functions.php

<?php

/**
 * Adding a new task
 */
function add(array $argv): string
{
  if (!isset($argv[2])) return "Task description required\n";

  global $data;

  $id = count($data) + 1;

  foreach ($data as $key => $value) {
    if ($value['id'] == $id) $id++;
  }

  array_push($data, [
    'id' => $id,
    'description' => $argv[2],
    'status' => 'todo',
    'created_at' => date('Y-m-d H:i:s'),
    'updated_at' => date('Y-m-d H:i:s'),
  ]);

  file_put_contents('tasks.json', json_encode($data, JSON_PRETTY_PRINT));

  return "Task added successfully (ID: $id)\n";
}

/** 
 * Listing all tasks or listing tasks by status
 */
function show(array $argv)
{
  global $data;

  if (isset($argv[2])) {
    $status = ['todo', 'in progress', 'done'];

    if (!in_array($argv[2], $status)) return "Status not found\n";

    $result = "\nFilter (Status: {$argv[2]})\n";
    $filteredData = [];

    foreach ($data as $task)
      if ($task['status'] == $argv[2])
        array_push($filteredData, $task);

    $data = $filteredData;
  } else {
    $result = "\nFilter (None)\n";
  }

  $result .= "\nTasks:\n";

  foreach ($data as $task) {
    $result .= "\n";

    foreach ($task as $taskKey => $taskValue)
      $result .= "{$taskKey}: {$taskValue}\n";
  }

  return $result . "\n";
}

/**
 * Updating tasks
 */
function update(array $argv): string
{
  if (!isset($argv[2]) || !isset($argv[3]))
    return "Updated task description or id required\n";

  global $data;

  foreach ($data as $key => $value) {
    if ($value['id'] == $argv[2]) {
      $id = $argv[2];
      $data[$key]['description'] = $argv[3];
      $data[$key]['updated_at'] = date('Y-m-d H:i:s');

      file_put_contents('tasks.json', json_encode($data, JSON_PRETTY_PRINT));

      return "Task updated successfully (ID: $id)\n";
    }
  }

  return "Id not found\n";
}

/**
 * Marking a task as in progress or done
 */
function mark(array $argv): string
{
  if (!isset($argv[2])) return "Task id required\n";

  global $data;

  foreach ($data as $key => $value) {
    if ($value['id'] == $argv[2]) {
      $id = $argv[2];
      $data[$key]['status'] = $argv[1] === 'mark-in-progress' ? 'in progress' : 'done';
      $data[$key]['updated_at'] = date('Y-m-d H:i:s');

      file_put_contents('tasks.json', json_encode($data, JSON_PRETTY_PRINT));

      return "Task status updated to {$data[$key]['status']} (ID: $id)\n";
    }
  }

  return "Task id not found\n";
}

/**
 * Deleting tasks
 */
function delete(array $argv): string
{
  if (!isset($argv[2])) return "Task id required\n";

  global $data;

  foreach ($data as $key => $value) {
    if ($value['id'] == $argv[2]) {
      $id = $argv[2];
      unset($data[$key]);
      $data = array_values($data);

      file_put_contents('tasks.json', json_encode($data, JSON_PRETTY_PRINT));

      return "Task deleted successfully (ID: $id)\n";
    }
  }

  return "Task id not found\n";
}

/**
 * Display guide for using PHP Task Tracker CLI
 */
function help(): string
{
  $yellow = "\033[33m";
  $green = "\033[32m";
  $reset = "\033[0m";

  $help =
    $green . "\nPHP Task Tracker CLI \n" . $reset . PHP_EOL .
    $yellow . 'Usage:' . $reset . PHP_EOL .
    "php task-cli.php [arguments]\n\n" .
    $yellow . "Available arguments:" . $reset . PHP_EOL .
    "  add [task_name]                       Add new task
  update [task_id] [new_description]    Update task description
  delete [task_id]                      Delete a task
  mark-in-progress [task_id]            Update task status to in progress
  mark-done [task_id]                   Update task status to done
  list                                  List all tasks
  list [status]                         List tasks by status (todo, in progress, or done)\n\n";

  return $help;
}