/*
 * agent_server.c — WebSocket server for agent tool commands
 *
 * Uses libsoup's SoupServer to provide a WebSocket endpoint at /agent.
 * External AI agents connect, send JSON tool commands, and receive
 * JSON responses. The server also supports plain HTTP GET to / for
 * status discovery (curl-testable without a WebSocket client).
 */

#include "agent_server.h"
#include "agent_mcp.h"
#include "settings.h"

#include <libsoup/soup.h>
#include <string.h>
#include <stdlib.h>

/* Forward declarations from agent_tools.c */
extern cJSON *agent_tools_dispatch(cJSON *request, SoupWebsocketConnection *conn);

/* ── Static state ─────────────────────────────────────────────────── */

static SoupServer          *g_server       = NULL;
static int                  g_port         = 0;
static gboolean             g_running      = FALSE;
static GPtrArray           *g_clients      = NULL;  /* array of SoupWebsocketConnection* */
static agent_login_callback_t g_login_cb   = NULL;

/* ── Client management ────────────────────────────────────────────── */

static void on_ws_message(SoupWebsocketConnection *conn,
                          SoupWebsocketDataType    type,
                          GBytes                   *message,
                          gpointer                 user_data);
static void on_ws_closed(SoupWebsocketConnection *conn, gpointer user_data);
static void on_ws_error(SoupWebsocketConnection *conn, gpointer user_data);

/* Forward declarations */
static void on_websocket_handler(SoupServer               *server,
                                  SoupServerMessage        *msg,
                                  const char               *path,
                                  SoupWebsocketConnection  *conn,
                                  gpointer                  user_data);

static void track_client(SoupWebsocketConnection *conn) {
    if (g_clients == NULL) {
        g_clients = g_ptr_array_new();
    }
    /* Take an extra reference so the connection isn't destroyed when
     * the websocket handler callback returns. */
    g_object_ref(conn);
    g_ptr_array_add(g_clients, conn);

    g_signal_connect(conn, "message", G_CALLBACK(on_ws_message), NULL);
    g_signal_connect(conn, "closed",  G_CALLBACK(on_ws_closed),  NULL);
    g_signal_connect(conn, "error",   G_CALLBACK(on_ws_error),   NULL);

    g_print("[agent] Client connected (%d total)\n", g_clients->len);
}

static void untrack_client(SoupWebsocketConnection *conn) {
    if (g_clients == NULL) return;
    /* Remove from array and release our reference. */
    g_ptr_array_remove_fast(g_clients, conn);
    g_object_unref(conn);
    g_print("[agent] Client disconnected (%d remaining)\n",
            g_clients ? g_clients->len : 0);
}

/* ── Send helpers ─────────────────────────────────────────────────── */

static void send_json_to_client(SoupWebsocketConnection *conn, const char *json_str) {
    if (soup_websocket_connection_get_state(conn) != SOUP_WEBSOCKET_STATE_OPEN) {
        return;
    }
    soup_websocket_connection_send_text(conn, json_str);
}

static void send_json_to_all(const char *json_str) {
    if (g_clients == NULL) return;
    for (guint i = 0; i < g_clients->len; i++) {
        SoupWebsocketConnection *conn = g_ptr_array_index(g_clients, i);
        send_json_to_client(conn, json_str);
    }
}

/* ── WebSocket callbacks ──────────────────────────────────────────── */

static void on_ws_message(SoupWebsocketConnection *conn,
                          SoupWebsocketDataType    type,
                          GBytes                   *message,
                          gpointer                 user_data) {
    (void)user_data;
    (void)type;

    gsize size = 0;
    const gchar *data = g_bytes_get_data(message, &size);
    if (data == NULL || size == 0) return;

    /* Parse the JSON request. */
    cJSON *request = cJSON_ParseWithLength(data, size);
    if (request == NULL) {
        const char *err_json = "{\"success\":false,\"error\":{\"code\":\"INVALID_JSON\","
                               "\"message\":\"Failed to parse JSON request\"}}";
        send_json_to_client(conn, err_json);
        return;
    }

    /* Dispatch the tool. Pass the WebSocket connection so async tools
     * (snapshot, eval) can send their response directly when JS completes. */
    cJSON *response = agent_tools_dispatch(request, conn);
    cJSON_Delete(request);

    if (response == NULL) {
        /* NULL means the tool is sending its response asynchronously
         * (e.g. snapshot, eval). Don't send anything here. */
        return;
    }

    /* Send the response. */
    char *response_str = cJSON_PrintUnformatted(response);
    if (response_str) {
        send_json_to_client(conn, response_str);
        free(response_str);
    }
    cJSON_Delete(response);
}

static void on_ws_closed(SoupWebsocketConnection *conn, gpointer user_data) {
    (void)user_data;
    untrack_client(conn);
}

static void on_ws_error(SoupWebsocketConnection *conn, gpointer user_data) {
    (void)user_data;
    g_printerr("[agent] WebSocket error on client\n");
    untrack_client(conn);
}

