#include "aliases.h"
#include "lexer_data.h"
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define STRING_BUF_LENGTH 100

INTERNAL void fill_table(void);
INTERNAL void write_table(FILE *fp);

INTERNAL void set_column_width(lexer_state_t state);
INTERNAL const char *get_input_string(lexer_input_t input);
INTERNAL const char *get_state_string(lexer_state_t state);

INTERNAL lexer_state_t lexer_state_machine(lexer_state_t state,
                                           lexer_input_t input);
INTERNAL lexer_state_t handle_lexer_start(lexer_input_t input);
INTERNAL lexer_state_t handle_last_collection(char input);
INTERNAL lexer_state_t handle_object(lexer_input_t input);
INTERNAL lexer_state_t handle_array(lexer_input_t input);
INTERNAL lexer_state_t handle_key(lexer_input_t input);
INTERNAL lexer_state_t handle_value(lexer_input_t input);
INTERNAL lexer_state_t handle_string(lexer_input_t input);
INTERNAL lexer_state_t handle_string_end(lexer_input_t input);
INTERNAL lexer_state_t handle_escape_sequence(lexer_input_t input);
INTERNAL lexer_state_t handle_unicode_hex(lexer_input_t input,
                                          lexer_state_t return_state);
INTERNAL lexer_state_t handle_decimal(lexer_input_t input);
INTERNAL lexer_state_t handle_number(lexer_input_t input);
INTERNAL lexer_state_t handle_fraction(lexer_input_t input);
INTERNAL lexer_state_t handle_exponent(lexer_input_t input);
INTERNAL lexer_state_t handle_exp_sign(lexer_input_t input);
INTERNAL lexer_state_t handle_power(lexer_input_t input);
INTERNAL lexer_state_t handle_number_end(lexer_input_t input);
INTERNAL lexer_state_t handle_true(lexer_input_t input,
                                   lexer_state_t start_state);
INTERNAL lexer_state_t handle_false(lexer_input_t input,
                                    lexer_state_t start_state);
INTERNAL lexer_state_t handle_null(lexer_input_t input,
                                   lexer_state_t start_state);
INTERNAL lexer_state_t handle_keyword_end(lexer_input_t input);

INTERNAL i32 column_width = 0;

INTERNAL lexer_state_t state_table[COUNT_LEXER_STATES][COUNT_LEXER_INPUTS] = {
    0};

INTERNAL const char *input_strings[COUNT_LEXER_STATES] = {
    [LEXER_INPUT_WHITE_SPACE] = "WHITE_SPACE",
    [LEXER_INPUT_OPEN_BRACE] = "OPEN_BRACE",
    [LEXER_INPUT_CLOSE_BRACE] = "CLOSE_BRACE",
    [LEXER_INPUT_OPEN_BRACKET] = "OPEN_BRACKET",
    [LEXER_INPUT_CLOSE_BRACKET] = "CLOSE_BRACKET",
    [LEXER_INPUT_COMMA] = "COMMA",
    [LEXER_INPUT_COLON] = "COLON",
    [LEXER_INPUT_DOUBLE_QUOTE] = "DOUBLE_QUOTE",
    [LEXER_INPUT_BACK_SLASH] = "BACK_SLASH",
    [LEXER_INPUT_FORWARD_SLASH] = "FORWARD_SLASH",
    [LEXER_INPUT_LOWER_A] = "LOWER_A",
    [LEXER_INPUT_LOWER_B] = "LOWER_B",
    [LEXER_INPUT_LOWER_C] = "LOWER_C",
    [LEXER_INPUT_LOWER_D] = "LOWER_D",
    [LEXER_INPUT_LOWER_E] = "LOWER_E",
    [LEXER_INPUT_LOWER_F] = "LOWER_F",
    [LEXER_INPUT_LOWER_L] = "LOWER_L",
    [LEXER_INPUT_LOWER_N] = "LOWER_N",
    [LEXER_INPUT_LOWER_R] = "LOWER_R",
    [LEXER_INPUT_LOWER_S] = "LOWER_S",
    [LEXER_INPUT_LOWER_T] = "LOWER_T",
    [LEXER_INPUT_LOWER_U] = "LOWER_U",
    [LEXER_INPUT_UPPER_A] = "UPPER_A",
    [LEXER_INPUT_UPPER_B] = "UPPER_B",
    [LEXER_INPUT_UPPER_C] = "UPPER_C",
    [LEXER_INPUT_UPPER_D] = "UPPER_D",
    [LEXER_INPUT_UPPER_E] = "UPPER_E",
    [LEXER_INPUT_UPPER_F] = "UPPER_F",
    [LEXER_INPUT_MINUS] = "MINUS",
    [LEXER_INPUT_PLUS] = "PLUS",
    [LEXER_INPUT_DECIMAL] = "DECIMAL",
    [LEXER_INPUT_ZERO] = "ZERO",
    [LEXER_INPUT_NON_ZERO] = "NON_ZERO",
    [LEXER_INPUT_OTHER] = "OTHER",
};

