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

const Clutter = imports.gi.Clutter;
const GDesktopEnums = imports.gi.GDesktopEnums;
const Gio = imports.gi.Gio;
const GLib = imports.gi.GLib;
const GnomeDesktop = imports.gi.GnomeDesktop;
const Lang = imports.lang;
const Meta = imports.gi.Meta;
const Signals = imports.signals;

const Main = imports.ui.main;
const Params = imports.misc.params;
const Tweener = imports.ui.tweener;

const BACKGROUND_SCHEMA = 'org.gnome.desktop.background';
const PRIMARY_COLOR_KEY = 'primary-color';
const SECONDARY_COLOR_KEY = 'secondary-color';
const COLOR_SHADING_TYPE_KEY = 'color-shading-type';
const BACKGROUND_STYLE_KEY = 'picture-options';
const PICTURE_OPACITY_KEY = 'picture-opacity';
const PICTURE_URI_KEY = 'picture-uri';

const FADE_ANIMATION_TIME = 1.0;

// These parameters affect how often we redraw.
// The first is how different (percent crossfaded) the slide show
// has to look before redrawing and the second is the minimum
// frequency (in seconds) we're willing to wake up
const ANIMATION_OPACITY_STEP_INCREMENT = 4.0;
const ANIMATION_MIN_WAKEUP_INTERVAL = 1.0;

let _backgroundCache = null;

const BackgroundCache = new Lang.Class({
    Name: 'BackgroundCache',

    _init: function() {
       this._patterns = [];
       this._images = [];
       this._pendingFileLoads = [];
       this._fileMonitors = {};
    },

    getPatternContent: function(params) {
        params = Params.parse(params, { monitorIndex: 0,
                                        color: null,
                                        secondColor: null,
                                        shadingType: null,
                                        effects: Meta.BackgroundEffects.NONE });

        let content = null;

        let candidateContent = null;
        for (let i = 0; i < this._patterns.length; i++) {
            if (this._patterns[i].get_shading() != params.shadingType)
                continue;

            if (!params.color.equal(this._patterns[i].get_color()))
                continue;

            if (params.shadingType != GDesktopEnums.BackgroundShading.SOLID &&
                !params.secondColor.equal(this._patterns[i].get_second_color()))
                continue;

            candidateContent = this._patterns[i];

            if (params.effects != this._patterns[i].effects)
                continue;

            break;
        }

        if (candidateContent) {
            content = candidateContent.copy(params.monitorIndex, params.effects);
        } else {
            content = new Meta.Background({ meta_screen: global.screen,
                                            monitor: params.monitorIndex,
                                            effects: params.effects });

            if (params.shadingType == GDesktopEnums.BackgroundShading.SOLID) {
                content.load_color(params.color);
            } else {
                content.load_gradient(params.shadingType, params.color, params.secondColor);
            }
        }

        this._patterns.push(content);
        return content;
    },

    _monitorFile: function(filename) {
        if (this._fileMonitors[filename])
            return;

        let file = Gio.File.new_for_path(filename);
        let monitor = file.monitor(Gio.FileMonitorFlags.NONE, null);

        let signalId = monitor.connect('changed',
                                       Lang.bind(this, function() {
                                           for (let i = 0; i < this._images.length; i++) {
                                               if (this._images[i].get_filename() == filename)
                                                   this._images.splice(i, 1);
                                           }

                                           monitor.disconnect(signalId);

                                           this.emit('file-changed', filename);
                                       }));

        this._fileMonitors[filename] = monitor;
    },

    _removeContent: function(contentList, content) {
        let index = contentList.indexOf(content);
        if (index < 0)
            throw new Error("Trying to remove invalid content: " + content);
        contentList.splice(index, 1);
    },

    removePatternContent: function(content) {
        this._removeContent(this._patterns, content);
    },

    removeImageContent: function(content) {
        let filename = content.get_filename();

        let hasOtherUsers = this._images.some(function(content) { return filename == content.get_filename(); });
        if (!hasOtherUsers)
            delete this._fileMonitors[filename];

        this._removeContent(this._images, content);
    },

    _loadImageContent: function(params) {
        params = Params.parse(params, { monitorIndex: 0,
                                        style: null,
                                        filename: null,
                                        effects: Meta.BackgroundEffects.NONE,
                                        cancellable: null,
                                        onFinished: null });

        for (let i = 0; i < this._pendingFileLoads.length; i++) {
            if (this._pendingFileLoads[i].filename == params.filename &&
                this._pendingFileLoads[i].style == params.style) {
                this._pendingFileLoads[i].callers.push({ shouldCopy: true,
                                                         monitorIndex: params.monitorIndex,
                                                         effects: params.effects,
                                                         onFinished: params.onFinished });
                return;
            }
        }

