designcraft/apps/designcraft-web/src/web.rs

//! The browser shell: web `Services`, drag-and-drop, and the eframe web runner.

use super::browser_policy::{has_query_flag, mime_for};
use designcraft_engine::Session;
use designcraft_ui_egui::{DesignApp, ImportRequest, ImportedFile, Inbox, Services};
use wasm_bindgen::JsCast as _;

const DOC_EXTS: &[&str] = &["designcraft", "idml", "indd", "indt"];
const IMAGE_EXTS: &[&str] = &[
    "png",
    "jpg",
    "jpeg",
    "gif",
    "webp",
    "tif",
    "tiff",
    "bmp",
    "psd",
    "svg",
    "pdf",
    "ai",
    "txt",
    "docx",
    "rtf",
    "md",
    "xlsx",
    "idml",
    "designcraft",
];
const CANVAS_ID: &str = "designcraft_canvas";
const LOADING_ID: &str = "designcraft_loading";

pub fn start() {
    eframe::WebLogger::init(log::LevelFilter::Info).ok();
    wasm_bindgen_futures::spawn_local(async {
        let Some(document) = web_sys::window().and_then(|w| w.document()) else {
            log::error!("no document");
            return;
        };
        let Some(canvas) = document.get_element_by_id(CANVAS_ID).and_then(|e| e.dyn_into::<web_sys::HtmlCanvasElement>().ok()) else {
            log::error!("missing <canvas id=\"{CANVAS_ID}\">");
            return;
        };
        let mut options = eframe::WebOptions::default();
        if has_query_flag(&query(), "webgl")
            && let eframe::egui_wgpu::WgpuSetup::CreateNew(create) = &mut options.wgpu_options.wgpu_setup
        {
            create.instance_descriptor.backends = eframe::wgpu::Backends::GL;
        }
        let result = eframe::WebRunner::new()
            .start(
                canvas,
                options,
                Box::new(move |cc| {
                    if let Some(rs) = &cc.wgpu_render_state {
                        log::info!("designcraft-web: wgpu backend {:?}", rs.adapter.get_info().backend);
                    }
                    let inbox: Inbox = Inbox::default();
                    let mut app = DesignApp::new(Session::new(), services(inbox.clone(), cc.egui_ctx.clone()));
                    if has_query_flag(&query(), "sample") {
                        let _ = app.run("file.newSample", serde_json::json!({}));
                    }
                    Ok(Box::new(WebShell { app, inbox }))
                }),
            )
            .await;
        if let Some(el) = document.get_element_by_id(LOADING_ID) {
            match result {
                Ok(()) => el.remove(),
                Err(e) => el.set_inner_html(&format!("<p>DesignCraft failed to start: {e:?}</p><p>A browser with WebGPU or WebGL2 is required.</p>")),
            }
        }
    });
}

fn query() -> String {
    web_sys::window().and_then(|w| w.location().search().ok()).unwrap_or_default()
}

/// Wraps the app to read dropped files asynchronously (browsers can't read them synchronously)
/// and feed them through the inbox.
struct WebShell {
    app: DesignApp,
    inbox: Inbox,
}

impl eframe::App for WebShell {
    fn logic(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
        let dropped = ctx.input_mut(|i| std::mem::take(&mut i.raw.dropped_files));
        for f in dropped {
            let request = self.app.import_request("drop");
            let inbox = self.inbox.clone();
            let ctx = ctx.clone();
            wasm_bindgen_futures::spawn_local(async move {
                let name = f.path().file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_else(|| "dropped".into());
                match f.bytes_async().await {
                    Ok(bytes) => {
                        inbox.lock().unwrap_or_else(|e| e.into_inner()).push(ImportedFile { request, name, bytes });
                        ctx.request_repaint();
                    }
                    Err(e) => log::error!("couldn't read dropped file {name}: {e}"),
                }
            });
        }
        self.app.logic(ctx);
    }

    fn raw_input_hook(&mut self, ctx: &egui::Context, raw: &mut egui::RawInput) {
        designcraft_ui_egui::drop_key_name_text(raw, ctx.text_edit_focused() || self.app.canvas_ime());
        self.app.raw_input_hook(raw);
    }

    fn ui(&mut self, ui: &mut egui::Ui, _frame: &mut eframe::Frame) {
        self.app.ui(ui);
    }
}

fn services(inbox: Inbox, ctx: egui::Context) -> Services {
    let open_inbox = inbox.clone();
    Services {
        open_async: Some(Box::new(move |request: ImportRequest| {
            let inbox = open_inbox.clone();
            let ctx = ctx.clone();
            let dialog = if request.purpose == "swatches" {
                rfd::AsyncFileDialog::new().add_filter("Swatch Exchange (ASE)", &["ase"])
            } else if request.purpose == "place" {
                rfd::AsyncFileDialog::new().add_filter("Graphics", IMAGE_EXTS)
            } else {
                rfd::AsyncFileDialog::new().add_filter("DesignCraft, IDML or InDesign", DOC_EXTS)
            };
            wasm_bindgen_futures::spawn_local(async move {
                let Some(file) = dialog.pick_file().await else {
                    return;
                };
                let bytes = file.read().await;
                inbox.lock().unwrap_or_else(|e| e.into_inner()).push(ImportedFile { request, name: file.file_name(), bytes });
                ctx.request_repaint();
            });
        })),
        // Exports ask for a name; the browser decides where the download goes.
        pick_save: Some(Box::new(|name: &str| Some(name.to_string()))),
        write: Some(Box::new(|name: &str, bytes: &[u8]| download(name, bytes))),
        download: Some(Box::new(|name: &str, bytes: &[u8]| {
            if let Err(e) = download(name, bytes) {
                log::error!("download of {name} failed: {e}");
            }
        })),
        inbox: Some(inbox),
        ..Default::default()
    }
}

/// Trigger a browser download of `bytes` named after the last component of `path`.
fn download(path: &str, bytes: &[u8]) -> Result<(), String> {
    let js = |e: wasm_bindgen::JsValue| format!("{e:?}");
    let name = std::path::Path::new(path).file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_else(|| "designcraft".into());
    let window = web_sys::window().ok_or("no window")?;
    let document = window.document().ok_or("no document")?;
    let parts = js_sys::Array::of1(&js_sys::Uint8Array::from(bytes));
    let opts = web_sys::BlobPropertyBag::new();
    opts.set_type(mime_for(&name));
    let blob = web_sys::Blob::new_with_u8_array_sequence_and_options(&parts, &opts).map_err(js)?;
    let url = web_sys::Url::create_object_url_with_blob(&blob).map_err(js)?;
    let a: web_sys::HtmlAnchorElement = document.create_element("a").map_err(js)?.dyn_into().map_err(|_| "not an anchor")?;
    a.set_href(&url);
    a.set_download(&name);
    a.style().set_property("display", "none").map_err(js)?;
    let body = document.body().ok_or("no body")?;
    body.append_child(&a).map_err(js)?;
    a.click();
    a.remove();
    // Revoke after the click has been dispatched; the download keeps its own reference.
    let revoke = wasm_bindgen::closure::Closure::once_into_js(move || {
        web_sys::Url::revoke_object_url(&url).ok();
    });
    window.set_timeout_with_callback_and_timeout_and_arguments_0(revoke.unchecked_ref(), 10_000).map_err(js)?;
    Ok(())
}