/*
 *
 * Copyright 2023 Oleg Borodin  <borodin@unix7.org>
 *
 */


#ifdef __linux__
#define _GNU_SOURCE
#endif

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/time.h>
//#include <sys/event.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>


#include <limits.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <pthread.h>
#include <poll.h>
#include <signal.h>

#include <cllexer.h>
#include <clparser.h>
#include <cflexer.h>
#include <cfparser.h>
#include <massert.h>
#include <rcache.h>
#include <jlexer.h>
#include <jparser.h>
#include <jblock.h>


#include <config.h>
#include <cworker.h>
#include <logger.h>

static const int64_t default_port = 9002;
static cworker_t* pworker = NULL;

static int mkdirall(const char* path, mode_t mode);
void sighandler(int signum);

static int cworker_readconf(const cworker_t* worker) {
    log_debug("Configuration reading");

    int conffd = -1;
    if ((conffd = open(srv_configpath, O_RDONLY)) < 0) {
        log_error("Configuration file opening error: %s %s", strerror(errno), srv_configpath);
        return -1;
    }

    rcache_t cache;
    cflexer_t lexer;
    cfparser_t parser;

    rcache_init(&cache, conffd);
    cflexer_init(&lexer, &cache);
    cfparser_init(&parser, &lexer);

    if (cfparser_parse(&parser) < 0) {
        log_error("Configuration parsing error");
        return -1;
    }

    cfparser_bind(&parser, CFVALTYPE_INT, "port", (void *)&(worker->port));
    cfparser_bind(&parser, CFVALTYPE_BOOL, "nofork", (void *)&(worker->nofork));

    cfparser_destroy(&parser);
    cflexer_destroy(&lexer);
    rcache_destroy(&cache);

    return 0;
}

static int cworker_readopts(const cworker_t* worker, char** argv, int argc) {
    log_debug("Reading options");

    cllexer_t lexer;
    clparser_t parser;

    cllexer_init(&lexer);
    clparser_init(&parser, &lexer);

    clparser_bind(&parser, CLVALTYPE_INT, "port", (void *)&(worker->port));
    clparser_bind(&parser, CLVALTYPE_BOOL, "nofork", (void *)&(worker->nofork));

    if (clparser_parse(&parser, &argv[1], argc - 1) < 0) {
        log_error("Args parsing error");
        return -1;
    }
    clparser_destroy(&parser);
    return 0;
}

static int cworker_openlog(cworker_t* worker) {
    if (!worker->nofork) {
        log_debug("Redirect output");
        if (mkdirall(srv_logpath, S_IRWXU|S_IRGRP|S_IXGRP) < 0) {
            log_error("Log dir creating error: %s %s", strerror(errno), srv_logpath);
        }

        if ((worker->logfd = open(srv_logpath, O_WRONLY|O_APPEND|O_CREAT, S_IRUSR|S_IWUSR|S_IRGRP)) < 0) {
            log_error("Log file opening error: %s %s", strerror(errno), srv_logpath);
            return -1;
        }
        dup2(worker->logfd, STDOUT_FILENO);
        dup2(worker->logfd, STDERR_FILENO);
    }
    return 0;
}

int cworker_writepid(const cworker_t* worker) {
    if (!worker->nofork) {

        log_debug("Write pid file");

        if (mkdirall(srv_runpath, S_IRWXU|S_IRGRP|S_IXGRP) < 0) {
            log_error("Run directory creating error: %s %s", strerror(errno), srv_runpath);
        }

        int pid_fd = -1;
        if ((pid_fd = open(srv_runpath, O_WRONLY|O_TRUNC|O_CREAT, S_IRUSR|S_IWUSR|S_IRGRP)) < 0) {
            log_error("Process ID file opening error: %s %s", strerror(errno), srv_runpath);
            return -1;
        }
        if (dprintf(pid_fd, "%d", getpid()) < 0) {
            log_error("Process ID file writing error: %s %s", strerror(errno), srv_runpath);
            close(pid_fd);
            return -1;
        }
        close(pid_fd);
    }
    return 0;
}


int cworker_init(cworker_t* worker, char** argv, int argc) {
    log_init();

    log_debug("Init service");
    worker->port = default_port;
    worker->nofork = true;
    worker->socket = 0;
    worker->logfd = 0;
    pworker = worker;

    if (cworker_readconf(worker) < 0) {
        log_error("Config reading  error");
        return -1;
    }
    if (cworker_readopts(worker, argv, argc) < 0) {
        log_error("Options reading error");
        return -1;
    }
    if (!worker->nofork) {
        if (cworker_openlog(worker) < 0) {
            log_error("Log opening error");
            return -1;
        }
    }
    log_debug("Listening port: %d", worker->port);

    return 0;
}

int cworker_detach(const cworker_t* worker) {
    if (!worker->nofork) {
        log_debug("Service detaching");
        int childpid = -1;
        if((childpid = fork()) < 0) {
            log_error("Fork error %d: %s ", errno, strerror(errno));
            return -1;
        }
        if (childpid == 0) {
            log_debug("Service forked");
            return 0;
            // child
        } else {
            // parent
            exit(0);
        }
    }
    return 0;
}

int cworker_build(cworker_t* worker) {
    log_debug("Service building");

    signal(SIGCHLD, SIG_IGN);
    signal(SIGHUP, sighandler);
    signal(SIGTERM, sighandler);

