/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2026 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"
#include "../SDL_dialog_utils.h"

#include "../../core/linux/SDL_dbus.h"

#ifdef SDL_USE_LIBDBUS

#include <errno.h>
#include <libgen.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#define PORTAL_DESTINATION "org.freedesktop.portal.Desktop"
#define PORTAL_PATH "/org/freedesktop/portal/desktop"
#define PORTAL_INTERFACE "org.freedesktop.portal.FileChooser"

#define SIGNAL_SENDER "org.freedesktop.portal.Desktop"
#define SIGNAL_INTERFACE "org.freedesktop.portal.Request"
#define SIGNAL_NAME "Response"
#define SIGNAL_FILTER "type='signal', sender='"SIGNAL_SENDER"', interface='"SIGNAL_INTERFACE"', member='"SIGNAL_NAME"', path='"

#define HANDLE_LEN 10

#define WAYLAND_HANDLE_PREFIX "wayland:"
#define X11_HANDLE_PREFIX "x11:"

typedef struct {
    SDL_DialogFileCallback callback;
    void *userdata;
    const char *path;
} SignalCallback;

static void DBus_AppendStringOption(SDL_DBusContext *dbus, DBusMessageIter *options, const char *key, const char *value)
{
    DBusMessageIter options_pair, options_value;

    dbus->message_iter_open_container(options, DBUS_TYPE_DICT_ENTRY, NULL, &options_pair);
    dbus->message_iter_append_basic(&options_pair, DBUS_TYPE_STRING, &key);
    dbus->message_iter_open_container(&options_pair, DBUS_TYPE_VARIANT, "s", &options_value);
    dbus->message_iter_append_basic(&options_value, DBUS_TYPE_STRING, &value);
    dbus->message_iter_close_container(&options_pair, &options_value);
    dbus->message_iter_close_container(options, &options_pair);
}

static void DBus_AppendBoolOption(SDL_DBusContext *dbus, DBusMessageIter *options, const char *key, int value)
{
    DBusMessageIter options_pair, options_value;

    dbus->message_iter_open_container(options, DBUS_TYPE_DICT_ENTRY, NULL, &options_pair);
    dbus->message_iter_append_basic(&options_pair, DBUS_TYPE_STRING, &key);
    dbus->message_iter_open_container(&options_pair, DBUS_TYPE_VARIANT, "b", &options_value);
    dbus->message_iter_append_basic(&options_value, DBUS_TYPE_BOOLEAN, &value);
    dbus->message_iter_close_container(&options_pair, &options_value);
    dbus->message_iter_close_container(options, &options_pair);
}

static void DBus_AppendFilter(SDL_DBusContext *dbus, DBusMessageIter *parent, const SDL_DialogFileFilter filter)
{
    DBusMessageIter filter_entry, filter_array, filter_array_entry;
    char *state = NULL, *patterns, *pattern, *glob_pattern;
    int zero = 0;

    dbus->message_iter_open_container(parent, DBUS_TYPE_STRUCT, NULL, &filter_entry);
    dbus->message_iter_append_basic(&filter_entry, DBUS_TYPE_STRING, &filter.name);
    dbus->message_iter_open_container(&filter_entry, DBUS_TYPE_ARRAY, "(us)", &filter_array);

    /* Copy the filter string, converting to a case-insensitive version.
     * For example, for case-insensitive matching of '*.png', the pattern '*.[pP][nN][gG]' is used.
     */
    const size_t len = SDL_strlen(filter.pattern) + 1;
    patterns = SDL_malloc(len * 4); // Single characters may be expanded to 4 characters.
    if (!patterns) {
        goto cleanup;
    }
    for (size_t i = 0, p = 0; i < len; ++i) {
        if ((filter.pattern[i] >= 'a' && filter.pattern[i] <= 'z') ||
            (filter.pattern[i] >= 'A' && filter.pattern[i] <= 'Z')) {
            patterns[p++] = '[';
            patterns[p++] = SDL_tolower(filter.pattern[i]);
            patterns[p++] = SDL_toupper(filter.pattern[i]);
            patterns[p++] = ']';
        } else {
            patterns[p++] = filter.pattern[i];
        }
    }

