#include "../../../vm/vm.h"
#include <stdio.h>

#define FRAMES_SIZE 128
#define CODE_SIZE 8192
#define MEMORY_SIZE 65536
u8 lmem[MEMORY_SIZE] = {0};
u32 lcode[CODE_SIZE] = {0};
Frame lframes[FRAMES_SIZE] = {0};


u32 syscall(u32 id, u32 size, u32 mem_ptr) {
  USED(size);
  switch(id) {
    case SYSCALL_CONSOLE_WRITE: {
      u32 size = *(u32 *)(mem + mem_ptr);
      u32 ptr = mem_ptr + 4;
      for (u32 i = 0; i < size; i++) {
        putchar(mem[ptr + i]);
      }
      putchar('\n');
      return 0;
    }
    case SYSCALL_CONSOLE_READ: {
      for (u32 i = 0; i < size; i++) {
        u8 ch = getchar();
        if (ch == '\0')
          break;
        if (ch == '\n')
          break;
        mem[mem_ptr + i] = ch;
      }
    }
    return 0;
  }
  return 1; // generic error
}

void test_add_two_num() {
  i32 main_local_count = 4; 
  mp += (4 * main_local_count);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 0, 1);
  code[cp++] = ENCODE_B(OP_PUSH, 0, 0);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 1, 1);
  code[cp++] = ENCODE_B(OP_PUSH, 1, 0);
  i32 add = cp + 5;
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 2, add);
  code[cp++] = ENCODE_A(OP_CALL, 2, 3, 0);
  code[cp++] = ENCODE_A(OP_INT_TO_STR, 4, 3, 0);
  code[cp++] = ENCODE_A(OP_SYSCALL, SYSCALL_CONSOLE_WRITE, 1, 4);
  code[cp++] = ENCODE_A(OP_HALT, 0, 0, 0);

  /* add */
  code[cp++] = ENCODE_A(OP_ADD_INT, 2, 1, 0);
  code[cp++] = ENCODE_B(OP_RETURN, 2, 0);
}

void test_fibonacci() {
  /* function main() */
  i32 fib = 7;  
  i32 base_case = 21;
  /* fib(35) */
  /*0*/ code[cp++] = ENCODE_B(OP_LOAD_IMM, 0, 35);
  /*1*/ code[cp++] = ENCODE_B(OP_PUSH, 0, 0);
  /*2*/ code[cp++] = ENCODE_B(OP_LOAD_IMM, 1, fib);
  /*3*/ code[cp++] = ENCODE_A(OP_CALL, 1, 2, 0);
  /**/ /* print */
  /*4*/ code[cp++] = ENCODE_A(OP_INT_TO_STR, 3, 2, 0);
  /*5*/ code[cp++] = ENCODE_A(OP_SYSCALL, SYSCALL_CONSOLE_WRITE, 1, 3);
  /*6*/ code[cp++] = ENCODE_A(OP_HALT, 0, 0, 0);
  /**/ /* function fib (int n) int */
  /*9*/ code[cp++] = ENCODE_B(OP_LOAD_IMM, 8, fib);
  /*10*/ code[cp++] = ENCODE_B(OP_LOAD_IMM, 1, 2);
  /*11*/ code[cp++] = ENCODE_B(OP_LOAD_IMM, 2, base_case);
  /*12*/ code[cp++] = ENCODE_A(OP_JLT_INT, 2, 0, 1);
  /*13*/ code[cp++] = ENCODE_B(OP_LOAD_IMM, 3, 1);
  /*14*/ code[cp++] = ENCODE_A(OP_SUB_INT, 4, 0, 3);
  /*15*/ code[cp++] = ENCODE_B(OP_PUSH, 4, 0);
  /*16*/ code[cp++] = ENCODE_A(OP_CALL, 8, 5, 0);
  /*17*/ code[cp++] = ENCODE_B(OP_LOAD_IMM, 3, 2);
  /*18*/ code[cp++] = ENCODE_A(OP_SUB_INT, 4, 0, 3);
  /*19*/ code[cp++] = ENCODE_B(OP_PUSH, 4, 0);
  /*20*/ code[cp++] = ENCODE_A(OP_CALL, 8, 6, 0);
  /*21*/ code[cp++] = ENCODE_A(OP_ADD_INT, 7, 6, 5);
  /*22*/ code[cp++] = ENCODE_B(OP_RETURN, 7, 0);
  /*23*/ code[cp++] = ENCODE_B(OP_RETURN, 0, 0);
}

i32 main() {
  mem = lmem;
  code = lcode;
  frames = lframes;
  lc = 0;
  mp = 0;
  cp = 0;
  pc = 0;
  fp = 0;
  interrupt = 0;
  status = 0;

  /* test_add_two_num(); */
  test_fibonacci();

  while(step_vm()) {
    // do stuff
  }
  return 0;
}