// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-

const ByteArray = imports.byteArray;

const Gio = imports.gi.Gio;
const GLib = imports.gi.GLib;
const Gtk = imports.gi.Gtk;
const Signals = imports.signals;
const St = imports.gi.St;

const AppletManager = imports.ui.appletManager;
const Config = imports.misc.config;
const DeskletManager = imports.ui.deskletManager;
const ExtensionSystem = imports.ui.extensionSystem;
const SearchProviderManager = imports.ui.searchProviderManager;
const Main = imports.ui.main;
const {requireModule, unloadModule, getModuleByIndex} = imports.misc.fileUtils;
const {queryCollection} = imports.misc.util;

var State = {
    INITIALIZING: 0,
    LOADED: 1,
    ERROR: 2,
    OUT_OF_DATE: 3
};

// Xlets using imports.gi.NMClient. This should be removed in Cinnamon 4.2+,
// after these applets have been updated on Spices.
var knownCinnamon4Conflicts = [
    // Applets
    'turbonote@iksws.com.b',
    'vnstat@linuxmint.com',
    'netusagemonitor@pdcurtis',
    // Desklets
    'netusage@30yavash.com'
];

// macro for creating extension types
function _createExtensionType(name, folder, manager, overrides){
    let type = {
        name: name,
        folder: folder,
        requiredFunctions: ["main"],
        requiredProperties: ["uuid", "name", "description"],
        niceToHaveProperties: [],
        roles: {},
        callbacks: {
            finishExtensionLoad: manager.finishExtensionLoad,
            prepareExtensionUnload: manager.prepareExtensionUnload,
            prepareExtensionReload: manager.prepareExtensionReload
        },
        userDir: GLib.build_filenamev([global.userdatadir, folder]),
        legacyMeta: {}
    };

    Object.assign(type, overrides);

    // Add signal methods
    Signals.addSignalMethods(type);

    // create user directories if they don't exist.
    let dir = Gio.file_new_for_path(type.userDir)
    try {
        if(!dir.query_exists(null))
            dir.make_directory_with_parents(null);
    } catch(e){
        global.logError(e);
    }

    return type;
}

/**
 * const Type:
 * @EXTENSION: Cinnamon extensions
 * @APPLET: Cinnamon panel applets
 *
 * @name: Upper case first character name for printing messages
 *        Also converted to lowercase to find the correct javascript file
 * @folder: The folder name within the system and user cinnamon folders
 * @requiredFunctions: Functions that must exist in the main javascript file
 * @requiredProperties: Properties that must be set in the metadata.json file
 * @niceToHaveProperties: Properties that are encouraged to be set in the metadata.json file
 * @roles: Roles an extension can assume. Values will be set internally, set to null.
 *         key => name of the role, value => reference to the extension object
 * @callbacks: Callbacks used to do some manual actions on load / unload
 *
 * Extension types with some attributes helping to load these extension types.
 * Properties are nested, with lowerCamelCase properties (e.g. requiredFunctions) as sub-properties of CAPITAL one (EXTENSION). Thus they are referred to as, e.g., Type.EXTENSION.requiredFunctions
 */
var startTime;
var extensions = [];
var Type = {
    EXTENSION: _createExtensionType("Extension", "extensions", ExtensionSystem, {
        requiredFunctions: ["init", "disable", "enable"],
        requiredProperties: ["uuid", "name", "description", "cinnamon-version"],
        niceToHaveProperties: ["url"],
    }),
    APPLET: _createExtensionType("Applet", "applets", AppletManager, {
        roles: {
            notifications: null,
            windowlist: null,
            windowattentionhandler: null,
            panellauncher: null,
            tray: null
        }
    }),
    DESKLET: _createExtensionType("Desklet", "desklets", DeskletManager, {
        roles: {
            notifications: null,
            windowlist: null,
            windowattentionhandler: null
        }
    }),
    SEARCH_PROVIDER: _createExtensionType("Search provider", "search_providers", SearchProviderManager, {
        requiredFunctions: ["perform_search", "on_result_selected"]
    })
};

