import { ScrollView } from "std-widgets.slint";
import { AppTheme, LayoutMetrics } from "../design-system.slint";
import { TypeScale } from "../typography.slint";
import { ToolbarIconButton } from "controls.slint";

export struct ActionMenuEntry {
    id: string,
    title: string,
    icon: image,
    disabled: bool,
    destructive: bool,
}

// Application-owned action menu with one interaction and accessibility
// contract. Slint has no custom menu/menu-item accessibility roles, so
// the popup is exposed as a labeled list whose entries are buttons.
export component ActionMenu inherits Rectangle {
    in property <[ActionMenuEntry]> entries: [];
    in property <image> icon;
    in property <color> icon-color: AppTheme.secondary;
    in property <bool> compact: false;
    in property <bool> interactive: true;
    in property <string> tooltip-text;
    in property <string> trigger-accessible-id: "";
    in property <length> menu-width: 280px;
    in property <length> max-menu-height: 560px;
    in property <bool> align-right: true;
    callback activated(string);

    private property <length> item-height: root.compact ? LayoutMetrics.touch-target : 36px;
    private property <int> highlighted-index: -1;
    private property <length> scroll-y: 0px;
    private property <length> menu-visible-height: 0px;
    private property <bool> menu-open: menu-popup.is-open;

    width: root.compact ? LayoutMetrics.touch-target : LayoutMetrics.desktop-icon-button-size;
    height: root.compact ? LayoutMetrics.touch-target : LayoutMetrics.desktop-icon-button-size;

    function move-highlight(direction: int) {
        if root.entries.length == 0 { root.highlighted-index = -1; return; }
        root.highlighted-index = direction > 0
            ? (root.highlighted-index + 1 >= root.entries.length ? 0 : root.highlighted-index + 1)
            : (root.highlighted-index <= 0 ? root.entries.length - 1 : root.highlighted-index - 1);
        root.bring-highlight-into-view();
    }

    function bring-highlight-into-view() {
        if root.highlighted-index < 0 { return; }
        let item-y = 4px + root.highlighted-index * root.item-height;
        if item-y + root.scroll-y < 0px {
            root.scroll-y = -item-y;
        } else if item-y + root.item-height + root.scroll-y > root.menu-visible-height {
            root.scroll-y = root.menu-visible-height - item-y - root.item-height;
        }
    }

    function activate-highlighted(pointer: bool) {
        if root.highlighted-index < 0 || root.entries[root.highlighted-index].disabled {
            return;
        }
        let id = root.entries[root.highlighted-index].id;
        menu-popup.close();
        trigger.focus();
        if pointer { trigger.pointer-activated(); }
        root.activated(id);
    }

    trigger := ToolbarIconButton {
        compact: root.compact;
        width: parent.width;
        height: parent.height;
        interactive: root.interactive;
        icon: root.icon;
        icon-color: root.icon-color;
        idle-background: AppTheme.control-bg;
        hover-background: AppTheme.muted-control-bg;
        active-background: AppTheme.muted-control-bg;
        active: root.menu-open;
        tooltip-text: root.tooltip-text;
        accessible-id: root.trigger-accessible-id;
        accessible-expanded: root.menu-open;
        clicked => {
            if root.menu-open {
                menu-popup.close();
            } else {
                root.scroll-y = 0px;
                root.highlighted-index = root.entries.length > 0 ? 0 : -1;
                menu-popup.show();
            }
        }
    }

    menu-popup := PopupWindow {
        x: root.align-right ? root.width - self.width : 0px;
        y: root.height + 4px;
        width: root.menu-width;
        height: min(root.max-menu-height, root.entries.length * root.item-height + 8px);
        close-policy: close-on-click-outside;
        forward-focus: menu-focus;

        menu-frame := Rectangle {
            border-radius: 8px;
            border-width: 1px;
            border-color: AppTheme.border;
            background: AppTheme.surface-raised;
            drop-shadow-blur: 18px;
            drop-shadow-offset-y: 5px;
            drop-shadow-color: #0000002e;
            clip: true;
            accessible-role: groupbox;
            accessible-label: root.tooltip-text;

            menu-focus := FocusScope {
                capture-key-pressed(event) => {
                    if event.text == Key.DownArrow {
                        root.move-highlight(1);
                        return accept;
                    }
                    if event.text == Key.UpArrow {
                        root.move-highlight(-1);
                        return accept;
                    }
                    if event.text == Key.Home {
                        root.highlighted-index = root.entries.length > 0 ? 0 : -1;
                        root.bring-highlight-into-view();
                        return accept;
                    }
                    if event.text == Key.End {
                        root.highlighted-index = root.entries.length - 1;
                        root.bring-highlight-into-view();
                        return accept;
                    }
                    if event.text == Key.Return || event.text == Key.Space {
                        root.activate-highlighted(false);
                        return accept;
                    }
                    if event.text == Key.Escape || event.text == Key.LeftArrow {
                        menu-popup.close();
                        trigger.focus();
                        return accept;
                    }
                    if event.text == Key.Tab {
                        menu-popup.close();
                        trigger.focus();
                        return reject;
                    }
                    reject
                }

                menu-scroll := ScrollView {
                    accessible-role: list;
                    accessible-label: root.tooltip-text;
                    accessible-item-count: root.entries.length;
                    content-y <=> root.scroll-y;
                    content-height: max(self.visible-height, root.entries.length * root.item-height + 8px);
                    horizontal-scrollbar-policy: as-needed;
                    changed visible-height => { root.menu-visible-height = self.visible-height; }

                    VerticalLayout {
                        padding: 4px;
                        spacing: 0px;

                        for entry[index] in root.entries : menu-row := Rectangle {
                            height: root.item-height;
                            border-radius: 5px;
                            background: index == root.highlighted-index || menu-hit.has-hover
                                ? AppTheme.control-bg : transparent;
                            opacity: entry.disabled ? 0.45 : 1;

                            Image {
                                x: 18px - self.width / 2;
                                y: (parent.height - self.height) / 2;
                                width: LayoutMetrics.icon-size;
                                height: LayoutMetrics.icon-size;
                                source: entry.icon;
                                colorize: entry.destructive ? AppTheme.destructive : AppTheme.secondary;
                                image-fit: contain;
                                accessible-role: none;
                            }

                            Text {
                                x: 36px;
                                width: parent.width - 48px;
                                height: parent.height;
                                text: entry.title;
                                color: entry.destructive ? AppTheme.destructive : AppTheme.heading;
                                font-size: TypeScale.body;
                                font-weight: 500;
                                vertical-alignment: center;
                                overflow: elide;
                            }

                            menu-hit := TouchArea {
                                enabled: !entry.disabled;
                                accessible-role: button;
                                accessible-label: entry.title;
                                accessible-item-index: index;
                                accessible-action-default => {
                                    root.highlighted-index = index;
                                    root.activate-highlighted(false);
                                }
                                changed has-hover => {
                                    if self.has-hover && !entry.disabled {
                                        root.highlighted-index = index;
                                    }
                                }
                                clicked => {
                                    root.highlighted-index = index;
                                    root.activate-highlighted(true);
                                }
                                mouse-cursor: entry.disabled ? default : pointer;
                            }
                        }
                    }
                }
            }
        }
    }
}