/**
 * @file NCDUdevMonitor.c
 * @author Ambroz Bizjak <ambrop7@gmail.com>
 * 
 * @section LICENSE
 * 
 * This file is part of BadVPN.
 * 
 * BadVPN is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 * 
 * BadVPN is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <stddef.h>

#include <system/BLog.h>

#include <udevmonitor/NCDUdevMonitor.h>

#include <generated/blog_channel_NCDUdevMonitor.h>

#define STDBUF_EXEC "/usr/bin/stdbuf"
#define UDEVADM_EXEC "/sbin/udevadm"
#define PARSER_BUF_SIZE 16384
#define PARSER_MAX_PROPERTIES 256

static void report_error (NCDUdevMonitor *o)
{
    ASSERT(!o->process_running)
    ASSERT(!o->input_running)
    
    DEBUGERROR(&o->d_err, o->handler_error(o->user, (o->process_was_error || o->input_was_error)));
}

static void process_handler_terminated (NCDUdevMonitor *o, int normally, uint8_t normally_exit_status)
{
    DebugObject_Access(&o->d_obj);
    ASSERT(o->process_running)
    
    BLog(BLOG_INFO, "process terminated");
    
    // set process not running (so we don't try to kill it)
    o->process_running = 0;
    
    // remember process error
    o->process_was_error = !(normally && normally_exit_status == 0);
    
    if (!o->input_running) {
        report_error(o);
        return;
    }
}

static void process_handler_closed (NCDUdevMonitor *o, int is_error)
{
    DebugObject_Access(&o->d_obj);
    ASSERT(o->input_running)
    
    if (is_error) {
        BLog(BLOG_ERROR, "pipe error");
    } else {
        BLog(BLOG_INFO, "pipe closed");
    }
    
    // disconnect connector
    StreamRecvConnector_DisconnectInput(&o->connector);
    
    // set input not running
    o->input_running = 0;
    
    // remember input error
    o->input_was_error = is_error;
    
    if (!o->process_running) {
        report_error(o);
        return;
    }
}

static void parser_handler (NCDUdevMonitor *o)
{
    DebugObject_Access(&o->d_obj);
    
    o->handler_event(o->user);
    return;
}

int NCDUdevMonitor_Init (NCDUdevMonitor *o, BReactor *reactor, BProcessManager *manager, int is_info_mode, void *user,
                         NCDUdevMonitor_handler_event handler_event,
                         NCDUdevMonitor_handler_error handler_error)
{
    ASSERT(is_info_mode == 0 || is_info_mode == 1)
    
    // init arguments
    o->user = user;
    o->handler_event = handler_event;
    o->handler_error = handler_error;
    
    // construct arguments
    const char *argv_monitor[] = {STDBUF_EXEC, "-o", "L", UDEVADM_EXEC, "monitor", "--udev", "--property", NULL};
    const char *argv_info[] = {STDBUF_EXEC, "-o", "L", UDEVADM_EXEC, "info", "--query", "all", "--export-db", NULL};
    const char **argv = (is_info_mode ? argv_info : argv_monitor);
    
    // init process
    if (!BInputProcess_Init(&o->process, STDBUF_EXEC, (char **)argv, NULL, reactor, manager, o,
                            (BInputProcess_handler_terminated)process_handler_terminated,
                            (BInputProcess_handler_closed)process_handler_closed
    )) {
        BLog(BLOG_ERROR, "BInputProcess_Init failed");
        goto fail0;
    }
    
    // init connector
    StreamRecvConnector_Init(&o->connector, BReactor_PendingGroup(reactor));
    StreamRecvConnector_ConnectInput(&o->connector, BInputProcess_GetInput(&o->process));
    
    // init parser
    if (!NCDUdevMonitorParser_Init(&o->parser, StreamRecvConnector_GetOutput(&o->connector), PARSER_BUF_SIZE, PARSER_MAX_PROPERTIES,
                                   is_info_mode, BReactor_PendingGroup(reactor), o,
                                   (NCDUdevMonitorParser_handler)parser_handler
    )) {
        BLog(BLOG_ERROR, "NCDUdevMonitorParser_Init failed");
        goto fail1;
    }
    
    // set process running, input running
    o->process_running = 1;
    o->input_running = 1;
    
    DebugError_Init(&o->d_err, BReactor_PendingGroup(reactor));
    DebugObject_Init(&o->d_obj);
    return 1;
    
fail1:
    StreamRecvConnector_Free(&o->connector);
    BInputProcess_Kill(&o->process);
    BInputProcess_Free(&o->process);
fail0:
    return 0;
}

void NCDUdevMonitor_Free (NCDUdevMonitor *o)
{
    DebugObject_Free(&o->d_obj);
    DebugError_Free(&o->d_err);
    
    // free parser
    NCDUdevMonitorParser_Free(&o->parser);
    
    // free connector
    StreamRecvConnector_Free(&o->connector);
    
    // kill process it it's running
    if (o->process_running) {
        BInputProcess_Kill(&o->process);
    }
    
    // free process
    BInputProcess_Free(&o->process);
}

void NCDUdevMonitor_Done (NCDUdevMonitor *o)
{
    DebugObject_Access(&o->d_obj);
    DebugError_AssertNoError(&o->d_err);
    NCDUdevMonitorParser_AssertReady(&o->parser);
    
    NCDUdevMonitorParser_Done(&o->parser);
}

int NCDUdevMonitor_IsReadyEvent (NCDUdevMonitor *o)
{
    DebugObject_Access(&o->d_obj);
    DebugError_AssertNoError(&o->d_err);
    NCDUdevMonitorParser_AssertReady(&o->parser);
    
    return NCDUdevMonitorParser_IsReadyEvent(&o->parser);
}
void NCDUdevMonitor_AssertReady (NCDUdevMonitor *o)
{
    DebugObject_Access(&o->d_obj);
    DebugError_AssertNoError(&o->d_err);
    NCDUdevMonitorParser_AssertReady(&o->parser);
}

int NCDUdevMonitor_GetNumProperties (NCDUdevMonitor *o)
{
    DebugObject_Access(&o->d_obj);
    DebugError_AssertNoError(&o->d_err);
    NCDUdevMonitorParser_AssertReady(&o->parser);
    
    return NCDUdevMonitorParser_GetNumProperties(&o->parser);
}

void NCDUdevMonitor_GetProperty (NCDUdevMonitor *o, int index, const char **name, const char **value)
{
    DebugObject_Access(&o->d_obj);
    DebugError_AssertNoError(&o->d_err);
    NCDUdevMonitorParser_AssertReady(&o->parser);
    
    NCDUdevMonitorParser_GetProperty(&o->parser, index, name, value);
}