package service

import (
	"context"
	"regexp"
	"strings"
	"time"

	"watch-party-backend/internal/core/episode"
)

// Service implements the episode.UseCases port.
type Service struct {
	repo episode.Repository
}

func NewEpisodeService(r episode.Repository) *Service {
	return &Service{repo: r}
}

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

func (s *Service) ListArchive(ctx context.Context) ([]episode.ArchiveEpisode, error) {
	c, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	return s.repo.ListArchive(c)
}

func (s *Service) GetCurrent(ctx context.Context) (episode.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$`)

const defaultStartTime = "22:00:00"

func parseHHMMSSToDuration(hhmmss string) (time.Duration, error) {
	parts := strings.Split(hhmmss, ":")
	if len(parts) != 3 {
		return 0, episode.ErrInvalidPlayback
	}
	hours, err := time.ParseDuration(parts[0] + "h")
	if err != nil {
		return 0, err
	}
	mins, err := time.ParseDuration(parts[1] + "m")
	if err != nil {
		return 0, err
	}
	secs, err := time.ParseDuration(parts[2] + "s")
	if err != nil {
		return 0, err
	}
	return hours + mins + secs, nil
}

func (s *Service) SetCurrent(ctx context.Context, id int64, start string) (episode.Episode, error) {
	if !hhmmss.MatchString(start) {
		return episode.Episode{}, episode.ErrInvalidStartTime
	}
	c, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	if err := s.repo.SetCurrent(c, id, start); err != nil {
		return episode.Episode{}, err
	}
	return s.repo.GetCurrent(c)
}

func (s *Service) Create(ctx context.Context, in episode.NewShowInput) (episode.Episode, error) {
	if in.EpNum <= 0 || strings.TrimSpace(in.EpTitle) == "" || strings.TrimSpace(in.SeasonName) == "" {
		return episode.Episode{}, episode.ErrInvalidShowInput
	}
	in.StartTime = strings.TrimSpace(in.StartTime)
	if in.StartTime == "" {
		in.StartTime = defaultStartTime
	}
	if !hhmmss.MatchString(in.StartTime) {
		return episode.Episode{}, episode.ErrInvalidStartTime
	}
	if !hhmmss.MatchString(in.PlaybackLength) {
		return episode.Episode{}, episode.ErrInvalidPlayback
	}
	dur, err := parseHHMMSSToDuration(in.PlaybackLength)
	if err != nil || dur <= 0 {
		return episode.Episode{}, episode.ErrInvalidPlayback
	}

	c, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	return s.repo.Create(c, in)
}

func (s *Service) MoveToArchive(ctx context.Context, ids []int64) (episode.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 episode.MoveResult{}, episode.ErrEmptyIDs
	}

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

func (s *Service) Delete(ctx context.Context, id int64) error {
	c, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	return s.repo.Delete(c, id)
}