import { graphEmitter } from '../graph/emitGraph';
import {
  type DeclaredPort,
  edgesInto,
  edgesOutOf,
  type Graph,
  graphFingerprint,
  type GraphNode,
} from '../graph/Graph';
import type { GraphLookup } from '../graph/lookup';
import { resolveDef, terminalNode } from '../graph/nested';
import { inlineValue, type NodeDef } from '../graph/NodeRegistry';
import { asNumber } from '../graph/values';
import type { InstrumentAsset } from '../model/Asset';
import { graphLookup } from '../model/graphLookup';
import { textOf } from '../model/Properties';
import { findAssetOf, type Project } from '../model/Project';
import { playedSoundOf } from '../properties/playedSound';
import { resolveAssetProps } from '../properties/resolve';
import { volumeOf } from '../properties/sounds';
import { soundFxBuildFor } from '../soundfx/compile';
import {
  type FxAmount,
  type FxEnvelopePlan,
  type FxModPlan,
  type FxPlan,
  type FxStagePlan,
  held,
  isSoundFxNodeDef,
  SOUND_FX_INPUT,
  SOUND_FX_OUTPUT,
  SoundFxMix,
  type SoundFxNodeDef,
  withPitch,
  withStages,
} from '../soundfx/nodes';
import {
  ENVELOPE_ROWS,
  INSTRUMENT_ENVELOPE,
  INSTRUMENT_NOTES,
  INSTRUMENT_OUTPUT,
  INSTRUMENT_PARAMETERS,
  INSTRUMENT_SAMPLE,
  INSTRUMENT_SOUND_FX,
  InstrumentOutput,
  isInstrumentNodeDef,
  loops,
  noteNameKey,
  noteOutputKey,
  noteParam,
  notesRange,
  samplePlay,
  singleNotes,
  VELOCITY_PARAM,
} from './nodes';
import { MIDDLE_C, noteFrequency } from './notes';

/**
 * What an instrument's graph reaches outside itself: the sounds its Samples play and the sound FX
 * its Sound FX nodes send them through. `key` changes whenever one of them does, so a cached note is
 * compiled again when the sound or the FX it was made of is edited.
 */
export interface InstrumentSources {
  lookup: GraphLookup;
  sound(assetId: string): { file: string; volume: number } | null;
  soundFx(assetId: string): FxPlan | null;
  key(assetId: string): string;
}

export function instrumentSourcesOf(project: Project): InstrumentSources {
  return {
    lookup: graphLookup(project),
    sound: (assetId) => {
      const asset = findAssetOf(project, assetId, 'sound');
      if (!asset) return null;
      // An asset without a file stays without one, so the Sample can say so.
      const file = asset.file ? playedSoundOf(project, asset) : '';
      return { file, volume: volumeOf(resolveAssetProps(project, asset)) };
    },
    soundFx: (assetId) => {
      const asset = findAssetOf(project, assetId, 'soundfx');
      return asset ? soundFxBuildFor(asset).compiled : null;
    },
    key: (assetId) => {
      const sound = findAssetOf(project, assetId, 'sound');
      if (sound) return `${playedSoundOf(project, sound)}@${volumeOf(resolveAssetProps(project, sound))}`;
      const fx = findAssetOf(project, assetId, 'soundfx');
      return fx ? graphFingerprint(fx.graph) : '';
    },
  };
}

export interface InstrumentBuild {
  /** What the note is made of: the one sound at the Output, or none for silence. */
  layers: readonly FxPlan[];
  /** Per node id, what keeps the graph from compiling. */
  problems: Record<string, string>;
  /** One line for the tab: empty once compiled. */
  reason: string;
}

/**
 * What travels along an edge of an instrument: sounds (none where nothing plays for this note), a
 * number, whether a trigger is on for this note, or the curve of an Envelope (#335).
 */
type Value = { plans: FxPlan[] } | { amount: FxAmount } | { on: boolean } | { curve: FxModPlan };

const SILENT: Value = { plans: [] };

type Def = SoundFxNodeDef | (NodeDef & { instrument: true });

function isInstrumentDef(def: NodeDef): def is Def {
  if (isInstrumentNodeDef(def)) return true;
  return isSoundFxNodeDef(def) && def.type !== SOUND_FX_INPUT && def.type !== SOUND_FX_OUTPUT;
}

