// Small platform shims for things the desktop build does natively but the web
// (wasm) build must handle differently or skip.

/// Open a URL in the user's browser. The desktop launches the default handler;
/// the web opens a new tab (the button click is a user gesture, so it isn't
/// caught by the pop-up blocker). Focus of the opened page is left to the
/// OS / browser.
#[cfg(not(target_arch = "wasm32"))]
pub fn open_url(url: &str) {
    let _ = open::that(url);
}

#[cfg(target_arch = "wasm32")]
pub fn open_url(url: &str) {
    if let Some(window) = web_sys::window() {
        let _ = window.open_with_url_and_target(url, "_blank");
    }
}

/// Web: read text from the system clipboard via the async Clipboard API.
/// iced's own `clipboard::read` is a no-op on the web (the browser clipboard is
/// async + permission-gated), so the editor paste paths use this instead. The
/// Ctrl+V keypress that drives it is a user gesture, so the read is permitted.
/// Returns `None` when denied, empty, or unsupported.
#[cfg(target_arch = "wasm32")]
pub async fn read_clipboard_text() -> Option<String> {
    let clipboard = web_sys::window()?.navigator().clipboard();
    let value = wasm_bindgen_futures::JsFuture::from(clipboard.read_text())
        .await
        .ok()?;
    value.as_string()
}

/// Web: write text to the system clipboard (fire-and-forget). Backs Ctrl+C in
/// plain text_input fields, whose iced-internal copy is a no-op on the web
/// (#346). The triggering keypress is a user gesture, so the write is allowed.
#[cfg(target_arch = "wasm32")]
pub fn write_clipboard_text(text: &str) {
    if let Some(window) = web_sys::window() {
        let _ = window.navigator().clipboard().write_text(text);
    }
}

/// Web: replay `text` into the focused iced widget as synthetic KeyboardEvents
/// dispatched on the winit canvas. This is the only route INTO a focused
/// text_input on the web — iced's clipboard read is a no-op there and it
/// exposes no insert-text operation (#346). Control characters are dropped
/// and the length capped so a runaway clipboard can't wedge the event loop.
#[cfg(target_arch = "wasm32")]
pub fn synthesize_typing(text: &str) {
    let Some(canvas) = web_sys::window()
        .and_then(|w| w.document())
        .and_then(|d| d.query_selector("canvas").ok().flatten())
    else {
        return;
    };
    for ch in text.chars().filter(|c| !c.is_control()).take(1024) {
        let init = web_sys::KeyboardEventInit::new();
        init.set_key(&ch.to_string());
        init.set_bubbles(true);
        init.set_cancelable(true);
        for kind in ["keydown", "keyup"] {
            if let Ok(ev) =
                web_sys::KeyboardEvent::new_with_keyboard_event_init_dict(kind, &init)
            {
                let _ = canvas.dispatch_event(&ev);
            }
        }
    }
}

/// Turn an `rfd` file handle into a `PathBuf` the rest of the app keys on.
///
/// Desktop returns the real filesystem path. The browser has no path, so we
/// synthesize one from the file name — enough for the app to compile and track
/// the document name; actual byte I/O on the web reads the handle directly
/// (a follow-up).
#[cfg(not(target_arch = "wasm32"))]
pub fn handle_path(h: &rfd::FileHandle) -> std::path::PathBuf {
    let p = h.path().to_path_buf();
    // Every dialog result funnels through here — remember its folder so the
    // next dialog opens where the user left off.
    crate::config::remember_dialog_dir(&p);
    p
}

#[cfg(target_arch = "wasm32")]
pub fn handle_path(h: &rfd::FileHandle) -> std::path::PathBuf {
    std::path::PathBuf::from(h.file_name())
}

/// New async file dialog seeded with the last directory a dialog was used in.
/// All pickers should start from this instead of `rfd::AsyncFileDialog::new()`.
#[cfg(not(target_arch = "wasm32"))]
pub fn file_dialog() -> rfd::AsyncFileDialog {
    let dlg = rfd::AsyncFileDialog::new();
    match crate::config::last_dialog_dir() {
        Some(dir) => dlg.set_directory(dir),
        None => dlg,
    }
}

/// Web: no filesystem paths, nothing to remember.
#[cfg(target_arch = "wasm32")]
pub fn file_dialog() -> rfd::AsyncFileDialog {
    rfd::AsyncFileDialog::new()
}

/// Trigger a browser download of `bytes` as `name`. Builds a Blob, points a
/// hidden `<a download>` at it and clicks it programmatically — because this
/// runs inside the Save button's click (a user gesture), the file downloads
/// immediately with no extra "click to download" link. Web only.
#[cfg(target_arch = "wasm32")]
pub fn download_bytes(name: &str, bytes: &[u8]) {
    use wasm_bindgen::JsCast;
    let Some(window) = web_sys::window() else { return };
    let Some(document) = window.document() else { return };
    let array = js_sys::Uint8Array::from(bytes);
    let parts = js_sys::Array::new();
    parts.push(&array.buffer());
    let Ok(blob) = web_sys::Blob::new_with_u8_array_sequence(&parts) else {
        return;
    };
    let Ok(url) = web_sys::Url::create_object_url_with_blob(&blob) else {
        return;
    };
    if let Ok(el) = document.create_element("a") {
        let a: web_sys::HtmlAnchorElement = el.unchecked_into();
        a.set_href(&url);
        a.set_download(name);
        a.click();
    }
    let _ = web_sys::Url::revoke_object_url(&url);
}

