#include "mongoose.h"
#include "index.h"
#include "gsl.h"
#include "agsl.h"
#include "lgsl.h"
#include "clauses.h"

#include <string.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <locale.h>

char *port = "33368"; // sneed, backwards, in phone number, with the last number changed to 8 cuz sneedmc.org is already on 33367

void trim(char *str) {
    char *_str = str;
    int len = strlen(_str);

    while(*_str && *_str == '/') ++_str, --len;

    memmove(str, _str, len + 1);
}

// I stole this directly from stack overflow.
char** str_split(char* a_str, const char a_delim)
{
    char** result    = 0;
    size_t count     = 0;
    char* tmp        = a_str;
    char* last_comma = 0;
    char delim[2];
    delim[0] = a_delim;
    delim[1] = 0;

    /* Count how many elements will be extracted. */
    while (*tmp)
    {
        if (a_delim == *tmp)
        {
            count++;
            last_comma = tmp;
        }
        tmp++;
    }

    /* Add space for trailing token. */
    count += last_comma < (a_str + strlen(a_str) - 1);

    /* Add space for terminating null string so caller
       knows where the list of returned strings ends. */
    count++;

    result = malloc(sizeof(char*) * count);

    if (result)
    {
        size_t idx  = 0;
        char* token = strtok(a_str, delim);

        while (token)
        {
            assert(idx < count);
            *(result + idx++) = strdup(token);
            token = strtok(0, delim);
        }
        assert(idx == count - 1);
        *(result + idx) = 0;
    }

    return result;
}

int arrlen(char **a_arr) {
    int count = 0;
    while (a_arr[count] != NULL) count++;
    return count;
}

// compare N chars of s1 to s2
bool eq(const char *s1, const char *s2, int n) {
    return strncmp(s1, s2, n) == 0;
}

void handle_url_req(struct mg_connection *nc, char *host, char *link) {
    char *a_host = strdup(host);
    char **host_elements = str_split(a_host, '.');

    free(a_host);

    if (arrlen(host_elements) == 3) {
        // FIXME: index.html goes here.
        return mg_http_reply(nc, 200, "Content-Type: text/html\r\n", "%s\r\n", INDEX_HTML);
    }

    char *b_host = strdup(host_elements[0]);
    char **host_clauses = str_split(b_host, '-');

    free(b_host);

    size_t startclause = 18;
    char *license;
    if (eq(host_elements[0], "gsl", 3)) {
        license = strdup(GSL);
    } else if (eq(host_elements[0], "agsl", 4)) {
        license = strdup(AGSL);
    } else if (eq(host_elements[0], "lgsl", 4)) {
        license = strdup(LGSL);
        startclause = 7;
    } else {
        mg_http_reply(nc, 404, "", "Not Found");
    }

    int clausenum = startclause;

    char *jogger = malloc(strlen(JOGGER_NOTICE) + 2);
    char *farmer = malloc(strlen(FARMER_NOTICE) + 2);
    char *dwarf = malloc(strlen(DWARF_NOTICE) + 2);
    char *output_clauses[3] = {"", "", ""};

    bool jogger_shown = false;
    bool farmer_shown = false;
    bool dwarf_shown = false;
    if (arrlen(host_clauses) > 1) {
        for (size_t i = 0; i < strlen(host_clauses[1]); i++) {
            if (host_clauses[1][i] == 'n' && !jogger_shown) {
                snprintf(jogger, strlen(JOGGER_NOTICE) + 2, JOGGER_NOTICE, clausenum);
                output_clauses[clausenum - startclause] = jogger;
                clausenum++;
                jogger_shown = true;
            } else if (host_clauses[1][i] == 'd' && !dwarf_shown) {
                snprintf(dwarf, strlen(DWARF_NOTICE) + 2, DWARF_NOTICE, clausenum);
                output_clauses[clausenum - startclause] = dwarf;
                clausenum++;
                dwarf_shown = true;
            } else if (host_clauses[1][i] == 'f' && !farmer_shown) {
                snprintf(farmer, strlen(FARMER_NOTICE) + 2, FARMER_NOTICE, clausenum);
                output_clauses[clausenum - startclause] = farmer;
                clausenum++;
                farmer_shown = true;
            } else {
                continue;
            }
        }
    }

    mg_http_reply(nc, 200, "Content-Type: text/plain; charset=utf-8\r\n", license, output_clauses[0], output_clauses[1], output_clauses[2], host);

    free(host_elements);
    free(host_clauses);

    free(jogger);
    free(dwarf);
    free(farmer);
}

static void ev_handler(struct mg_connection *nc, int ev, void *p, void *f) {
    if (ev == MG_EV_HTTP_MSG) {
        struct mg_http_message *hm = (struct mg_http_message *) p;
        char *uri = malloc(hm->uri.len + 1);

        snprintf(uri, hm->uri.len + 1, "%s", hm->uri.ptr);
        trim(uri);

        // Host parsing here.
        struct mg_str *pmhost = mg_http_get_header(hm, "Host");
        struct mg_str mhost;
        if (pmhost == NULL) {
            fprintf(stderr, "request sent with no Host header");
            free(uri);
            mg_http_reply(nc, 400, "", "Please include a Host header.");
            return;
        }

        mhost = *pmhost;
        char *host = malloc(mhost.len + 1);
        snprintf(host, mhost.len + 1, "%s", mhost.ptr);

        if (strncmp(hm->method.ptr, "GET", hm->method.len) == 0){
            if (eq(uri, "favicon.ico", 12) || eq(uri, "sneedcube.png", 14)) {
                struct mg_http_serve_opts opts = {.root_dir = "/srv/gsl"};   // Serve local dir
                if (ev == MG_EV_HTTP_MSG) mg_http_serve_dir(nc, p, &opts);
                return;
            }
            handle_url_req(nc, host, uri);
        } else {
            mg_http_reply(nc, 405, "Allow: GET\r\n", "");
        }
        free(uri);
        free(host);
    }
}

int main(int argc, char *argv[]) {
    setlocale(LC_CTYPE, "");
    int index;
    int c;

    opterr = 0;
    setvbuf(stdout, NULL, _IONBF, 0);

    while ((c = getopt (argc, argv, "p:h")) != -1) {
        switch (c) {
        case 'p':
            port = optarg;
            break;
        case 'h':
            printf("gsl: host the GSL licenses\n");
            printf("usage: %s [-p port]\n\n", argv[0]);
            printf("options:\n");
            printf("-p <port>\t\tport to use (default 33368)\n");
            printf("source: https://git.sneedmc.org/sneederix/gsl");
            return 0;
        case '?':
            if (optopt == 'p') {
                fprintf(stderr, "Option -%c requires an argument.\n", optopt);
            }
            else if (isprint (optopt)) {
                fprintf(stderr, "Unknown option `-%c'.\n", optopt);
            }
            else {
                fprintf(stderr, "Unknown option character `\\x%x'.\n", optopt);
            }
            return 1;
        default:
            abort();
        }
    }

    for (index = optind; index < argc; index++) {
        printf ("Non-option argument %s\n", argv[index]);
    }

    struct mg_mgr mgr;
    struct mg_connection *nc;

    mg_mgr_init(&mgr);
    printf("Starting web server on port %s\n", port);
    char *str_port = malloc(20);
    sprintf(str_port, "http://0.0.0.0:%s", port);
    nc = mg_http_listen(&mgr, str_port, ev_handler, &mgr);
    if (nc == NULL) {
        printf("Failed to create listener\n");
        return 1;
    }

    for (;;) { mg_mgr_poll(&mgr, 1000); }
    mg_mgr_free(&mgr);
    return 0;
}