctx).Model(&model.User{}).Where("id = ?", id).
		Updates(map[string]any{
			"password":   user.Password,
			"updated_at": time.Now(),
		}).Error
}

func (s *userServiceImpl) VerifyPassword(ctx context.Context, id uint64, password string) bool {
	var user model.User
	if err := db.DB(ctx).Where("id = ?", id).First(&user).Error; err != nil {
		pkgu.DummyCheckPassword(password)
		return false
	}
	return user.CheckPassword(password)
}

func (s *userServiceImpl) UpdateLastLogin(ctx context.Context, id uint64, _ string) error {
	return db.DB(ctx).Model(&model.User{}).Where("id = ?", id).
		Updates(map[string]any{
			"last_login_at": time.Now(),
			"updated_at":    time.Now(),
		}).Error
}

func (s *userServiceImpl) ListUsers(ctx context.Context, page, pageSize int, keyword string) ([]*contracts.UserDTO, int64, error) {
	if page <= 0 {
		page = 1
	}
	if pageSize <= 0 {
		pageSize = 20
	}

	filter := repository.AdminUserListFilter{
		Username: keyword,
		Page:     page,
		PageSize: pageSize,
	}

	total, users, err := repository.ListAdminUsers(ctx, filter)
	if err != nil {
		return nil, 0, err
	}

	dtos := make([]*contracts.UserDTO, 0, len(users))
	for i := range users {
		dtos = append(dtos, toUserDTO(&users[i]))
	}

	return dtos, total, nil
}

func (s *userServiceImpl) SetUserActive(ctx context.Context, id uint64, active bool) error {
	return repository.UpdateUserActive(ctx, id, active)
}

func (s *userServiceImpl) SetUserAdmin(ctx context.Context, id uint64, admin bool) error {
	return db.DB(ctx).Model(&model.User{}).Where("id = ?", id).Update("is_admin", admin).Error
}