        this._pendingFileLoads.push({ filename: params.filename,
                                      style: params.style,
                                      callers: [{ shouldCopy: false,
                                                  monitorIndex: params.monitorIndex,
                                                  effects: params.effects,
                                                  onFinished: params.onFinished }] });

        let content = new Meta.Background({ meta_screen: global.screen,
                                            monitor: params.monitorIndex,
                                            effects: params.effects });

        content.load_file_async(params.filename,
                                params.style,
                                params.cancellable,
                                Lang.bind(this,
                                          function(object, result) {
                                              try {
                                                  content.load_file_finish(result);

                                                  this._monitorFile(params.filename);
                                                  this._images.push(content);
                                              } catch(e) {
                                                  content = null;
                                              }

                                              for (let i = 0; i < this._pendingFileLoads.length; i++) {
                                                  let pendingLoad = this._pendingFileLoads[i];
                                                  if (pendingLoad.filename != params.filename ||
                                                      pendingLoad.style != params.style)
                                                      continue;

                                                  for (let j = 0; j < pendingLoad.callers.length; j++) {
                                                      if (pendingLoad.callers[j].onFinished) {
                                                          let newContent;

                                                          if (content && pendingLoad.callers[j].shouldCopy) {
                                                              newContent = content.copy(pendingLoad.callers[j].monitorIndex,
                                                                                        pendingLoad.callers[j].effects);
                                                              this._images.push(newContent);
                                                          } else {
                                                              newContent = content;
                                                          }

                                                          pendingLoad.callers[j].onFinished(newContent);
                                                      }
                                                  }

                                                  this._pendingFileLoads.splice(i, 1);
                                              }
                                          }));
    },

    getImageContent: function(params) {
        params = Params.parse(params, { monitorIndex: 0,
                                        style: null,
                                        filename: null,
                                        effects: Meta.BackgroundEffects.NONE,
                                        cancellable: null,
                                        onFinished: null });

        let content = null;

        let candidateContent = null;
        for (let i = 0; i < this._images.length; i++) {
            if (this._images[i].get_style() != params.style)
                continue;

            if (this._images[i].get_filename() != params.filename)
                continue;

            if (params.style == GDesktopEnums.BackgroundStyle.SPANNED &&
                this._images[i].monitor != params.monitorIndex)
                continue;

            candidateContent = this._images[i];

            if (params.effects != this._images[i].effects)
                continue;

            break;
        }

        if (candidateContent) {
            content = candidateContent.copy(params.monitorIndex, params.effects);

            if (params.cancellable && params.cancellable.is_cancelled())
                content = null;
            else
                this._images.push(content);

            if (params.onFinished)
                params.onFinished(content);
        } else {
            this._loadImageContent({ filename: params.filename,
                                     style: params.style,
                                     effects: params.effects,
                                     monitorIndex: params.monitorIndex,
                                     cancellable: params.cancellable,
                                     onFinished: params.onFinished });

        }
    },

    getAnimation: function(params) {
        params = Params.parse(params, { filename: null,
                                        onLoaded: null });

        if (this._animationFilename == params.filename) {
            if (params.onLoaded) {
                GLib.idle_add(GLib.PRIORITY_DEFAULT, Lang.bind(this, function() {
                    params.onLoaded(this._animation);
                    return GLib.SOURCE_REMOVE;
                }));
            }
        }

        let animation = new Animation({ filename: params.filename });

        animation.load(Lang.bind(this, function() {
                           this._monitorFile(params.filename);
                           this._animationFilename = params.filename;
                           this._animation = animation;

                           if (params.onLoaded) {
                               GLib.idle_add(GLib.PRIORITY_DEFAULT, Lang.bind(this, function() {
                                   params.onLoaded(this._animation);
                                   return GLib.SOURCE_REMOVE;
                               }));
                           }
                       }));
    }
});
Signals.addSignalMethods(BackgroundCache.prototype);

function getBackgroundCache() {
    if (!_backgroundCache)
        _backgroundCache = new BackgroundCache();
    return _backgroundCache;
}

const Background = new Lang.Class({
    Name: 'Background',

    _init: function(params) {
        params = Params.parse(params, { monitorIndex: 0,
                                        layoutManager: Main.layoutManager,
                                        effects: Meta.BackgroundEffects.NONE,
                                        settings: null });
        this.actor = new Meta.BackgroundGroup();
        this.actor._delegate = this;

        this._destroySignalId = this.actor.connect('destroy',
                                                   Lang.bind(this, this._destroy));

