import {
  Array,
  ArrayPrototypePush,
  ArrayPrototypeSort as sort,
  ArrayPrototypeSplice as splice,
  IteratorPrototype,
  Map,
  MapPrototypeGet,
  MapPrototypeHas,
  MapPrototypeSet,
  ObjectDefineProperty,
  ObjectGetOwnPropertyDescriptor,
  ObjectSetPrototypeOf,
  ReflectApply,
  ReflectOwnKeys,
  StringPrototypeSlice,
  SymbolIterator,
  SymbolToStringTag,
  TypeError,
  WeakMapPrototypeSet as weakSet,
} from "ext:core/primordials";
import { isObject, required, state, usv } from "ext:web/idl.js";
import { markUncloneable } from "ext:web/serialization.js";
import { op_url_search_parse, op_url_search_serialize } from "ext:core/ops";
import { params, privateArray, update } from "./state.js";
import type { SearchPair } from "ext:core/ops";
import type { ParamsState } from "./state.js";

type IteratorValues = { 0: SearchPair; 1: string; 2: string };

const arrayPrototype = Array.prototype;
function iterable(value: object, method: Function): Iterable<unknown> {
  return {
    [SymbolIterator]() {
      // for-of validates the returned iterator and owns IteratorClose.
      return ReflectApply(method, value, []) as Iterator<unknown>;
    },
  };
}

interface ParamsIterator<K extends keyof IteratorValues> extends IterableIterator<IteratorValues[K], undefined, unknown> {}
class ParamsIterator<K extends keyof IteratorValues> {
  #state: ParamsState;
  #index = 0;
  #kind: K;
  constructor(value: ParamsState, kind: K) {
    markUncloneable(this);
    this.#state = value;
    this.#kind = kind;
  }
  next(): IteratorResult<IteratorValues[K], undefined> {
    const value = this.#state;
    if (this.#index >= value.list.length) {
      return { value: undefined, done: true };
    }
    const pair = value.list[this.#index++];
    return {
      value: (this.#kind === 0 ? [pair[0], pair[1]] : pair[this.#kind - 1]) as IteratorValues[K],
      done: false,
    };
  }
}
delete (ParamsIterator.prototype as { constructor?: Function }).constructor;
ObjectDefineProperty(ParamsIterator.prototype, "next", { enumerable: true });
ObjectSetPrototypeOf(ParamsIterator.prototype, IteratorPrototype);
ObjectDefineProperty(ParamsIterator.prototype, SymbolToStringTag, {
  value: "URLSearchParams Iterator",
  configurable: true,
});