    pattern = SDL_strtok_r(patterns, ";", &state);
    while (pattern) {
        size_t max_len = SDL_strlen(pattern) + 3;

        dbus->message_iter_open_container(&filter_array, DBUS_TYPE_STRUCT, NULL, &filter_array_entry);
        dbus->message_iter_append_basic(&filter_array_entry, DBUS_TYPE_UINT32, &zero);

        glob_pattern = SDL_calloc(max_len, sizeof(char));
        if (!glob_pattern) {
            goto cleanup;
        }
        glob_pattern[0] = '*';
        /* Special case: The '*' filter doesn't need to be rewritten */
        if (pattern[0] != '*' || pattern[1]) {
            glob_pattern[1] = '.';
            SDL_strlcat(glob_pattern + 2, pattern, max_len);
        }
        dbus->message_iter_append_basic(&filter_array_entry, DBUS_TYPE_STRING, &glob_pattern);
        SDL_free(glob_pattern);

        dbus->message_iter_close_container(&filter_array, &filter_array_entry);
        pattern = SDL_strtok_r(NULL, ";", &state);
    }

cleanup:
    SDL_free(patterns);

    dbus->message_iter_close_container(&filter_entry, &filter_array);
    dbus->message_iter_close_container(parent, &filter_entry);
}

static void DBus_AppendFilters(SDL_DBusContext *dbus, DBusMessageIter *options, const SDL_DialogFileFilter *filters, int nfilters)
{
    DBusMessageIter options_pair, options_value, options_value_array;
    static const char *filters_name = "filters";

    dbus->message_iter_open_container(options, DBUS_TYPE_DICT_ENTRY, NULL, &options_pair);
    dbus->message_iter_append_basic(&options_pair, DBUS_TYPE_STRING, &filters_name);
    dbus->message_iter_open_container(&options_pair, DBUS_TYPE_VARIANT, "a(sa(us))", &options_value);
    dbus->message_iter_open_container(&options_value, DBUS_TYPE_ARRAY, "(sa(us))", &options_value_array);
    for (int i = 0; i < nfilters; i++) {
        DBus_AppendFilter(dbus, &options_value_array, filters[i]);
    }
    dbus->message_iter_close_container(&options_value, &options_value_array);
    dbus->message_iter_close_container(&options_pair, &options_value);
    dbus->message_iter_close_container(options, &options_pair);
}

static void DBus_AppendByteArray(SDL_DBusContext *dbus, DBusMessageIter *options, const char *key, const char *value)
{
    DBusMessageIter options_pair, options_value, options_array;

    dbus->message_iter_open_container(options, DBUS_TYPE_DICT_ENTRY, NULL, &options_pair);
    dbus->message_iter_append_basic(&options_pair, DBUS_TYPE_STRING, &key);
    dbus->message_iter_open_container(&options_pair, DBUS_TYPE_VARIANT, "ay", &options_value);
    dbus->message_iter_open_container(&options_value, DBUS_TYPE_ARRAY, "y", &options_array);
    do {
        dbus->message_iter_append_basic(&options_array, DBUS_TYPE_BYTE, value);
    } while (*value++);
    dbus->message_iter_close_container(&options_value, &options_array);
    dbus->message_iter_close_container(&options_pair, &options_value);
    dbus->message_iter_close_container(options, &options_pair);
}

static DBusHandlerResult DBus_MessageFilter(DBusConnection *conn, DBusMessage *msg, void *data)
{
    SDL_DBusContext *dbus = SDL_DBus_GetContext();
    SignalCallback *signal_data = (SignalCallback *)data;

    if (dbus->message_is_signal(msg, SIGNAL_INTERFACE, SIGNAL_NAME) &&
        dbus->message_has_path(msg, signal_data->path)) {
        DBusMessageIter signal_iter, result_array, array_entry, value_entry, uri_entry;
        uint32_t result;
        size_t length = 2, current = 0;
        const char **path = NULL;

        dbus->message_iter_init(msg, &signal_iter);
        // Check if the parameters are what we expect
        if (dbus->message_iter_get_arg_type(&signal_iter) != DBUS_TYPE_UINT32) {
            goto not_our_signal;
        }
        dbus->message_iter_get_basic(&signal_iter, &result);

        if (result == 1 || result == 2) {
            // cancelled
            const char *result_data[] = { NULL };
            signal_data->callback(signal_data->userdata, result_data, -1); // TODO: Set this to the last selected filter
            goto done;