// Create a dummy metadata object when metadata parsing failed or was not done yet.
function createMetaDummy(uuid, path, state) {
    return {name: uuid, description: 'Metadata load failed', state: state, path: path, error: ''};
}

function getExtension(uuid) {
    return queryCollection(extensions, {uuid});
}

function formatError(uuid, message) {
    return `[${uuid}]: ${message}`;
}

function logError(message, uuid, error, state) {
    let errorMessage = formatError(uuid, message);
    if (!error) {
        error = new Error(errorMessage);
    } else {
        error.message = `\n${formatError(uuid, error.message)}`;
        error.message += `\n${errorMessage}`;
    }

    error.stack = error.stack.split('\n')
        .filter(function(line) {
            return !line.match(/<Promise>|wrapPromise/);
        })
        .join('\n');

    global.logError(error);

    // An error during initialization leads to unloading the extension again.
    let extension = getExtension(uuid);
    if (extension) {
        extension.meta.state = state || State.ERROR;
        extension.meta.error += message;
        if (extension.meta.state === State.INITIALIZING) {
            extension.unlockRoles();
            extension.unloadStylesheet();
            extension.unloadIconDirectory();
            forgetExtension(uuid, Type[extension.upperType]);
        }
    }
    error._alreadyLogged = true;
    return error;
}

function ensureFileExists(file) {
    if (!file.query_exists(null)) {
        throw logError(`File not found: ${file.get_path()}`);
    }
}

// The Extension object itself
function Extension(type, uuid) {
    let extension = getExtension(uuid);
    if (extension) {
        return Promise.resolve(true);
    }
    let force = false;
    if (uuid.substr(0, 1) === '!') {
        uuid = uuid.replace(/^!/, '');
        force = true;
    }
    let dir = findExtensionDirectory(uuid, type.userDir, type.folder);

    if (dir == null) {
        forgetExtension(uuid, type, true);
        return Promise.resolve(null);
    }
    return this._init(dir, type, uuid, force);
}

Extension.prototype = {
    _init: function(dir, type, uuid, force) {
        this.name = type.name;
        this.uuid = uuid;
        this.dir = dir;
        this.upperType = type.name.toUpperCase().replace(/\s/g, "_");
        this.lowerType = type.name.toLowerCase().replace(/\s/g, "_");
        this.theme = null;
        this.stylesheet = null;
        this.iconDirectory = null;
        this.meta = createMetaDummy(uuid, dir.get_path(), State.INITIALIZING);

        let isPotentialNMClientConflict = knownCinnamon4Conflicts.indexOf(uuid) > -1;

        const finishLoad = () => {
            // Many xlets still use appletMeta/deskletMeta to get the path
            type.legacyMeta[uuid] = {path: this.meta.path};

            ensureFileExists(this.dir.get_child(`${this.lowerType}.js`));
            this.loadStylesheet(this.dir.get_child('stylesheet.css'));

            if (this.stylesheet) {
                Main.themeManager.connect('theme-set', () => {
                    this.loadStylesheet(this.dir.get_child('stylesheet.css'));
                });
            }
            this.loadIconDirectory(this.dir);
            // get [extension/applet/desklet].js
            return requireModule(
                `${this.meta.path}/${this.lowerType}.js`, // path
                this.meta.path, // dir,
                this.meta, // meta
                this.lowerType, // type
                true, // async
                true // returnIndex
            );
        };

        return loadMetaData({
            state: this.meta.state,
            path: this.meta.path,
            uuid: uuid,
            userDir: type.userDir,
            folder: type.folder,
            force: force
        }).then((meta) => {
            // Timer needs to start after the first initial I/O, otherwise every applet shows as taking 1-2 seconds to load.
            // Maybe because of how promises are wired up in CJS?
            // https://github.com/linuxmint/cjs/blob/055da399c794b0b4d76ecd7b5fabf7f960f77518/modules/_lie.js#L9
            startTime = new Date().getTime();
            this.meta = meta;

            if (!force) {
                this.validateMetaData();
            }

            return findExtensionSubdirectory(this.dir).then((dir) => {
                this.dir = dir;
                this.meta.path = this.dir.get_path();

