#include <libgen.h>
#define GEBS_NO_PREFIX
#define GEBS_IMPLEMENTATION
#include "gebs/gebs.h"
#include "mongoose/mongoose.h"
#define STB_DS_IMPLEMENTATION
#include "stb/stb_ds.h"

typedef void (*Route_Handler)(struct mg_connection *conn, struct mg_http_message *msg);

typedef struct {
    char *key; // path
    Route_Handler value;
} Route;

Route *route_hashtable = NULL;

void event_handler(struct mg_connection *conn, int ev, void *ev_data)
{
    if (ev == MG_EV_HTTP_MSG) {
        struct mg_http_message *msg = (struct mg_http_message *)ev_data;

        char key[MG_PATH_MAX] = {0};
        strncpy(key, msg->uri.buf, msg->uri.len);
        Route_Handler handler = shget(route_hashtable, key);
        handler(conn, msg);
    }
}

bool gpp1(char *path, NString_List *env, String_Builder *out)
{
    Cmd cmd = {0};
    defer { cmd_free(&cmd); }

    cmd_append(&cmd, "./gpp1");
    cmd_append(&cmd, "-H");
    cmd_append(&cmd, "-x");
    cmd_append(&cmd, "--nostdinc");
    cmd_append(&cmd, path);

    for (size_t i = 0; i < env->count; i++) {
        cmd_append(&cmd, env->items[i]);
    }

    return cmd_run_collect(&cmd, out) == 0;
}

void handle_page_not_found(struct mg_connection *conn, struct mg_http_message *msg)
{
    NString_List env = {0};
    defer { list_free(&env); }

    list_append(&env, fmt("-DURL=%.*s", msg->uri.len, msg->uri.buf));

    String_Builder out = {0};
    defer { sb_free(&out); }
    bool ok = gpp1("./tmpls/page-missing.t", &env, &out);
    sb_finish(&out);

    if (!ok) {
        mg_http_reply(conn, 500, "Content-Type: text/html\r\n", "Internal server error ;(");
    } else {
        mg_http_reply(conn, 200, "Content-Type: text/html\r\n", out.items);
    }
}

void handle_simple_css(struct mg_connection *conn, struct mg_http_message *msg)
{
    struct mg_http_serve_opts opts = { 0 };
    mg_http_serve_file(conn, msg, "./assets/simple.min.css", &opts);
}

void handle_favicon(struct mg_connection *conn, struct mg_http_message *msg)
{
    struct mg_http_serve_opts opts = { 0 };
    mg_http_serve_file(conn, msg, "./assets/favicon.ico", &opts);
}

void handle_home(struct mg_connection *conn, struct mg_http_message *msg)
{
    NString_List env = {0};
    defer { list_free(&env); }

    String_Builder out = {0};
    defer { sb_free(&out); }
    bool ok = gpp1("./tmpls/index.t", &env, &out);
    sb_finish(&out);

    if (!ok) {
        mg_http_reply(conn, 500, "Content-Type: text/html\r\n", "Internal server error ;(");
    } else {
        mg_http_reply(conn, 200, "Content-Type: text/html\r\n", out.items);
    }
}

static void init_route_hashtable(void)
{
    shdefault(route_hashtable, &handle_page_not_found);
    shput(route_hashtable,      "/page-missing",        &handle_page_not_found);
    shput(route_hashtable,      "/simple.min.css",      &handle_simple_css);
    shput(route_hashtable,      "/favicon.ico",         &handle_favicon);
    shput(route_hashtable,      "/",                    &handle_home);
}

int main(int argc, char ** argv)
{
    mg_log_set(MG_LL_DEBUG);
    struct mg_mgr mgr;
    mg_mgr_init(&mgr);
    init_route_hashtable();

    mg_http_listen(&mgr, "http://localhost:8080", &event_handler, NULL);

    for (;;) {
        mg_mgr_poll(&mgr, 1000);
        scratch_arena_reset();
    }
    
    mg_mgr_free(&mgr);
    shfree(route_hashtable);

    return 0;
}