using Gee;
using Gdk;
using Gtk;

using Dino.Entities;

namespace Dino.Ui {

public class AccountSwitcher : Box {

    public signal void account_filter_changed(Account? account);

    public Account? selected_account { get; private set; default = null; }

    private StreamInteractor stream_interactor;
    private Box bars_box = new Box(Orientation.HORIZONTAL, 0);
    private HashMap<Account, AccountColorBar> bars = new HashMap<Account, AccountColorBar>(Account.hash_func, Account.equals_func);
    private AllAccountsBar? all_bar = null;
    private ulong account_color_changed_handler_id = 0;

    construct {
        orientation = Orientation.HORIZONTAL;
        add_css_class("dino-account-switcher");
        bars_box.margin_start = 0;
        bars_box.margin_end = 0;
        bars_box.margin_top = 0;
        bars_box.margin_bottom = 0;
        bars_box.hexpand = true;
        bars_box.halign = Align.FILL;
        bars_box.add_css_class("dino-account-switcher-bars");
        append(bars_box);
    }

    public AccountSwitcher init(StreamInteractor stream_interactor) {
        this.stream_interactor = stream_interactor;

        stream_interactor.account_added.connect(on_account_added);
        stream_interactor.account_removed.connect(on_account_removed);
        account_color_changed_handler_id = Dino.Application.get_default().settings.account_color_changed.connect(on_account_color_changed);

        rebuild();

        weak_ref((self_obj) => {
            AccountSwitcher self = (AccountSwitcher) self_obj;
            self.stream_interactor.account_added.disconnect(self.on_account_added);
            self.stream_interactor.account_removed.disconnect(self.on_account_removed);
            if (self.account_color_changed_handler_id != 0) {
                Dino.Application.get_default().settings.disconnect(self.account_color_changed_handler_id);
                self.account_color_changed_handler_id = 0;
            }
        });

        return this;
    }

    private void rebuild() {
        Widget? child = bars_box.get_first_child();
        while (child != null) {
            Widget? next = child.get_next_sibling();
            bars_box.remove(child);
            child = next;
        }
        bars.clear();

        Gee.List<Account> accounts = stream_interactor.get_accounts();
        all_bar = new AllAccountsBar(accounts);
        all_bar.clicked.connect(on_all_clicked);
        bars_box.append(all_bar);

        foreach (Account account in accounts) {
            add_account(account);
        }

        if (selected_account != null && !bars.has_key(selected_account)) {
            selected_account = null;
            account_filter_changed(null);
        }

        update_selection();
    }

    private void on_account_added(Account account) {
        if (bars.has_key(account)) return;
        add_account(account);
        if (all_bar != null) all_bar.set_accounts(stream_interactor.get_accounts());
        update_selection();
    }

    private void on_account_removed(Account account) {
        if (bars.has_key(account)) {
            AccountColorBar bar = bars[account];
            bars.unset(account);
            bars_box.remove(bar);
        }

        if (all_bar != null) all_bar.set_accounts(stream_interactor.get_accounts());

        if (selected_account != null && selected_account.equals(account)) {
            selected_account = null;
            update_selection();
            account_filter_changed(null);
        }
    }

    private void add_account(Account account) {
        AccountColorBar bar = new AccountColorBar(account);
        bar.clicked.connect(() => on_bar_clicked(account));
        bars_box.append(bar);
        bars[account] = bar;
    }

    private void on_all_clicked() {
        if (selected_account == null) return;

        selected_account = null;
        update_selection();
        account_filter_changed(null);
    }

    private void on_bar_clicked(Account account) {
        if (selected_account != null && selected_account.equals(account)) {
            selected_account = null;
        } else {
            selected_account = account;
        }

        update_selection();
        account_filter_changed(selected_account);
    }

    private void update_selection() {
        if (all_bar != null) {
            all_bar.set_active(selected_account == null);
        }
        foreach (var entry in bars.entries) {
            entry.value.set_active(selected_account != null && entry.key.equals(selected_account));
        }
    }

    private void on_account_color_changed(Account account, string color) {
        if (bars.has_key(account)) {
            bars[account].redraw();
        }
        if (all_bar != null) {
            all_bar.redraw();
        }
    }
}

private class AccountColorBar : Button {

    public Account account { get; private set; }

    private DrawingArea drawing_area = new DrawingArea() { hexpand=true, vexpand=true };
    private double bar_opacity = 1.0;

    public AccountColorBar(Account account) {
        this.account = account;

        add_css_class("flat");
        add_css_class("dino-account-color-bar");
        hexpand = true;
        set_child(drawing_area);
        drawing_area.set_draw_func(draw);

        set_tooltip_text(account.display_name);
    }

    public void set_active(bool active) {
        bar_opacity = active ? 1.0 : 0.4;
        redraw();
    }

    public void redraw() {
        drawing_area.queue_draw();
    }

    private void draw(DrawingArea area, Cairo.Context context, int width, int height) {
        RGBA color = RGBA();
        if (!color.parse(Dino.Application.get_default().settings.get_account_color(account))) return;

        color.alpha = (float) (color.alpha * bar_opacity);
        Gdk.cairo_set_source_rgba(context, color);
        context.rectangle(0, 0, width, height);
        context.fill();
    }
}

private class AllAccountsBar : Button {

    private Gee.List<Account>? accounts = null;
    private DrawingArea drawing_area = new DrawingArea() { hexpand=true, vexpand=true };

    public AllAccountsBar(Gee.List<Account> accounts) {
        this.accounts = accounts;

        add_css_class("flat");
        add_css_class("dino-account-color-bar");
        add_css_class("dino-account-all-bar");
        set_child(drawing_area);
        drawing_area.set_draw_func(draw);
        set_tooltip_text(_("All conversations"));
    }

    public void set_accounts(Gee.List<Account> accounts) {
        this.accounts = accounts;
        redraw();
    }

    public void redraw() {
        drawing_area.queue_draw();
    }

    public void set_active(bool active) {
        if (active) {
            remove_css_class("dimmed");
        } else {
            add_css_class("dimmed");
        }
    }

    private void draw(DrawingArea area, Cairo.Context context, int width, int height) {
        if (accounts == null || accounts.size == 0) {
            context.set_source_rgba(0.5, 0.5, 0.5, 0.3);
            context.rectangle(0, 0, width, height);
            context.fill();
            return;
        }

        if (accounts.size == 1) {
            RGBA color = RGBA();
            if (!color.parse(Dino.Application.get_default().settings.get_account_color(accounts[0]))) return;
            Gdk.cairo_set_source_rgba(context, color);
            context.rectangle(0, 0, width, height);
            context.fill();
            return;
        }

        Cairo.Pattern gradient = new Cairo.Pattern.linear(0, 0, width, 0);
        for (int i = 0; i < accounts.size; i++) {
            RGBA color = RGBA();
            if (!color.parse(Dino.Application.get_default().settings.get_account_color(accounts[i]))) continue;
            gradient.add_color_stop_rgba((double) i / (accounts.size - 1), color.red, color.green, color.blue, color.alpha);
        }

        context.set_source(gradient);
        context.rectangle(0, 0, width, height);
        context.fill();
    }
}

}