#include <libgen.h>
#include <pthread.h>
#include <ftw.h>
#include <signal.h>
#include <sys/sendfile.h>

#define GEBS_IMPLEMENTATION
#include "gebs/gebs.h"
#include "mongoose/mongoose.h"
#define STB_DS_IMPLEMENTATION
#include "stb/stb_ds.h"

#include "routes.h"
#include "baked.h"
#include "timer.h"
#include "CONFIG.h"
#include "clonestr.h"
#include "locked.h"

static locked(Route *) route_hashtable = locked_init(nil);
static locked(char *)  baked_dump_path   = locked_init(nil);

void run_in_thread(void *(*f)(void *), void *p)
{
    pthread_t tid = 0;
    pthread_attr_t attr;
    pthread_attr_init(&attr);
    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
    pthread_create(&tid, &attr, f, p);
    pthread_attr_destroy(&attr);
}

void *route_thread_function(void *param)
{
    Route_Thread_Data *data = (Route_Thread_Data *)param;

    struct mg_http_message http_msg = {0};
    int r = mg_http_parse(data->message.buf, data->message.len, &http_msg);
    if (r <= 0) {
        Route_Result result = {0};
        result.status_code = 400;
        result.type = ROUTE_RESULT_DYNAMIC;
        /* list_append(&result.headers, clonestr("Content-Type: text/plain")); */
        sb_append_nstr(&result.body, "Could not parse HTTP request");
        sb_finish(&result.body);
        mg_wakeup(data->mgr, data->conn_id, &result, sizeof(result));
        free(data->message.buf);
        free(data);
        return nil;
    }

    if (mg_match(http_msg.uri, mg_str("/bakedres/*"), nil)) {
        Route_Result result = {0};
        result.type = ROUTE_RESULT_STATIC;

        char *p = malloc(http_msg.uri.len+1);
        strncpy(p, http_msg.uri.buf, http_msg.uri.len);
        p[http_msg.uri.len] = 0;

        char *file = basename(p);
        char *full_path = malloc(PATH_MAX);

        lockx(&baked_dump_path);
        snprintf(full_path, PATH_MAX, "%s/%s", baked_dump_path.value, file);
        unlockx(&baked_dump_path);

        sb_append_nstr(&result.body, full_path);
        sb_finish(&result.body);
        free(full_path);
        free(p);
        mg_wakeup(data->mgr, data->conn_id, &result, sizeof(result));
        free(data->message.buf);
        free(data);
        return nil;
    }

    char key[MG_PATH_MAX] = {0};
    strncpy(key, http_msg.uri.buf, http_msg.uri.len);
    lockx(&route_hashtable);
    ssize_t idx = shgeti(route_hashtable.value, key);

    Route_Result result = {0};
    route_hashtable.value[idx].value(&http_msg, &result, route_hashtable.value[idx].context_data);
    unlockx(&route_hashtable);
    mg_wakeup(data->mgr, data->conn_id, &result, sizeof(result));

    free(data->message.buf);
    free(data);

    return nil;
}

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;

        Route_Thread_Data *data = calloc(1, sizeof(*data));
        data->message = mg_strdup(msg->message);
        data->conn_id = conn->id;
        data->mgr = conn->mgr;
        run_in_thread(&route_thread_function, data);
    } else if (ev == MG_EV_WAKEUP) {
        struct mg_str *data = (struct mg_str *)ev_data;
        Route_Result *result = (Route_Result *)data->buf;
        defer {
            for (size_t i = 0; i < result->headers.count; i++) {
                free(result->headers.items[i]);
            }
            list_free(&result->headers);
            sb_free(&result->body);
        }
    
        Gebs_String_Builder sb = {0};
        defer { sb_free(&sb); }
        nsl_join(&result->headers, &sb, "\r\n");
        if (result->headers.count > 0) {
            sb_append_nstr(&sb, "\r\n");
        }
        sb_finish(&sb);

        if (result->type == ROUTE_RESULT_DYNAMIC) {
            mg_http_reply(conn, result->status_code, sb.items, "%s", result->body.items);
        } else if (result->type == ROUTE_RESULT_STATIC) {
            char *path = result->body.items;
            mg_http_serve_file(conn, ev_data, path, &(struct mg_http_serve_opts){0});
        }
    }
}


void route_hashtable_put_blogs(Baked_Resource *resource, void *udata)
{
    if ((strlen(resource->key) >= strlen("blog-"))
     && strncmp(resource->key, "blog-", strlen("blog-")) == 0) {
        char *path = malloc(MG_PATH_MAX);
        snprintf(path, MG_PATH_MAX, "/%s", resource->key);
        shput(route_hashtable.value, path, &route_generic_blog);
        route_hashtable.value[shgeti(route_hashtable.value, path)].context_data = (void *)resource;
    }
}