/** The parameters the Parameters node declares, in their order, each with its default. */
export function instrumentParams(graph: Graph): readonly DeclaredPort[] {
  return terminalNode(graph, INSTRUMENT_PARAMETERS)?.ports ?? [];
}

/**
 * One note of an instrument (#331): the graph walked back from the Output, with the triggers that
 * stand for this note on and every other one off. A source whose trigger is off is silence, and so
 * is everything it alone feeds; a Mix with one silent side is its other side. `note` and `frequency`
 * are numbers here, `velocity` and the parameters stay open for every voice to fill in.
 */
export function compileInstrument(graph: Graph, note: number, sources: InstrumentSources): InstrumentBuild {
  const walk = graphEmitter<Def, Value>(graph, {
    isDef: isInstrumentDef,
    noun: 'instrument',
    resolve: (node, def) =>
      def.derivePorts ? ((resolveDef(node, graph, sources.lookup) as Def | undefined) ?? def) : def,
    emit: (def, inputs, node) => emitNode(def, inputs, node),
    unfed: (node, port) => {
      if (port.type === 'number') return { amount: { value: asNumber(inlineValue(node, port)) } };
      // An Envelope that only moves numbers has no sound to shape.
      if (node.type === INSTRUMENT_ENVELOPE && edgesOutOf(graph, node.id, 'out').length === 0) return SILENT;
      walk.problem(
        node,
        port.type === 'trigger'
          ? 'Nothing triggers it: connect it to a Notes node'
          : 'Nothing comes in: connect it to a Sample',
      );
      return null;
    },
    conform: (node, port, value) => {
      if ('curve' in value) {
        if (port.type === 'number' && port.followsEnvelope)
          return { amount: { value: value.curve.from.value, mod: value.curve } };
        walk.problem(node, `"${port.label}" cannot follow an Envelope`);
        return null;
      }
      const fits =
        port.type === 'audio'
          ? 'plans' in value
          : port.type === 'trigger'
            ? 'on' in value
            : 'amount' in value;
      if (fits) return value;
      walk.problem(
        node,
        `"${port.label}" takes ${port.type === 'audio' ? 'a sound' : port.type === 'trigger' ? 'a trigger' : 'a number'}`,
      );
      return null;
    },
    // Only a trigger takes more than one edge: either one turns it on.
    gather: (_node, _port, values) => ({ on: values.some((v) => 'on' in v && v.on) }),
  });

  function emitNode(def: Def, inputs: Record<string, Value>, node: GraphNode): Record<string, Value> {
    const plansAt = (key: string) => {
      const value = inputs[key];
      return value && 'plans' in value ? value.plans : [];
    };
    const amounts: Record<string, FxAmount> = {};
    for (const [key, value] of Object.entries(inputs)) if ('amount' in value) amounts[key] = value.amount;
    switch (node.type) {
      case INSTRUMENT_NOTES:
        return notesOutputs(node, note);
      case INSTRUMENT_PARAMETERS:
        return Object.fromEntries(
          (node.ports ?? []).map((port) => [
            port.key,
            { amount: { value: port.default ?? 0, param: port.key } },
          ]),
        );
      case INSTRUMENT_SAMPLE: {
        const plan = sampleOf(node, note);
        const trigger = inputs.trigger;
        return { out: plan && trigger && 'on' in trigger && trigger.on ? { plans: [plan] } : SILENT };
      }
      case INSTRUMENT_SOUND_FX: {
        const fx = sources.soundFx(textOf(node.params.fx ?? ''));
        const arriving = plansAt('in');
        return { out: { plans: fx ? arriving.map((plan) => throughFx(fx, plan, amounts)) : arriving } };
      }
      case INSTRUMENT_ENVELOPE: {
        const envelope = envelopeOf(node, amounts);
        const curve = {
          envelope,
          from: held(amounts.from, ENVELOPE_ROWS.from),
          to: held(amounts.to, ENVELOPE_ROWS.to),
        };
        return {
          out: { plans: plansAt('in').map((plan) => withStages(plan, [{ kind: 'envelope', envelope }])) },
          value: { curve },
        };
      }
      case INSTRUMENT_OUTPUT:
        return { out: { plans: plansAt('in') } };
    }
    if (!isSoundFxNodeDef(def)) return {};
    if (def.type === SoundFxMix.type) {
      const [a] = plansAt('a');
      const [b] = plansAt('b');
      if (!a || !b) return { out: { plans: a ? [a] : b ? [b] : [] } };
      return { out: { plans: [def.emit({ a, b }, amounts, node.params)] } };
    }
    const [arriving] = plansAt('in');
    return { out: arriving ? { plans: [def.emit({ in: arriving }, amounts, node.params)] } : SILENT };
  }