INTERNAL const char *state_strings[COUNT_LEXER_STATES] = {
    [LEXER_STATE_ERROR] = "LEXER_STATE_ERROR",
    [LEXER_STATE_START] = "LEXER_STATE_START",
    [LEXER_STATE_VALUE] = "LEXER_STATE_VALUE",
    [LEXER_STATE_VALUE_END] = "LEXER_STATE_VALUE_END",
    [LEXER_STATE_OBJECT_START] = "LEXER_STATE_OBJECT_START",
    [LEXER_STATE_OBJECT] = "LEXER_STATE_OBJECT",
    [LEXER_STATE_OBJECT_END] = "LEXER_STATE_OBJECT_END",
    [LEXER_STATE_ARRAY_START] = "LEXER_STATE_ARRAY_START",
    [LEXER_STATE_ARRAY] = "LEXER_STATE_ARRAY",
    [LEXER_STATE_ARRAY_END] = "LEXER_STATE_ARRAY_END",
    [LEXER_STATE_LAST_COLLECTION] = "LEXER_STATE_LAST_COLLECTION",
    [LEXER_STATE_KEY] = "LEXER_STATE_KEY",
    [LEXER_STATE_KEY_END] = "LEXER_STATE_KEY_END",
    [LEXER_STATE_DECIMAL] = "LEXER_STATE_DECIMAL",
    [LEXER_STATE_NUMBER] = "LEXER_STATE_NUMBER",
    [LEXER_STATE_FRACTION] = "LEXER_STATE_FRACTION",
    [LEXER_STATE_EXPONENT] = "LEXER_STATE_EXPONENT",
    [LEXER_STATE_EXP_SIGN] = "LEXER_STATE_EXP_SIGN",
    [LEXER_STATE_POWER] = "LEXER_STATE_POWER",
    [LEXER_STATE_NUMBER_END] = "LEXER_STATE_NUMBER_END",
    [LEXER_STATE_STRING] = "LEXER_STATE_STRING",
    [LEXER_STATE_STRING_END] = "LEXER_STATE_STRING_END",
    [LEXER_STATE_ESCAPE_SEQUENCE] = "LEXER_STATE_ESCAPE_SEQUENCE",
    [LEXER_STATE_UNICODE_HEX1] = "LEXER_STATE_UNICODE_HEX1",
    [LEXER_STATE_UNICODE_HEX2] = "LEXER_STATE_UNICODE_HEX2",
    [LEXER_STATE_UNICODE_HEX3] = "LEXER_STATE_UNICODE_HEX3",
    [LEXER_STATE_UNICODE_HEX4] = "LEXER_STATE_UNICODE_HEX4",
    [LEXER_STATE_T] = "LEXER_STATE_T",
    [LEXER_STATE_TR] = "LEXER_STATE_TR",
    [LEXER_STATE_TRU] = "LEXER_STATE_TRU",
    [LEXER_STATE_TRUE] = "LEXER_STATE_TRUE",
    [LEXER_STATE_F] = "LEXER_STATE_F",
    [LEXER_STATE_FA] = "LEXER_STATE_FA",
    [LEXER_STATE_FAL] = "LEXER_STATE_FAL",
    [LEXER_STATE_FALS] = "LEXER_STATE_FALS",
    [LEXER_STATE_FALSE] = "LEXER_STATE_FALSE",
    [LEXER_STATE_N] = "LEXER_STATE_N",
    [LEXER_STATE_NU] = "LEXER_STATE_NU",
    [LEXER_STATE_NUL] = "LEXER_STATE_NUL",
    [LEXER_STATE_NULL] = "LEXER_STATE_NULL",
    [LEXER_STATE_KEYWORD_END] = "LEXER_STATE_KEYWORD_END",
};

