package user

import (
	"context"
	"errors"
	"fmt"
	"tercul/internal/app/authz"
	"tercul/internal/domain"
	platform_auth "tercul/internal/platform/auth"
)

// UserCommands contains the command handlers for the user aggregate.
type UserCommands struct {
	repo     domain.UserRepository
	authzSvc *authz.Service
}

// NewUserCommands creates a new UserCommands handler.
func NewUserCommands(repo domain.UserRepository, authzSvc *authz.Service) *UserCommands {
	return &UserCommands{
		repo:     repo,
		authzSvc: authzSvc,
	}
}

// CreateUserInput represents the input for creating a new user.
type CreateUserInput struct {
	Username  string
	Email     string
	Password  string
	FirstName string
	LastName  string
	Role      domain.UserRole
}

// CreateUser creates a new user.
func (c *UserCommands) CreateUser(ctx context.Context, input CreateUserInput) (*domain.User, error) {
	user := &domain.User{
		Username:  input.Username,
		Email:     input.Email,
		Password:  input.Password,
		FirstName: input.FirstName,
		LastName:  input.LastName,
		Role:      input.Role,
	}
	err := c.repo.Create(ctx, user)
	if err != nil {
		return nil, err
	}
	return user, nil
}

// UpdateUserInput represents the input for updating an existing user.
type UpdateUserInput struct {
	ID          uint
	Username    *string
	Email       *string
	Password    *string
	FirstName   *string
	LastName    *string
	DisplayName *string
	Bio         *string
	AvatarURL   *string
	Role        *domain.UserRole
	Verified    *bool
	Active      *bool
	CountryID   *uint
	CityID      *uint
	AddressID   *uint
}

// UpdateUser updates an existing user.
func (c *UserCommands) UpdateUser(ctx context.Context, input UpdateUserInput) (*domain.User, error) {
	actorID, ok := platform_auth.GetUserIDFromContext(ctx)
	if !ok {
		return nil, domain.ErrUnauthorized
	}

	can, err := c.authzSvc.CanUpdateUser(ctx, actorID, input.ID)
	if err != nil {
		return nil, err
	}
	if !can {
		return nil, domain.ErrForbidden
	}

	user, err := c.repo.GetByID(ctx, input.ID)
	if err != nil {
		if errors.Is(err, domain.ErrEntityNotFound) {
			return nil, fmt.Errorf("%w: user with id %d not found", domain.ErrEntityNotFound, input.ID)
		}
		return nil, err
	}

	// Apply partial updates
	if input.Username != nil {
		user.Username = *input.Username
	}
	if input.Email != nil {
		user.Email = *input.Email
	}
	if input.Password != nil {
		if err := user.SetPassword(*input.Password); err != nil {
			return nil, err
		}
	}
	if input.FirstName != nil {
		user.FirstName = *input.FirstName
	}
	if input.LastName != nil {
		user.LastName = *input.LastName
	}
	if input.DisplayName != nil {
		user.DisplayName = *input.DisplayName
	}
	if input.Bio != nil {
		user.Bio = *input.Bio
	}
	if input.AvatarURL != nil {
		user.AvatarURL = *input.AvatarURL
	}
	if input.Role != nil {
		user.Role = *input.Role
	}
	if input.Verified != nil {
		user.Verified = *input.Verified
	}
	if input.Active != nil {
		user.Active = *input.Active
	}
	if input.CountryID != nil {
		user.CountryID = input.CountryID
	}
	if input.CityID != nil {
		user.CityID = input.CityID
	}
	if input.AddressID != nil {
		user.AddressID = input.AddressID
	}

	err = c.repo.Update(ctx, user)
	if err != nil {
		return nil, err
	}
	return user, nil
}

// DeleteUser deletes a user by ID.
func (c *UserCommands) DeleteUser(ctx context.Context, id uint) error {
	actorID, ok := platform_auth.GetUserIDFromContext(ctx)
	if !ok {
		return domain.ErrUnauthorized
	}

	can, err := c.authzSvc.CanUpdateUser(ctx, actorID, id) // Re-using CanUpdateUser for deletion
	if err != nil {
		return err
	}
	if !can {
		return domain.ErrForbidden
	}

	return c.repo.Delete(ctx, id)
}