  /** A Sample's sound, or null after saying why it has none – also where its trigger is off. */
  function sampleOf(node: GraphNode, played: number): FxPlan | null {
    const id = textOf(node.params.sound ?? '');
    const sound = id ? sources.sound(id) : null;
    if (!id) walk.problem(node, 'No sound picked');
    else if (!sound) walk.problem(node, 'That sound is gone');
    else if (!sound.file) walk.problem(node, 'The sound has no file');
    if (!sound?.file) return null;
    const follows = node.params.followNote !== false;
    const shift = follows ? played - noteParam(node.params, 'root', MIDDLE_C) : 0;
    const play = samplePlay(node.params);
    const loop = loops(play);
    return {
      pitch: shift === 0 ? [] : [{ value: shift }],
      stages: [],
      source: {
        file: sound.file,
        volume: sound.volume,
        loop,
        loopStart: loop ? Math.max(0, asNumber(node.params.loopStart ?? 0)) : 0,
        loopEnd: loop ? Math.max(0, asNumber(node.params.loopEnd ?? 0)) : 0,
        gate: play === 'gate' || play === 'loop',
      },
    };
  }

  const output = graph.nodes.find((n) => n.type === INSTRUMENT_OUTPUT);
  if (!output) return { layers: [], problems: walk.problems, reason: 'No Output node' };
  // Saved while the Output still took any number of sounds: only the first would be heard.
  if (edgesInto(graph, output.id, 'in').length > 1)
    walk.problem(output, 'Takes one sound: put a Mix in front of it to play several');
  const arrived = walk.input(output, InstrumentOutput.inputs[0]!);
  const failed = walk.firstProblem();
  if (failed !== null || !arrived || !('plans' in arrived))
    return { layers: [], problems: walk.problems, reason: failed ?? 'Cannot compile' };
  return { layers: arrived.plans, problems: walk.problems, reason: '' };
}

/** An Envelope's times and level, held to its rows; one fed by a parameter is filled in as its note starts. */
function envelopeOf(node: GraphNode, amounts: Readonly<Record<string, FxAmount>>): FxEnvelopePlan {
  const rows = ENVELOPE_ROWS;
  return {
    id: node.id,
    attack: held(amounts.attack, rows.attack),
    decay: held(amounts.decay, rows.decay),
    sustain: held(amounts.sustain, rows.sustain),
    release: held(amounts.release, rows.release),
  };
}

/** The outputs of a Notes node for one note: its triggers, and the note as numbers. */
function notesOutputs(node: GraphNode, note: number): Record<string, Value> {
  const { from, to } = notesRange(node.params);
  const inside = note >= from && note <= to;
  const outputs: Record<string, Value> = {
    any: { on: inside },
    note: { amount: { value: note } },
    frequency: { amount: { value: noteFrequency(note) } },
    velocity: { amount: { value: 1, param: VELOCITY_PARAM, min: 0, max: 1 } },
  };
  if (singleNotes(node.params))
    for (let at = from; at <= to; at++) outputs[noteOutputKey(at)] = { on: at === note };
  return outputs;
}