                // If an xlet has known usage of imports.gi.NMClient, we require them to have a
                // 4.0 directory. It is the only way to assume they are patched for Cinnamon 4 from here.
                if (isPotentialNMClientConflict && this.meta.path.indexOf(`/4.0`) === -1) {
                    throw new Error(`Found unpatched usage of imports.gi.NMClient for ${this.lowerType} ${uuid}`);
                }

                return finishLoad();
            });
        }).then((moduleIndex) => {
            if (moduleIndex == null) {
                throw new Error(`Could not find module index: ${moduleIndex}`);
            }
            this.moduleIndex = moduleIndex;
            for (let i = 0; i < type.requiredFunctions.length; i++) {
                let func = type.requiredFunctions[i];
                if (!getModuleByIndex(moduleIndex)[func]) {
                    throw new Error(`Function "${func}" is missing`);
                }
            }

            // Add the extension to the global collection
            extensions.push(this);

            if(!type.callbacks.finishExtensionLoad(extensions.length - 1)) {
                throw new Error(`${type.name} ${uuid}: Could not create ${this.lowerType} object.`);
            }
            this.finalize();
            Main.cinnamonDBusService.EmitXletAddedComplete(true, uuid);
        }).catch((e) => {
             // Silently fail to load xlets that aren't actually installed -
             //   but no error, since the user can't do anything about it anyhow
             //   (short of editing gsettings).  Silent failure is consistent with
             //   other reactions in Cinnamon to missing items (e.g. panel launchers
             //   just don't show up if their program isn't installed, but we don't
             //   remove them or anything)
            Main.cinnamonDBusService.EmitXletAddedComplete(false, uuid);
            Main.xlet_startup_error = true;
            forgetExtension(uuid, type);
            if (e._alreadyLogged) {
                return;
            }
            logError(`Error importing ${this.lowerType}.js from ${uuid}`, uuid, e);
        });
    },

    finalize: function() {
        this.meta.state = State.LOADED;

        Type[this.upperType].emit('extension-loaded', this.uuid);

        let endTime = new Date().getTime();
        global.log(`Loaded ${this.lowerType} ${this.uuid} in ${endTime - startTime} ms`);
        startTime = new Date().getTime();
    },
    validateMetaData: function() {
        // Some properties are required to run
        this.checkProperties(Type[this.upperType].requiredProperties, true);

        // Others are nice to have
        this.checkProperties(Type[this.upperType].niceToHaveProperties, false);

        if (this.meta.uuid != this.uuid) {
            throw logError(`uuid "${this.meta.uuid}" from metadata.json does not match directory name.`, this.uuid);
        }

        // If cinnamon versions are set check them
        if ('cinnamon-version' in this.meta && !versionCheck(this.meta['cinnamon-version'], Config.PACKAGE_VERSION)) {
            throw logError('Extension is not compatible with current Cinnamon version', this.uuid, null, State.OUT_OF_DATE);
        }

