var Memory = require('chip/memory');

class Bank{
  constructor(mem){
    this.__mem = [mem];
    this.__idx = 0;
  }

  get mem(){return this.__mem[this.__idx];}

  get idx(){return this.__idx;}
  set idx(i){
    if (i >= 0 && i < this.__mem.length)
      this.__idx = i;
  }

  addMemModule(mem){
    if (!(mem instanceof Memory))
      throw new ValueError("Only Memory instances can be added to MMC Banks.");
    if (this.__mem.length >= 4)
      throw new RangeError("Bank handling maximum memory modules.");
    if (this.__mem.length > 0 && mem.size !== this.__mem[0].size)
      throw new RangeError("Memory module does not match size of already connected memory modules on this bank.");
    this.__mem.push(mem);
  }
}

class MMC{
  constructor(){
    this.__banks = [];
  }

  get size(){
    return this.__banks.reduce((acc, b)=>{
      acc += b.mem.size;
    }, 0);
  }

  get banks(){return this.__banks.length;}

  // TODO: Add a get/set for the memory address. This should handle banking and memory address offsets.
  // TODO: Add a get/set for memory data at the current address.
  // TODO: Add method for adding memory modules}
  // TODO: Add a connection between a memory address and the triggering of bank switching.
}

module.exports = MMC;