/**
 * A sound sent through a sound FX: the plan of the FX with the sound set in where its Input was, and
 * each of its parameters bound to what arrives at the input of that name – held to the FX's row, as
 * a value handed to the FX itself would be. One left open keeps its default.
 */
function throughFx(fx: FxPlan, sound: FxPlan, given: Readonly<Record<string, FxAmount>>): FxPlan {
  const bind = (amount: FxAmount): FxAmount => {
    if (amount.param === undefined) return amount;
    const fed = given[amount.param];
    if (!fed) return amount;
    const value = Math.max(amount.min ?? -Infinity, Math.min(amount.max ?? Infinity, fed.value));
    return fed.param === undefined
      ? { value }
      : { value, param: fed.param, min: amount.min, max: amount.max };
  };
  const stages = fx.stages.map((stage) => bindStage(stage, bind));
  if ('mix' in fx)
    return {
      ...fx,
      mix: bind(fx.mix),
      a: throughFx(fx.a, sound, given),
      b: throughFx(fx.b, sound, given),
      stages,
    };
  const pitched = fx.pitch.reduce((plan, semitones) => withPitch(plan, bind(semitones)), sound);
  return withStages(pitched, stages);
}

function bindStage(stage: FxStagePlan, bind: (amount: FxAmount) => FxAmount): FxStagePlan {
  if (stage.kind === 'gain') return { ...stage, db: bind(stage.db) };
  if (stage.kind === 'filter') return { ...stage, gain: bind(stage.gain) };
  if (stage.kind === 'pass')
    return { ...stage, cutoff: bind(stage.cutoff), resonance: bind(stage.resonance) };
  if (stage.kind === 'envelope') return stage;
  if (stage.kind === 'crush')
    return { ...stage, bits: bind(stage.bits), rate: bind(stage.rate), mix: bind(stage.mix) };
  return {
    ...stage,
    time: bind(stage.time),
    feedback: bind(stage.feedback),
    damping: bind(stage.damping),
    mix: bind(stage.mix),
  };
}

const builds = new Map<string, { fingerprint: string; notes: Map<number, InstrumentBuild> }>();

/**
 * One note of the asset, compiled again only when what it is made of has changed: the graph, or a
 * sound or sound FX it names. A note is played far more often than its instrument is edited.
 */
export function instrumentBuildFor(
  asset: InstrumentAsset,
  note: number,
  sources: InstrumentSources,
): InstrumentBuild {
  const named = asset.graph.nodes
    .map((node) => textOf(node.params[node.type === INSTRUMENT_SOUND_FX ? 'fx' : 'sound'] ?? ''))
    .filter((id) => id !== '');
  const fingerprint = `${graphFingerprint(asset.graph)}|${named.map((id) => sources.key(id)).join('|')}`;
  let cached = builds.get(asset.id);
  if (!cached || cached.fingerprint !== fingerprint) {
    cached = { fingerprint, notes: new Map() };
    builds.set(asset.id, cached);
  }
  let build = cached.notes.get(note);
  if (!build) {
    build = compileInstrument(asset.graph, note, sources);
    cached.notes.set(note, build);
  }
  return build;
}

/**
 * The instrument's problems, the same for every note: the walk from the Output reaches every node
 * whatever is played, only the triggers differ.
 */
export function instrumentCheck(asset: InstrumentAsset, sources: InstrumentSources): InstrumentBuild {
  return instrumentBuildFor(asset, MIDDLE_C, sources);
}

/** Which notes of the keyboard make a sound at all: those inside a Notes node's range. */
export function playedNotes(graph: Graph): Set<number> {
  const notes = new Set<number>();
  for (const node of graph.nodes) {
    if (node.type !== INSTRUMENT_NOTES) continue;
    const { from, to } = notesRange(node.params);
    for (let note = from; note <= to; note++) notes.add(note);
  }
  return notes;
}

/** The notes a Notes node with single notes has given a name of their own (a drum kit's). */
export function namedNotes(graph: Graph): Map<number, string> {
  const names = new Map<number, string>();
  for (const node of graph.nodes) {
    if (node.type !== INSTRUMENT_NOTES || !singleNotes(node.params)) continue;
    const { from, to } = notesRange(node.params);
    for (let note = from; note <= to; note++) {
      const name = textOf(node.params[noteNameKey(note)] ?? '').trim();
      if (name && !names.has(note)) names.set(note, name);
    }
  }
  return names;
}