/**
 * What a song keeps to itself (#355): a sound, a pattern or a sound FX made in a song is an asset like
 * any other, so everything that finds an asset by its id finds it, but its `owner` names the song.
 * The lists of assets leave it out. The places of its song may share it (#357): the song itself, its
 * tracks and its items. `settleEmbedded` holds a song to that after every edit, so a paste from another
 * song gets a copy of its own and what nothing uses any more goes.
 */
import type { Graph } from '../graph/Graph';
import { SOUND_FX_INPUT, SOUND_FX_OUTPUT } from '../graph/nested';
import { newId } from '../ids';
import type { Asset, SongAsset } from '../model/Asset';
import type { AssetType } from '../model/AssetTypes';
import type { PropertyBag } from '../model/Properties';
import { findAsset, findAssetOf, type Project } from '../model/Project';
import { assetNamedBy, renewClipIds } from '../model/sound';
import { ASSET_FX_KEY, assetFxOf, NO_FX } from '../properties/assetFx';
import { nextNumberedName } from '../commands/naming';
import { PATTERN_SIGN_KEY, PATTERN_TEMPO_KEY, patternInstrument } from './pattern';
import { type SongItem, songMeter, songTempo, type SongTrack } from './song';
import { signOf } from './time';

export const EMBEDDABLE_TYPES: readonly AssetType[] = ['sound', 'pattern', 'soundfx'];

/**
 * The rows of an embedded asset that do nothing in a song: how it repeats is the song's. A pattern
 * keeps its tempo and meter (#363), as one of the project does.
 */
const HIDDEN_ROWS: Partial<Record<AssetType, readonly string[]>> = {
  sound: ['loop'],
};

export function isEmbeddable(type: AssetType): boolean {
  return EMBEDDABLE_TYPES.includes(type);
}

export function isEmbedded(asset: Asset): boolean {
  return (asset.owner ?? '') !== '';
}

/** In front of the name of what the song keeps to itself, wherever it is named. */
export const EMBEDDED_MARK = '•';

export function markedName(asset: Asset): string {
  return isEmbedded(asset) ? `${EMBEDDED_MARK} ${asset.name}` : asset.name;
}

/** The assets a list offers: all but those a song keeps to itself. */
export function listedAssets(project: Project): Asset[] {
  return project.assets.filter((a) => !isEmbedded(a));
}

export function embeddedIn(project: Project, songId: string): Asset[] {
  return project.assets.filter((a) => a.owner === songId);
}

/** The song an asset belongs to; undefined for a project asset. */
export function ownerSong(project: Project, asset: Asset): SongAsset | undefined {
  const owner = asset.owner ? findAsset(project, asset.owner) : undefined;
  return owner?.type === 'song' ? owner : undefined;
}

export function isRowHiddenWhenEmbedded(asset: Asset, key: string): boolean {
  return isEmbedded(asset) && (HIDDEN_ROWS[asset.type]?.includes(key) ?? false);
}

/** "Song › Take 1" for an embedded asset, its own name for any other. */
export function assetTitle(project: Project, asset: Asset): string {
  const song = ownerSong(project, asset);
  return song ? `${song.name} › ${asset.name}` : asset.name;
}

/** The tempo and the meter of a song, as the props a pattern made in it starts with. */
export function songClockProps(props: PropertyBag): PropertyBag {
  return { [PATTERN_TEMPO_KEY]: songTempo(props), [PATTERN_SIGN_KEY]: signOf(songMeter(props)) };
}

/**
 * A copy of a project asset for the song to keep to itself (#355), to bend without touching the rest.
 * `ids` says what the asset and its clips (#357) are called in the copy.
 */
export function embeddedCopy(asset: Asset, song: SongAsset): { copy: Asset; ids: Map<string, string> } {
  const copy: Asset = { ...structuredClone(asset), id: newId(), owner: song.id };
  const ids = new Map([[asset.id, copy.id]]);
  renewClipIds(copy, ids);
  return { copy, ids };
}

/** "Pattern 1", 2, 3 … ("Sound FX 1" …): the first number none of what the song keeps to itself has. */
export function embeddedName(project: Project, songId: string, base: string): string {
  return nextNumberedName(
    embeddedIn(project, songId).map((a) => a.name),
    base,
  );
}