interface URLSearchParams {
  [Symbol.iterator](): ParamsIterator<0>;
}
class URLSearchParams {
  constructor(init: unknown = "") {
    const list = privateArray<string[]>();
    if (isObject(init)) {
      const method = init[SymbolIterator];
      if (method !== undefined && method !== null) {
        if (typeof method !== "function") {
          throw new TypeError("Invalid iterator");
        }
        for (const pair of iterable(init, method)) {
          if (!isObject(pair)) {
            throw new TypeError("Query pairs must be sequences");
          }
          const method = pair[SymbolIterator];
          if (typeof method !== "function") {
            throw new TypeError("Query pairs must be sequences");
          }
          const values = privateArray<string>();
          for (const item of iterable(pair, method)) {
            ArrayPrototypePush(values, usv(item));
          }
          ArrayPrototypePush(list, values);
        }
        for (let index = 0; index < list.length; index++) {
          if (list[index].length !== 2) {
            throw new TypeError("Query pairs must have exactly two items");
          }
        }
      } else {
        const keys = new Map<string, number>();
        const ownKeys = ReflectOwnKeys(init);
        for (let index = 0; index < ownKeys.length; index++) {
          const key = ownKeys[index];
          if (!ObjectGetOwnPropertyDescriptor(init, key)?.enumerable) continue;
          const name = usv(key);
          const value = usv(init[key]);
          if (MapPrototypeHas(keys, name)) {
            list[MapPrototypeGet(keys, name)!][1] = value;
          } else {
            MapPrototypeSet(keys, name, list.length);
            ArrayPrototypePush(list, privateArray([name, value]));
          }
        }
      }
    } else {
      const text = usv(init);
      const parsed = op_url_search_parse(
        text[0] === "?" ? StringPrototypeSlice(text, 1) : text,
      );
      for (let index = 0; index < parsed.length; index++) {
        ArrayPrototypePush(list, privateArray(parsed[index]));
      }
    }
    // Pair lengths are checked only after the entire sequence has been converted.
    weakSet(params, this, { list: list as SearchPair[], url: null });
  }
  get size(): number {
    return state(params, this).list.length;
  }
  append(rawName: unknown, rawValue: unknown): void {
    const data = state(params, this);
    required(arguments.length, 2);
    const name = usv(rawName);
    const value = usv(rawValue);
    ArrayPrototypePush(data.list, privateArray<SearchPair>([name, value]));
    update(data);
  }
  delete(rawName: unknown, rawValue: unknown = undefined): void {
    const data = state(params, this);
    required(arguments.length, 1);
    const name = usv(rawName);
    const value = rawValue === undefined ? undefined : usv(rawValue);
    for (let index = 0; index < data.list.length;) {
      const pair = data.list[index];
      if (pair[0] === name && (value === undefined || pair[1] === value)) {
        splice(data.list, index, 1);
      } else index++;
    }
    update(data);
  }
  get(rawName: unknown): string | null {
    const data = state(params, this);
    required(arguments.length, 1);
    const name = usv(rawName);
    for (let index = 0; index < data.list.length; index++) {
      if (data.list[index][0] === name) return data.list[index][1];
    }
    return null;
  }
  getAll(rawName: unknown): string[] {
    const data = state(params, this);
    required(arguments.length, 1);
    const name = usv(rawName);
    const result = privateArray<string>();
    for (let index = 0; index < data.list.length; index++) {
      if (data.list[index][0] === name) {
        ArrayPrototypePush(result, data.list[index][1]);
      }
    }
    ObjectSetPrototypeOf(result, arrayPrototype);
    return result;
  }
  has(rawName: unknown, rawValue: unknown = undefined): boolean {
    const data = state(params, this);
    required(arguments.length, 1);
    const name = usv(rawName);
    const value = rawValue === undefined ? undefined : usv(rawValue);
    for (let index = 0; index < data.list.length; index++) {
      const pair = data.list[index];
      if (pair[0] === name && (value === undefined || pair[1] === value)) {
        return true;
      }
    }
    return false;
  }
  set(rawName: unknown, rawValue: unknown): void {
    const data = state(params, this);
    required(arguments.length, 2);
    const name = usv(rawName);
    const value = usv(rawValue);
    let found = false;
    for (let index = 0; index < data.list.length;) {
      if (data.list[index][0] !== name) index++;
      else if (found) splice(data.list, index, 1);
      else {
        data.list[index++][1] = value;
        found = true;
      }
    }
    if (!found) ArrayPrototypePush(data.list, privateArray<SearchPair>([name, value]));
    update(data);
  }
  sort(): void {
    const data = state(params, this);
    // JS string comparison supplies the required UTF-16 ordering, not UTF-8 ordering.
    sort(data.list, (a, b) => a[0] < b[0] ? -1 : a[0] > b[0] ? 1 : 0);
    update(data);
  }
  forEach(callback: (value: string, name: string, parent: URLSearchParams) => void, thisArg: unknown = undefined): void {
    const data = state(params, this);
    required(arguments.length, 1);
    if (typeof callback !== "function") {
      throw new TypeError("Callback must be callable");
    }
    for (let index = 0; index < data.list.length; index++) {
      const pair = data.list[index];
      ReflectApply(callback, thisArg, [pair[1], pair[0], this]);
    }
  }
  entries(): ParamsIterator<0> {
    return new ParamsIterator(state(params, this), 0);
  }
  keys(): ParamsIterator<1> {
    return new ParamsIterator(state(params, this), 1);
  }
  values(): ParamsIterator<2> {
    return new ParamsIterator(state(params, this), 2);
  }
  toString(): string {
    return op_url_search_serialize(state(params, this).list);
  }
}

export { URLSearchParams };