/*
 * Copyright 2022 Olaf Wintermann
 *
 * Permission is hereby granted, free of charge, to any person obtaining a 
 * copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation 
 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the 
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in 
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
 * DEALINGS IN THE SOFTWARE.
 */

#include "player.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/fcntl.h>
#include <spawn.h>
#include <sys/wait.h>
#include <signal.h>
#include <poll.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <pthread.h>



extern char **environ;

#define STR_BUFSIZE 512
#define WID_ARG_BUFSIZE 24

#define PLAYER_POLL_TIMEOUT 500
#define PLAYER_IN_BUFSIZE   8192

static void* start_player(void *data);

static void player_io(Player *p);

void PlayerOpenFile(MainWindow *win) {
    pthread_t tid;
    if(pthread_create(&tid, NULL, start_player, win)) {
        perror("pthread_create");
    }
}

static int prepare_player(Player *player, char *log_arg, char *ipc_arg) {
    // create tmp directory for IPC
    char *player_tmp = NULL;
    char buf[STR_BUFSIZE];
    snprintf(buf, STR_BUFSIZE, "/tmp/uwplayer-%x", rand());
    int mkdir_success = 0;
    for(int t=0;t<5;t++) {
        if(!mkdir(buf, S_IRWXU)) {
            mkdir_success = 1;
            break;
        } else if(errno != EEXIST) {
            break;
        }
    }
    if(!mkdir_success) return 1;
    player_tmp = strdup(buf);
    player->tmp = player_tmp;
    
    // prepare log/ipc args and create log fifo
    int err = 0;
    
    if(snprintf(log_arg, STR_BUFSIZE, "--log-file=%s/%s", player_tmp, "log.fifo") >= STR_BUFSIZE) {
        err = 1;
    }
    if(snprintf(ipc_arg, STR_BUFSIZE, "--input-ipc-server=%s/%s", player_tmp, "ipc.socket") >= STR_BUFSIZE) {
        err = 1;
    }
    
    snprintf(buf, STR_BUFSIZE, "%s/log.fifo", player_tmp);
    if(err || mkfifo(buf, S_IRUSR|S_IWUSR)) {
        rmdir(player_tmp);
        return 1;
    }
    
    return 0;
}

static int start_player_process(Player *player, MainWindow *win) {
    char log_arg[STR_BUFSIZE];
    char ipc_arg[STR_BUFSIZE];
    
    if(prepare_player(player, log_arg, ipc_arg)) {
        return 1;
    }
    
    char *player_bin = "/usr/local/bin/mpv"; // TODO: get bin from settings
    
    // -wid parameter value for embedding the player in the player_widget
    Window wid = XtWindow(win->player_widget);
    char wid_arg[WID_ARG_BUFSIZE];
    if(snprintf(wid_arg, WID_ARG_BUFSIZE, "%lu", wid) >= WID_ARG_BUFSIZE) {
        return 1;
    }
    
    // create player arg list
    char *args[32];
    args[0] = player_bin;
    args[1] = "-wid";
    args[2] = wid_arg;
    args[3] = "--no-terminal";
    args[4] = log_arg;
    args[5] = ipc_arg;
    args[6] = win->file;
    args[7] = NULL;
    
    posix_spawn_file_actions_t actions;
    posix_spawn_file_actions_init(&actions);
    
    //posix_spawn_file_actions_adddup2(&actions, pin[0], STDIN_FILENO);
    //posix_spawn_file_actions_adddup2(&actions, pout[1], STDOUT_FILENO);
    
    // start player
    pid_t player_pid;
    if(posix_spawn(&player_pid, player_bin, &actions, NULL, args, environ)) {
        perror("posix_spawn");
        return 1;
    }
    posix_spawn_file_actions_destroy(&actions);
    
    player->process = player_pid;
    player->isactive = TRUE;
    
    return 0;
}

static int wait_for_ipc(Player *player) {
    char buf[STR_BUFSIZE];
    snprintf(buf, STR_BUFSIZE, "%s/log.fifo", player->tmp); // cannot fail
    