        // If a role is set, make sure it's a valid one
        let meta_role_list_str = this.meta['role'];
        if (meta_role_list_str) {
            let meta_roles = meta_role_list_str.replace(" ", "").split(",");
            for (let role of meta_roles) {
                if (!(role in Type[this.upperType].roles)) {
                    throw logError(`Unknown role definition: ${role} in metadata.json`, this.uuid);
                }
            }
        }
    },

    checkProperties: function(properties, fatal) {
        for (let i = 0; i < properties.length; i++) {
            if (!this.meta[properties[i]]) {
                let msg = `Missing property "${properties[i]}" in metadata.json`;
                if(fatal)
                    throw logError(msg, this.uuid);
                else
                    global.logWarning(formatError(this.uuid, msg));
            }
        }
    },

    loadStylesheet: function (file) {
        if (file.query_exists(null)) {
            try {
                let themeContext = St.ThemeContext.get_for_stage(global.stage);
                this.theme = themeContext.get_theme();
            } catch (e) {
                throw logError('Error trying to get theme', this.uuid, e);
            }

            try {
                let path = file.get_path();
                this.theme.load_stylesheet(path);
                this.stylesheet = path;
            } catch (e) {
                throw logError('Stylesheet parse error', this.uuid, e);
            }
        }
    },

    unloadStylesheet: function () {
        if (this.theme != null && this.stylesheet != null) {
            try {
                this.theme.unload_stylesheet(this.stylesheet);
            } catch (e) {
                global.logError('Error unloading stylesheet', e);
            }
        }
    },

    loadIconDirectory: function(dir) {
        let iconDir = dir.get_child("icons");
        if (iconDir.query_exists(null)) {
            let path = iconDir.get_path();
            this.iconDirectory = path;
            Gtk.IconTheme.get_default().append_search_path(path);
        }
    },

    unloadIconDirectory: function() {
        if (this.iconDirectory) {
            let iconTheme = Gtk.IconTheme.get_default();
            let searchPath = iconTheme.get_search_path();
            for (let i = 0; i < searchPath.length; i++) {
                if (searchPath[i] == this.iconDirectory) {
                    searchPath.splice(i,1);
                    iconTheme.set_search_path(searchPath);
                    break;
                }
            }
        }
    },

    lockRole: function(roleProvider) {
        if (this.meta && this.meta.role) {
            let meta_role_list_str = this.meta.role;
            let meta_roles = meta_role_list_str.replace(" ", "").split(",");

            let avail_roles = [];

            for (let role of meta_roles) {
                if (Type[this.upperType].roles[role] !== this.uuid) {
                    if (Type[this.upperType].roles[role] != null) {
                        continue;
                    }

                    avail_roles.push(role);
                }
            }

            if (avail_roles.length == 0) {
                return false;
            }

            if (roleProvider != null) {
                for (let role of avail_roles) {
                    Type[this.upperType].roles[role] = this.uuid;
                    this.roleProvider = roleProvider;
                    global.log(`Role locked: ${role}`);
                }
            }
        }

        return true;
    },

    unlockRoles: function() {
        if (this.meta.role) {
            let meta_role_list_str = this.meta.role;
            let meta_roles = meta_role_list_str.replace(" ", "").split(",");

            for (let role of meta_roles) {
                if (Type[this.upperType].roles[role] === this.uuid) {
                    Type[this.upperType].roles[role] = null;
                    this.roleProvider = null;
                    global.log(`Role unlocked: ${role}`);
                }
            }
        }
    }
}

/**
* versionCheck:
* @required: an array of minimum versions we are compatible with
* @current: the version we have
*
* Check if a component is compatible for an extension.
* @required is an array, and at least one version must be lower than the current version.
* @current must be in the format <major>.<minor>.<point>.<micro>
* <micro> is always ignored
* <point> is ignored if not specified (so you can target the whole release)
* <minor> and <major> must match
* Each target version must be at least <major> and <minor>
*/
function versionCheck(required, current) {
    let currentArray = current.split('.');
    let currentMajor = parseInt(currentArray[0]);
    let currentMinor = parseInt(currentArray[1]);
    for (let i = 0; i < required.length; i++) {
        let requiredArray = required[i].split('.');
        requiredMajor = parseInt(requiredArray[0]);
        requiredMinor = parseInt(requiredArray[1]);
        if (currentMajor > requiredMajor || (currentMajor == requiredMajor  && currentMinor >= requiredMinor)) {
            return true;
        }
    }
    return false;
}

