#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <getopt.h>
#include <unistd.h>
#include <sysexits.h>
#include <errno.h>

#include <patty/ax25.h>
#include <patty/daemon.h>
#include <patty/conf.h>

#define DEFAULT_CONFIG_FILE "/etc/patty/pattyd.conf"
#define DEFAULT_IFNAME      "kiss0"

static int usage(int argc, char **argv, const char *message, ...) {
    if (message != NULL) {
        va_list args;

        va_start(args, message);
        vfprintf(stderr, message, args);
         fprintf(stderr, "\n");
        va_end(args);
    }

    fprintf(stderr, "usage: %s [-f] [-c pattyd.conf]\n"
                    "       %s [-f] -s patty.sock MYCALL /dev/ttyXYZ [tioflags ...]\n",
        argv[0], argv[0]);

    return EX_USAGE;
}

static int handle_sock(patty_daemon *daemon,
                       int lineno,
                       int argc,
                       char **argv) {
    if (argc != 2) {
        fprintf(stderr, "Invalid arguments for 'sock' on line %d\n", lineno);

        goto error_invalid_args;
    }

    if (patty_daemon_set_sock_path(daemon, argv[1]) < 0) {
        fprintf(stderr, "Line %d: unable to set socket path to %s: %s",
            lineno, argv[1], strerror(errno));

        goto error_set_sock_path;
    }

    return 0;

error_set_sock_path:
error_invalid_args:
    return -1;
}

static int handle_pid(patty_daemon *daemon,
                      int lineno,
                      int argc,
                      char **argv) {
    if (argc != 2) {
        fprintf(stderr, "Invalid arguments for 'sock' on line %d\n", lineno);

        goto error_invalid_args;
    }

    if (patty_daemon_set_pidfile(daemon, argv[1]) < 0) {
        fprintf(stderr, "Line %d: Unable to set pidfile to %s: %s",
            lineno, argv[1], strerror(errno));

        goto error_set_pidfile;
    }

    return 0;

error_set_pidfile:
error_invalid_args:
    return -1;
}

struct if_context {
    patty_daemon *daemon;
    patty_ax25_addr addr;
    patty_kiss_tnc_info info;
};

static int handle_if_ax25(struct if_context *ctx,
                          int lineno,
                          char *opt,
                          char *value) {
    if (patty_ax25_pton(value, &ctx->addr) < 0) {
        fprintf(stderr, "Line %d: Invalid interface address '%s'\n",
            lineno, value);

        goto error_pton;
    }

    return 0;

error_pton:
    return -1;
}

static int handle_if_kiss(struct if_context *ctx,
                          int lineno,
                          char *opt,
                          char *value) {
    ctx->info.flags |= PATTY_KISS_TNC_DEVICE;
    ctx->info.device = value;

    return 0;
}

static int handle_if_baud(struct if_context *ctx,
                          int lineno,
                          char *opt,
                          char *value) {
    ctx->info.flags |= PATTY_KISS_TNC_BAUD;
    ctx->info.baud   = atoi(value);

    return 0;
}

static int handle_if_flow(struct if_context *ctx,
                          int lineno,
                          char *opt,
                          char *value) {
    if (strcmp(value, "xonxoff") == 0) {
        ctx->info.flow = PATTY_KISS_TNC_FLOW_XONXOFF;
    } else if (strcmp(value, "crtscts") == 0) {
        ctx->info.flow = PATTY_KISS_TNC_FLOW_CRTSCTS;
    } else {
        fprintf(stderr, "Line %d: Invalid flow control '%s'\n",
            lineno, value);

        goto error_invalid_flow;
    }

    ctx->info.flags |= PATTY_KISS_TNC_FLOW;

    return 0;

error_invalid_flow:
    return -1;
}

struct if_opt_handler {
    char *name;
    int (*func)(struct if_context *, int, char *, char *);
};

static struct if_opt_handler if_opt_handlers[] = {
    { "ax25", handle_if_ax25 },
    { "kiss", handle_if_kiss },
    { "baud", handle_if_baud },
    { "flow", handle_if_flow },
    { NULL,   NULL           }
};

static int handle_if_opt(struct if_context *ctx,
                         int lineno,
                         char *opt,
                         char *value) {
    int i;

    for (i=0; if_opt_handlers[i].name; i++) {
        if (strcmp(opt, if_opt_handlers[i].name) == 0) {
            return if_opt_handlers[i].func(ctx, lineno, opt, value);
        }
    }

    fprintf(stderr, "Line %d: Invalid interface option '%s'\n",
        lineno, opt);

    return -1;
}

static int handle_if(patty_daemon *daemon,
                     int lineno,
                     int argc,
                     char **argv) {
    char *name;
    struct if_context ctx;
    patty_ax25_if *iface;

    int i;

    if (argc < 2) {
        fprintf(stderr, "Line %d: No interface name provided\n", lineno);

        goto error_no_ifname;
    }

    if (argc < 3) {
        fprintf(stderr, "Line %d: No interface options provided\n", lineno);