    // open log
    int fd_log = open(buf, O_RDONLY);
    if(fd_log < 0) {
        perror("Cannot open log");
        return 1;
    }
    player->log = fd_log;
    
    // read log until IPC socket is created
    char *scan_str = "Listening to IPC";
    int scan_pos = 0;
    int scan_len = strlen(scan_str);
    int ipc_listen = 0;
    ssize_t r;
    while((r = read(fd_log, buf, STR_BUFSIZE)) > 0) {
        for(int i=0;i<r;i++) {
            char c = buf[i];
            char *s_str = buf+i;
            
            if(scan_pos == scan_len) {
                ipc_listen = 1;
                break;
            }
            
            if(scan_str[scan_pos] == c) {
                scan_pos++;
            } else {
                scan_pos = 0;
            }
        }
        if(ipc_listen) break;
    }
    
    return 0;
}

static int connect_to_ipc(Player *player) {
    // connect to IPC socket
    int fd_ipc = socket(AF_UNIX, SOCK_STREAM, 0);
    if(fd_ipc < 0) {
        perror("Cannot create IPC socket");
        return 1;
    }
    player->ipc = fd_ipc;
    
    char buf[STR_BUFSIZE];
    snprintf(buf, STR_BUFSIZE, "%s/%s", player->tmp, "ipc.socket"); // cannot fail
    
    struct sockaddr_un ipc_addr;
    memset(&ipc_addr, 0, sizeof(struct sockaddr_un));
    ipc_addr.sun_family = AF_UNIX;
    memcpy(ipc_addr.sun_path, buf, strlen(buf));
    if(connect(fd_ipc, (struct sockaddr *)&ipc_addr, sizeof(ipc_addr)) == -1) {
        perror("Cannot connect to IPC socket");
        return 1;
    }
    
    return 0;
}

static void* start_player(void *data) {
    MainWindow *win = data;
    
    Player *player = malloc(sizeof(Player));
    memset(player, 0, sizeof(Player));
    
    // start mpv
    if(start_player_process(player, win)) {
        PlayerDestroy(player);
        return NULL;
    } 
    
    // wait until IPC socket is ready
    if(wait_for_ipc(player)) {
        PlayerDestroy(player);
        return NULL;
    }
     
    if(connect_to_ipc(player)) {
        PlayerDestroy(player);
        return NULL;
    }
    
    // set player in main window
    if(win->player) {
        PlayerDestroy(win->player);
    }
    win->player = player;
    
    // IO
    player_io(player);
    
    return NULL;
}

static void player_io(Player *p) {
    int flags = fcntl(p->log, F_GETFL, 0);
    fcntl(p->log, F_SETFL, flags | O_NONBLOCK);
    
    struct pollfd fds[2];
    fds[0].fd = p->log;
    fds[0].events = POLLIN;
    fds[0].revents = 0;
    fds[1].fd = p->ipc;
    fds[1].events = POLLIN;
    fds[1].revents = 0;
    
    char buf[PLAYER_IN_BUFSIZE];
    while(poll(fds, 2, PLAYER_POLL_TIMEOUT)) {
        if(fds[0].revents == POLLIN) {
            // clean up fifo
            read(fds[0].fd, buf, PLAYER_IN_BUFSIZE);
        }
        
        if(fds[1].revents == POLLIN) {
            ssize_t r;
            if((r = read(fds[1].fd, buf, PLAYER_IN_BUFSIZE)) <= 0) {
                break;
            }
            
            write(1, buf, r);
            
        }
        
        char *cmd = "{ \"command\": [\"get_property\", \"playback-time\"] }\n";
        write(p->ipc, cmd, strlen(cmd));
    }
}

void PlayerDestroy(Player *p) {
    if(p->log >= 0) {
        close(p->log);
    }
    if(p->ipc >= 0) {
        close(p->ipc);
    }
    
    if(p->tmp) {
        free(p->tmp);
    }
    
    if(p->isactive) {
        kill(p->process, SIGTERM);
    }
    
    free(p);
}