/// Short platform string for bug reports: OS + architecture on the desktop,
/// the browser user-agent on the web.
#[cfg(not(target_arch = "wasm32"))]
pub fn platform_info() -> String {
    format!("{} {}", std::env::consts::OS, std::env::consts::ARCH)
}

#[cfg(target_arch = "wasm32")]
pub fn platform_info() -> String {
    web_sys::window()
        .and_then(|w| w.navigator().user_agent().ok())
        .map(|ua| format!("Web — {ua}"))
        .unwrap_or_else(|| "Web (wasm)".to_string())
}

/// Percent-encode `s` for use in a URL query value (e.g. a GitHub issue
/// `?body=`). Encodes everything outside the unreserved set.
pub fn percent_encode(s: &str) -> String {
    let mut out = String::with_capacity(s.len());
    for &b in s.as_bytes() {
        match b {
            b'A'..=b'Z' | b'a'..=b'z' | b'0'..=b'9' | b'-' | b'_' | b'.' | b'~' => {
                out.push(b as char)
            }
            _ => out.push_str(&format!("%{b:02X}")),
        }
    }
    out
}

/// Web renderer-error surface (#414): wgpu / naga report pipeline and shader
/// failures through the `log` facade and then leave the canvas empty — with no
/// logger installed the message is lost, so a broken GPU path looks like "the
/// app draws nothing" with a clean console. Mirror every Error-level record to
/// the browser console AND into a fixed DOM banner whose text is selectable
/// (the canvas UI is not), with a one-click Copy button, so a failing user can
/// paste the exact error into a bug report. Panics land in the same banner via
/// a chained hook.
#[cfg(target_arch = "wasm32")]
pub mod web_diag {
    use std::sync::Mutex;

    /// Cap on banner entries so a per-frame error can't grow the DOM forever.
    const MAX_LINES: u32 = 12;

    /// Last banner message + repeat count, for collapsing a hot error loop
    /// into one line with an `(xN)` suffix.
    static LAST: Mutex<(String, u32)> = Mutex::new((String::new(), 0));

    struct BannerLogger;

    impl log::Log for BannerLogger {
        fn enabled(&self, meta: &log::Metadata) -> bool {
            meta.level() <= log::Level::Error
        }
        fn log(&self, record: &log::Record) {
            if record.level() > log::Level::Error {
                return;
            }
            let msg = format!("[{}] {}", record.target(), record.args());
            web_sys::console::error_1(&wasm_bindgen::JsValue::from_str(&msg));
            show_banner(&msg);
        }
        fn flush(&self) {}
    }

    /// Install the logger + panic mirror. Call once at web startup, AFTER
    /// `console_error_panic_hook::set_once` so the chained hook keeps the
    /// console stack trace.
    pub fn init() {
        let console_hook = std::panic::take_hook();
        std::panic::set_hook(Box::new(move |info| {
            show_banner(&info.to_string());
            console_hook(info);
        }));
        if log::set_boxed_logger(Box::new(BannerLogger)).is_ok() {
            log::set_max_level(log::LevelFilter::Error);
        }
    }

    /// Append `msg` to the on-page banner, creating the overlay on first use.
    fn show_banner(msg: &str) {
        let Some(doc) = web_sys::window().and_then(|w| w.document()) else {
            return;
        };
        let pre = match doc.get_element_by_id("ocs-err-text") {
            Some(pre) => pre,
            None => {
                let Some(body) = doc.body() else { return };
                let Ok(overlay) = doc.create_element("div") else {
                    return;
                };
                overlay.set_id("ocs-err");
                let _ = overlay.set_attribute(
                    "style",
                    "position:fixed;top:0;left:0;right:0;z-index:2147483647;\
                     background:#5c1a1a;color:#ffdddd;font:12px monospace;\
                     padding:8px 12px;max-height:40vh;overflow:auto;\
                     user-select:text;cursor:text;",
                );
                // Inline `onclick` keeps this dependency-free (no JS closures):
                // Copy puts the full error text on the clipboard; Dismiss
                // removes the overlay so the app stays usable underneath.
                overlay.set_inner_html(
                    "<div><b>OpenCADStudio renderer error</b> — please copy \
                     this into a bug report: \
                     <button style=\"margin-left:8px\" onclick=\"navigator.clipboard.writeText(\
                     document.getElementById('ocs-err-text').innerText)\">Copy</button> \
                     <button onclick=\"document.getElementById('ocs-err').remove()\">\
                     Dismiss</button></div>\
                     <pre id=\"ocs-err-text\" style=\"margin:6px 0 0;\
                     white-space:pre-wrap;user-select:text;\"></pre>",
                );
                let _ = body.append_child(&overlay);
                match doc.get_element_by_id("ocs-err-text") {
                    Some(pre) => pre,
                    None => return,
                }
            }
        };
        // Collapse repeats: an error thrown every frame becomes one line with
        // a running (xN) counter instead of MAX_LINES copies of itself.
        let mut last = match LAST.lock() {
            Ok(g) => g,
            Err(p) => p.into_inner(),
        };
        if last.0 == msg {
            last.1 += 1;
            if let Some(line) = pre.last_element_child() {
                line.set_text_content(Some(&format!("{msg} (x{})", last.1)));
            }
            return;
        }
        *last = (msg.to_string(), 1);
        if pre.child_element_count() >= MAX_LINES {
            if let Some(first) = pre.first_element_child() {
                first.remove();
            }
        }
        if let Ok(line) = doc.create_element("div") {
            line.set_text_content(Some(msg));
            let _ = pre.append_child(&line);
        }
    }
}