#include <microhttpd.h>
#include <sha256.h>
#define NOH_IMPLEMENTATION
#include "noh.h"

#define NO_AUTH
/* To disable Basic auth for testing:
#define NO_AUTH
This will ignore any auth headers and always log in with username demo.
*/

#define SV Noh_String_View
#define sv noh_sv_from_cstr

static enum MHD_Result send_response(struct MHD_Connection *connection, int status, SV message) {
    struct MHD_Response *response = MHD_create_response_from_buffer(
        message.count, (void*)message.elems, MHD_RESPMEM_PERSISTENT);
    if (!response) return MHD_NO;

    enum MHD_Result ret = MHD_queue_response(connection, status, response);
    MHD_destroy_response(response);
    return ret;
}

static enum MHD_Result handle_opds(struct MHD_Connection *connection, SV url, SV base_path, SV username) {
    Noh_String fs_path = {0};
    noh_string_append_sv(&fs_path, base_path);
    noh_string_append_cstr(&fs_path, "/");
    noh_string_append_sv(&fs_path, username);
    noh_string_append_cstr(&fs_path, "/");
    noh_string_append_sv(&fs_path, url);

    noh_log(NOH_INFO, "Physical path: "Nsv_Fmt, Nsv_Arg(fs_path));
    return send_response(connection, 200, sv("TODO: OPDS\n"));
}

static enum MHD_Result handle_get(struct MHD_Connection *connection, SV url, SV base_path, SV username) {
    (void)url;
    (void)username;
    (void)base_path;
    return send_response(connection, 200, sv("TODO: Get\n"));
}

bool is_slash(const char c) { return c == '/'; }

static enum MHD_Result request_handler(
        void *cls,
        struct MHD_Connection *connection,
        const char *_url, const char *method, const char *version,
        const char *upload_data, size_t *upload_data_size,
        void **con_cls) {
    (void)con_cls; (void)upload_data; (void)upload_data_size;
    SV base_path = *(SV*)cls;

    noh_log(NOH_INFO, "Request: %s %s %s", version, method, _url);

    SV username;
#ifdef NO_AUTH
    username = sv("demo");
#else
    struct MHD_BasicAuthInfo  *auth = MHD_basic_auth_get_username_password3(connection);
    if (!auth) return send_response(connection, 401, sv(""));

    username = (SV){ .elems = auth->username, .count = auth->username_len };
    SV password = { .elems = auth->password, .count = auth->password_len };

    // TODO: Read username from user config.
    if (!noh_sv_eq(password, sv("jaja"))) return send_response(connection, 401, sv(""));
#endif

    noh_log(NOH_INFO, "Authenticated as "Nsv_Fmt, Nsv_Arg(username));

    if (strcmp(method, "GET") != 0) return send_response(connection, 405, sv(""));

    SV url = sv(_url);
    noh_sv_trim_left(&url, is_slash);
    SV controller = noh_sv_chop_by_delim(&url, '/');

    if (noh_sv_eq_ci(controller, sv("opds"))) return handle_opds(connection, url, base_path, username);
    if (noh_sv_eq_ci(controller, sv("get"))) return handle_get(connection, url, base_path, username);
    return send_response(connection, 404, sv(""));
}

void show_usage(char *program_name, char *error) {
    noh_log(NOH_INFO, "Usage:");
    noh_log(NOH_INFO, "%s port library_path", program_name);
    noh_log(NOH_INFO, "  port: The port to listen to, between 1000 and 65535.");
    noh_log(NOH_INFO, "  library_path: The path where the epub libraries are located.");
    noh_log(NOH_INFO, "              The root of this path should have a users.txt file with the usernames and passwords of valid users.");
    noh_log(NOH_INFO, "              For each user, ther must be a subdirectory where this user's library is located.");
    noh_log(NOH_INFO, "");
    noh_log(NOH_ERROR, "%s", error);
    exit(1);
}

int main(int argc, char **argv)
{
    // Parse input parameters.
    char *program_name = noh_shift_args(&argc, &argv);

    if (argc < 1) show_usage(program_name, "Port not provided.");
    char *port_str = noh_shift_args(&argc, &argv);

    int port = atoi(port_str);
    if (port < 1000 || port > 65535) show_usage(program_name, "Invalid port.");

    if (argc < 1) show_usage(program_name, "Library path not provided.");
    char *library_path = noh_shift_args(&argc, &argv);
    SV base_path = sv(library_path);

    struct MHD_Daemon *server;

    // Start the HTTP server
    server = MHD_start_daemon(
        MHD_USE_INTERNAL_POLLING_THREAD,
        port,
        NULL, NULL,
        &request_handler, &base_path,
        MHD_OPTION_END);

    if (!server) {
        fprintf(stderr, "Failed to start server\n");
        return 1;
    }

    printf("Server is running on http://0.0.0.0:%d\n", port);

    // Keep the server running
    getchar();

    // Stop the server
    MHD_stop_daemon(server);

    return 0;
}