        this._settings = params.settings;
        this._monitorIndex = params.monitorIndex;
        this._layoutManager = params.layoutManager;
        this._effects = params.effects;
        this._fileWatches = {};
        this._pattern = null;
        // contains a single image for static backgrounds and
        // two images (from and to) for slide shows
        this._images = {};

        this._brightness = 1.0;
        this._vignetteSharpness = 0.2;
        this._cancellable = new Gio.Cancellable();
        this.isLoaded = false;

        this._settingsChangedSignalId = this._settings.connect('changed', Lang.bind(this, function() {
                                            this.emit('changed');
                                        }));

        this._load();
    },

    _destroy: function() {
        this._cancellable.cancel();

        if (this._updateAnimationTimeoutId) {
            GLib.source_remove (this._updateAnimationTimeoutId);
            this._updateAnimationTimeoutId = 0;
        }

        let i;
        let keys = Object.keys(this._fileWatches);
        for (i = 0; i < keys.length; i++) {
            this._cache.disconnect(this._fileWatches[keys[i]]);
        }
        this._fileWatches = null;

        if (this._pattern) {
            if (this._pattern.content)
                this._cache.removePatternContent(this._pattern.content);

            this._pattern.destroy();
            this._pattern = null;
        }

        keys = Object.keys(this._images);
        for (i = 0; i < keys.length; i++) {
            let actor = this._images[keys[i]];

            if (actor.content)
                this._cache.removeImageContent(actor.content);

            actor.destroy();
            this._images[keys[i]] = null;
        }

        this.actor.disconnect(this._destroySignalId);
        this._destroySignalId = 0;

        if (this._settingsChangedSignalId != 0)
            this._settings.disconnect(this._settingsChangedSignalId);
        this._settingsChangedSignalId = 0;
    },

    _setLoaded: function() {
        if (this.isLoaded)
            return;

        this.isLoaded = true;

        GLib.idle_add(GLib.PRIORITY_DEFAULT, Lang.bind(this, function() {
            this.emit('loaded');
            return GLib.SOURCE_REMOVE;
        }));
    },

    _loadPattern: function() {
        let colorString, res, color, secondColor;

        colorString = this._settings.get_string(PRIMARY_COLOR_KEY);
        [res, color] = Clutter.Color.from_string(colorString);
        colorString = this._settings.get_string(SECONDARY_COLOR_KEY);
        [res, secondColor] = Clutter.Color.from_string(colorString);

        let shadingType = this._settings.get_enum(COLOR_SHADING_TYPE_KEY);

        let content = this._cache.getPatternContent({ monitorIndex: this._monitorIndex,
                                                      effects: this._effects,
                                                      color: color,
                                                      secondColor: secondColor,
                                                      shadingType: shadingType });

        this._pattern = new Meta.BackgroundActor();
        this.actor.add_child(this._pattern);

        this._pattern.content = content;
    },

    _watchCacheFile: function(filename) {
        if (this._fileWatches[filename])
            return;

        let signalId = this._cache.connect('file-changed',
                                           Lang.bind(this, function(cache, changedFile) {
                                               if (changedFile == filename) {
                                                   this.emit('changed');
                                               }
                                           }));
        this._fileWatches[filename] = signalId;
    },

    _ensureImage: function(index) {
        if (this._images[index])
            return;

        let actor = new Meta.BackgroundActor();

        // The background pattern is the first actor in
        // the group, and all images should be above that.
        this.actor.insert_child_at_index(actor, index + 1);
        this._images[index] = actor;
    },

    _updateImage: function(index, content, filename) {
        content.brightness = this._brightness;
        content.vignette_sharpness = this._vignetteSharpness;

        let image = this._images[index];
        if (image.content)
            this._cache.removeImageContent(content);
        image.content = content;
        this._watchCacheFile(filename);
    },

    _updateAnimationProgress: function() {
        if (this._images[1])
            this._images[1].opacity = this._animation.transitionProgress * 255;

        this._queueUpdateAnimation();
    },

    _updateAnimation: function() {
        this._updateAnimationTimeoutId = 0;

        this._animation.update(this._layoutManager.monitors[this._monitorIndex]);
        let files = this._animation.keyFrameFiles;

        if (files.length == 0) {
            this._setLoaded();
            this._queueUpdateAnimation();
            return;
        }

        let numPendingImages = files.length;
        for (let i = 0; i < files.length; i++) {
            if (this._images[i] && this._images[i].content &&
                this._images[i].content.get_filename() == files[i]) {

                numPendingImages--;
                if (numPendingImages == 0)
                    this._updateAnimationProgress();
                continue;
            }
            this._cache.getImageContent({ monitorIndex: this._monitorIndex,
                                          effects: this._effects,
                                          style: this._style,
                                          filename: files[i],
                                          cancellable: this._cancellable,
                                          onFinished: Lang.bind(this, function(content, i) {
                                              numPendingImages--;

