DeviceManager/src/lib/undo-redo.ts

import { persistentWritable } from "$lib/storage";
import { derived } from "svelte/store";
import { hashChord, type Chord } from "$lib/serial/chord";
import {
  deviceChords,
  deviceLayout,
  deviceSettings,
} from "$lib/serial/connection";
import { KEYMAP_CODES } from "$lib/serial/keymap-codes";

export enum ChangeType {
  Layout,
  Chord,
  Setting,
}

export interface LayoutChange {
  type: ChangeType.Layout;
  id: number;
  layer: number;
  action: number;
  profile?: number;
}

export interface ChordChange {
  type: ChangeType.Chord;
  deleted?: true;
  id: number[];
  actions: number[];
  phrase: number[];
}

export interface SettingChange {
  type: ChangeType.Setting;
  id: number;
  setting: number;
  profile?: number;
}

export interface ChangeInfo {
  isApplied: boolean;
  isCommitted?: boolean;
}

export type Change = LayoutChange | ChordChange | SettingChange;

export const changes = persistentWritable<Change[][]>("changes", []);

export interface Overlay {
  layout: Array<Array<Map<number, number> | undefined> | undefined>;
  chords: Map<string, Chord & { deleted: boolean }>;
  settings: Array<Map<number, number> | undefined>;
}

export const overlay = derived(changes, (changes) => {
  const overlay: Overlay = {
    layout: [],
    chords: new Map(),
    settings: [],
  };

  for (const changeset of changes) {
    for (const change of changeset) {
      switch (change.type) {
        case ChangeType.Layout:
          change.profile ??= 0;
          overlay.layout[change.profile] ??= [];
          overlay.layout[change.profile]![change.layer] ??= new Map();
          overlay.layout[change.profile]![change.layer]!.set(
            change.id,
            change.action,
          );
          break;
        case ChangeType.Chord:
          overlay.chords.set(JSON.stringify(change.id), {
            actions: change.actions,
            phrase: change.phrase,
            deleted: change.deleted ?? false,
          });
          break;
        case ChangeType.Setting:
          change.profile ??= 0;
          overlay.settings[change.profile] ??= new Map();
          overlay.settings[change.profile]!.set(change.id, change.setting);
          break;
      }
    }
  }

  return overlay;
});

export const settings = derived(
  [overlay, deviceSettings],
  ([overlay, profiles]) =>
    profiles.map((settings, profile) =>
      settings.map<{ value: number } & ChangeInfo>((value, id) => ({
        value: overlay.settings[profile]?.get(id) ?? value,
        isApplied: !overlay.settings[profile]?.has(id),
      })),
    ),
);

export type KeyInfo = { action: number } & ChangeInfo;
export const layout = derived([overlay, deviceLayout], ([overlay, profiles]) =>
  profiles.map((layout, profile) =>
    layout.map(
      (actions, layer) =>
        actions.map<KeyInfo>((action, id) => ({
          action: overlay.layout[profile]?.[layer]?.get(id) ?? action,
          isApplied: !overlay.layout[profile]?.[layer]?.has(id),
        })) as [KeyInfo, KeyInfo, KeyInfo],
    ),
  ),
);

export type ChordInfo = Chord &
  ChangeInfo & {
    phraseChanged: boolean;
    actionsChanged: boolean;
    sortBy: string;
  } & {
    id: number[];
    deleted: boolean;
  };
export const chords = derived(
  [overlay, deviceChords, KEYMAP_CODES],
  ([overlay, chords, codes]) => {
    const newChords = new Set(overlay.chords.keys());

    const changedChords = chords.map<ChordInfo>((chord) => {
      const id = JSON.stringify(chord.actions);
      if (overlay.chords.has(id)) {
        newChords.delete(id);
        const changedChord = overlay.chords.get(id)!;
        return {
          id: chord.actions,
          // use the old phrase for stable editing
          sortBy: chord.phrase.map((it) => codes.get(it)?.id ?? it).join(),
          actions: changedChord.actions,
          phrase: changedChord.phrase,
          actionsChanged: id !== JSON.stringify(changedChord.actions),
          phraseChanged:
            JSON.stringify(chord.phrase) !==
            JSON.stringify(changedChord.phrase),
          isApplied: false,
          deleted: changedChord.deleted,
        };
      } else {
        return {
          id: chord.actions,
          sortBy: chord.phrase.map((it) => codes.get(it)?.id ?? it).join(),
          actions: chord.actions,
          phrase: chord.phrase,
          phraseChanged: false,
          actionsChanged: false,
          isApplied: true,
          deleted: false,
        };
      }
    });
    for (const id of newChords) {
      const chord = overlay.chords.get(id)!;
      changedChords.push({
        sortBy: "",
        isApplied: false,
        actionsChanged: true,
        phraseChanged: false,
        deleted: chord.deleted,
        id: JSON.parse(id),
        phrase: chord.phrase,
        actions: chord.actions,
      });
    }

    return changedChords.sort(({ sortBy: a }, { sortBy: b }) =>
      a.localeCompare(b),
    );
  },
);

export const chordHashes = derived(
  chords,
  (chords) =>
    new Map(chords.map((chord) => [hashChord(chord.actions), chord] as const)),
);