// Copyright (C) 2026 Danilo M. <danix@danix.xyz>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2 as
// published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

import Quickshell
import Quickshell.Io
import Quickshell.Wayland
import QtQuick

Scope {
    id: root

    property bool open: false
    property string monitor: "DP-1"
    property var items: []
    property string query: ""

    // Horizontal shear of the strip's tiles, as a fraction of their height.
    readonly property real slant: -0.25
    readonly property int step: 210

    readonly property var screenObj:
        Quickshell.screens.find(s => s.name === root.monitor) ?? Quickshell.screens[0]

    readonly property var shown: {
        const q = root.query.toLowerCase();
        return root.items.filter(g => g.name.toLowerCase().includes(q));
    }

    // The strip is a loop, so the list repeats until it fills the screen
    // width: a short library would otherwise leave gaps in the circle.
    readonly property var reel: {
        if (!root.shown.length) return [];
        const slots = Math.ceil(root.screenObj.width / root.step) + 2;
        let out = [];
        while (out.length < slots) out = out.concat(root.shown);
        return out;
    }

    function launch(g) {
        if (!g) return;
        // -silent keeps the Steam window down whether or not Steam is running.
        // Ids are strings: a shortcut's game id does not fit a JS number.
        Quickshell.execDetached(["steam", "-silent",
            g.installed ? `steam://rungameid/${g.id}` : `steam://install/${g.appid}`]);
        root.open = false;
    }

    // The list is read on every opening; the owned games come from a cache
    // that a Web API call refreshes in the background, then the list is
    // read again.
    onOpenChanged: if (open) {
        root.query = "";
        list.running = true;
        refresh.running = true;
    }

    Process {
        id: list
        command: ["/usr/bin/python3", `${Quickshell.shellDir}/games.py`]
        stdout: StdioCollector {
            onStreamFinished: {
                try { root.items = JSON.parse(text); } catch (e) { root.items = []; }
            }
        }
    }

    Process {
        id: refresh
        command: ["/usr/bin/python3", `${Quickshell.shellDir}/games.py`, "--refresh"]
        onExited: code => { if (code === 0 && root.open) list.running = true; }
    }

    // A config with no visible window exits, reporting nothing. This 1x1
    // click-through window holds the shell open while the overlay is hidden.
    PanelWindow {
        anchors { top: true; left: true }
        implicitWidth: 1
        implicitHeight: 1
        color: "transparent"
        exclusionMode: ExclusionMode.Ignore
        mask: Region {}
        WlrLayershell.keyboardFocus: WlrKeyboardFocus.None
    }

    LazyLoader {
        active: root.open

        PanelWindow {
            id: win
            readonly property var game: root.reel[strip.currentIndex]
            readonly property color bg: Qt.rgba(Theme.crust.r, Theme.crust.g, Theme.crust.b, 0.94)

            screen: root.screenObj
            anchors { top: true; left: true; right: true; bottom: true }
            color: win.bg
            exclusionMode: ExclusionMode.Ignore
            WlrLayershell.layer: WlrLayer.Overlay
            WlrLayershell.namespace: "keystone-games"
            WlrLayershell.keyboardFocus: WlrKeyboardFocus.Exclusive

            MouseArea {
                anchors.fill: parent
                onClicked: root.open = false
            }

            // The selected game, large: Steam's wide hero art, or the cover
            // when there is none, fading into the background at the bottom.
            Item {
                anchors { top: parent.top; left: parent.left; right: parent.right; bottom: strip.top }

                Image {
                    anchors.fill: parent
                    source: win.game ? (win.game.hero || win.game.cover ? `file://${win.game.hero || win.game.cover}` : "") : ""
                    fillMode: Image.PreserveAspectCrop
                    asynchronous: true
                }

                Rectangle {
                    anchors.fill: parent
                    gradient: Gradient {
                        GradientStop { position: 0.45; color: "transparent" }
                        GradientStop { position: 1.0; color: win.bg }
                    }
                }

                Column {
                    anchors { left: parent.left; bottom: parent.bottom; margins: 80 }
                    spacing: 8

                    Text {
                        text: win.game?.name ?? (root.items.length ? "No match" : "")
                        color: Theme.text
                        font.family: Theme.fontFamily
                        font.pixelSize: 56
                        font.bold: true
                    }
                    Text {
                        visible: !!win.game
                        text: !win.game ? ""
                            : !win.game.installed ? "Not installed  ·  Enter installs"
                            : win.game.last ? `Last played ${new Date(win.game.last * 1000).toLocaleDateString(Qt.locale(), "d MMMM yyyy")}`
                            : "Never played"
                        color: win.game?.installed ? Theme.subtext : Theme.peach
                        font.family: Theme.fontFamily
                        font.pixelSize: 20
                    }
                }
            }