                                              if (!content) {
                                                  this._setLoaded();
                                                  if (numPendingImages == 0)
                                                      this._updateAnimationProgress();
                                                  return;
                                              }

                                              this._ensureImage(i);
                                              this._updateImage(i, content, files[i]);

                                              if (numPendingImages == 0) {
                                                  this._setLoaded();
                                                  this._updateAnimationProgress();
                                              }
                                          }, i)
                                        });
        }
    },

    _queueUpdateAnimation: function() {
        if (this._updateAnimationTimeoutId != 0)
            return;

        if (!this._cancellable || this._cancellable.is_cancelled())
            return;

        if (!this._animation.transitionDuration)
            return;

        let nSteps = 255 / ANIMATION_OPACITY_STEP_INCREMENT;
        let timePerStep = (this._animation.transitionDuration * 1000) / nSteps;

        let interval = Math.max(ANIMATION_MIN_WAKEUP_INTERVAL * 1000,
                                timePerStep);

        if (interval > GLib.MAXUINT32)
            return;

        this._updateAnimationTimeoutId = GLib.timeout_add(GLib.PRIORITY_DEFAULT,
                                                      interval,
                                                      Lang.bind(this, function() {
                                                                    this._updateAnimationTimeoutId = 0;
                                                                    this._updateAnimation();
                                                                    return GLib.SOURCE_REMOVE;
                                                                }));
    },

    _loadAnimation: function(filename) {
        this._cache.getAnimation({ filename: filename,
                                             onLoaded: Lang.bind(this, function(animation) {
                                                 this._animation = animation;

                                                 if (!this._animation || this._cancellable.is_cancelled()) {
                                                     this._setLoaded();
                                                     return;
                                                 }

                                                 this._updateAnimation();
                                                 this._watchCacheFile(filename);
                                             })
                                           });
    },

    _loadImage: function(filename) {
        this._cache.getImageContent({ monitorIndex: this._monitorIndex,
                                      effects: this._effects,
                                      style: this._style,
                                      filename: filename,
                                      cancellable: this._cancellable,
                                      onFinished: Lang.bind(this, function(content) {
                                          if (content) {
                                              this._ensureImage(0);
                                              this._updateImage(0, content, filename);
                                          }
                                          this._setLoaded();
                                      })
                                    });
    },

    _loadFile: function(filename) {
        if (filename.endsWith('.xml'))
            this._loadAnimation(filename);
        else
            this._loadImage(filename);
    },

    _load: function () {
        this._cache = getBackgroundCache();

        this._loadPattern();

        this._style = this._settings.get_enum(BACKGROUND_STYLE_KEY);
        if (this._style == GDesktopEnums.BackgroundStyle.NONE) {
            this._setLoaded();
            return;
        }

        let uri = this._settings.get_string(PICTURE_URI_KEY);
        let filename;
        if (GLib.uri_parse_scheme(uri) != null)
            filename = Gio.File.new_for_uri(uri).get_path();
        else
            filename = uri;

        if (!filename) {
            this._setLoaded();
            return;
        }

        this._loadFile(filename);
    },

    get brightness() {
        return this._brightness;
    },

    set brightness(factor) {
        this._brightness = factor;
        if (this._pattern && this._pattern.content)
            this._pattern.content.brightness = factor;

        let keys = Object.keys(this._images);
        for (let i = 0; i < keys.length; i++) {
            let image = this._images[keys[i]];
            if (image && image.content)
                image.content.brightness = factor;
        }
    },

    get vignetteSharpness() {
        return this._vignetteSharpness;
    },

    set vignetteSharpness(sharpness) {
        this._vignetteSharpness = sharpness;
        if (this._pattern && this._pattern.content)
            this._pattern.content.vignette_sharpness = sharpness;

        let keys = Object.keys(this._images);
        for (let i = 0; i < keys.length; i++) {
            let image = this._images[keys[i]];
            if (image && image.content)
                image.content.vignette_sharpness = sharpness;
        }
    }
});
Signals.addSignalMethods(Background.prototype);

const SystemBackground = new Lang.Class({
    Name: 'SystemBackground',

    _init: function() {
        this._cache = getBackgroundCache();
        this.actor = new Meta.BackgroundActor();