INTERNAL const char *filename = "./include/lexer/lexer_state_transitions.table";

int main(void) {
  FILE *fp = fopen(filename, "w");
  if (!fp) {
    printf("Failed to open file\n");

    return EXIT_FAILURE;
  }

  fill_table();

  write_table(fp);

  fclose(fp);

  return EXIT_SUCCESS;
}

INTERNAL void fill_table(void) {
  lexer_state_t state;
  lexer_input_t input;

  for (u64 i = 0; i < COUNT_LEXER_STATES; ++i) {
    state = (lexer_state_t)i;

    for (u64 j = 0; j < COUNT_LEXER_INPUTS; ++j) {
      input = (lexer_input_t)j;

      state_table[i][j] = (lexer_state_t)lexer_state_machine(state, input);
    }
  }
}

void write_table(FILE *fp) {
  const char *array_open = "{ ";
  const u64 array_open_length = strlen(array_open);

  const char *array_close = "},";
  const u64 array_close_length = strlen(array_close);

  const char *comment = "//";
  const u64 comment_length = strlen(comment);

  const char *table_header_end = "   \n";
  const u64 table_header_end_length = strlen(table_header_end);

  char output[STRING_BUF_LENGTH] = {0};
  u64 length = 0;

  for (u64 i = 0; i < COUNT_LEXER_STATES; ++i) {
    set_column_width((lexer_state_t)i);
  }

  fwrite(comment, sizeof(char), comment_length, fp);

  i32 column_white_space = 0;

  for (u64 i = 0; i < COUNT_LEXER_INPUTS; ++i) {
    const char *input_str = get_input_string((lexer_input_t)i);
    column_white_space = (column_width - strlen(input_str)) / 2;

    sprintf(output, "%*s%*s| ", column_width - column_white_space, input_str,
            column_white_space, " ");
    length = strlen(output);
    fwrite(output, sizeof(char), length, fp);
  }

  fwrite(table_header_end, sizeof(char), table_header_end_length, fp);

  for (u64 i = 0; i < COUNT_LEXER_STATES; ++i) {
    fwrite(array_open, sizeof(char), array_open_length, fp);

    for (u64 j = 0; j < COUNT_LEXER_INPUTS; ++j) {
      sprintf(output, "%*s, ", column_width,
              get_state_string((lexer_state_t)state_table[i][j]));
      length = strlen(output);
      fwrite(output, sizeof(char), length, fp);
    }

    fwrite(array_close, sizeof(char), array_close_length, fp);

    sprintf(output, "  // %s\n", get_state_string((lexer_state_t)i));
    length = strlen(output);
    fwrite(output, sizeof(char), length, fp);

    memset(output, 0, STRING_BUF_LENGTH);
  }
}

INTERNAL void set_column_width(lexer_state_t state) {
  if (state >= COUNT_LEXER_STATES) {
    return;
  }

  const char *output = state_strings[state];
  i32 length = strlen(output);

  column_width = length > column_width ? length : column_width;
}

INTERNAL const char *get_input_string(lexer_input_t input) {
  if (input >= COUNT_LEXER_INPUTS) {
    return "";
  }

  return input_strings[input];
}

INTERNAL const char *get_state_string(lexer_state_t state) {
  if (state >= COUNT_LEXER_STATES) {
    return "";
  }

