feat: an endpoint for asking questions

1 files changed, 71 insertions, 0 deletions

diff --git a/ask.php b/ask.php
new file mode 100644
index 0000000..d334deb
--- /dev/null
+++ b/ask.php
@@ -0,0 +1,71 @@
+<?php
+include_once $_SERVER['DOCUMENT_ROOT'] . '/config.php';
+
+$question = $_POST['question'] ?? null;
+$max_length = min(max(intval($_POST['max_length'] ?? '100'), 20), 200);
+
+$db = new PDO(DB_URL, DB_USER, DB_PASS);
+
+// choosing a random word from the question
+$question_parts = $question ? explode(' ', $question ?? '') : [];
+$start_word = null;
+
+while ($start_word == null && !empty($question_parts)) {
+  $word_index = random_int(0, count($question_parts) - 1);
+  $start_word = $question_parts[$word_index];
+
+  $stmt = $db->prepare('SELECT id FROM chains WHERE from_word = ?');
+  $stmt->execute([$start_word]);
+  $row = $stmt->fetch(PDO::FETCH_ASSOC);
+
+  if (!$row) {
+    $start_word = null;
+    array_splice($question_parts, $word_index, 1);
+  }
+}
+
+// selecting a random word from db if there is no question
+if (!$question) {
+  $stmt = $db->query('SELECT from_word FROM chains ORDER BY rand() LIMIT 1');
+  $stmt->execute();
+
+  if ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
+    $start_word = $row['from_word'];
+  }
+}
+
+if (!$start_word && !$question) {
+  http_response_code(400);
+  header('Content-Type: application/json');
+  echo json_encode([
+    'status_code' => 400,
+    'message' => 'No question.',
+    'data' => null
+  ], JSON_UNESCAPED_SLASHES);
+  exit;
+}
+
+// generating markov chain
+$output = [];
+
+while (strlen(implode(' ', $output)) < $max_length) {
+  array_push($output, $start_word);
+  $stmt = $db->prepare('SELECT to_word FROM chains WHERE from_word = ? ORDER BY rand() LIMIT 1');
+  $stmt->execute([$start_word]);
+  $row = $stmt->fetch(PDO::FETCH_ASSOC);
+  if (!$row) {
+    break;
+  }
+  $start_word = $row['to_word'];
+}
+
+header('Content-Type: application/json');
+
+echo json_encode([
+  'status_code' => 200,
+  'message' => null,
+  'data' => [
+    'answer' => implode(' ', $output) ?: '...'
+  ]
+], JSON_UNESCAPED_SLASHES);
+?>