        this._cache.getImageContent({ style: GDesktopEnums.BackgroundStyle.WALLPAPER,
                                      filename: global.datadir + '/theme/noise-texture.png',
                                      effects: Meta.BackgroundEffects.NONE,
                                      onFinished: Lang.bind(this, function(content) {
                                          this.actor.content = content;
                                          this.emit('loaded');
                                      })
                                    });

        this.actor.connect('destroy', Lang.bind(this, this._onDestroy));
    },

    _onDestroy: function() {
        this._cache.removeImageContent(this.actor.content);
    },
});
Signals.addSignalMethods(SystemBackground.prototype);

const Animation = new Lang.Class({
    Name: 'Animation',

    _init: function(params) {
        params = Params.parse(params, { filename: null });

        this.filename = params.filename;
        this.keyFrameFiles = [];
        this.transitionProgress = 0.0;
        this.transitionDuration = 0.0;
        this.loaded = false;
    },

    load: function(callback) {
        let file = Gio.File.new_for_path(this.filename);

        this._show = new GnomeDesktop.BGSlideShow({ filename: this.filename });

        this._show.load_async(null,
                              Lang.bind(this,
                                        function(object, result) {
                                            this.loaded = true;
                                            if (callback)
                                                callback();
                                        }));
    },

    update: function(monitor) {
        this.keyFrameFiles = [];

        if (!this._show)
            return;

        if (this._show.get_num_slides() < 1)
            return;

        let [progress, duration, isFixed, file1, file2] = this._show.get_current_slide(monitor.width, monitor.height);

        this.transitionDuration = duration;
        this.transitionProgress = progress;

        if (file1)
            this.keyFrameFiles.push(file1);

        if (file2)
            this.keyFrameFiles.push(file2);
    },
});
Signals.addSignalMethods(Animation.prototype);

const BackgroundManager = new Lang.Class({
    Name: 'BackgroundManager',

    _init: function(params) {
        params = Params.parse(params, { container: null,
                                        layoutManager: Main.layoutManager,
                                        monitorIndex: null,
                                        effects: Meta.BackgroundEffects.NONE,
                                        controlPosition: true,
                                        settingsSchema: BACKGROUND_SCHEMA });

        this._settings = new Gio.Settings({ schema: params.settingsSchema });
        this._container = params.container;
        this._layoutManager = params.layoutManager;
        this._effects = params.effects;
        this._monitorIndex = params.monitorIndex;
        this._controlPosition = params.controlPosition;

        this.background = this._createBackground();
        this._newBackground = null;
    },

    destroy: function() {
        if (this._newBackground) {
            this._newBackground.actor.destroy();
            this._newBackground = null;
        }

        if (this.background) {
            this.background.actor.destroy();
            this.background = null;
        }
    },

    _updateBackground: function() {
        let newBackground = this._createBackground();
        newBackground.vignetteSharpness = this.background.vignetteSharpness;
        newBackground.brightness = this.background.brightness;
        newBackground.visible = this.background.visible;

        newBackground.loadedSignalId = newBackground.connect('loaded',
            Lang.bind(this, function() {
                newBackground.disconnect(newBackground.loadedSignalId);
                newBackground.loadedSignalId = 0;
                Tweener.addTween(this.background.actor,
                                 { opacity: 0,
                                   time: FADE_ANIMATION_TIME,
                                   transition: 'easeOutQuad',
                                   onComplete: Lang.bind(this, function() {
                                       if (this._newBackground != newBackground) {
                                           /* Not interesting, we queued another load */
                                           newBackground.actor.destroy();
                                           return;
                                       }

                                       this.background.actor.destroy();
                                       this.background = newBackground;
                                       this._newBackground = null;

                                       this.emit('changed');
                                   })
                                 });
        }));

        this._newBackground = newBackground;
    },

    _createBackground: function() {
        let background = new Background({ monitorIndex: this._monitorIndex,
                                          layoutManager: this._layoutManager,
                                          effects: this._effects,
                                          settings: this._settings });
        this._container.add_child(background.actor);

        let monitor = this._layoutManager.monitors[this._monitorIndex];

        background.actor.set_size(monitor.width, monitor.height);
        if (this._controlPosition) {
            background.actor.set_position(monitor.x, monitor.y);
            background.actor.lower_bottom();
        }

        background.changeSignalId = background.connect('changed', Lang.bind(this, function() {
            background.disconnect(background.changeSignalId);
            background.changeSignalId = 0;
            this._updateBackground();
        }));

        background.actor.connect('destroy', Lang.bind(this, function() {
            if (background.changeSignalId)
                background.disconnect(background.changeSignalId);

            if (background.loadedSignalId)
                background.disconnect(background.loadedSignalId);
        }));

        return background;
    },
});
Signals.addSignalMethods(BackgroundManager.prototype);