  return state_strings[state];
}

lexer_state_t lexer_state_machine(lexer_state_t state, lexer_input_t input) {
  switch (state) {
  case LEXER_STATE_START:
    return handle_lexer_start(input);
  case LEXER_STATE_VALUE:
    return handle_value(input);
  case LEXER_STATE_OBJECT:
    return handle_object(input);
  case LEXER_STATE_ARRAY:
    return handle_array(input);
  case LEXER_STATE_KEY:
    return handle_key(input);
  case LEXER_STATE_DECIMAL:
    return handle_decimal(input);
  case LEXER_STATE_NUMBER:
    return handle_number(input);
  case LEXER_STATE_FRACTION:
    return handle_fraction(input);
  case LEXER_STATE_EXPONENT:
    return handle_exponent(input);
  case LEXER_STATE_EXP_SIGN:
    return handle_exp_sign(input);
  case LEXER_STATE_POWER:
    return handle_power(input);
  case LEXER_STATE_NUMBER_END:
    return handle_number_end(input);
  case LEXER_STATE_STRING:
    return handle_string(input);
  case LEXER_STATE_STRING_END:
    return handle_string_end(input);
  case LEXER_STATE_ESCAPE_SEQUENCE:
    return handle_escape_sequence(input);
  case LEXER_STATE_UNICODE_HEX1:
    return handle_unicode_hex(input, LEXER_STATE_UNICODE_HEX2);
  case LEXER_STATE_UNICODE_HEX2:
    return handle_unicode_hex(input, LEXER_STATE_UNICODE_HEX3);
  case LEXER_STATE_UNICODE_HEX3:
    return handle_unicode_hex(input, LEXER_STATE_UNICODE_HEX4);
  case LEXER_STATE_UNICODE_HEX4:
    return handle_unicode_hex(input, LEXER_STATE_STRING);
  case LEXER_STATE_T:
    return handle_true(input, LEXER_STATE_T);
  case LEXER_STATE_TR:
    return handle_true(input, LEXER_STATE_TR);
  case LEXER_STATE_TRU:
    return handle_true(input, LEXER_STATE_TRU);
  case LEXER_STATE_F:
    return handle_false(input, LEXER_STATE_F);
  case LEXER_STATE_FA:
    return handle_false(input, LEXER_STATE_FA);
  case LEXER_STATE_FAL:
    return handle_false(input, LEXER_STATE_FAL);
  case LEXER_STATE_FALS:
    return handle_false(input, LEXER_STATE_FALS);
  case LEXER_STATE_N:
    return handle_null(input, LEXER_STATE_N);
  case LEXER_STATE_NU:
    return handle_null(input, LEXER_STATE_NU);
  case LEXER_STATE_NUL:
    return handle_null(input, LEXER_STATE_NUL);
  case LEXER_STATE_KEYWORD_END:
    return handle_keyword_end(input);
  case LEXER_STATE_LAST_COLLECTION:
    return handle_last_collection(input);
  case LEXER_STATE_TRUE:
  case LEXER_STATE_FALSE:
  case LEXER_STATE_NULL:
  case LEXER_STATE_OBJECT_START:
  case LEXER_STATE_ARRAY_START:
  case LEXER_STATE_OBJECT_END:
  case LEXER_STATE_ARRAY_END:
  case LEXER_STATE_KEY_END:
  case LEXER_STATE_VALUE_END:
  case LEXER_STATE_ERROR:
  case COUNT_LEXER_STATES:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_lexer_start(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_START;
  case LEXER_INPUT_OPEN_BRACE:
    return LEXER_STATE_OBJECT_START;
  case LEXER_INPUT_OPEN_BRACKET:
    return LEXER_STATE_ARRAY_START;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_last_collection(char input) {
  if (input == LEXER_INPUT_WHITE_SPACE) {
    return LEXER_STATE_LAST_COLLECTION;
  }

  return LEXER_STATE_ERROR;
}

lexer_state_t handle_object(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_OBJECT;
  case LEXER_INPUT_DOUBLE_QUOTE:
    return LEXER_STATE_KEY;
  case LEXER_INPUT_CLOSE_BRACE:
    return LEXER_STATE_OBJECT_END;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_array(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_ARRAY;
  case LEXER_INPUT_CLOSE_BRACKET:
    return LEXER_STATE_ARRAY_END;
  default:
    return handle_value(input);
  }
}

