public class Tuba.Views.Timeline : AccountHolder, Streamable, Views.ContentBase {

	public string url { get; construct set; }
	public bool is_public { get; construct set; default = false; }
	private Type _accepts = typeof (API.Status);
	public Type accepts {
		get { return _accepts; }
		set {
			_accepts = value;
			update_time_signal ();
		}
	}
	#if !USE_LISTVIEW
		public bool use_queue { get; set; default = true; }
	#endif

	private int _batch_size_min = 10;
	public int batch_size_min {
		get { return _batch_size_min; }
		set {
			assert (value >= 10);
			_batch_size_min = value;
		}
	}
	protected InstanceAccount? account { get; set; default = null; }

	// forces the timeline to keep fetching pages until it gets at least
	// the minimum amount of items set by batch_size_min
	// useful for timelines that should_hide a lot
	public bool force_at_least_min { get; set; default = false; }
	public bool is_last_page { get; set; default = false; }
	public string? page_next { get; set; }
	public string? page_prev { get; set; }
	#if !USE_LISTVIEW
		Entity[] entity_queue = {};
		protected int entity_queue_size { get; set; default=0; }
	#endif

	private Adw.Spinner pull_to_refresh_spinner;
	private bool _is_pulling = false;
	private bool is_pulling {
		get {
			return _is_pulling;
		}
		set {
			if (_is_pulling != value) {
				if (value) {
					scrolled_overlay.add_overlay (pull_to_refresh_spinner);
					scrolled.sensitive = false;
				} else {
					scrolled_overlay.remove_overlay (pull_to_refresh_spinner);
					scrolled.sensitive = true;
					pull_to_refresh_spinner.margin_top = 32;
					pull_to_refresh_spinner.height_request = 32;
				}
				_is_pulling = value;
			}
		}
	}

	private void on_drag_update (double x, double y) {
		if (scrolled.vadjustment.value != 0.0 || (y <= 15 && !is_pulling)) return;
		is_pulling = true;

		double clean_y = y;
		if (y > 150) {
			clean_y = 150;
		} else if (y < -32) {
			clean_y = -32;
		}

		if (clean_y > 32) {
			pull_to_refresh_spinner.margin_top = (int) clean_y;
			pull_to_refresh_spinner.height_request = pull_to_refresh_spinner.width_request = 32;
		} else if (clean_y > 0) {
			pull_to_refresh_spinner.height_request = pull_to_refresh_spinner.width_request = (int) clean_y;
		} else {
			pull_to_refresh_spinner.margin_top = 32;
			pull_to_refresh_spinner.height_request = pull_to_refresh_spinner.width_request = 0;
		}
	}

	private void on_drag_end (double x, double y) {
		if (scrolled.vadjustment.value == 0.0 && pull_to_refresh_spinner.margin_top >= 125) {
			on_manual_refresh ();
		}

		is_pulling = false;
	}

	construct {
		empty_state_title = _("No Posts");

		pull_to_refresh_spinner = new Adw.Spinner () {
			height_request = 32,
			width_request = 32,
			margin_top = 32,
			margin_bottom = 32,
			halign = Gtk.Align.CENTER,
			valign = Gtk.Align.START,
			css_classes = { "osd", "circular-spinner" }
		};

		#if !USE_LISTVIEW
			reached_close_to_top.connect (finish_queue);
		#endif

		app.refresh.connect (refresh_if_mapped);
		status_button.clicked.connect (on_manual_refresh);

		construct_account_holder ();

		construct_streamable ();
		stream_event[InstanceAccount.EVENT_NEW_POST].connect (on_new_post);

		if (accepts == typeof (API.Status)) {
			stream_event[InstanceAccount.EVENT_EDIT_POST].connect (on_edit_post);
			stream_event[InstanceAccount.EVENT_DELETE_POST].connect (on_delete_post);
		}

		settings.notify["show-spoilers"].connect (on_refresh);
		settings.notify["show-preview-cards"].connect (on_refresh);
		settings.notify["enlarge-custom-emojis"].connect (on_refresh);