/**
 * versionLeq:
 * @a (string): the first version
 * @b (string): the second version
 *
 * Returns: whether a <= b
 */
function versionLeq(a, b) {
    a = a.split('.');
    b = b.split('.');

    if (a.length == 2)
        a.push(0);

    if (b.length == 2)
        b.push(0);

    for (let i = 0; i < 3; i++) {
        if (a[i] == b[i])
            continue;
        else if (a[i] > b[i])
            return false;
        else
            return true;
    }
    return true;
}

// Returns a string version of a State value
function getMetaStateString(state) {
    switch (state) {
        case State.INITIALIZING:
            return _("Initializing");
        case State.LOADED:
            return _("Loaded");
        case State.ERROR:
            return _("Error");
        case State.OUT_OF_DATE:
            return _("Out of date");
    }
    return 'Unknown'; // Not translated, shouldn't appear
}

/**
 * loadExtension:
 *
 * @uuid (string): uuid of xlet
 * @type (Extension.Type): type of xlet
 */
function loadExtension(uuid, type) {
    return new Extension(type, uuid);
}

/**
 * unloadExtension:
 *
 * @uuid (string): uuid of xlet
 * @type (Extension.Type): type of xlet
 * @deleteConfig (bool): delete also config files, defaults to true
 */
function unloadExtension(uuid, type, deleteConfig = true, reload = false) {
    let extensionIndex = queryCollection(extensions, {uuid}, true);
    if (extensionIndex > -1) {
        let extension = extensions[extensionIndex];
        extension.unlockRoles();

        // Try to disable it -- if it's ERROR'd, we can't guarantee that,
        // but it will be removed on next reboot, and hopefully nothing
        // broke too much.
        try {
            if (reload) {
                Type[extension.upperType].callbacks.prepareExtensionReload(extension);
            }
            Type[extension.upperType].callbacks.prepareExtensionUnload(extension, deleteConfig);
        } catch (e) {
            logError(`Error disabling ${extension.lowerType} ${extension.uuid}`, extension.uuid, e);
        }
        extension.unloadStylesheet();
        extension.unloadIconDirectory();

        Type[extension.upperType].emit('extension-unloaded', extension.uuid);

        forgetExtension(extensionIndex, uuid, type, true);
    }
}

function forgetExtension(extensionIndex, uuid, type, forgetMeta) {
    if (typeof extensions[extensionIndex] !== 'undefined') {
        unloadModule(extensions[extensionIndex].moduleIndex);
        try {
           delete imports[type.folder][uuid];
        } catch (e) {}
        if (forgetMeta) {
            extensions[extensionIndex] = undefined;
            extensions.splice(extensionIndex, 1);
        }
    }
}

/**
 * reloadExtension:
 *
 * @uuid (string): uuid of xlet
 * @type (Extension.Type): type of xlet
 *
 * Reloads an xlet. Useful when the source has changed.
 */
function reloadExtension(uuid, type) {
    let extension = getExtension(uuid);

    if (extension) {
        unloadExtension(uuid, type, false, true);
        Main._addXletDirectoriesToSearchPath();

        if (extension.meta.force_loaded) {
            uuid = "!" + uuid;
        }
        loadExtension(uuid, type);
        return;
    }

    loadExtension(uuid, type);
}

function findExtensionDirectory(uuid, userDir, folder) {
    let dir, dirPath;
    if (!GLib.getenv('CINNAMON_TROUBLESHOOT')) {
        dirPath = `${userDir}/${uuid}`;
        dir = Gio.file_new_for_path(dirPath);
        if (dir.query_file_type(Gio.FileQueryInfoFlags.NONE, null) === Gio.FileType.DIRECTORY) {
            return dir;
        }
    }