        goto error_no_options;
    }

    if (argc % 2 != 0) {
        fprintf(stderr, "Line %d: Invalid number of values provided\n", lineno);

        goto error_invalid_values;
    }

    memset(&ctx, '\0', sizeof(ctx));
    ctx.daemon = daemon;

    name = argv[1];

    for (i=2; i<argc; i+=2) {
        char *opt   = argv[i],
             *value = argv[i+1];

        if (handle_if_opt(&ctx, lineno, opt, value) < 0) {
            goto error_handle_if_opt;
        }
    }

    if ((iface = patty_ax25_if_new(PATTY_AX25_IF_KISS_TNC,
                                   name,
                                   &ctx.info,
                                   &ctx.addr)) == NULL) {
        goto error_if_new;
    } else {
        int fd = patty_kiss_tnc_fd(iface->tnc);
        char *pty;

        if (isatty(fd) && (pty = ptsname(fd)) != NULL) {
            printf("if %s pty %s\n", name, pty);
        }
    }

    if (patty_daemon_if_add(daemon, iface) < 0) {
        fprintf(stderr, "Line %d: Unable to create interface %s: %s\n",
            lineno, name, strerror(errno));

        goto error_daemon_if_add;
    }

    return 0;

error_daemon_if_add:
    patty_ax25_if_destroy(iface);

error_if_new:
error_handle_if_opt:
error_invalid_values:
error_no_options:
error_no_ifname:
    return -1;
}

static int handle_route(patty_daemon *daemon,
                        int lineno,
                        int argc,
                        char **argv) {
    if (argc < 2) {
        fprintf(stderr, "Line %d: Invalid route declaration\n", lineno);

        goto error_invalid_route;
    }

    if (strcmp(argv[1], "default") == 0) {
        if (argc != 4 || strcmp(argv[2], "if") != 0) {
            fprintf(stderr, "Line %d: Invalid default route declaration\n",
                lineno);

            goto error_invalid_route;
        }

        if (patty_daemon_route_add_default(daemon, argv[3]) < 0) {
            fprintf(stderr, "Line %d: Unable to add default route for interface %s: %s\n",
                lineno, argv[3], strerror(errno));

            goto error_daemon_route_add;
        }
    } else if (strcmp(argv[1], "station") == 0) {
        if (argc < 7 || strcmp(argv[3], "if") != 0 || strcmp(argv[5], "path") != 0) {
            fprintf(stderr, "Line %d: Invalid station route declaration\n",
                lineno);

            goto error_invalid_route;
        }

        if (patty_daemon_route_add(daemon,
                                   argv[4],
                                   argv[2],
                                   (const char **)&argv[6],
                                   argc - 6) < 0) {
            fprintf(stderr, "Line %d: Unable to add route for interface %s: %s\n",
                lineno, argv[4], strerror(errno));

            goto error_daemon_route_add;
        }
    } else {
        fprintf(stderr, "Line %d: Invalid route type '%s'\n",
            lineno, argv[1]);

        goto error_invalid_route;
    }

    return 0;

error_daemon_route_add:
error_invalid_route:
    return -1;
}

struct config_handler {
    const char *name;
    int (*func)(patty_daemon *, int, int, char **);
};

struct config_handler handlers[] = {
    { "sock",  handle_sock   },
    { "pid",   handle_pid    },
    { "if",    handle_if     },
    { "route", handle_route  },
    { NULL,   NULL           }
};

static int handle_config_line(patty_conf_file *file,
                              patty_list *line,
                              void *ctx) {
    patty_daemon *daemon = ctx;
    patty_list_item *item  = line->first;

    int argc   = (int)line->length,
        i      = 0,
        ret    = 0,
        lineno = 0;

    char **argv;

    if (!item) {
        return 0;
    }

    if ((argv = malloc((argc + 1) * sizeof(char *))) == NULL) {
        goto error_malloc_argv;
    }

    while (item) {
        patty_conf_token *token = item->value;

        if (lineno == 0) {
            lineno = token->lineno;
        }

        argv[i++] = token->text;

        item = item->next;
    }

    argv[argc] = NULL;

    for (i=0; handlers[i].name; i++) {
        if (strcmp(argv[0], handlers[i].name) == 0) {
            ret = handlers[i].func(daemon, lineno, argc, argv);

            goto done;
        }
    }

    fprintf(stderr, "Unknown configuration value '%s'\n", argv[0]);

done:
    free(argv);

    return ret;

error_malloc_argv:
    return -1;
}

static int handle_simple_config(patty_daemon *daemon,
                                int argc,
                                char *argv0,
                                char **argv) {
    patty_ax25_if *iface;
    patty_ax25_addr addr;

    patty_kiss_tnc_info info = {
        .flags  = PATTY_KISS_TNC_DEVICE,
        .device = argv[2] 
    };

    int i;

