feat: implement the production HTTP API

include/http_api.h

@@ -0,0 +1,54 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "application.h"
+#include "app_config.h"
+
+typedef enum { HTTP_API_GET, HTTP_API_POST } http_api_method_t;
+typedef enum {
+  HTTP_API_ROUTE_INFO,
+  HTTP_API_ROUTE_HEALTH,
+  HTTP_API_ROUTE_JOIN,
+  HTTP_API_ROUTE_RESUME,
+  HTTP_API_ROUTE_CONFIG,
+  HTTP_API_ROUTE_START,
+  HTTP_API_ROUTE_SHOT,
+  HTTP_API_ROUTE_REMATCH,
+  HTTP_API_ROUTE_ABORT,
+  HTTP_API_ROUTE_STATE,
+} http_api_route_t;
+
+typedef struct {
+  uint32_t uptime_ms;
+  uint32_t free_heap_bytes;
+  uint32_t minimum_free_heap_bytes;
+  uint32_t largest_free_block_bytes;
+  uint8_t connected_clients;
+  uint16_t rejected_input;
+  const char *wifi_state;
+} http_api_health_t;
+
+typedef struct {
+  http_api_method_t method;
+  http_api_route_t route;
+  bool content_type_json;
+  bool target_too_large;
+  const char *body;
+  size_t body_length;
+  const char *session_token;
+} http_api_request_t;
+
+typedef struct {
+  uint16_t status;
+  char body[kStateMessageCapacity];
+  size_t body_length;
+} http_api_response_t;
+
+typedef struct { application_t *application; http_api_health_t health; } http_api_t;
+
+void http_api_init(http_api_t *api, application_t *application);
+void http_api_set_health(http_api_t *api, const http_api_health_t *health);
+bool http_api_handle(http_api_t *api, const http_api_request_t *request, http_api_response_t *response);