#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <stdarg.h>

#include "assembler.h"
#include "field.h"
#include "lc3.h"
#include "symbol.h"
#include "tokens.h"
#include "util.h"

/** Global variable containing the head of the linked list of structures */
static line_info_t* infoHead;

/** Global variable containing the tail of the linked list of structures */
static line_info_t* infoTail;

/** Global variable containing information about the current line */
static line_info_t* currInfo;

void asm_init_line_info (line_info_t* info) {
  if (info) {
    info->next        = NULL;
    info->lineNum     = srcLineNum;
    info->address     = currAddr;
    info->machineCode = 0;
    info->opcode      = OP_INVALID;
    info->form        = 0;
    info->reg1        = -1;
    info->reg2        = -1;
    info->reg3        = -1;
    info->immediate   = 0;
    info->reference   = NULL;
  }
}

void asm_print_line_info (line_info_t* info) {
  if (info) {
    printf("%3d: address: x%04x machineCode:%04x op: %s form: %d reg1:%3d, reg2:%3d reg3:%3d imm: %d ref: %s\n",
           info->lineNum, info->address, info->machineCode,
           lc3_get_opcode_name(info->opcode), info->form, info->reg1,
           info->reg2, info->reg3, info->immediate, info->reference);
  }
 }

/* based on code from http://www.eskimo.com/~scs/cclass/int/sx11c.html */
void asm_error (char* msg, ...) {
   numErrors++;
   va_list argp;
   fprintf(stderr, "ERROR %3d: ", srcLineNum);
   va_start(argp, msg);
   vfprintf(stderr, msg, argp);
   va_end(argp);
   fprintf(stderr, "\n");
}

void asm_init (void) {
  infoHead = infoTail = currInfo = NULL; 
  tokens_init();
  lc3_sym_tab = symbol_init(0); 
}

/** @todo implement this function */
void asm_pass_one (char* asm_file_name, char* sym_file_name) {
}

/** @todo implement this function */
void asm_pass_two (char* obj_file_name) {
}

/** @todo implement this function */
void asm_term (void) {
}

/** @todo implement this function */
char* check_for_label (char* token) {
  return token;
}

/** @todo implement this function */
void check_line_syntax (char* token) {
  printf("check_line_syntax('%s')\n", token);
}

/** @todo implement this function */
void encode_operand (operand_t operand) {
}

/** @todo implement this function */
void encode_PC_offset_or_error (int width) {
}

/** @todo implement this function */
void get_comma_or_error (void) {
}

/** @todo implement this function */
void get_immediate_or_error (char* token, int width, int isSigned) {
}

/** @todo implement this function */
void get_PC_offset_or_error (char* token) {
}

/** @todo implement this function */
int get_reg_or_error (char *token) {
  return -1;
}

/** @todo implement this function */
FILE *open_read_or_error (char* file_name) {
  return NULL;
}

/** @todo implement this function */
FILE *open_write_or_error (char* file_name) {
  return NULL;
}

/** @todo implement this function */
void get_operand (operand_t operand, char* token) {
  switch (operand) {
    case FMT_R1:
      currInfo->reg1 = get_reg_or_error(token);
      break;

    default:
      break;
  }
}

// can use ints instead of unsigned ints as long as v is never negative. This
// is true for the use in LC3 assembler.
// see http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetKernighan
int count_bits (int v) {
  return 0;
}

/** @todo implement this function */
void scan_operands (operands_t operands) {
  printf("scan_operands() for %s\n", lc3_get_format_name(operands));
  int operandCount = 0;
  int numOperands  = count_bits(operands);
  int errorCount   = numErrors;

  for (operand_t op = FMT_R1; op <= FMT_STR; op <<= 1) {
    if (errorCount != numErrors)
      return; // error, so skip processing remainder of line

    // add code here
  }
}

/** @todo implement this function */
void update_address (void) {
}