package lidarr

import (
	"context"
	"encoding/json"
	"fmt"
	"net/url"
	"strconv"
)

// What Lidarr holds on disk and how it maps it (Scribe milestone #498).
//
// Lidarr maps one file to each track of the ONE release it monitors per album.
// A file it holds but maps to no track is "unmapped": removing it opens no hole.
// Removing a mapped file does, and Lidarr fills the hole by downloading again —
// which is why Minstrel's duplicate resolver asks before it deletes anything.

// TrackFile is a file Lidarr holds on disk.
type TrackFile struct {
	ID      int    `json:"id"`
	Path    string `json:"path"`
	AlbumID int    `json:"albumId"`
}

// ListUnmappedTrackFiles hits GET /api/v1/trackfile?unmapped=true: files under
// Lidarr's root folders that it has scanned but matched to no track.
func (c *Client) ListUnmappedTrackFiles(ctx context.Context) ([]TrackFile, error) {
	resp, err := c.get(ctx, "/api/v1/trackfile", url.Values{"unmapped": {"true"}})
	if err != nil {
		return nil, err
	}
	defer func() { _ = resp.Body.Close() }()
	var out []TrackFile
	if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
		return nil, fmt.Errorf("%w: decode unmapped track files: %v", ErrInvalidPayload, err)
	}
	return out, nil
}

// AlbumRelease is one edition of an album as Lidarr knows it: the 14×12" vinyl
// box set, the 2×CD deluxe, the digital standard. Exactly one is Monitored.
type AlbumRelease struct {
	ID             int    `json:"id"`
	Title          string `json:"title"`
	Disambiguation string `json:"disambiguation"`
	Format         string `json:"format"`
	TrackCount     int    `json:"trackCount"`
	MediumCount    int    `json:"mediumCount"`
	Monitored      bool   `json:"monitored"`
}

// ReleaseTrack is one track of a release.
type ReleaseTrack struct {
	ID           int    `json:"id"`
	Title        string `json:"title"`
	MediumNumber int    `json:"mediumNumber"`
	TrackFileID  int    `json:"trackFileId"`
}

// GetAlbumReleases hits GET /api/v1/album/{id} and returns the album's releases.
func (c *Client) GetAlbumReleases(ctx context.Context, albumID int) ([]AlbumRelease, error) {
	resp, err := c.get(ctx, "/api/v1/album/"+strconv.Itoa(albumID), nil)
	if err != nil {
		return nil, err
	}
	defer func() { _ = resp.Body.Close() }()
	var album struct {
		Releases []AlbumRelease `json:"releases"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&album); err != nil {
		return nil, fmt.Errorf("%w: decode album: %v", ErrInvalidPayload, err)
	}
	return album.Releases, nil
}

// ListAlbumTracks hits GET /api/v1/track?albumId= : the tracks of the release
// Lidarr monitors for that album.
func (c *Client) ListAlbumTracks(ctx context.Context, albumID int) ([]ReleaseTrack, error) {
	return c.listTracks(ctx, url.Values{"albumId": {strconv.Itoa(albumID)}})
}

// ListReleaseTracks hits GET /api/v1/track?albumReleaseId= : the tracks of one
// release, monitored or not.
func (c *Client) ListReleaseTracks(ctx context.Context, releaseID int) ([]ReleaseTrack, error) {
	return c.listTracks(ctx, url.Values{"albumReleaseId": {strconv.Itoa(releaseID)}})
}

func (c *Client) listTracks(ctx context.Context, q url.Values) ([]ReleaseTrack, error) {
	resp, err := c.get(ctx, "/api/v1/track", q)
	if err != nil {
		return nil, err
	}
	defer func() { _ = resp.Body.Close() }()
	var out []ReleaseTrack
	if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
		return nil, fmt.Errorf("%w: decode tracks: %v", ErrInvalidPayload, err)
	}
	return out, nil
}

// SetMonitoredRelease makes releaseID the album's monitored release.
//
// It is the round trip Lidarr's own "edit album" makes: GET the album resource,
// flip `monitored` on its releases, PUT the whole resource back. Lidarr's
// UpdateAlbum publishes AlbumEditedEvent, and when the monitored release changed,
// AlbumEditedService unlinks the album's track files and queues
// RescanFoldersCommand for the artist's folder, which maps the files on disk to
// the new release's tracks. Files the new release has no track for come out of
// that rescan unmapped. (Lidarr source, develop: Music/Services/
// AlbumEditedService.cs and AlbumService.UpdateAlbum.)
//
// The resource is kept as raw JSON so every field Lidarr sent goes back
// unchanged; only the releases' monitored flags differ. Returns ErrNotFound when
// the album has no release with that id.
func (c *Client) SetMonitoredRelease(ctx context.Context, albumID, releaseID int) error {
	path := "/api/v1/album/" + strconv.Itoa(albumID)
	resp, err := c.get(ctx, path, nil)
	if err != nil {
		return err
	}
	var album map[string]any
	err = json.NewDecoder(resp.Body).Decode(&album)
	_ = resp.Body.Close()
	if err != nil {
		return fmt.Errorf("%w: decode album: %v", ErrInvalidPayload, err)
	}

	releases, _ := album["releases"].([]any)
	found := false
	for _, r := range releases {
		rel, ok := r.(map[string]any)
		if !ok {
			continue
		}
		id, _ := rel["id"].(float64)
		match := int(id) == releaseID
		rel["monitored"] = match
		found = found || match
	}
	if !found {
		return fmt.Errorf("%w: release %d on album %d", ErrNotFound, releaseID, albumID)
	}

	body, err := json.Marshal(album)
	if err != nil {
		return fmt.Errorf("%w: marshal album: %v", ErrInvalidPayload, err)
	}
	putResp, err := c.put(ctx, path, body)
	if err != nil {
		return err
	}
	_ = putResp.Body.Close()
	return nil
}