        } else if (result) {
            // some error occurred
            signal_data->callback(signal_data->userdata, NULL, -1);
            goto done;
        }

        if (!dbus->message_iter_next(&signal_iter)) {
            goto not_our_signal;
        }

        if (dbus->message_iter_get_arg_type(&signal_iter) != DBUS_TYPE_ARRAY) {
            goto not_our_signal;
        }

        dbus->message_iter_recurse(&signal_iter, &result_array);

        while (dbus->message_iter_get_arg_type(&result_array) == DBUS_TYPE_DICT_ENTRY) {
            const char *method;

            dbus->message_iter_recurse(&result_array, &array_entry);
            if (dbus->message_iter_get_arg_type(&array_entry) != DBUS_TYPE_STRING) {
                goto not_our_signal;
            }

            dbus->message_iter_get_basic(&array_entry, &method);
            if (!SDL_strcmp(method, "uris")) {
                // we only care about the selected file paths
                break;
            }

            if (!dbus->message_iter_next(&result_array)) {
                goto not_our_signal;
            }
        }

        if (!dbus->message_iter_next(&array_entry)) {
            goto not_our_signal;
        }

        if (dbus->message_iter_get_arg_type(&array_entry) != DBUS_TYPE_VARIANT) {
            goto not_our_signal;
        }
        dbus->message_iter_recurse(&array_entry, &value_entry);

        if (dbus->message_iter_get_arg_type(&value_entry) != DBUS_TYPE_ARRAY) {
            goto not_our_signal;
        }
        dbus->message_iter_recurse(&value_entry, &uri_entry);

        path = SDL_malloc(length * sizeof(const char *));
        if (!path) {
            signal_data->callback(signal_data->userdata, NULL, -1);
            goto done;
        }

        while (dbus->message_iter_get_arg_type(&uri_entry) == DBUS_TYPE_STRING) {
            const char *uri = NULL;

            if (current >= length - 1) {
                ++length;
                const char **newpath = SDL_realloc(path, length * sizeof(const char *));
                if (!newpath) {
                    signal_data->callback(signal_data->userdata, NULL, -1);
                    goto done;
                }
                path = newpath;
            }

            dbus->message_iter_get_basic(&uri_entry, &uri);

            // https://flatpak.github.io/xdg-desktop-portal/docs/doc-org.freedesktop.portal.FileChooser.html
            // Returned paths will always start with 'file://'; SDL_URIToLocal() truncates it.
            char *decoded_uri = SDL_malloc(SDL_strlen(uri) + 1);
            if (SDL_URIToLocal(uri, decoded_uri)) {
                path[current] = decoded_uri;
            } else {
                SDL_free(decoded_uri);
                SDL_SetError("Portal dialogs: Unsupported protocol: %s", uri);
                signal_data->callback(signal_data->userdata, NULL, -1);
                goto done;
            }

            dbus->message_iter_next(&uri_entry);
            ++current;
        }
        path[current] = NULL;
        signal_data->callback(signal_data->userdata, path, -1); // TODO: Fetch the index of the filter that was used
done:
        dbus->connection_remove_filter(conn, &DBus_MessageFilter, signal_data);

        if (path) {
            for (size_t i = 0; i < current; ++i) {
                SDL_free((char *)path[i]);
            }
            SDL_free(path);
        }
        SDL_free((void *)signal_data->path);
        SDL_free(signal_data);
        return DBUS_HANDLER_RESULT_HANDLED;
    }

not_our_signal:
    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}

void SDL_Portal_ShowFileDialogWithProperties(SDL_FileDialogType type, SDL_DialogFileCallback callback, void *userdata, SDL_PropertiesID props)
{
    const char *method;
    const char *method_title;

