import { validationError as error } from "./error.js";

function getMixinMap(all, unique) {
  const map = new Map();
  const includes = all.filter((def) => def.type === "includes");
  for (const include of includes) {
    const mixin = unique.get(include.includes);
    if (!mixin) {
      continue;
    }
    const array = map.get(include.target);
    if (array) {
      array.push(mixin);
    } else {
      map.set(include.target, [mixin]);
    }
  }
  return map;
}

/**
 * @typedef {ReturnType<typeof groupDefinitions>} Definitions
 */
function groupDefinitions(all) {
  const unique = new Map();
  const duplicates = new Set();
  const partials = new Map();
  for (const def of all) {
    if (def.partial) {
      const array = partials.get(def.name);
      if (array) {
        array.push(def);
      } else {
        partials.set(def.name, [def]);
      }
      continue;
    }
    if (!def.name) {
      continue;
    }
    if (!unique.has(def.name)) {
      unique.set(def.name, def);
    } else {
      duplicates.add(def);
    }
  }
  return {
    all,
    unique,
    partials,
    duplicates,
    mixinMap: getMixinMap(all, unique),
    cache: {
      typedefIncludesDictionary: new WeakMap(),
      dictionaryIncludesRequiredField: new WeakMap(),
    },
  };
}

function* checkDuplicatedNames({ unique, duplicates }) {
  for (const dup of duplicates) {
    const { name } = dup;
    const message = `The name "${name}" of type "${
      unique.get(name).type
    }" was already seen`;
    yield error(dup.tokens.name, dup, "no-duplicate", message);
  }
}

function* validateIterable(ast) {
  const defs = groupDefinitions(ast);
  for (const def of defs.all) {
    if (def.validate) {
      yield* def.validate(defs);
    }
  }
  yield* checkDuplicatedNames(defs);
}

// Remove this once all of our support targets expose `.flat()` by default
function flatten(array) {
  if (array.flat) {
    return array.flat();
  }
  return [].concat(...array);
}

/**
 * @param {import("./productions/base.js").Base[]} ast
 * @return {import("./error.js").WebIDLErrorData[]} validation errors
 */
export function validate(ast) {
  return [...validateIterable(flatten(ast))];
}