//! In-app **Markdown cheatsheet** window: a quick reference for the markdown
//! md-manuscript understands, plus the manuscript-specific conventions (chapter
//! metadata, the draft-marker header, and comments) applied at export time.
//!
//! Pure rendering — the caller owns the `open` flag so the window's ✕ works via
//! [`egui::Window::open`].

use eframe::egui;

/// The Markdown syntax cheatsheet window.
pub fn cheatsheet_window(ctx: &egui::Context, open: &mut bool) {
    egui::Window::new("📝 Markdown Cheatsheet")
        .open(open)
        .resizable(true)
        .default_width(560.0)
        .default_height(560.0)
        .show(ctx, |ui| {
            egui::ScrollArea::vertical().show(ui, cheatsheet_body);
        });
}

fn cheatsheet_body(ui: &mut egui::Ui) {
    intro(
        ui,
        "The markdown md-manuscript renders on export. Left column is what you type.",
    );

    section(ui, "Headings");
    syntax(
        ui,
        "cs-headings",
        &[
            ("# Heading", "A top-level heading (nested under the chapter title on export)."),
            ("## Sub-heading", "A second-level heading; deeper levels use more #."),
        ],
    );
    note(
        ui,
        "On export, every heading is pushed down one level so it sits beneath the \
         chapter's own title. See “Chapter metadata” below for setting that title.",
    );

    section(ui, "Emphasis & inline");
    syntax(
        ui,
        "cs-inline",
        &[
            ("**bold**", "Bold text."),
            ("*italic*", "Italic text (also _italic_)."),
            ("***bold italic***", "Both at once."),
            ("~~strike~~", "Strikethrough."),
            ("`code`", "Inline monospaced code."),
            ("[text](https://url)", "A hyperlink."),
        ],
    );

    section(ui, "Formatting hotkeys");
    syntax(
        ui,
        "cs-keys",
        &[
            ("Ctrl/Cmd + B", "Bold the selection (**…**)."),
            ("Ctrl/Cmd + I", "Italicise the selection (*…*)."),
            ("Ctrl/Cmd + E", "Inline code (`…`)."),
            ("Ctrl/Cmd + Shift + X", "Strikethrough (~~…~~)."),
            ("Ctrl/Cmd + K", "Wrap as a link and select the url to replace."),
            ("Ctrl/Cmd + F", "Open the find bar."),
            ("Ctrl/Cmd + H", "Open find/replace (replace field focused)."),
        ],
    );
    note(
        ui,
        "Wrapping keys apply to the selected text (or the caret, for an empty \
         selection); pressing the same key on already-wrapped text removes the \
         markers. In the find bar, Enter / Shift+Enter step through matches and \
         Esc closes it.",
    );

    section(ui, "Paragraphs & breaks");
    syntax(
        ui,
        "cs-para",
        &[
            ("blank line", "Separates paragraphs."),
            ("--- (on its own line)", "A horizontal rule — handy as a scene break."),
        ],
    );

    section(ui, "Lists");
    syntax(
        ui,
        "cs-lists",
        &[
            ("- item", "An unordered list item (also * item or + item)."),
            ("  - nested", "Indent two spaces to nest a sub-item."),
            ("1. item", "An ordered (numbered) list item."),
            ("> quote", "A blockquote."),
        ],
    );

    section(ui, "Code blocks");
    syntax(
        ui,
        "cs-code",
        &[
            ("```", "Open and close a fenced code block on their own lines."),
            ("    four-space indent", "An indented code block."),
        ],
    );

    section(ui, "Chapter metadata");
    syntax(
        ui,
        "cs-meta",
        &[
            ("# Title: Chapter Name", "Sets this file's chapter heading on export."),
            ("# Slug: a caption", "A caption shown beneath the chapter title."),
        ],
    );
    note(
        ui,
        "These lines are lifted out and removed from the exported prose. Without a \
         # Title:, the chapter falls back to a manual override (the title field) or \
         its position number.",
    );

    section(ui, "Editorial header & comments");
    syntax(
        ui,
        "cs-header",
        &[
            ("### Rough Draft:", "The draft marker — everything above it is your working header."),
            ("<!-- note -->", "A comment; dropped on export (may span multiple lines)."),
        ],
    );
    note(
        ui,
        "The draft marker text is configurable in the top bar. Everything above the \
         marker line is treated as notes and left out of the export; leave the marker \
         blank to export the whole file. Comments are removed everywhere.",
    );

    section(ui, "Grammar & spelling");
    body(
        ui,
        "Press ✓ Check (or the Grammar panel) to run the current file through your \
         LanguageTool server — configure it in Settings ▸ LanguageTool. Spelling issues \
         are underlined in red, grammar/style in blue.",
    );
}

// --- small rendering helpers --------------------------------------------------

fn intro(ui: &mut egui::Ui, text: &str) {
    ui.label(egui::RichText::new(text).italics().weak());
    ui.add_space(4.0);
}

fn section(ui: &mut egui::Ui, title: &str) {
    ui.add_space(8.0);
    ui.heading(title);
    ui.separator();
}

fn body(ui: &mut egui::Ui, text: &str) {
    ui.label(text);
}

fn note(ui: &mut egui::Ui, text: &str) {
    ui.add_space(2.0);
    ui.label(egui::RichText::new(format!("ⓘ {text}")).small().weak());
}

/// A two-column grid of `syntax/meaning` rows (syntax in a highlighted monospace).
fn syntax(ui: &mut egui::Ui, id: &str, rows: &[(&str, &str)]) {
    egui::Grid::new(id)
        .num_columns(2)
        .striped(true)
        .spacing([18.0, 4.0])
        .show(ui, |ui| {
            for (s, v) in rows {
                ui.label(
                    egui::RichText::new(*s)
                        .monospace()
                        .color(egui::Color32::from_rgb(120, 170, 120)),
                );
                ui.label(*v);
                ui.end_row();
            }
        });
}