    SDL_Window *window = SDL_GetPointerProperty(props, SDL_PROP_FILE_DIALOG_WINDOW_POINTER, NULL);
    SDL_DialogFileFilter *filters = SDL_GetPointerProperty(props, SDL_PROP_FILE_DIALOG_FILTERS_POINTER, NULL);
    int nfilters = (int) SDL_GetNumberProperty(props, SDL_PROP_FILE_DIALOG_NFILTERS_NUMBER, 0);
    bool allow_many = SDL_GetBooleanProperty(props, SDL_PROP_FILE_DIALOG_MANY_BOOLEAN, false);
    const char *default_location = SDL_GetStringProperty(props, SDL_PROP_FILE_DIALOG_LOCATION_STRING, NULL);
    const char *accept = SDL_GetStringProperty(props, SDL_PROP_FILE_DIALOG_ACCEPT_STRING, NULL);
    char *location_name = NULL;
    char *location_folder = NULL;
    struct stat statbuf;
    bool open_folders = false;
    bool save_file_existing = false;
    bool save_file_new_named = false;

    switch (type) {
    case SDL_FILEDIALOG_OPENFILE:
        method = "OpenFile";
        method_title = SDL_GetStringProperty(props, SDL_PROP_FILE_DIALOG_TITLE_STRING, "Open File");
        break;

    case SDL_FILEDIALOG_SAVEFILE:
        method = "SaveFile";
        method_title = SDL_GetStringProperty(props, SDL_PROP_FILE_DIALOG_TITLE_STRING, "Save File");
        if (default_location) {
            if (stat(default_location, &statbuf) == 0) {
                save_file_existing = S_ISREG(statbuf.st_mode);
            } else if (errno == ENOENT) {
                char *dirc = SDL_strdup(default_location);
                if (dirc) {
                    location_folder = SDL_strdup(dirname(dirc));
                    SDL_free(dirc);
                    if (location_folder) {
                        save_file_new_named = (stat(location_folder, &statbuf) == 0) && S_ISDIR(statbuf.st_mode);
                    }
                }
            }

            if (save_file_existing || save_file_new_named) {
                char *basec = SDL_strdup(default_location);
                if (basec) {
                    location_name = SDL_strdup(basename(basec));
                    SDL_free(basec);
                }
            }
        }
        break;

    case SDL_FILEDIALOG_OPENFOLDER:
        method = "OpenFile";
        method_title = SDL_GetStringProperty(props, SDL_PROP_FILE_DIALOG_TITLE_STRING, "Open Folder");
        open_folders = true;
        break;

    default:
        /* This is already checked in ../SDL_dialog.c; this silences compiler warnings */
        SDL_SetError("Invalid file dialog type: %d", type);
        callback(userdata, NULL, -1);
        goto cleanup;
    }

    SDL_DBusContext *dbus = SDL_DBus_GetContext();
    DBusError error;
    DBusMessage *msg;
    DBusMessageIter params, options;
    const char *signal_id = NULL;
    char *handle_str, *filter;
    int filter_len;
    static uint32_t handle_id = 0;
    static char *default_parent_window = "";
    SDL_PropertiesID window_props = SDL_GetWindowProperties(window);

    const char *err_msg = validate_filters(filters, nfilters);

    dbus->error_init(&error);

    if (err_msg) {
        SDL_SetError("%s", err_msg);
        callback(userdata, NULL, -1);
        goto cleanup;
    }

    if (dbus == NULL) {
        SDL_SetError("Failed to connect to DBus");
        callback(userdata, NULL, -1);
        goto cleanup;
    }

    msg = dbus->message_new_method_call(PORTAL_DESTINATION, PORTAL_PATH, PORTAL_INTERFACE, method);
    if (msg == NULL) {
        SDL_SetError("Failed to send message to portal");
        callback(userdata, NULL, -1);
        goto cleanup;
    }

    dbus->message_iter_init_append(msg, &params);

    handle_str = default_parent_window;
    if (window_props) {
        const char *parent_handle = SDL_GetStringProperty(window_props, SDL_PROP_WINDOW_WAYLAND_XDG_TOPLEVEL_EXPORT_HANDLE_STRING, NULL);
        if (parent_handle) {
            size_t len = SDL_strlen(parent_handle);
            len += sizeof(WAYLAND_HANDLE_PREFIX) + 1;
            handle_str = SDL_malloc(len * sizeof(char));
            if (!handle_str) {
                callback(userdata, NULL, -1);
                goto cleanup;
            }