void init_route_hashtable(void)
{
    lockx(&route_hashtable);
    shdefault(route_hashtable.value, &route_page_not_found);
    shput(route_hashtable.value,    clonestr("/"),              &route_home);
    shput(route_hashtable.value,    clonestr("/page-missing"),  &route_page_not_found);
    shput(route_hashtable.value,    clonestr("/blog"),          &route_blog);
#if MY_DEBUG
    shput(route_hashtable.value,    clonestr("/build-id"),      &route_build_id);
#endif

    baked_resource_each(&route_hashtable_put_blogs, nil);
    unlockx(&route_hashtable);
}

void free_route_hashtable(void)
{
    lockx(&route_hashtable);
    for (size_t i = 0; i < shlen(route_hashtable.value); i++) {
        free(route_hashtable.value[i].key);
    }
    shfree(route_hashtable.value);
    unlockx(&route_hashtable);
}

char *init_baked_dump(void)
{
    char template[] = "/tmp/aboba-bakedres.XXXXXX";
    char *baked_dump1 = mkdtemp(template);
    char *baked_dump = malloc(strlen(baked_dump1)+1);
    strcpy(baked_dump, baked_dump1);

    if (baked_dump == nil) {
        LOGE("Could not create bakedres dump\n");
        return nil;
    }
    LOGI("bakedres dump dir is %s\n", baked_dump);

    return baked_dump;
}

int baked_dump_rm_cb(const char *path,
                   discard const struct stat *st,
                   discard int type,
                   discard struct FTW *ftw)
{
    return remove(path);
}

bool free_baked_dump(char *baked_dump)
{
    LOGI("Removing bakedres dump %s\n", baked_dump);
    bool ok = nftw(baked_dump, baked_dump_rm_cb, FOPEN_MAX, FTW_DEPTH | FTW_MOUNT | FTW_PHYS) != -1;
    if (!ok) {
        LOGE("Could not remove %s\n", baked_dump);
    }
    free(baked_dump);
    return ok;
}

// https://stackoverflow.com/questions/2180079/how-can-i-copy-a-file-on-unix-using-c
int cp(const char* source, const char* destination)
{
    int result = 0;
    int input, output;
    if ((input = open(source, O_RDONLY)) == -1)
    {
        return -1;
    }
    if ((output = creat(destination, 0660)) == -1)
    {
        close(input);
        return -1;
    }

    // sendfile will work with non-socket output (i.e. regular file) under
    // Linux 2.6.33+ and some other unixy systems.
    struct stat file_stat = {0};
    result = fstat(input, &file_stat);
    off_t copied = 0;
    while (result == 0 && copied < file_stat.st_size) {
        ssize_t written = sendfile(output, input, &copied, SSIZE_MAX);
        copied += written;
        if (written == -1) {
            result = -1;
        }
    }

    close(input);
    close(output);

    return result;
}

void copy_baked_resources_to_baked_dump(Baked_Resource *resource, void *udata)
{
    char *baked_dump = (char *)udata;
    char path[PATH_MAX];
    get_baked_resource_path(resource->key, path, sizeof(path));
    char dest[PATH_MAX];
    snprintf(dest, sizeof(dest), "%s/%s", baked_dump, resource->key);
    cp(path, dest);
}

void populate_baked_dump(char *baked_dump)
{
    lock_baked_resources();
    baked_resource_each(&copy_baked_resources_to_baked_dump, baked_dump);
    unlock_baked_resources();
}

volatile bool alive = true;

void graceful_shutdown(int no) { alive = false; }

int main(int argc, char ** argv)
{
    signal(SIGINT, &graceful_shutdown);
    start_timer();

    init_baked_resources();
    lockx(&baked_dump_path);
    if ((baked_dump_path.value = init_baked_dump()) == nil) {
        return 1;
    }
    populate_baked_dump(baked_dump_path.value);
    unlockx(&baked_dump_path);

    mg_log_set(MG_LL_DEBUG);
    struct mg_mgr mgr;
    mg_mgr_init(&mgr);
    init_route_hashtable();
    defer { free_route_hashtable(); }

    mg_wakeup_init(&mgr);
    mg_http_listen(&mgr, CONFIG_LISTEN_URL, &event_handler, NULL);

    while (alive) {
        mg_mgr_poll(&mgr, 1000);
        scratch_arena_reset();
    }
    
    mg_mgr_free(&mgr);

    lockx(&baked_dump_path);
    free_baked_dump(baked_dump_path.value);
    unlockx(&baked_dump_path);
    free_baked_resources();

    return 0;
}