import type { GraphLookup } from '../graph/lookup';
import { startStateOf, statesOf, transitionsOf } from '../graph/stateMachine';
import { pictureSize } from '../properties/aspect';
import { resolveAssetProps } from '../properties/resolve';
import { bagWithoutItemTypes } from './Properties';
import { typeFields } from './structTypes';
import { findAssetOf, type Project } from './Project';
import { resolvePicture } from './texture';

/**
 * What a graph may see of the project around it. A behavior's `defaults` are its variable values;
 * every call starts from a copy of them, except for the variables it keeps (#229).
 */
export function graphLookup(project: Project): GraphLookup {
  return {
    behavior: (assetId) => {
      const asset = findAssetOf(project, assetId, 'behavior');
      if (!asset) return null;
      return {
        name: asset.name,
        graph: asset.graph,
        defaults: bagWithoutItemTypes(resolveAssetProps(project, asset)),
        kept: asset.keptVariables ?? [],
      };
    },
    machine: (assetId) => {
      const asset = findAssetOf(project, assetId, 'statemachine');
      if (!asset) return null;
      return {
        name: asset.name,
        states: statesOf(asset.graph),
        transitions: transitionsOf(asset.graph),
        start: startStateOf(asset.graph, asset.start),
      };
    },
    curve: (assetId) => findAssetOf(project, assetId, 'curve')?.points ?? null,
    structType: (assetId) => {
      const asset = findAssetOf(project, assetId, 'struct');
      return asset ? { name: asset.name, fields: typeFields(asset).map((f) => f.key) } : null;
    },
    textureSize: (pictureId) => {
      const ref = resolvePicture(project, pictureId);
      return ref ? pictureSize(ref) : null;
    },
  };
}