    for (i=3; i<argc; i++) {
        if (strcmp(argv[i], "crtscts") == 0) {
            info.flags |= PATTY_KISS_TNC_FLOW;
            info.flow   = PATTY_KISS_TNC_FLOW_CRTSCTS;
        } else if (strcmp(argv[i], "xonxoff") == 0) {
            info.flags |= PATTY_KISS_TNC_FLOW;
            info.flow   = PATTY_KISS_TNC_FLOW_XONXOFF;
        } else if (argv[i][0] >= '0' && argv[i][0] <= '9') {
            int baud = atoi(argv[i]);

            info.flags |= PATTY_KISS_TNC_BAUD;
            info.baud   = baud;
        } else {
            fprintf(stderr, "%s: Invalid device setting '%s'\n",
                argv0, argv[i]);

            goto error_invalid_device_setting;
        }
    }

    if (patty_daemon_set_sock_path(daemon, argv[0]) < 0) {
        fprintf(stderr, "%s: Unable to set socket path to %s: %s\n",
            argv0, argv[0], strerror(errno));

        goto error_set_sock_path;
    }

    if (patty_ax25_pton(argv[1], &addr) < 0) {
        fprintf(stderr, "%s: Invalid callsign '%s'\n",
            argv0, argv[1]);

        goto error_invalid_callsign;
    }

    if ((iface = patty_ax25_if_new(PATTY_AX25_IF_KISS_TNC,
                                   DEFAULT_IFNAME,
                                   &info,
                                   &addr)) == NULL) {
        fprintf(stderr, "%s: Unable to create network interface %s: %s\n",
            argv0, DEFAULT_IFNAME, strerror(errno));

        goto error_if_new;
    } else {
        int fd = patty_kiss_tnc_fd(iface->tnc);
        char *pty;

        if (isatty(fd) && (pty = ptsname(fd)) != NULL) {
            printf("if %s pty %s\n", DEFAULT_IFNAME, pty);
        }
    }

    if (patty_daemon_if_add(daemon, iface) < 0) {
        fprintf(stderr, "%s: Unable to add interface %s: %s\n",
            argv0, DEFAULT_IFNAME, strerror(errno));

        goto error_daemon_if_add;
    }

    if (patty_daemon_route_add_default(daemon, DEFAULT_IFNAME) < 0) {
        fprintf(stderr, "%s: Unable to add default route to %s: %s\n",
            argv0, DEFAULT_IFNAME, strerror(errno));

        goto error_daemon_route_add_default;
    }

    return 0;

error_daemon_route_add_default:
error_daemon_if_add:
error_if_new:
error_invalid_callsign:
error_invalid_device_setting:
error_set_sock_path:
    return -1;
}

enum flags {
    FLAG_FG,
    FLAG_STANDALONE,
    FLAG_COUNT
};

int main(int argc, char **argv) {
    int ret = 0,
        index,
        ch,
        flags[FLAG_COUNT];

    struct option opts[] = {
        { "fg",         no_argument,       &flags[FLAG_FG],          1  },
        { "config",     required_argument, NULL,                    'c' },
        { "standalone", no_argument,       &flags[FLAG_STANDALONE],  1  },
        { NULL,         no_argument,       NULL,                     0  }
    };

    char *config_file = DEFAULT_CONFIG_FILE;

    patty_daemon *daemon;

    memset(flags, '\0', sizeof(flags));

    if ((daemon = patty_daemon_new()) == NULL) {
        fprintf(stderr, "%s: %s: %s\n",
            argv[0], "patty_daemon_new()", strerror(errno));

        goto error_daemon_new;
    }

    while ((ch = getopt_long(argc, argv, "fc:s", opts, &index)) >= 0) {
        switch (ch) {
            case '?':
                ret = usage(argc, argv, NULL);
                goto error_invalid_args;

            case 'c':
                config_file = optarg;
                break;

            case 's':
                flags[FLAG_STANDALONE] = 1;
                break;

            default:
                break;
        }
    }

    if (flags[FLAG_STANDALONE]) {
        if (argc - optind < 1) {
            ret = usage(argc, argv, "No socket path provided");

            goto error_config;
        } else if (argc - optind < 2) {
            ret = usage(argc, argv, "No device path provided");

            goto error_config;
        } else if (argc - optind < 3) {
            ret = usage(argc, argv, "No callsign provided");

            goto error_config;
        }

        if (handle_simple_config(daemon,
                                 argc - optind,
                                 argv[0],
                                 argv + optind) < 0) {
            goto error_config;
        }
    } else if (patty_conf_read(config_file, handle_config_line, daemon) < 0) {
        if (errno) {
            fprintf(stderr, "%s: %s: %s: %s\n",
                argv[0], "patty_conf_read()", config_file, strerror(errno));
        }

        goto error_config;
    }

    if (patty_daemon_run(daemon) < 0) {
        fprintf(stderr, "%s: %s: %s\n",
            argv[0], "patty_daemon_run()", strerror(errno));

        goto error_daemon_run;
    }

    patty_daemon_destroy(daemon);

    return 0;

error_daemon_run:
error_config:
error_invalid_args:
    patty_daemon_destroy(daemon);

error_daemon_new:
    return ret;
}