feat: implement sessions, lobby, roles, and rematch lifecycle

src/session_manager.c

@@ -0,0 +1,91 @@
+#include "session_manager.h"
+
+#include <stddef.h>
+#include <string.h>
+
+static bool valid_utf8_scalar(const unsigned char *text, size_t remaining, size_t *bytes) {
+  if (text[0] < 0x80U) { *bytes = 1; return text[0] >= 0x20U && text[0] != '<' && text[0] != '>'; }
+  if (text[0] >= 0xC2U && text[0] <= 0xDFU && remaining >= 2 && (text[1] & 0xC0U) == 0x80U) { *bytes = 2; return true; }
+  if (text[0] >= 0xE0U && text[0] <= 0xEFU && remaining >= 3 && (text[1] & 0xC0U) == 0x80U && (text[2] & 0xC0U) == 0x80U) { *bytes = 3; return true; }
+  if (text[0] >= 0xF0U && text[0] <= 0xF4U && remaining >= 4 && (text[1] & 0xC0U) == 0x80U && (text[2] & 0xC0U) == 0x80U && (text[3] & 0xC0U) == 0x80U) { *bytes = 4; return true; }
+  return false;
+}
+
+static bool sanitize_name(const char *name, char output[kDisplayNameBytes + 1]) {
+  if (name == NULL) return false;
+  size_t input = 0;
+  size_t written = 0;
+  uint8_t scalars = 0;
+  while (name[input] != '\0') {
+    size_t bytes = 0;
+    if (!valid_utf8_scalar((const unsigned char *)&name[input], strlen(&name[input]), &bytes)) return false;
+    if (written + bytes > kDisplayNameBytes || ++scalars > 20U) return false;
+    memcpy(&output[written], &name[input], bytes);
+    input += bytes;
+    written += bytes;
+  }
+  output[written] = '\0';
+  return scalars != 0U;
+}
+
+static int8_t first_free(const session_manager_t *manager, uint8_t start, uint8_t end) {
+  for (uint8_t index = start; index < end; ++index) if (!manager->entries[index].occupied) return (int8_t)index;
+  return -1;
+}
+
+void session_manager_init(session_manager_t *manager) {
+  if (manager != NULL) memset(manager, 0, sizeof(*manager));
+}
+
+session_result_t session_manager_join(session_manager_t *manager, role_t requested_role, const char *name,
+                                      random_source_t random, uint8_t *session_index) {
+  if (manager == NULL || session_index == NULL || random.next_u32 == NULL) return SESSION_RESULT_UNAUTHORIZED;
+  char sanitized[kDisplayNameBytes + 1] = {0};
+  if (!sanitize_name(name, sanitized)) return SESSION_RESULT_INVALID_NAME;
+  int8_t selected = -1;
+  if (requested_role == ROLE_PLAYER_1) selected = first_free(manager, 0, 1);
+  else if (requested_role == ROLE_PLAYER_2) selected = first_free(manager, 1, 2);
+  else if (requested_role == ROLE_SPECTATOR) selected = first_free(manager, kPlayerCapacity, kSessionCapacity);
+  else return SESSION_RESULT_INVALID_ROLE;
+  if (selected < 0) return requested_role == ROLE_SPECTATOR ? SESSION_RESULT_NO_SPECTATOR_SLOT : SESSION_RESULT_NO_PLAYER_SLOT;
+  session_t candidate = {.role = requested_role, .occupied = true, .connected = true};
+  memcpy(candidate.name, sanitized, sizeof(candidate.name));
+  for (uint8_t offset = 0; offset < kSessionTokenBytes; offset += 4) {
+    const uint32_t value = random.next_u32(random.context);
+    for (uint8_t byte = 0; byte < 4; ++byte) candidate.token[offset + byte] = (uint8_t)(value >> (byte * 8U));
+  }
+  manager->entries[selected] = candidate;
+  *session_index = (uint8_t)selected;
+  return SESSION_RESULT_OK;
+}
+
+session_result_t session_manager_resume(session_manager_t *manager, const uint8_t token[kSessionTokenBytes], uint8_t *session_index) {
+  if (manager == NULL || token == NULL || session_index == NULL) return SESSION_RESULT_UNAUTHORIZED;
+  for (uint8_t index = 0; index < kSessionCapacity; ++index) {
+    session_t *session = &manager->entries[index];
+    if (session->occupied && memcmp(session->token, token, kSessionTokenBytes) == 0) {
+      session->connected = true;
+      *session_index = index;
+      return SESSION_RESULT_OK;
+    }
+  }
+  return SESSION_RESULT_UNAUTHORIZED;
+}
+
+bool session_manager_disconnect(session_manager_t *manager, uint8_t session_index) {
+  if (manager == NULL || session_index >= kSessionCapacity || !manager->entries[session_index].occupied) return false;
+  if (manager->entries[session_index].role == ROLE_SPECTATOR) memset(&manager->entries[session_index], 0, sizeof(session_t));
+  else manager->entries[session_index].connected = false;
+  return true;
+}
+
+session_result_t session_manager_leave(session_manager_t *manager, uint8_t session_index, phase_t phase) {
+  if (manager == NULL || session_index >= kSessionCapacity || !manager->entries[session_index].occupied) return SESSION_RESULT_UNAUTHORIZED;
+  if (manager->entries[session_index].role != ROLE_SPECTATOR && phase != PHASE_LOBBY) return SESSION_RESULT_WRONG_PHASE;
+  memset(&manager->entries[session_index], 0, sizeof(session_t));
+  return SESSION_RESULT_OK;
+}
+
+bool session_manager_player_present(const session_manager_t *manager, uint8_t player_index) {
+  return manager != NULL && player_index < kPlayerCapacity && manager->entries[player_index].occupied;
+}