// 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 QtQuick
import "../.."

Column {
    id: page

    signal close

    // mail-watcher's heartbeat, written every 60s. Read once per open: the
    // page is behind a Loader, so opening it rebuilds the FileView and reads
    // the current file. Watch is deliberately not used, because the heartbeat
    // is written by atomic replace (tmpfile + rename) and an inotify watch
    // held on the old inode dies with it.
    property bool watcherAlive: false
    property int watcherDead: 0
    property int watcherExpected: 0

    // The same staleness rule as mail-watcher's heartbeat_is_healthy: dead
    // threads or a heartbeat older than 300s mean the watcher needs a look.
    // Backoff is healthy, so it never turns the dot.
    function readHeartbeat(payload) {
        page.watcherAlive = false;
        page.watcherDead = 0;
        page.watcherExpected = 0;

        let data = null;
        try { data = JSON.parse(payload); } catch (e) { return; }
        if (!data || typeof data.ts !== "string") return;

        const ts = Date.parse(data.ts);
        if (isNaN(ts) || (Date.now() - ts) / 1000 > 300) return;

        page.watcherAlive = true;
        page.watcherDead = Number(data.dead) || 0;
        page.watcherExpected = Number(data.expected) || 0;
    }

    readonly property color watcherColor:
        !watcherAlive ? Theme.red
        : watcherDead > 0 ? Theme.yellow
        : Theme.green

    readonly property string watcherText:
        !watcherAlive ? "watcher not running"
        : watcherDead > 0 ? `${watcherDead} folder(s) dead, check the log`
        : `watcher ok · ${watcherExpected} folders`

    spacing: 10

    FileView {
        id: heartbeat
        path: `${Quickshell.env("HOME")}/.local/state/mail-watcher.heartbeat`
        onLoaded: page.readHeartbeat(text())
        onLoadFailed: page.readHeartbeat("")
    }

    Item {
        width: parent.width
        implicitHeight: totalText.implicitHeight

        Text {
            id: totalText
            anchors.right: parent.right
            // A dash rather than a possibly-wrong number while any account is
            // still unknown.
            text: Accounts.anyUnknown ? "—" : `${Accounts.total} unread`
            color: Theme.subtext
            font.family: Theme.fontFamily
            font.pixelSize: Theme.fontSize
        }
    }

    Text {
        visible: Accounts.error !== ""
        width: parent.width
        text: Accounts.error
        color: Theme.red
        wrapMode: Text.WordWrap
        font.family: Theme.fontFamily
        font.pixelSize: Theme.fontSize - 2
    }

    Repeater {
        model: Accounts.accounts

        Column {
            required property var modelData
            width: page.width
            spacing: 4

            Item {
                width: parent.width
                implicitHeight: 26

                Rectangle {
                    id: dot
                    anchors.verticalCenter: parent.verticalCenter
                    width: 8; height: 8; radius: 4
                    // The account's own colour from the config. Per-account
                    // identity, not a palette.
                    color: modelData.color || Theme.accent
                }

                Text {
                    anchors { left: dot.right; leftMargin: 10; verticalCenter: parent.verticalCenter }
                    text: modelData.label
                    color: Theme.text
                    font.family: Theme.fontFamily
                    font.pixelSize: Theme.fontSize
                }

                Text {
                    anchors { right: parent.right; verticalCenter: parent.verticalCenter }
                    text: modelData.count < 0 ? "—" : String(modelData.count)
                    color: modelData.count > 0 ? Theme.text : Theme.subtext
                    font.family: Theme.fontFamily
                    font.pixelSize: Theme.fontSize
                    font.bold: modelData.count > 0
                }
            }

            // The newest three unread threads. Read-only: qtmaildir takes no
            // arguments, so there is no way to ask it for a particular thread.
            Repeater {
                model: modelData.threads

                Column {
                    required property var modelData
                    width: page.width - 18
                    x: 18
                    spacing: 1
                    bottomPadding: 4

                    Item {
                        width: parent.width
                        implicitHeight: who.implicitHeight

                        Text {
                            id: who
                            anchors.left: parent.left
                            width: parent.width - when.implicitWidth - 10
                            text: modelData.authors
                            elide: Text.ElideRight
                            color: Theme.subtext
                            font.family: Theme.fontFamily
                            font.pixelSize: Theme.fontSize - 3
                        }

                        Text {
                            id: when
                            anchors.right: parent.right
                            text: modelData.date
                            color: Theme.overlay
                            font.family: Theme.fontFamily
                            font.pixelSize: Theme.fontSize - 3
                        }
                    }

                    Text {
                        width: parent.width
                        text: modelData.subject
                        elide: Text.ElideRight
                        color: Theme.text
                        font.family: Theme.fontFamily
                        font.pixelSize: Theme.fontSize - 2
                    }
                }
            }
        }
    }

    Rectangle { width: parent.width; height: 1; color: Qt.alpha(Theme.text, 0.12) }

    // Watcher health. Green when idling, yellow when a folder gave up, red
    // when there is no fresh heartbeat at all.
    Item {
        width: parent.width
        implicitHeight: 22

        Rectangle {
            id: watcherDot
            anchors.verticalCenter: parent.verticalCenter
            width: 8; height: 8; radius: 4
            color: page.watcherColor
        }

        Text {
            anchors { left: watcherDot.right; leftMargin: 10; verticalCenter: parent.verticalCenter }
            text: page.watcherText
            color: Theme.subtext
            font.family: Theme.fontFamily
            font.pixelSize: Theme.fontSize - 2
        }
    }

    Rectangle { width: parent.width; height: 1; color: Qt.alpha(Theme.text, 0.12) }

    Row {
        anchors.right: parent.right
        spacing: 10

        Button {
            text: "Open qtmaildir"
            onClicked: { Accounts.openClient(); page.close(); }
        }
    }
}