/** What a sound FX made in a song starts as (#355): the Input wired to the Output, so it lets the sound through. */
export function passThroughFxGraph(): Graph {
  const input = newId();
  const output = newId();
  return {
    nodes: [
      { id: input, type: SOUND_FX_INPUT, x: 0, y: 0, params: {} },
      { id: output, type: SOUND_FX_OUTPUT, x: 260, y: 0, params: {} },
    ],
    edges: [{ id: newId(), from: { node: input, port: 'out' }, to: { node: output, port: 'in' } }],
  };
}

/**
 * The instrument a pattern made at `tick` on a track is played with: that of the pattern item there
 * that starts last before it, else of the first one after; '' on a track without one.
 */
export function instrumentNear(
  project: Project,
  items: readonly SongItem[],
  track: string,
  tick: number,
): string {
  const patterns = items
    .filter((i) => i.track === track && i.kind === 'pattern')
    .sort((a, b) => a.tick - b.tick);
  const near = patterns.filter((i) => i.tick <= tick).at(-1) ?? patterns[0];
  if (!near) return '';
  if (near.instrument !== '') return near.instrument;
  const pattern = findAssetOf(project, near.asset, 'pattern');
  return pattern ? patternInstrument(pattern.props) : '';
}

/** A place in a song that names an asset, in the order the places claim what they name. */
interface Slot {
  id: string;
  types: readonly AssetType[];
  set(id: string): void;
}

function slotsOf(props: SongAsset['props'], tracks: SongTrack[], items: SongItem[]): Slot[] {
  const slots: Slot[] = [
    { id: assetFxOf(props), types: ['soundfx'], set: (id) => (props[ASSET_FX_KEY] = id) },
  ];
  for (const track of tracks) slots.push({ id: track.fx, types: ['soundfx'], set: (id) => (track.fx = id) });
  for (const item of items) {
    slots.push({ id: item.asset, types: [item.kind], set: (id) => (item.asset = id) });
    slots.push({ id: item.fx, types: ['soundfx'], set: (id) => (item.fx = id) });
  }
  return slots;
}

/** The embedded assets the places of these items name, wherever they belong: what a copy of them takes along. */
export function embeddedUsedBy(project: Project, items: readonly SongItem[]): Asset[] {
  const named = new Set(
    items.flatMap((i) => [i.asset, i.fx]).map((id) => assetNamedBy(project.assets, id)?.id),
  );
  return project.assets.filter((a) => isEmbedded(a) && named.has(a.id));
}

export interface Settled {
  /** Copies made for a place whose asset another place claimed first, or that belongs elsewhere. */
  added: Asset[];
  /** The song's own assets nothing names any more. */
  dropped: string[];
}

/**
 * Holds the song to what it keeps to itself, writing the places in `tracks` and `items` (fresh lists
 * the caller owns). The places of the song share its assets (#357), so the clips of one take serve
 * many items. A place naming an asset of another song gets a copy, one for all places naming it; one
 * naming an asset that is gone but in `spare` – what was copied along with items – gets that back.
 * The song's own props are only read: they claim, never copy.
 */
export function settleEmbedded(
  project: Project,
  song: SongAsset,
  tracks: SongTrack[],
  items: SongItem[],
  spare: readonly Asset[] = [],
): Settled {
  const claimed = new Set<string>();
  const added: Asset[] = [];
  const copies = new Map<string, Map<string, string>>();
  const taken = new Set(project.assets.map((a) => a.id));
  const own = { ...song.props };
  slotsOf(own, tracks, items).forEach((slot, index) => {
    if (slot.id === '' || slot.id === NO_FX) return;
    // A place may name a clip of a sound (#357): the sound is what it claims.
    const found = assetNamedBy(project.assets, slot.id) ?? assetNamedBy(added, slot.id);
    const source = found ?? assetNamedBy(spare, slot.id);
    if (!source || !slot.types.includes(source.type) || (found && !isEmbedded(found))) return;
    if (found?.owner === song.id) {
      claimed.add(found.id);
      return;
    }
    if (index === 0) return;
    let ids = copies.get(source.id);
    if (!ids) {
      const fresh = found !== undefined || taken.has(source.id);
      const id = fresh ? newId() : source.id;
      const copy: Asset = { ...structuredClone(source), id, owner: song.id };
      ids = new Map([[source.id, id]]);
      if (fresh) renewClipIds(copy, ids);
      copies.set(source.id, ids);
      taken.add(id);
      added.push(copy);
      claimed.add(id);
    }
    slot.set(ids.get(slot.id) ?? ids.get(source.id) ?? slot.id);
  });
  const dropped = project.assets.filter((a) => a.owner === song.id && !claimed.has(a.id)).map((a) => a.id);
  return { added, dropped };
}