		#if !USE_LISTVIEW
			content.bind_model (model, on_create_model_widget);
		#endif

		var drag = new Gtk.GestureDrag ();
		drag.drag_update.connect (on_drag_update);
		drag.drag_end.connect (on_drag_end);
		this.add_controller (drag);

		var shortcutscontroller = new Gtk.ShortcutController ();
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl>0"),
			new Gtk.NamedAction ("app.reset-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl>KP_0"),
			new Gtk.NamedAction ("app.reset-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl>plus"),
			new Gtk.NamedAction ("app.increase-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl><Shift>plus"),
			new Gtk.NamedAction ("app.increase-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl>equal"),
			new Gtk.NamedAction ("app.increase-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl><Shift>equal"),
			new Gtk.NamedAction ("app.increase-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl>KP_Add"),
			new Gtk.NamedAction ("app.increase-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl><Shift>KP_Add"),
			new Gtk.NamedAction ("app.increase-font-size")
		));

		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl>minus"),
			new Gtk.NamedAction ("app.decrease-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl><Shift>minus"),
			new Gtk.NamedAction ("app.decrease-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl>underscore"),
			new Gtk.NamedAction ("app.decrease-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl><Shift>underscore"),
			new Gtk.NamedAction ("app.decrease-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl>KP_Subtract"),
			new Gtk.NamedAction ("app.decrease-font-size")
		));
		shortcutscontroller.add_shortcut (new Gtk.Shortcut (
			Gtk.ShortcutTrigger.parse_string ("<Ctrl><Shift>KP_Subtract"),
			new Gtk.NamedAction ("app.decrease-font-size")
		));
		this.add_controller (shortcutscontroller);

		update_time_signal ();
	}
	~Timeline () {
		debug (@"Destroying Timeline $label");

		destruct_account_holder ();
		destruct_streamable ();

		#if !USE_LISTVIEW
			content.bind_model (null, null);
			entity_queue = {};
			entity_queue_size = 0;
		#endif
	}

	protected void refresh_if_mapped () {
		if (!this.get_mapped ()) return;
		on_manual_refresh ();
	}

	private static Type[] acceptable_time_types = {
		typeof (API.Status),
		typeof (API.Conversation),
		typeof (API.Announcement),
		typeof (API.GroupedNotificationsResults.NotificationGroup),
		typeof (API.Notification)
	};
	private void update_time_signal () {
		if (accepts in acceptable_time_types) {
			if (!this.is_public) app.time_update.connect (on_time_update);
		} else {
			app.time_update.disconnect (on_time_update);
		}
	}

	private void on_time_update () {
		if (!this.get_mapped () || this.is_public) return;

		for (int i = 0; i < uint.min (model.n_items, 250); i++) {
			var status_widget = content.get_row_at_index (i) as Widgets.Status;
			if (status_widget != null) {
				status_widget.update_time ();
			}
		}
	}

	#if !USE_LISTVIEW
		public override void unbind_listboxes () {
			destruct_account_holder ();
			destruct_streamable ();
			base.unbind_listboxes ();
		}
	#endif

	public override void dispose () {
		destruct_streamable ();
		base.dispose ();
	}

	private void cleanup_timeline_api () {
		this.page_prev = null;
		this.page_next = null;
		this.is_last_page = false;
		this.needs_attention = false;
		this.badge_number = 0;
	}

	public override void clear () {
		if (request_cancellable != null) request_cancellable.cancel ();
		cleanup_timeline_api ();
		base.clear ();
	}

	protected override void clear_all_but_first (int i = 1) {
		cleanup_timeline_api ();
		base.clear_all_but_first (i);
	}

	public void get_pages (string? header) {
		page_next = page_prev = null;
		if (header == null) {
			is_last_page = true;
			return;
		};

		var pages = header.split (",");
		foreach (var page in pages) {
			var sanitized = page
				.replace ("<", "")
				.replace (">", "")
				.split (";")[0];

			if ("rel=\"prev\"" in page)
				page_prev = sanitized;
			else
				page_next = sanitized;
		}

		is_last_page = page_prev != null & page_next == null;
	}

	public virtual string get_req_url () {
		if (page_next != null)
			return page_next;
		return url;
	}