    if((worker->socket = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
        log_debug("Socket creating error %d: %s", errno, strerror(errno));
        return -1;
    }
    int optval = 1;
    if (setsockopt(worker->socket, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)) < 0) {
        log_debug("Socket option setting error %d: %s", errno, strerror(errno));
        return -1;
    }

    struct sockaddr addr;
    struct sockaddr_in* paddr = (struct sockaddr_in*)&addr;
    paddr->sin_family = AF_INET;
    paddr->sin_addr.s_addr = INADDR_ANY;
    paddr->sin_port = htons(worker->port);

    if (bind(worker->socket, (struct sockaddr*)paddr, sizeof(struct sockaddr_in)) < 0) {
        log_debug("Socket binding error %d: %s ", errno, strerror(errno));
        return -1;
    }
    int backlog = 100;
    if (listen(worker->socket, backlog) < 0) {
        log_debug("Socket listening error %d: %s ", errno, strerror(errno));
        return -1;
    }
    return 0;
}

int cworker_handler(const cworker_t* worker, int socket);

int cworker_run(const cworker_t* worker) {
    log_debug("Service running");

    while (1) {
        int newsocket = 0;
        if ((newsocket = accept(worker->socket, NULL, 0)) > 3) {

            int childpid = -1;
            if((childpid = fork()) < 0) {
                log_error("Fork error %d: %s ", errno, strerror(errno));
                continue;
            }
            if (childpid == 0) {
                /* Child */
                log_debug("Service %d forked", getpid());
                signal(SIGHUP, SIG_IGN);
                signal(SIGTERM, SIG_IGN);

                struct timeval tv = { .tv_sec = 5, .tv_usec = 0 };
                if (setsockopt(newsocket, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(struct timeval)) < 0) {
                    log_debug("Socket option setting error %d: %s ", errno, strerror(errno));
                    return -1;
                }
                int res = cworker_handler(worker, newsocket);
                log_debug("Handler %d done with res code %d", getpid(), res);
                close(newsocket);
                return 0;
            } else {
                /* Parent */
                close(newsocket);
            }
        }
    }
    close(worker->socket);

    return 0;
}


int cworker_handler(const cworker_t* worker, int socket) {
    int err = 0;

    rcache_t cache;
    jlexer_t lexer;
    jparser_t parser;

    rcache_init(&cache, socket);
    jlexer_init(&lexer, &cache);
    jparser_init(&parser, &lexer);

    if (jparser_parse(&parser) < 0) {
        log_error("Cannot parse json");
        err = -1;
        goto exit;
    }

    int64_t id = 0;
    int64_t timeout = 0;
    char* name = "none";

    if (jparser_bind(&parser, JVALTYPE_NUM, "id", (void *)&id) < 0) {
        log_error("Cannot bind id");
    }
    if (jparser_bind(&parser, JVALTYPE_NUM, "timeout", (void *)&timeout) < 0) {
        log_error("Cannot bind timeout");
    }

    if (jparser_bind(&parser, JVALTYPE_STR, "name", (void *)&name) < 0) {
        log_error("Cannot bind name");
    }


    char* msg = NULL;
    asprintf(&msg, "hello, %s!", name);

    jblock_t jb;
    jblock_init(&jb);
    jblock_addstr(&jb, "message", msg);
    jblock_addbool(&jb, "error", false);
    jblock_addint(&jb, "id", id);
    jblock_addint(&jb, "timeout", timeout);

    for (int64_t i = 0; i < timeout; i++) {
        log_debug("The handler slept for %ld second from %ld", i + 1, timeout);
        sleep(1);
    }

    char* jsonstr = NULL;
    jblock_outjson(&jb, &jsonstr);
    jblock_destroy(&jb);

    size_t jsize = strlen(jsonstr);
    ssize_t wsize = write(socket, jsonstr, jsize);
    if (wsize < 0) {
        log_error("Write error: %s", strerror(errno));
    }
    if (wsize != jsize && wsize >= 0 ) {
        log_error("Wrote only %ld from %ld", (size_t)wsize, jsize);
    }

    free(jsonstr);
    //free(name);
    free(msg);

    exit:
        jparser_destroy(&parser);
        jlexer_destroy(&lexer);
        rcache_destroy(&cache);

    return err;
}

void cworker_shutdown(cworker_t* worker) {
    log_warning("Shutdown service %d", getpid());
    if (worker->socket != 0) {
        close(worker->socket);
        worker->logfd = 0;
    }
    if (worker->logfd != 0) {
        close(worker->logfd);
        worker->logfd = 0;
    }
    wait(NULL);
    log_destroy();
}


void sighandler(int signum) {
    log_warning("Handle signal %d", signum);
    if (signum == SIGHUP) {
       log_warning("Handle HUP signal");
    } else if (signum == SIGTERM) {
        log_warning("Handle TERM signal");
        if (pworker != NULL) {
            cworker_shutdown(pworker);
            sleep(1);
            exit(0);
        }
    }
}


static int mkdirall(const char* path, mode_t mode) {
    char buffer[PATH_MAX];
    size_t psize = strlen(path);
    if (psize > PATH_MAX) {
        return -1;
    }
    if (psize == 0) return 0;
    if (psize == 1 && path[0] == '/') {
        return 0;
    }
    for (int i = 1; i < psize; i++) {
        if (path[i] == '/') {
            strncpy(buffer, path, i);
            buffer[i] = '\0';
            if (mkdir(buffer, mode) < 0) {
                if (errno != EEXIST) {
                    return -1;
                }
            }
        }
    }
    return 0;
}