package service

import (
	"context"
	"errors"
	"strings"
	"time"

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

var ErrInvalidTime = errors.New("invalid start_time (expected HH:MM or 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) {
	// normalize and validate time as HH:MM:SS
	normalized, err := normalizeHHMMSS(start)
	if err != nil {
		return repo.Episode{}, ErrInvalidTime
	}

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

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

func normalizeHHMMSS(s string) (string, error) {
	s = strings.TrimSpace(s)
	if len(s) == 5 { // HH:MM → append seconds
		s += ":00"
	}
	// Strict parse/format to 24h
	t, err := time.Parse("15:04:05", s)
	if err != nil {
		return "", err
	}
	return t.Format("15:04:05"), nil
}