            // Keys reach a focused item, not a window: the search field
            // takes them all and steers the strip. It shows only what is typed.
            TextInput {
                id: field
                anchors { right: parent.right; top: parent.top; margins: 60 }
                focus: true
                color: Theme.text
                font.family: Theme.fontFamily
                font.pixelSize: 28
                onTextEdited: root.query = text

                Keys.onEscapePressed: root.open = false
                Keys.onLeftPressed: strip.decrementCurrentIndex()
                Keys.onRightPressed: strip.incrementCurrentIndex()
                Keys.onReturnPressed: root.launch(win.game)
                Keys.onEnterPressed: root.launch(win.game)
            }

            // An endless strip: PathView wraps, and the tile at the centre
            // is the selection.
            PathView {
                id: strip
                anchors { left: parent.left; right: parent.right; bottom: parent.bottom; bottomMargin: 120 }
                height: 300
                model: root.reel
                pathItemCount: Math.min(count, Math.ceil((width + 2 * root.step) / root.step))
                preferredHighlightBegin: 0.5
                preferredHighlightEnd: 0.5
                highlightRangeMode: PathView.StrictlyEnforceRange
                highlightMoveDuration: 220
                onModelChanged: currentIndex = 0

                path: Path {
                    startX: -root.step
                    startY: strip.height / 2
                    PathLine { x: strip.width + root.step; y: strip.height / 2 }
                }

                delegate: Item {
                    id: tile
                    required property var modelData
                    required property int index
                    readonly property bool current: PathView.isCurrentItem
                    width: 160
                    height: 160
                    z: current ? 1 : 0
                    scale: current ? 1.5 : 1
                    Behavior on scale { NumberAnimation { duration: 160 } }

                    // A parallelogram: the tile is sheared about its middle
                    // and clips to that shape; the art inside is sheared back
                    // so it stands straight, and widened to reach both edges.
                    Item {
                        anchors.fill: parent
                        clip: true
                        transform: Matrix4x4 {
                            matrix: Qt.matrix4x4(1, root.slant, 0, -root.slant * tile.height / 2,
                                                 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1)
                        }

                        Rectangle { anchors.fill: parent; color: Theme.surface }

                        Image {
                            x: -tile.height * Math.abs(root.slant) / 2
                            width: parent.width + tile.height * Math.abs(root.slant)
                            height: parent.height
                            transform: Matrix4x4 {
                                matrix: Qt.matrix4x4(1, -root.slant, 0, root.slant * tile.height / 2,
                                                     0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1)
                            }
                            source: tile.modelData.cover ? `file://${tile.modelData.cover}` : ""
                            sourceSize.width: 480
                            fillMode: Image.PreserveAspectCrop
                            asynchronous: true
                            // Not installed: greyed until selected.
                            opacity: tile.modelData.installed || tile.current ? 1 : 0.35
                        }

                        // No cover: the initial stands in for it.
                        Text {
                            anchors.centerIn: parent
                            visible: !tile.modelData.cover
                            text: tile.modelData.name.charAt(0)
                            color: Theme.text
                            font.family: Theme.fontFamily
                            font.pixelSize: 64
                            font.bold: true
                        }

                        // Not installed: a peach frame, the colour of the
                        // preview's "Not installed" line.
                        Rectangle {
                            anchors.fill: parent
                            color: "transparent"
                            border.width: tile.current ? 3 : tile.modelData.installed ? 0 : 2
                            border.color: tile.modelData.installed ? Theme.accent : Theme.peach
                        }
                    }

                    MouseArea {
                        anchors.fill: parent
                        onClicked: tile.current ? root.launch(tile.modelData) : strip.currentIndex = tile.index
                    }
                }

                // The wheel steps one tile a notch.
                MouseArea {
                    anchors.fill: parent
                    acceptedButtons: Qt.NoButton
                    onWheel: wheel => {
                        const d = wheel.angleDelta.y || wheel.angleDelta.x;
                        if (d < 0) strip.incrementCurrentIndex();
                        else if (d > 0) strip.decrementCurrentIndex();
                    }
                }
            }
        }
    }
}