	//  public virtual Request append_params (Request req) {
	//  	if (page_next == null)
	//  		return req.with_param ("limit", settings.timeline_page_size.clamp (this.batch_size_min, 40).to_string ());
	//  	else
	//  		return req;
	//  }

	public virtual void append_params_v2 (RequestV2 req) {
		if (page_next == null)
			req.add_parameter ("limit", settings.timeline_page_size.clamp (this.batch_size_min, 40).to_string ());
	}

	protected bool has_finished_request { get; private set; default = false; }
	public virtual void on_request_finish () {
		has_finished_request = true;
		base.on_bottom_reached (); // **base.**
	}

	protected GLib.Cancellable? request_cancellable { get; set; default = null; }
	public async virtual void request () {
		if (request_cancellable != null) request_cancellable.cancel ();
		var req = new RequestV2 (get_req_url ()) {
			account = account,
			ctx = this
		};
		request_cancellable = req.cancellable;
		append_params_v2 (req);

		GLib.InputStream in_stream;
		Soup.MessageHeaders response_headers;

		try {
			in_stream = yield req.exec (out response_headers);
			Json.Parser parser = yield Network.get_parser_from_inputstream_async (in_stream);
			if (request_cancellable.is_cancelled ()) return;

			Object[] to_add = {};
			Network.parse_array (parser, node => {
				var e = Helper.Entity.from_json (node, accepts);
				if (!(should_hide (e))) to_add += e;
			});
			model.splice (model.get_n_items (), 0, to_add);

			if (response_headers != null)
				get_pages (response_headers.get_one ("Link"));

			if (to_add.length == 0)
				on_content_changed ();
			on_request_finish ();

			if (
				this.force_at_least_min
				&& (
					model.get_n_items () < this.batch_size_min
					|| to_add.length == 0
				)
			)
				on_bottom_reached ();
		} catch (GLib.IOError.CANCELLED e) {
			debug ("Message is cancelled.");
		} catch (GLib.Error e) {
			on_error (e.code, e.message);
		}
	}

	public override void on_error (int32 code, string reason) {
		if (base_status == null) {
			warning (@"Error while refreshing $label: $code $reason");

			app.toast ("%s: %s".printf (_("Network Error"), reason));
		} else {
			base.on_error (code, reason);
		}
	}

	public virtual void on_refresh () {
		#if !USE_LISTVIEW
			entity_queue = {};
			entity_queue_size = 0;
		#endif
		scrolled.vadjustment.value = 0;
		status_button.sensitive = false;
		clear ();
		base_status = new StatusMessage () { loading = true };
		has_finished_request = false;
		request.begin ();
	}

	public virtual void on_manual_refresh () {
		on_refresh ();
	}

	protected virtual void on_account_changed (InstanceAccount? acc) {
		account = acc;
		update_stream ();
		on_refresh ();
	}

	protected override void on_bottom_reached () {
		if (is_last_page) {
			debug ("Last page reached");
			return;
		}
		request.begin ();
	}



	// Streamable

	protected string? t_connection_url { get; set; }
	public bool subscribed { get; set; }

	protected override void on_streaming_policy_changed () {
		var allow_streaming = settings.live_updates;
		if (is_public)
			allow_streaming = allow_streaming && settings.public_live_updates;

		subscribed = allow_streaming;
	}

	public virtual string? get_stream_url () {
		return null;
	}

	public virtual bool should_hide (Entity entity) {
		var status_entity = entity as API.Status;
		if (status_entity != null) {
			return status_entity.formal.tuba_filter_hidden;
		}

		return false;
	}

	public virtual void on_new_post (Streamable.Event ev) {
		if (!has_finished_request) return;

		try {
			#if USE_LISTVIEW
				model.insert (0, Entity.from_json (accepts, ev.get_node ()));
			#else
				var entity = Entity.from_json (accepts, ev.get_node ());
				on_new_post_entity (entity);
			#endif
		} catch (Error e) {
			warning (@"Error getting Entity from json: $(e.message)");
		}
	}

	public void on_new_post_entity (Entity entity) {
		if (should_hide (entity)) return;

		if (use_queue && scrolled.vadjustment.value > 100) {
			entity_queue += entity;
			entity_queue_size += 1;
			return;
		}