            SDL_snprintf(handle_str, len, "%s%s", WAYLAND_HANDLE_PREFIX, parent_handle);
        } else {
            const Uint64 xid = (Uint64)SDL_GetNumberProperty(window_props, SDL_PROP_WINDOW_X11_WINDOW_NUMBER, 0);
            if (xid) {
                const size_t len = sizeof(X11_HANDLE_PREFIX) + 24; // A 64-bit number can be 20 characters max.
                handle_str = SDL_malloc(len * sizeof(char));
                if (!handle_str) {
                    callback(userdata, NULL, -1);
                    goto cleanup;
                }

                // The portal wants X11 window ID numbers in hex.
                SDL_snprintf(handle_str, len, "%s%" SDL_PRIx64, X11_HANDLE_PREFIX, xid);
            }
        }
    }

    dbus->message_iter_append_basic(&params, DBUS_TYPE_STRING, &handle_str);
    if (handle_str != default_parent_window) {
        SDL_free(handle_str);
    }

    dbus->message_iter_append_basic(&params, DBUS_TYPE_STRING, &method_title);
    dbus->message_iter_open_container(&params, DBUS_TYPE_ARRAY, "{sv}", &options);

    handle_str = SDL_malloc(sizeof(char) * (HANDLE_LEN + 1));
    if (!handle_str) {
        callback(userdata, NULL, -1);
        goto cleanup;
    }
    SDL_snprintf(handle_str, HANDLE_LEN, "%u", ++handle_id);
    DBus_AppendStringOption(dbus, &options, "handle_token", handle_str);
    SDL_free(handle_str);

    DBus_AppendBoolOption(dbus, &options, "modal", !!window);
    if (allow_many) {
        DBus_AppendBoolOption(dbus, &options, "multiple", 1);
    }
    if (open_folders) {
        DBus_AppendBoolOption(dbus, &options, "directory", 1);
    }
    if (filters) {
        DBus_AppendFilters(dbus, &options, filters, nfilters);
    }
    if (default_location) {
        if (save_file_existing && location_name) {
            /* Open a save dialog at an existing file */
            DBus_AppendByteArray(dbus, &options, "current_file", default_location);
            /* Setting "current_name" should not be necessary however the kde-desktop-portal sets the filename without an extension.
             * An alternative would be to match the extension to a filter and set "current_filter".
             */
            DBus_AppendStringOption(dbus, &options, "current_name", location_name);
        } else if (save_file_new_named && location_folder && location_name) {
            /* Open a save dialog at a location with a suggested name */
            DBus_AppendByteArray(dbus, &options, "current_folder", location_folder);
            DBus_AppendStringOption(dbus, &options, "current_name", location_name);
        } else {
            DBus_AppendByteArray(dbus, &options, "current_folder", default_location);
        }
    }
    if (accept) {
        DBus_AppendStringOption(dbus, &options, "accept_label", accept);
    }
    dbus->message_iter_close_container(&params, &options);

