#include <stdlib.h>
#include <stdio.h>
#include "emulator/a64instruction/a64instruction.h"
#include "emulator/a64instruction/a64instruction_global.h"
#include "emulator/emulator.h"
#include "emulator/fileio.h"
#include "global.h"
#include "emulator/print.h"
#include "emulator/decode.h"
#include "emulator/execute.h"
#include "emulator/machine_util.h"

extern a64inst_instruction *decode(word w);

int main(int argc, char **argv) {

  // Check the arguments
  if (argc == 1) {
    fprintf(stderr, "Error: An object file is required. Syntax: ./emulate <file_in> [<file_out>]");
    return EXIT_FAILURE;
  }

  FILE *out = stdout;
  if (argc > 2) {
    out = fopen(argv[2], "w");
    if (out == NULL) {
      fprintf(stderr, "Error: Could not open file %s\n", argv[2]);
      return EXIT_FAILURE;
    }
  }

  // Initialising the machine state
  Machine state = {0};
  state.memory = fileio_loadBin(argv[1], MEMORY_SIZE);
  state.conditionCodes = (PState){0, 1, 0, 0};
  state.pc = 0x0;
  
  
  // Fetch-decode-execute cycle
  word wrd;
  a64inst_instruction *inst;
  do {
    
    // Step 1: Fetch instruction at PC's address
    wrd = readMemory(state.memory, state.pc, a64inst_W);

    // Step 2: Decode instruction to internal representation
    inst = decode(wrd);

    // Step 3: Update processor state to reflect executing the instruction, and increment PC
    execute(&state, inst);

    if (inst->type != a64inst_BRANCH)
      state.pc += sizeof(word);
  } while (inst->type != a64inst_HALT);

  state.pc -= sizeof(word);
  
  printState(&state, out);
  free(state.memory);

  return EXIT_SUCCESS;
}