/**
 * Copyright (c) 2025 Dominic Masters
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include "input.h"
#include "util/memory.h"
#include "assert/assert.h"
#include <fcntl.h>

input_t INPUT;

inputmap_t INPUT_MAP[] = {
  {"w", INPUT_UP},
  {"s", INPUT_DOWN},
  {"a", INPUT_LEFT},
  {"d", INPUT_RIGHT},
  {" ", INPUT_ACTION},
  {"e", INPUT_ACTION},
  {"\n", INPUT_ACTION}, // Enter key
  {"\x1B", INPUT_CANCEL}, // Escape key
  {"\033[A", INPUT_UP},    // Up arrow
  {"\033[B", INPUT_DOWN},  // Down arrow
  {"\033[C", INPUT_RIGHT}, // Right arrow
  {"\033[D", INPUT_LEFT},  // Left arrow
  { 0 }
};

void inputEnableRawMode() {
  if (INPUT.isRawMode) return;
  tcgetattr(STDIN_FILENO, &INPUT.origin);
  struct termios raw = INPUT.origin;
  raw.c_lflag &= ~(ICANON | ECHO);
  tcsetattr(STDIN_FILENO, TCSANOW, &raw);
  INPUT.isRawMode = 1;
}

void inputDisableRawMode() {
  if(!INPUT.isRawMode) return;
  tcsetattr(STDIN_FILENO, TCSANOW, &INPUT.origin);
  INPUT.isRawMode = 0;
}

void inputSetNonBlocking() {
  int flags = fcntl(STDIN_FILENO, F_GETFL, 0);
  fcntl(STDIN_FILENO, F_SETFL, flags | O_NONBLOCK);
}

void inputInit() {
  memoryZero(&INPUT, sizeof(input_t));

  inputEnableRawMode();
  inputSetNonBlocking();
}

void inputUpdate() {
  char_t buffer[INPUT_BUFFER_SIZE];
  ssize_t n = read(STDIN_FILENO, buffer, sizeof(buffer) - 1);

  if(n < 0) {
    INPUT.previous = INPUT.current;
    INPUT.current = 0;
    return;
  }
  
  assertTrue(n < INPUT_BUFFER_SIZE, "Input buffer overflow");

  uint8_t val = 0;
  inputmap_t *map;
  uint8_t len;
  char_t *c;
  for(uint8_t i = 0; i < n; i++) {
    map = INPUT_MAP;

    do {
      len = strlen(map->key);

      if(i + len > n) {
        map++;
        continue;
      }

      c = buffer + i;
      if(memoryCompare(c, map->key, len) != 0) {
        map++;
        continue;
      }

      // Button was pressed
      val |= map->value;
      i += len - 1;
    } while(map->key);
  }
  
  INPUT.previous = INPUT.current;
  INPUT.current = val;
}

void inputDispose() {
  inputDisableRawMode();
}