    DBusMessage *reply = dbus->connection_send_with_reply_and_block(dbus->session_conn, msg, DBUS_TIMEOUT_INFINITE, &error);
    if (dbus->error_is_set(&error)) {
        SDL_SetError("Failed to open dialog via DBus, %s: %s", error.name, error.message);
        dbus->error_free(&error);
        callback(userdata, NULL, -1);
        goto cleanup;
    }

    if (reply) {
        DBusMessageIter reply_iter;
        dbus->message_iter_init(reply, &reply_iter);

        if (dbus->message_iter_get_arg_type(&reply_iter) == DBUS_TYPE_OBJECT_PATH) {
            dbus->message_iter_get_basic(&reply_iter, &signal_id);
        }
    }

    if (!signal_id) {
        SDL_SetError("Invalid response received by DBus");
        callback(userdata, NULL, -1);
        goto incorrect_type;
    }

    dbus->message_unref(msg);

    filter_len = SDL_strlen(SIGNAL_FILTER) + SDL_strlen(signal_id) + 2;
    filter = SDL_malloc(sizeof(char) * filter_len);
    if (!filter) {
        callback(userdata, NULL, -1);
        goto incorrect_type;
    }

    SDL_snprintf(filter, filter_len, SIGNAL_FILTER"%s'", signal_id);
    dbus->bus_add_match(dbus->session_conn, filter, &error);
    SDL_free(filter);

    if (dbus->error_is_set(&error)) {
        SDL_SetError("Failed to set up DBus listener for dialog, %s: %s", error.name, error.message);
        dbus->error_free(&error);
        callback(userdata, NULL, -1);
        goto cleanup;
    }

    SignalCallback *data = SDL_malloc(sizeof(SignalCallback));
    if (!data) {
        callback(userdata, NULL, -1);
        goto incorrect_type;
    }
    data->callback = callback;
    data->userdata = userdata;
    data->path = SDL_strdup(signal_id);
    if (!data->path) {
        SDL_free(data);
        callback(userdata, NULL, -1);
        goto incorrect_type;
    }

    /* TODO: This should be registered before opening the portal, or the filter will not catch
             the message if it is sent before we register the filter.
    */
    dbus->connection_add_filter(dbus->session_conn,
                                &DBus_MessageFilter, data, NULL);
    dbus->connection_flush(dbus->session_conn);

incorrect_type:
    dbus->message_unref(reply);

cleanup:
    SDL_free(location_name);
    SDL_free(location_folder);
}

bool SDL_Portal_detect(void)
{
    SDL_DBusContext *dbus = SDL_DBus_GetContext();
    DBusMessage *msg = NULL, *reply = NULL;
    char *reply_str = NULL;
    DBusMessageIter reply_iter;
    static int portal_present = -1;

    // No need for this if the result is cached.
    if (portal_present != -1) {
        return (portal_present > 0);
    }

    portal_present = 0;

    if (!dbus) {
        SDL_SetError("%s", "Failed to connect to DBus!");
        return false;
    }

    // Use introspection to get the available services.
    msg = dbus->message_new_method_call(PORTAL_DESTINATION, PORTAL_PATH, "org.freedesktop.DBus.Introspectable", "Introspect");
    if (!msg) {
        goto done;
    }

    reply = dbus->connection_send_with_reply_and_block(dbus->session_conn, msg, DBUS_TIMEOUT_USE_DEFAULT, NULL);
    dbus->message_unref(msg);
    if (!reply) {
        goto done;
    }

    if (!dbus->message_iter_init(reply, &reply_iter)) {
        goto done;
    }

    if (dbus->message_iter_get_arg_type(&reply_iter) != DBUS_TYPE_STRING) {
        goto done;
    }

    /* Introspection gives us a dump of all the services on the destination in XML format, so search the
     * giant string for the file chooser protocol.
     */
    dbus->message_iter_get_basic(&reply_iter, &reply_str);
    if (SDL_strstr(reply_str, PORTAL_INTERFACE)) {
        portal_present = 1; // Found it!
    }

done:
    if (reply) {
        dbus->message_unref(reply);
    }

    return (portal_present > 0);
}

#else

// Dummy implementation to avoid compilation problems

void SDL_Portal_ShowFileDialogWithProperties(SDL_FileDialogType type, SDL_DialogFileCallback callback, void *userdata, SDL_PropertiesID props)
{
    SDL_Unsupported();
    callback(userdata, NULL, -1);
}

bool SDL_Portal_detect(void)
{
    return false;
}

#endif // SDL_USE_LIBDBUS
