package service

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

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

var (
	ErrInvalidTime = errors.New("invalid start_time (expected HH:MM:SS)")
	ErrEmptyIDs    = errors.New("ids must not be empty")
)

type EpisodeService interface {
	GetCurrent(ctx context.Context) (repo.Episode, error)
	SetCurrent(ctx context.Context, id int64, start string) (repo.Episode, error)
	MoveToArchive(ctx context.Context, ids []int64) (repo.MoveResult, error)
	ListAll(ctx context.Context) ([]repo.Episode, error)
}

type episodeService struct {
	repo repo.EpisodeRepository
}

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

func (s *episodeService) ListAll(ctx context.Context) ([]repo.Episode, error) {
	c, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	return s.repo.ListAll(c)
}

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)
}

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

func (s *episodeService) SetCurrent(ctx context.Context, id int64, start string) (repo.Episode, error) {
	if !hhmmss.MatchString(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 s.repo.GetCurrent(c)
}

func (s *episodeService) MoveToArchive(ctx context.Context, ids []int64) (repo.MoveResult, error) {
	uniq := make([]int64, 0, len(ids))
	seen := make(map[int64]struct{}, len(ids))
	for _, id := range ids {
		if _, ok := seen[id]; !ok {
			seen[id] = struct{}{}
			uniq = append(uniq, id)
		}
	}
	if len(uniq) == 0 {
		return repo.MoveResult{}, ErrEmptyIDs
	}

	c, cancel := context.WithTimeout(ctx, 10*time.Second)
	defer cancel()
	return s.repo.MoveToArchive(c, uniq)
}