lexer_state_t handle_key(lexer_input_t input) { return LEXER_STATE_STRING; }

lexer_state_t handle_value(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_VALUE;
  case LEXER_INPUT_NON_ZERO:
  case LEXER_INPUT_MINUS:
    return LEXER_STATE_NUMBER;
  case LEXER_INPUT_ZERO:
    return LEXER_STATE_DECIMAL;
  case LEXER_INPUT_DOUBLE_QUOTE:
    return LEXER_STATE_STRING;
  case LEXER_INPUT_OPEN_BRACE:
    return LEXER_STATE_OBJECT_START;
  case LEXER_INPUT_OPEN_BRACKET:
    return LEXER_STATE_ARRAY_START;
  case LEXER_INPUT_LOWER_T:
    return LEXER_STATE_T;
  case LEXER_INPUT_LOWER_F:
    return LEXER_STATE_F;
  case LEXER_INPUT_LOWER_N:
    return LEXER_STATE_N;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_string(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_BACK_SLASH:
    return LEXER_STATE_ESCAPE_SEQUENCE;
  case LEXER_INPUT_DOUBLE_QUOTE:
    return LEXER_STATE_STRING_END;
  default:
    return LEXER_STATE_STRING;
  }
}

lexer_state_t handle_string_end(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_STRING_END;
  case LEXER_INPUT_COLON:
    return LEXER_STATE_KEY_END;
  case LEXER_INPUT_COMMA:
    return LEXER_STATE_VALUE_END;
  case LEXER_INPUT_CLOSE_BRACE:
    return LEXER_STATE_OBJECT_END;
  case LEXER_INPUT_CLOSE_BRACKET:
    return LEXER_STATE_ARRAY_END;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_escape_sequence(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_DOUBLE_QUOTE:
  case LEXER_INPUT_FORWARD_SLASH:
  case LEXER_INPUT_BACK_SLASH:
  case LEXER_INPUT_LOWER_B:
  case LEXER_INPUT_LOWER_F:
  case LEXER_INPUT_LOWER_N:
  case LEXER_INPUT_LOWER_R:
  case LEXER_INPUT_LOWER_T:
    return LEXER_STATE_STRING;
  case LEXER_INPUT_LOWER_U:
    return LEXER_STATE_UNICODE_HEX1;
  default:
    return LEXER_STATE_ERROR;
  }
}

INTERNAL lexer_state_t handle_unicode_hex(lexer_input_t input,
                                          lexer_state_t return_state) {
  switch (input) {
  case LEXER_INPUT_LOWER_A:
  case LEXER_INPUT_LOWER_B:
  case LEXER_INPUT_LOWER_C:
  case LEXER_INPUT_LOWER_D:
  case LEXER_INPUT_LOWER_E:
  case LEXER_INPUT_LOWER_F:
  case LEXER_INPUT_UPPER_A:
  case LEXER_INPUT_UPPER_B:
  case LEXER_INPUT_UPPER_C:
  case LEXER_INPUT_UPPER_D:
  case LEXER_INPUT_UPPER_E:
  case LEXER_INPUT_UPPER_F:
  case LEXER_INPUT_ZERO:
  case LEXER_INPUT_NON_ZERO:
    return return_state;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_decimal(lexer_input_t input) {
  if (input == LEXER_INPUT_DECIMAL) {
    return LEXER_STATE_FRACTION;
  }