/* ── WebSocket handler (called by SoupServer on new connection) ───── */

static void on_websocket_handler(SoupServer               *server,
                                  SoupServerMessage        *msg,
                                 const char               *path,
                                 SoupWebsocketConnection  *conn,
                                 gpointer                  user_data) {
    (void)server;
    (void)path;
    (void)msg;
    (void)user_data;
    track_client(conn);
}

/* ── HTTP handler for status (GET /) ──────────────────────────────── */

static void on_http_handler(SoupServer            *server,
                            SoupServerMessage     *msg,
                            const char            *path,
                            GHashTable            *query,
                            gpointer               user_data) {
    (void)server;
    (void)query;
    (void)user_data;

    if (g_strcmp0(path, "/") != 0) {
        soup_server_message_set_status(msg, 404, NULL);
        return;
    }

    /* Build a status JSON response. */
    cJSON *status = cJSON_CreateObject();
    cJSON_AddStringToObject(status, "name", "sovereign_browser agent server");
    cJSON_AddBoolToObject(status, "running", g_running);
    cJSON_AddNumberToObject(status, "port", g_port);
    cJSON_AddNumberToObject(status, "clients", g_clients ? g_clients->len : 0);

    /* Check login state via agent_tools (delegates to agent_login). */
    extern gboolean agent_is_logged_in(void);
    cJSON_AddBoolToObject(status, "logged_in", agent_is_logged_in());

    char *json_str = cJSON_PrintUnformatted(status);
    soup_server_message_set_status(msg, 200, NULL);
    soup_server_message_set_response(msg, "application/json",
                                      SOUP_MEMORY_TAKE, json_str, strlen(json_str));
    cJSON_Delete(status);
}

/* ── Public API ───────────────────────────────────────────────────── */

int agent_server_start(int port) {
    if (g_running) {
        g_print("[agent] Server already running on port %d\n", g_port);
        return 0;
    }

    GError *error = NULL;
    g_server = soup_server_new("server-header", "sovereign_browser-agent", NULL);
    if (g_server == NULL) {
        g_printerr("[agent] Failed to create SoupServer\n");
        return -1;
    }

    /* Add HTTP handler for status at /. */
    soup_server_add_handler(g_server, "/", on_http_handler, NULL, NULL);

    /* Add WebSocket handler at /agent. */
    soup_server_add_websocket_handler(g_server, "/agent", NULL, NULL,
                                       on_websocket_handler, NULL, NULL);

    /* Add MCP handler at /mcp. */
    agent_mcp_register(g_server);

    /* Listen on the specified port (0 = auto-assign). */
    soup_server_listen_local(g_server, port, 0, &error);
    if (error != NULL) {
        g_printerr("[agent] Failed to listen on port %d: %s\n", port, error->message);
        g_error_free(error);
        g_object_unref(g_server);
        g_server = NULL;
        return -1;
    }

    /* Get the actual bound port. */
    GSList *uris = soup_server_get_uris(g_server);
    if (uris != NULL) {
        GUri *uri = uris->data;
        g_port = g_uri_get_port(uri);
        g_slist_free(uris);
    } else {
        g_port = port;
    }

    g_running = TRUE;
    g_print("[agent] WebSocket server listening on ws://localhost:%d/agent\n", g_port);
    g_print("[agent] Status endpoint: http://localhost:%d/\n", g_port);
    return 0;
}

void agent_server_stop(void) {
    if (!g_running) return;

    /* Close all client connections and release our references. */
    if (g_clients != NULL) {
        for (guint i = 0; i < g_clients->len; i++) {
            SoupWebsocketConnection *conn = g_ptr_array_index(g_clients, i);
            soup_websocket_connection_close(conn, SOUP_WEBSOCKET_CLOSE_GOING_AWAY,
                                             "server shutting down");
            g_object_unref(conn);
        }
        g_ptr_array_free(g_clients, TRUE);
        g_clients = NULL;
    }

    if (g_server != NULL) {
        g_object_unref(g_server);
        g_server = NULL;
    }

    g_running = FALSE;
    g_port = 0;
    g_print("[agent] Server stopped\n");
}

int agent_server_get_port(void) {
    return g_port;
}

gboolean agent_server_is_running(void) {
    return g_running;
}

int agent_server_get_client_count(void) {
    return g_clients ? g_clients->len : 0;
}

void agent_server_emit_event(const char *event_name, cJSON *data) {
    if (!g_running || g_clients == NULL || g_clients->len == 0) {
        if (data) cJSON_Delete(data);
        return;
    }

    cJSON *event = cJSON_CreateObject();
    cJSON_AddStringToObject(event, "type", "event");
    cJSON_AddStringToObject(event, "event", event_name);
    if (data) {
        cJSON_AddItemToObject(event, "data", data);
    }

    char *json_str = cJSON_PrintUnformatted(event);
    if (json_str) {
        send_json_to_all(json_str);
        free(json_str);
    }
    cJSON_Delete(event);
}

void agent_server_set_login_callback(agent_login_callback_t cb) {
    g_login_cb = cb;
}

/* Called by agent_login.c when login succeeds — notifies main.c. */
void agent_server_notify_login(void) {
    if (g_login_cb) {
        g_login_cb();
    }
}