#define _POSIX_C_SOURCE 200809L
#include <err.h>
#include <jansson.h>
#include <string.h>
#include "app.h"
#include "http.h"
#include "log.h"

#define CLIENT_NAME "ap_client"
#define REGISTER_URL "https://%s/api/v1/apps"

static char *get_register_url(const char *domain)
{
    char *url;
    size_t size;

    size = strlen(REGISTER_URL) + strlen(domain) - 1;
    url = malloc(size);
    if (!url) {
        err(1, NULL);
        return NULL;
    }

    sprintf(url, REGISTER_URL, domain);
    return url;
}

static char *get_register_req()
{
    char *req;
    json_t *json_root;

    json_root = json_pack_ex(NULL, 1, "{s:s, s:s, s:s}", "client_name",
            CLIENT_NAME, "redirect_uris", "urn:ietf:wg:oauth:2.0:oob", "scopes",
            "read write push");
    if (!json_root) {
        return NULL;
    }

    req = json_dumps(json_root, 0);
    json_decref(json_root);

    return req;
}

static struct gs_app *get_register_resp(const char *data)
{
    struct gs_app *resp;
    json_t *json_root;
    json_t *cid, *csec;

    json_root = json_loads(data, 0, NULL);
    if (!json_root) {
        return NULL;
    }

    if (!json_is_object(json_root)) {
        json_decref(json_root);
        return NULL;
    }

    cid = json_object_get(json_root, "client_id");
    csec = json_object_get(json_root, "client_secret");
    if (!json_is_string(cid) || !json_is_string(csec)) {
        json_decref(json_root);
        return NULL;
    }

    resp = calloc(1, sizeof(struct gs_app));
    resp->client_id = strdup(json_string_value(cid));
    resp->client_secret = strdup(json_string_value(csec));

    json_decref(json_root);
    return resp;
}

struct gs_app *gs_app_register(const char *domain)
{
    char *url, *req_data, *resp_data;
    struct gs_app *resp;

    if (!domain || !*domain) {
        gs_log(GS_WARNING, "gs_app_register", "invalid argument");
        return NULL;
    }

    url = get_register_url(domain);
    if (!url) {
        gs_log(GS_WARNING, "gs_app_register", "invalid argument");
        return NULL;
    }

    req_data = get_register_req();
    if (!req_data) {
        free(url);
        return NULL;
    }

    resp_data = gs_http_post(url, NULL, req_data);
    free(url);
    free(req_data);
    if (!resp_data) {
        gs_log(GS_WARNING, "gs_app_register", "register request failed");
        return NULL;
    }

    resp = get_register_resp(resp_data);
    free(resp_data);
    if (!resp) {
        gs_log(GS_WARNING, "gs_app_register", "invalid response");
        return NULL;
    }

    return resp;
}