  return LEXER_STATE_ERROR;
}

lexer_state_t handle_number(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_ZERO:
  case LEXER_INPUT_NON_ZERO:
    return LEXER_STATE_NUMBER;
  case LEXER_INPUT_DECIMAL:
    return LEXER_STATE_FRACTION;
  case LEXER_INPUT_CLOSE_BRACE:
    return LEXER_STATE_OBJECT_END;
  case LEXER_INPUT_CLOSE_BRACKET:
    return LEXER_STATE_ARRAY_END;
  case LEXER_INPUT_COMMA:
    return LEXER_STATE_VALUE_END;
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_NUMBER_END;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_fraction(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_ZERO:
  case LEXER_INPUT_NON_ZERO:
    return LEXER_STATE_FRACTION;
  case LEXER_INPUT_CLOSE_BRACE:
    return LEXER_STATE_OBJECT_END;
  case LEXER_INPUT_CLOSE_BRACKET:
    return LEXER_STATE_ARRAY_END;
  case LEXER_INPUT_LOWER_E:
  case LEXER_INPUT_UPPER_E:
    return LEXER_STATE_EXPONENT;
  case LEXER_INPUT_COMMA:
    return LEXER_STATE_VALUE_END;
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_NUMBER_END;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_exponent(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_ZERO:
  case LEXER_INPUT_NON_ZERO:
    return LEXER_STATE_POWER;
  case LEXER_INPUT_PLUS:
  case LEXER_INPUT_MINUS:
    return LEXER_STATE_EXP_SIGN;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_exp_sign(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_ZERO:
  case LEXER_INPUT_NON_ZERO:
    return LEXER_STATE_POWER;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_power(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_ZERO:
  case LEXER_INPUT_NON_ZERO:
    return LEXER_STATE_POWER;
  case LEXER_INPUT_CLOSE_BRACE:
    return LEXER_STATE_OBJECT_END;
  case LEXER_INPUT_CLOSE_BRACKET:
    return LEXER_STATE_ARRAY_END;
  case LEXER_INPUT_COMMA:
    return LEXER_STATE_VALUE_END;
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_NUMBER_END;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_number_end(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_NUMBER_END;
  case LEXER_INPUT_CLOSE_BRACE:
    return LEXER_STATE_OBJECT_END;
  case LEXER_INPUT_CLOSE_BRACKET:
    return LEXER_STATE_ARRAY_END;
  case LEXER_INPUT_COMMA:
    return LEXER_STATE_VALUE_END;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_true(lexer_input_t input, lexer_state_t start_state) {
  switch (start_state) {
  case LEXER_STATE_T:
    return input == LEXER_INPUT_LOWER_R ? LEXER_STATE_TR : LEXER_STATE_ERROR;
  case LEXER_STATE_TR:
    return input == LEXER_INPUT_LOWER_U ? LEXER_STATE_TRU : LEXER_STATE_ERROR;
  case LEXER_STATE_TRU:
    return input == LEXER_INPUT_LOWER_E ? LEXER_STATE_TRUE : LEXER_STATE_ERROR;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_false(lexer_input_t input, lexer_state_t start_state) {
  switch (start_state) {
  case LEXER_STATE_F:
    return input == LEXER_INPUT_LOWER_A ? LEXER_STATE_FA : LEXER_STATE_ERROR;
  case LEXER_STATE_FA:
    return input == LEXER_INPUT_LOWER_L ? LEXER_STATE_FAL : LEXER_STATE_ERROR;
  case LEXER_STATE_FAL:
    return input == LEXER_INPUT_LOWER_S ? LEXER_STATE_FALS : LEXER_STATE_ERROR;
  case LEXER_STATE_FALS:
    return input == LEXER_INPUT_LOWER_E ? LEXER_STATE_FALSE : LEXER_STATE_ERROR;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_null(lexer_input_t input, lexer_state_t start_state) {
  switch (start_state) {
  case LEXER_STATE_N:
    return input == LEXER_INPUT_LOWER_U ? LEXER_STATE_NU : LEXER_STATE_ERROR;
  case LEXER_STATE_NU:
    return input == LEXER_INPUT_LOWER_L ? LEXER_STATE_NUL : LEXER_STATE_ERROR;
  case LEXER_STATE_NUL:
    return input == LEXER_INPUT_LOWER_L ? LEXER_STATE_NULL : LEXER_STATE_ERROR;
  default:
    return LEXER_STATE_ERROR;
  }
}

lexer_state_t handle_keyword_end(lexer_input_t input) {
  switch (input) {
  case LEXER_INPUT_WHITE_SPACE:
    return LEXER_STATE_KEYWORD_END;
  case LEXER_INPUT_CLOSE_BRACE:
    return LEXER_STATE_OBJECT_END;
  case LEXER_INPUT_CLOSE_BRACKET:
    return LEXER_STATE_ARRAY_END;
  case LEXER_INPUT_COMMA:
    return LEXER_STATE_VALUE_END;
  default:
    return LEXER_STATE_ERROR;
  }
}