#include <string.h>

#include <macros.h>
#include <constants.h>
#include <mongoose.h>
#include <logger.h>
#include <router.h>
#include <handlers.h>

#define HEADERS_FMT "Content-Type: %s"

// -2 for "%s" -1 for \0
#define HEADERS_FMT_LEN (sizeof(HEADERS_FMT) - 3)

static char*
add_extra_headers(char *extra_headers)
{
    char *result;
    size_t std_headers_len = strlen(global_config.http_server_opts.extra_headers);
    if(extra_headers == NULL)
    {
        result = malloc(sizeof(char) * (std_headers_len + 1));
        strcpy(result, global_config.http_server_opts.extra_headers);
        return result;
    }

    result = malloc(sizeof(char) * (std_headers_len + strlen(extra_headers) + 3));
    sprintf(result, "%s\r\n%s", global_config.http_server_opts.extra_headers, extra_headers);
    return result;
}

static void
send_response(struct mg_connection *nc, endpoint_response_t *response)
{
    if(response->status_code)
    {
        char *response_headers = malloc(sizeof(char) * (HEADERS_FMT_LEN + strlen(response->content_type) + 1));
        sprintf(response_headers, HEADERS_FMT, response->content_type);

        char *extra_headers = add_extra_headers(response_headers);
        mg_send_head(nc, response->status_code, response->content_length, extra_headers);
        mg_printf(nc, "%s", response->content);

        free(response_headers);
        free(extra_headers);

        if(response->alloced_content)
        {
            free((char*)response->content);
        }
    }
}

void
handler_connection(struct mg_connection *nc, int ev, void *p)
{
    if (ev == MG_EV_HTTP_REQUEST)
    {
        struct http_message *hm = (struct http_message *) p;
        LOG_TRACE("new http %.*s request for %.*s\n", hm->method.len, hm->method.p, hm->uri.len, hm->uri.p);

        endpoint_t *endpoint = router_find_endpoint(hm->uri.p, hm->uri.len, &hm->method);

        endpoint_response_t response;
        static const char content[] = "the server did not create a response";
        endpoint_response_text(&response, 500, content, STRLEN(content));

        if(!endpoint)
        {
            /* Normalize path - resolve "." and ".." (in-place). */
            if (!mg_normalize_uri_path(&hm->uri, &hm->uri)) {
                mg_http_send_error(nc, 400, global_config.http_server_opts.extra_headers);
                return;
            }
            char *request_file_org = malloc(sizeof(char) * hm->uri.len);
            strncpy(request_file_org, hm->uri.p + 1, hm->uri.len);
            request_file_org[hm->uri.len - 1] = '\0';

            char *request_file = request_file_org;
            while(request_file[0] == '/')
            {
                ++request_file;
            }

            LOG_DEBUG("%s\n", request_file);
            int access_result = access(request_file, R_OK);
            free(request_file_org);
            if(access_result != -1)
            {
                response.status_code = 0;
                mg_serve_http(nc, hm, global_config.http_server_opts);
                return;
            }
            else
            {
                endpoint = router_get_not_found_endpoint();
            }
        }

        if(!endpoint->func)
        {
            if(endpoint->method == HTTP_METHOD_OPTIONS)
            {
                char options_header[256]; // TODO make more generic
                sprintf(options_header, "Allow: OPTIONS%s%s%s%s",
                        endpoint->options & HTTP_METHOD_GET ? ", GET" : "",
                        endpoint->options & HTTP_METHOD_POST ? ", POST" : "",
                        endpoint->options & HTTP_METHOD_PUT ? ", PUT" : "",
                        endpoint->options & HTTP_METHOD_DELETE ? ", DELETE" : ""
                       );
                char *extra_headers = add_extra_headers(options_header);
                mg_send_head(nc, 204, 0, extra_headers);
                free(extra_headers);
            }
            else
            {
                mg_send_head(nc, 501, 0, "Content-Type: text/plain");
            }
        }
        else
        {
            endpoint->func(nc, hm, endpoint->args, &response);
            send_response(nc, &response);
        }

        for(int i = 0; i < endpoint->args_count; ++i)
        {
            if(endpoint->args[i].type == ENDPOINT_ARG_TYPE_STR)
            {
                free((char*)endpoint->args[i].value.v_str);
            }
        }
    }
}