#include "umbrella.h"
#include "daemon.h"
#include "unit.h"
#include "client.h"
#include "log.h"
#include "log_tail.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <sys/epoll.h>
#include <sys/signalfd.h>
#include <sys/wait.h>

/* Global daemon state — defined here, declared extern in umbrella.h */
Daemon g;

/* ── Signal handling ─────────────────────────────────────────────────────── */

static void handle_signal(void) {
    struct signalfd_siginfo info;
    ssize_t n = read(g.signal_fd, &info, sizeof(info));
    if (n != sizeof(info)) return;

    switch (info.ssi_signo) {
    case SIGTERM:
    case SIGINT:
        log_info("Received signal %d — shutting down", info.ssi_signo);
        g.running = 0;
        break;

    case SIGCHLD:
        /* Reap all finished child processes (action scripts, etc.) */
        while (1) {
            int status;
            pid_t pid = waitpid(-1, &status, WNOHANG);
            if (pid <= 0) break;

            /* Check if any managed STDIN unit matches this pid */
            for (int i = 0; i < g.unit_count; i++) {
                Unit *u = &g.units[i];
                if (u->console.type == CONSOLE_STDIN && u->pid == pid) {
                    if (WIFEXITED(status))
                        log_warn("Unit %s exited with code %d",
                                 u->name, WEXITSTATUS(status));
                    else if (WIFSIGNALED(status))
                        log_warn("Unit %s killed by signal %d",
                                 u->name, WTERMSIG(status));
                    u->state = STATE_CRASHED;
                    u->pid = 0;
                    break;
                }
            }
        }
        break;

    case SIGHUP:
        log_info("SIGHUP received — reloading units");
        log_tail_cleanup();
        /* Reload unit descriptors. Existing runtime state is preserved. */
        g.unit_count = 0;
        unit_load_all();
        log_tail_init();
        break;
    }
}

/* ── Process stdout handling ─────────────────────────────────────────────── */
/*
 * Called when a STDIN-type unit's stdout fd is readable.
 * Reads available output, pushes to ring buffer, broadcasts to clients.
 */
static void handle_process_output(int fd) {
    /* Find which unit owns this fd */
    Unit *u = NULL;
    for (int i = 0; i < g.unit_count; i++) {
        if (g.units[i].stdout_fd == fd) {
            u = &g.units[i];
            break;
        }
    }
    if (!u) return;

    char buf[RING_BUF_LINE_MAX];
    ssize_t n = read(fd, buf, sizeof(buf) - 1);
    if (n <= 0) {
        /* Process closed its stdout — mark as stopped */
        log_info("Unit %s stdout closed", u->name);
        epoll_ctl(g.epoll_fd, EPOLL_CTL_DEL, fd, NULL);
        close(fd);
        u->stdout_fd = -1;
        return;
    }

    buf[n] = '\0';
    ring_push(u->output, buf, n);
    client_broadcast_output(u->name, buf, 0);
}

/* ── Main event loop ─────────────────────────────────────────────────────── */

static void event_loop(void) {
    struct epoll_event events[64];

    while (g.running) {
        int n = epoll_wait(g.epoll_fd, events, 64, -1);
        if (n < 0) {
            if (errno == EINTR) continue;
            log_error("epoll_wait: %s", strerror(errno));
            break;
        }

        for (int i = 0; i < n; i++) {
            int fd = events[i].data.fd;
            uint32_t ev = events[i].events;

            if (fd == g.signal_fd) {
                handle_signal();

            } else if (fd == g.listen_fd) {
                client_accept(g.listen_fd);

            } else if (log_tail_fd_to_unit(fd) != NULL) {
		    log_tail_handle(fd);

	    } else {
                /* Check if this is a unit stdout fd */
                int is_unit_stdout = 0;
                for (int j = 0; j < g.unit_count; j++) {
                    if (g.units[j].stdout_fd == fd) {
                        is_unit_stdout = 1;
                        break;
                    }
                }

                if (is_unit_stdout) {
                    handle_process_output(fd);
                } else {
                    /* It's a client fd */
                    if (ev & (EPOLLRDHUP | EPOLLHUP | EPOLLERR)) {
                        client_remove(fd);
                    } else if (ev & EPOLLIN) {
                        if (client_handle(fd) < 0)
                            client_remove(fd);
                    }
                }
            }
        }
    }
}

/* ── Entry point ─────────────────────────────────────────────────────────── */

static void usage(const char *prog) {
    fprintf(stderr,
            "Usage: %s [options]\n"
            "  -f    Run in foreground (don't daemonize)\n"
            "  -d    Enable debug logging\n"
            "  -h    Show this help\n",
            prog);
}

int main(int argc, char *argv[]) {
    int foreground = 0;
    int debug = 0;
    int opt;

    while ((opt = getopt(argc, argv, "fdh")) != -1) {
        switch (opt) {
            case 'f': foreground = 1; break;
            case 'd': debug = 1;      break;
            case 'h': usage(argv[0]); return 0;
            default:  usage(argv[0]); return 1;
        }
    }

    /* Initialize logging before anything else */
    log_init(foreground ? NULL : UMBRELLA_LOG_FILE,
             debug ? LOG_DEBUG : LOG_INFO);
    log_info("umbrella %s starting", UMBRELLA_VERSION);

    /* Daemonize if not running in foreground */
    if (daemon_daemonize(foreground) != 0) {
        log_error("daemonize failed");
        return 1;
    }

    /* Set up epoll */
    g.epoll_fd = epoll_create1(EPOLL_CLOEXEC);
    if (g.epoll_fd < 0) {
        log_error("epoll_create1: %s", strerror(errno));
        return 1;
    }

    /* Initialize daemon (signals, pid file, directories) */
    if (daemon_init() != 0) {
        log_error("daemon_init failed");
        return 1;
    }

    /* Register signal fd with epoll */
    struct epoll_event ev;
    ev.events  = EPOLLIN;
    ev.data.fd = g.signal_fd;
    epoll_ctl(g.epoll_fd, EPOLL_CTL_ADD, g.signal_fd, &ev);

    /* Load unit descriptors */
    if (unit_load_all() < 0) {
        log_error("Failed to load units");
        daemon_cleanup();
        return 1;
    }

    log_tail_init();

    /* Set up listening socket */
    g.listen_fd = client_listen();
    if (g.listen_fd < 0) {
        log_error("Failed to create listen socket");
        daemon_cleanup();
        return 1;
    }

    ev.events  = EPOLLIN;
    ev.data.fd = g.listen_fd;
    epoll_ctl(g.epoll_fd, EPOLL_CTL_ADD, g.listen_fd, &ev);

    log_info("Ready. %d unit(s) loaded.", g.unit_count);
    g.running = 1;

    event_loop();

    log_info("Shutting down");
    log_tail_cleanup();
    daemon_cleanup();
    log_close();
    return 0;
}