package slack

import (
	"context"
	"fmt"

	"github.com/slack-go/slack"
	"github.com/target/goalert/permission"
	"github.com/target/goalert/validation"
)

func (s *ChannelSender) ValidateUser(ctx context.Context, id string) error {
	err := permission.LimitCheckAny(ctx, permission.User, permission.System)
	if err != nil {
		return err
	}

	_, err = s.User(ctx, id)
	if rootMsg(err) == "user_not_found" {
		return validation.NewGenericError("User not found.")
	}
	if err != nil {
		return fmt.Errorf("validate user: %w", err)
	}

	return nil
}

// User will lookup a single Slack user.
func (s *ChannelSender) User(ctx context.Context, id string) (*User, error) {
	err := permission.LimitCheckAny(ctx, permission.User, permission.System)
	if err != nil {
		return nil, err
	}

	usr, ok := s.userInfoCache.Get(id)
	if ok {

		name := usr.Profile.DisplayName
		if name == "" {
			name = usr.Name
		}
		return &User{
			ID:     usr.ID,
			Name:   name,
			TeamID: usr.TeamID,
		}, nil
	}

	// call slack api with team:name id and get user info to return
	err = s.withClient(ctx, func(c *slack.Client) error {
		usr, err = c.GetUserInfoContext(ctx, id)
		return err
	})
	if rootMsg(err) == "user_not_found" {
		return nil, validation.NewGenericError("User not found.")
	}
	if err != nil {
		return nil, fmt.Errorf("get user: %w", err)
	}

	s.userInfoCache.Add(id, usr)

	return &User{
		ID:     usr.ID,
		Name:   usr.Name,
		TeamID: usr.TeamID,
	}, nil
}