// The manual's table of contents, with the titles read from the manual itself.
//
// Chapter files are numbered so their order is their filename, and each one
// begins with its own title as a first-level heading. Reading that heading from
// the file rather than repeating it in QML means a chapter cannot be renamed in
// one place and not the other -- which is what had already happened by the time
// anybody compared the two. There is deliberately no `label:` beside a filename
// below; if one appears, the drift is back.
//
// Two pages need this list: the reader, and About's Manual card. Neither owns
// it, so it lives here and both instantiate it. This is the one place the
// chapter files are named.
//
// The chapters live beside the shell in manual/, reached through
// Quickshell.shellDir: that resolves whether or not the repository is where it
// usually is, and a path walked upward out of the shell directory does not.

import Quickshell
import Quickshell.Io
import QtQml
import QtQuick

Item {
    id: root

    // Display order is filename order.
    readonly property var chapters: [
        { file: "01-coming-from-another-desktop.md" },
        { file: "02-the-keyboard.md" },
        { file: "03-windows-and-workspaces.md" },
        { file: "04-when-something-breaks.md" },
        { file: "05-making-it-yours.md" }
    ]

    // file -> first heading, filled in as each file is read.
    property var headings: ({})

    // [{ file, title }]. A chapter whose file has not been read yet -- or
    // cannot be -- falls back to a title made out of its filename, so the list
    // is never blank and never a row of paths.
    readonly property var titled: root.chapters.map(chapter => ({
        file: chapter.file,
        title: String(root.headings[chapter.file] ?? "") !== ""
            ? root.headings[chapter.file]
            : root.titleFromFilename(chapter.file)
    }))

    function titleFromFilename(file: string): string {
        const stem = file.replace(/^\d+-/, "").replace(/\.md$/, "").replace(/-/g, " ");
        return stem.charAt(0).toUpperCase() + stem.slice(1);
    }

    // The first level-one heading, which every chapter opens with.
    function headingOf(text: string): string {
        for (const line of String(text ?? "").split("\n")) {
            const match = /^#\s+(.+?)\s*$/.exec(line);
            if (match)
                return match[1];
        }
        return "";
    }

    // Reassigned rather than mutated: a property change on a plain object does
    // not fire, and `titled` would keep answering with the old headings.
    function absorb(file: string, text: string): void {
        const next = Object.assign({}, root.headings);
        next[file] = root.headingOf(text);
        root.headings = next;
    }

    Instantiator {
        model: root.chapters

        delegate: FileView {
            required property var modelData

            path: Quickshell.shellDir + "/manual/" + modelData.file
            printErrors: false
            onLoaded: root.absorb(modelData.file, this.text())
            onLoadFailed: root.absorb(modelData.file, "")
        }
    }
}