import { MemoryPages, byte, word } from "js/types";
import { assertByte } from "./asserts";

export type Log = [address: word, value: byte, types: "read" | "write"];
export class TestMemory implements MemoryPages {
  private data: Buffer;
  private logging: boolean = false;
  private log: Log[] = [];

  constructor(private size: number) {
    this.data = Buffer.alloc(size << 8);
  }

  start() {
    return 0;
  }

  end() {
    return this.size - 1;
  }

  read(page: byte, off: byte) {
    assertByte(page);
    assertByte(off);

    const val = this.data[(page << 8) | off];
    if (this.logging) {
      this.log.push([(page << 8) | off, val, "read"]);
    }
    return val;
  }

  write(page: byte, off: byte, val: byte) {
    assertByte(page);
    assertByte(off);
    assertByte(val);

    if (this.logging) {
      this.log.push([(page << 8) | off, val, "write"]);
    }
    this.data[(page << 8) | off] = val;
  }

  reset() {
    this.log = [];
  }

  logStart() {
    this.log = [];
    this.logging = true;
  }

  logStop() {
    this.logging = false;
  }

  getLog() {
    return this.log;
  }
}