//! PDF viewer tab: embeds the Tauri-served PDF viewer in an iframe.
//!
//! The custom `brittle://` URI scheme serves:
//!   - `brittle://app/viewer?ref_id=<uuid>` — the viewer HTML page (PDF.js)
//!   - `brittle://app/pdf?ref_id=<uuid>`    — the raw PDF bytes
//!
//! Using an `<iframe>` keeps the viewer alive when the tab is hidden (via
//! `display:none`), so scrolling position and zoom are preserved across
//! tab switches.

use brittle_keymap::actions;
use leptos::prelude::*;
use wasm_bindgen::JsValue;

/// Renders the PDF viewer for a single reference.
///
/// `ref_id` must be the UUID string of a reference that has an attached PDF.
/// `is_active` indicates whether this is the currently visible PDF tab; when
/// `true`, keymap actions for PDF page navigation are forwarded into the iframe.
#[component]
pub fn PdfViewer(
    ref_id: String,
    is_active: Signal<bool>,
    initial_zoom: Option<f64>,
    initial_scroll_top: Option<f64>,
) -> impl IntoView {
    let mut url = format!("brittle://app/viewer?ref_id={ref_id}");
    if let Some(z) = initial_zoom       { url.push_str(&format!("&zoom={z}")); }
    if let Some(s) = initial_scroll_top { url.push_str(&format!("&scroll_top={s}")); }

    let iframe_ref = NodeRef::<leptos::html::Iframe>::new();

    let keymap_action = use_context::<crate::KeymapAction>()
        .expect("KeymapAction context missing")
        .0;

    Effect::new(move |_| {
        let Some(ev) = keymap_action.get() else { return };
        if !is_active.get_untracked() { return }

        let cmd = match ev.name.as_str() {
            actions::PDF_PAGE_NEXT => actions::PDF_PAGE_NEXT,
            actions::PDF_PAGE_PREV => actions::PDF_PAGE_PREV,
            _ => return,
        };

        let Some(iframe) = iframe_ref.get() else { return };
        if let Some(win) = iframe.content_window() {
            let _ = win.post_message(&JsValue::from_str(cmd), "*");
        }
    });

    view! {
        <iframe
            node_ref=iframe_ref
            class="pdf-frame"
            src=url
            // Intentionally no `sandbox` attribute — the brittle:// protocol
            // and PDF.js require unrestricted access within the webview.
        />
    }
}