package service

import (
	"context"
	"errors"
	"regexp"
	"time"

	"watch-party-backend/internal/repo"
)

var ErrInvalidTime = errors.New("invalid start_time (expected HH:MM:SS)")

type EpisodeService interface {
	GetCurrent(ctx context.Context) (repo.Episode, error)
	SetCurrent(ctx context.Context, id int64, start string) (repo.Episode, error)
}

type episodeService struct {
	repo repo.EpisodeRepository
}

func NewEpisodeService(r repo.EpisodeRepository) EpisodeService {
	return &episodeService{repo: r}
}

func (s *episodeService) GetCurrent(ctx context.Context) (repo.Episode, error) {
	c, cancel := context.WithTimeout(ctx, 3*time.Second)
	defer cancel()
	return s.repo.GetCurrent(c)
}

func (s *episodeService) SetCurrent(ctx context.Context, id int64, start string) (repo.Episode, error) {
	// Strict HH:MM:SS (24h, zero-padded) — e.g., 20:07:05
	if !isHHMMSS(start) {
		return repo.Episode{}, ErrInvalidTime
	}

	c, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()

	if err := s.repo.SetCurrent(c, id, start); err != nil {
		return repo.Episode{}, err
	}
	// return the new current row
	return s.repo.GetCurrent(c)
}

var hhmmss = regexp.MustCompile(`^(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d$`)

func isHHMMSS(s string) bool {
	if !hhmmss.MatchString(s) {
		return false
	}
	_, err := time.Parse("15:04:05", s)
	return err == nil
}