    let systemDataDirs = GLib.get_system_data_dirs();
    for (let i = 0; i < systemDataDirs.length; i++) {
        dirPath = `${systemDataDirs[i]}/cinnamon/${folder}/${uuid}`;
        dir = Gio.file_new_for_path(dirPath);
        if (dir.query_file_type(Gio.FileQueryInfoFlags.NONE, null) === Gio.FileType.DIRECTORY) {
            return dir;
        }
    }
    return null;
}

function getMetadata(uuid, type) {
    return loadMetaData({
        uuid,
        userDir: type.userDir,
        folder: type.folder
    });
}

function maybeAddWindowAttentionHandlerRole(meta) {
    const keywords = ['window-list', 'windowlist', 'taskbar'];

    keywords.some(element => {
        if (meta.uuid.includes(element)) {
            if (!meta.role) {
                meta.role = "windowattentionhandler";
            } else {
                if (!meta.role.includes("windowattentionhandler")) {
                    meta.role += ",windowattentionhandler";
                }
            }
        }
    });
}

function loadMetaData({state, path, uuid, userDir, folder, force}) {
    return new Promise((resolve, reject) => {
        let dir = findExtensionDirectory(uuid, userDir, folder);
        let meta;
        let metadataFile = dir.get_child('metadata.json');
        let oldState = state ? state : State.INITIALIZING;
        let oldPath = path ? path : dir.get_path();
        ensureFileExists(metadataFile);
        metadataFile.load_contents_async(null, (object, result) => {
            try {
                let [success, json] = metadataFile.load_contents_finish(result);
                if (!success) {
                    reject();
                    return;
                }
                meta = JSON.parse(ByteArray.toString(json));

                maybeAddWindowAttentionHandlerRole(meta);
            } catch (e) {
                logError(`Failed to load/parse metadata.json`, uuid, e);
                meta = createMetaDummy(uuid, oldPath, State.ERROR);

            }
            // Store some additional crap here
            meta.state = oldState;
            meta.path = oldPath;
            meta.error = '';
            meta.force_loaded = force;
            resolve(meta);
        });
    });
}

/**
 * findExtensionSubdirectory:
 * @dir (Gio.File): directory to search in
 *
 * For extensions that are shipped with multiple versions in different
 * directories, look for the largest available version that is less than or
 * equal to the current running version. If no such version is found, the
 * original directory is returned.
 *
 * Returns (Gio.File): directory object of the desired directory.
 */
function findExtensionSubdirectory(dir) {
    return new Promise(function(resolve, reject) {
        dir.enumerate_children_async(
            'standard::*',
            Gio.FileQueryInfoFlags.NONE,
            GLib.PRIORITY_DEFAULT,
            null,
            function(obj, res) {
            try {
                let fileEnum = obj.enumerate_children_finish(res);
                let info;
                let largest = null;
                while ((info = fileEnum.next_file(null)) != null) {
                    let fileType = info.get_file_type();
                    if (fileType !== Gio.FileType.DIRECTORY) {
                        continue;
                    }

                    let name = info.get_name();
                    if (!name.match(/^[1-9][0-9]*\.[0-9]+(\.[0-9]+)?$/)) {
                        continue;
                    }

                    if (versionLeq(name, Config.PACKAGE_VERSION) &&
                        (!largest || versionLeq(largest[0], name))) {
                        largest = [name, fileEnum.get_child(info)];
                    }
                }

                fileEnum.close(null);
                resolve(largest ? largest[1] : dir);
            } catch (e) {
                logError(`Error looking for extension version for ${dir.get_basename()} in directory ${dir}`, 'findExtensionSubdirectory', e);
                resolve(dir)
            }

        });
    });
}

function get_max_instances (uuid, type) {
    let extension = getExtension(uuid);

    if (extension && extension.uuid) {
        if (extension.meta['max-instances']) {
            let i = extension.meta['max-instances'];
            return parseInt(i);
        }
    }
    return 1;
}
