/**
 * SPDX-License-Identifier: MIT
 * SPDX-FileCopyrightText: 2015-2016 Johan Van den Brande
 *
 * @file	tokenizer.c
 */

#include "tokenizer.h"

#include <ctype.h>
#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "arch.h"
#include "array.h"
#include "hexdump.h"

static array *token_array = NULL;

add_token(T_ERROR, NULL);
add_token(T_EOF, NULL);
add_token(T_NUMBER, NULL);
add_token(T_STRING, NULL);
add_token(T_VARIABLE_STRING, NULL);
add_token(T_VARIABLE_NUMBER, NULL);
add_token(T_PLUS, "+");
add_token(T_MINUS, "-");
add_token(T_MULTIPLY, "*");
add_token(T_DIVIDE, "/");
add_token(T_LEFT_BANANA, "(");
add_token(T_RIGHT_BANANA, ")");
add_token(T_COLON, ":");
add_token(T_SEMICOLON, ";");
add_token(T_EQUALS, "=");
add_token(T_LESS, "<");
add_token(T_GREATER, ">");
add_token(T_COMMA, ",");

char *tokenizer_line = NULL;
char *tokenizer_p = NULL;
char *tokenizer_next_p = NULL;

token tokenizer_actual_token;
float tokenizer_actual_number;
char tokenizer_actual_char;
char tokenizer_actual_string[tokenizer_string_length];
char tokenizer_actual_variable[tokenizer_variable_length];

void tokenizer_setup(void) {
  token_array = array_new(sizeof(token_entry));
  tokenizer_register_token(&_T_ERROR);
  tokenizer_register_token(&_T_EOF);
  tokenizer_register_token(&_T_NUMBER);
  tokenizer_register_token(&_T_STRING);
  tokenizer_register_token(&_T_VARIABLE_STRING);
  tokenizer_register_token(&_T_VARIABLE_NUMBER);
  tokenizer_register_token(&_T_PLUS);
  tokenizer_register_token(&_T_MINUS);
  tokenizer_register_token(&_T_MULTIPLY);
  tokenizer_register_token(&_T_DIVIDE);
  tokenizer_register_token(&_T_LEFT_BANANA);
  tokenizer_register_token(&_T_RIGHT_BANANA);
  tokenizer_register_token(&_T_COLON);
  tokenizer_register_token(&_T_SEMICOLON);
  tokenizer_register_token(&_T_EQUALS);
  tokenizer_register_token(&_T_LESS);
  tokenizer_register_token(&_T_GREATER);
  tokenizer_register_token(&_T_COMMA);
}

void tokenizer_init(char *input) {
  tokenizer_line = input;
  tokenizer_p = tokenizer_next_p = tokenizer_line;
}

char *tokenizer_char_pointer(char *set) {
  if (set != NULL) {
    tokenizer_p = set;
    return NULL;
  }

  // Skip white space
  while (*tokenizer_p && isspace(*tokenizer_p)) {
    tokenizer_p++;
  }
  return tokenizer_p;
}

static bool isvarchar(char c) {
  if (c >= 'A' && c <= 'Z') {
    return true;
  }

  if (c == '$') {
    return true;
  }

  if (c >= '0' && c <= '9') {
    return true;
  }

  return false;
}

token _find_registered(void) {
  for (size_t i = 0; i < array_size(token_array); i++) {
    token_entry *entry = (token_entry *)array_get(token_array, i);
    if (entry->name == NULL) continue;

    if (strncmp(tokenizer_p, entry->name, strlen(entry->name)) == 0) {
      tokenizer_next_p = tokenizer_p + strlen(entry->name);
      tokenizer_p = tokenizer_next_p;
      return entry->token;
    }
  }
  return T_THE_END;
}

token tokenizer_get_next_token(void) {
  if (!*tokenizer_p) {
    return T_EOF;
  }

  // Skip white space
  while (*tokenizer_p && isspace(*tokenizer_p)) {
    tokenizer_p++;
  }

  // Check for number
  if (isdigit(*tokenizer_p) || *tokenizer_p == '.') {
    tokenizer_next_p = tokenizer_p;
    size_t l = 0;
    while (*tokenizer_next_p &&
           (isdigit(*tokenizer_next_p) || *tokenizer_next_p == '.')) {
      l++;
      tokenizer_next_p++;
    }
    char number[l + 1];
    memset(number, 0, l + 1);
    strncpy(number, tokenizer_p, l);
    number[l] = '\0';
    tokenizer_p = tokenizer_next_p;
    float f;
    sscanf(number, "%f", &f);
    tokenizer_actual_number = f;
    return T_NUMBER;
  }

  // Check for string
  if ('"' == *tokenizer_p) {
    tokenizer_p++;  // skip "
    tokenizer_next_p = tokenizer_p;
    size_t l = 0;
    while (*tokenizer_next_p && '"' != *tokenizer_next_p) {
      l++;
      tokenizer_next_p++;
    }

    if (*tokenizer_next_p) {
      tokenizer_next_p++;  // skip trailing "
    }

    if (l > 80) {
      return T_ERROR;
    }

    memcpy(tokenizer_actual_string, tokenizer_p, l);
    tokenizer_actual_string[l] = '\0';

    tokenizer_p = tokenizer_next_p;

    return T_STRING;
  }

  token t = _find_registered();
  if (t != T_THE_END) {
    return t;
  }

  // Check for variable
  tokenizer_next_p = tokenizer_p;
  size_t len = 0;
  while (*tokenizer_next_p && isvarchar(*tokenizer_next_p)) {
    len++;
    tokenizer_next_p++;
  }

  if (len > tokenizer_variable_length) {
    return T_ERROR;
  }

  if (len > 0) {
    memcpy(tokenizer_actual_variable, tokenizer_p, len);
    tokenizer_actual_variable[len] = '\0';
    tokenizer_p = tokenizer_next_p;
    if (tokenizer_actual_variable[len - 1] == '$') {
      return T_VARIABLE_STRING;
    }
    return T_VARIABLE_NUMBER;
  }

  return T_ERROR;
}

float tokenizer_get_number(void) { return tokenizer_actual_number; }

char *tokenizer_get_string(void) { return tokenizer_actual_string; }

void tokenizer_get_variable_name(char *name) {
  strncpy(name, tokenizer_actual_variable, sizeof(tokenizer_actual_variable));
}

void tokenizer_register_token(token_entry *entry) {
  array_push(token_array, entry);
}

void tokenizer_free_registered_tokens(void) {
  array_destroy(token_array);
}