		// This can occur on race conditions or multiple calls.
		// The post might already be in the timeline due to a refresh etc.
		// So just if the id exists already in the first page and remove it.
		if (accepts == typeof (API.Status)) {
			string e_id = ((API.Status) entity).id;
			for (uint i = 0; i < uint.min (model.n_items, settings.timeline_page_size.clamp (10, 40)); i++) {
				var status_obj = model.get_item (i) as API.Status;
				if (status_obj != null && status_obj.id == e_id) {
					safely_remove ((int) i);
				}
			}
		}

		model.insert (0, entity);
	}

	#if !USE_LISTVIEW
		private void finish_queue () {
			if (entity_queue.length == 0) return;
			model.splice (0, 0, (Object[])entity_queue);

			entity_queue = {};
			entity_queue_size = 0;
		}
	#endif


	public virtual void on_edit_post (Streamable.Event ev) {
		try {
			var entity = Entity.from_json (accepts, ev.get_node ());
			var entity_id = ((API.Status)entity).id;
			for (uint i = 0; i < model.get_n_items (); i++) {
				var status_obj = model.get_item (i) as API.Status;
				if (status_obj != null && status_obj.id == entity_id) {
					bool had_focus = was_focused ((int) i);
					model.remove (i);
					model.insert (i, entity);
					if (had_focus) focus_recover_actual ((int) i);
					break;
				}
			}
		} catch (Error e) {
			warning (@"Error getting Entity from json: $(e.message)");
		}
	}

	public virtual void on_delete_post (Streamable.Event ev) {
		try {
			var status_id = ev.get_string ();

			for (uint i = 0; i < model.get_n_items (); i++) {
				var status_obj = model.get_item (i) as API.Status;
				// Not sure if there can be both the original
				// and a boost of it at the same time.
				if (status_obj != null && (status_obj.id == status_id || status_obj.formal.id == status_id)) {
					safely_remove ((int) i);
					// If there can be both the original
					// and boosts at the same time, then
					// it shouldn't stop at the first find.
					break;
				}
			}
		} catch (Error e) {
			warning (@"Error getting String from json: $(e.message)");
		}
	}

	public virtual void on_remove_user (string user_id) {
		if (accepts != typeof (API.Status)) return;

		int should_refocus = -1;
		for (uint i = 0; i < model.get_n_items (); i++) {
			var status_obj = model.get_item (i) as API.Status;
			if (status_obj != null && ((status_obj.formal.account != null && status_obj.formal.account.id == user_id) || (status_obj.account != null && status_obj.account.id == user_id))) {
				if (was_focused ((int) i)) should_refocus = (int) i;
				model.remove (i);
			}
		}
		if (should_refocus > 0) focus_recover (should_refocus);
	}

	protected void safely_remove (int i) {
		bool refocus = was_focused (i);
		model.remove (i);
		if (refocus) focus_recover (i);
	}

	protected bool was_focused (int i) {
		if (this.get_mapped ()) {
			var w = content.get_row_at_index (i);
			if (w != null && w.get_mapped ()) {
				if (w.has_focus) {
					return true;
				} else {
					unowned var last_focus = app.main_window.get_focus ();
					return last_focus != null && last_focus is Gtk.Widget && last_focus.is_ancestor (w);
				}
			}
		}

		return false;
	}

	protected void focus_recover (int i) {
		if (this.get_mapped () && !focus_recover_actual (i)) {
			// try going backwards then
			focus_recover_actual (i - 1);
		}
	}

	protected bool focus_recover_actual (int i) {
		var w = content.get_row_at_index (i);
		if (w != null && w.get_mapped ()) {
			w.grab_focus ();
			return true;
		}

		return false;
	}
}
