package providers

import (
	"context"
	"errors"
	"strings"
)

// Looker is implemented by providers that can fetch one entry again by its
// ID, to refresh metadata that changed at the source.
type Looker interface {
	Lookup(ctx context.Context, providerID string) (Result, error)
}

// ErrGone means the source no longer has the entry (deleted or merged).
var ErrGone = errors.New("the source no longer has this entry")

// ErrNoSource means the entry wasn't added from a service that can be
// refreshed.
var ErrNoSource = errors.New("no source to refresh from")

// Lookup fetches an entry again from the service it came from. The
// provider is the one saved with the entry, whatever the current setting.
func (r *Registry) Lookup(ctx context.Context, category, provider, providerID string) (Result, error) {
	var l Looker
	c := r.creds(ctx)
	switch provider {
	case "tmdb":
		if c.TMDBKey == "" {
			return Result{}, NotConfiguredError{"TMDB", "Add a TMDB API key under Settings → Integrations."}
		}
		kind, _, _ := strings.Cut(providerID, ":")
		l = &tmdb{r: r, key: c.TMDBKey, kind: kind}
	case "tvdb":
		if c.TVDBKey == "" {
			return Result{}, NotConfiguredError{"TheTVDB", "Add a TheTVDB API key under Settings → Integrations."}
		}
		l = &tvdb{r: r, key: c.TVDBKey, pin: c.TVDBPin}
	case "igdb":
		if c.IGDBClientID == "" || c.IGDBClientSecret == "" {
			return Result{}, NotConfiguredError{"IGDB", "Add your Twitch client ID and secret under Settings → Integrations."}
		}
		l = &igdb{r: r, id: c.IGDBClientID, secret: c.IGDBClientSecret}
	case "deezer":
		l = &deezer{r: r, kind: category}
	case "musicbrainz":
		l = &musicbrainz{r: r, kind: category}
	case "wikipedia":
		l = &wikipedia{r: r, stage: category == "theater"}
	default:
		return Result{}, ErrNoSource
	}
	return l.Lookup(ctx, providerID)
}

// SameThing reports whether a refreshed title plausibly names the same
// entry: the titles share at least one word, ignoring bracketed qualifiers
// like "(Remastered)". A refresh that comes back with an unrelated title
// usually means a bad or reused ID, and shouldn't overwrite the entry.
func SameThing(a, b string) bool {
	wa, wb := strings.Fields(baseTitle(a)), strings.Fields(baseTitle(b))
	if len(wa) == 0 || len(wb) == 0 {
		return true
	}
	seen := map[string]bool{}
	for _, w := range wa {
		seen[w] = true
	}
	for _, w := range wb {
		if seen[w] {
			return true
		}
	}
	return false
}