BREP_app 0.2.0

//! In-app **Submit Bug** report.
//!
//! A toolbar button opens this flow. It captures, WITHOUT the report dialog in
//! the shot:
//!   * a **screenshot** of the whole application (egui UI + the 3D model) as it
//!     looked the instant the button was pressed,
//!   * the current **model** (the `.BREP.json` recipe), and
//!   * a user **description** (+ an optional email),
//! then POSTs them to the public reports endpoint (`v2.brep.io/api/report`).
//! ONE code path runs on both native and wasm.
//!
//! ## Screenshot-before-dialog
//! egui/eframe captures a screenshot of the FRAME (the composited surface, so it
//! includes the 3D viewport, which is an `egui_wgpu` paint callback into egui's
//! frame — see [`crate::viewport`]). We must not let the dialog appear in that
//! frame, so the flow is a small state machine:
//!   1. Button click → snapshot the model, send `ViewportCommand::Screenshot`,
//!      enter [`Phase::Capturing`]. The dialog is NOT drawn while capturing.
//!   2. A later frame delivers `Event::Screenshot`; we encode it to PNG, build a
//!      preview thumbnail, and enter [`Phase::Editing`] — only NOW is the dialog
//!      drawn, so the captured frame(s) never contain it.
//!   3. Submit builds a small multipart body by hand (no extra deps) and fires
//!      it through `ehttp`; the reply marshals back over an mpsc channel +
//!      `request_repaint`, exactly like [`crate::panels::step_parts`].

use std::sync::mpsc::Receiver;

use brep_render::engine_state::EngineState;
use eframe::egui;

/// The public reports endpoint the button posts to (the cadDev public server,
/// fronted by v2.brep.io). Accepts the multipart fields
/// `description`,`email`,`model`,`screenshot`.
const REPORT_URL: &str = "https://v2.brep.io/api/report";

/// Frames to wait for the screenshot event before giving up and opening the
/// dialog anyway (so a device that never delivers the capture can't hang the
/// flow). ~1s at 60fps; the persistent offscreen 3D means the capture normally
/// lands within a few frames.
const CAPTURE_TIMEOUT_FRAMES: u32 = 60;

/// Where the flow is between "button pressed" and "dialog closed".
#[derive(Default, PartialEq)]
enum Phase {
    /// Nothing in progress.
    #[default]
    Idle,
    /// Screenshot requested; dialog intentionally hidden so it isn't captured.
    Capturing { frames: u32 },
    /// Screenshot in hand; dialog open, collecting description + email.
    Editing,
    /// POST in flight.
    Sending,
}

pub struct BugReportPanel {
    phase: Phase,
    /// The problem description (required to submit).
    description: String,
    /// Optional reporter email.
    email: String,
    /// A short status / error line under the buttons.
    status: String,
    /// PNG bytes of the pre-dialog screenshot (UI + 3D), if captured.
    screenshot_png: Option<Vec<u8>>,
    /// A preview texture of the screenshot shown in the dialog.
    thumb: Option<egui::TextureHandle>,
    /// The model (`.BREP.json`) snapshotted at button-press time.
    model_json: String,
    /// The in-flight POST reply channel (drained each frame).
    response_rx: Option<Receiver<Result<(), String>>>,
    /// Per-frame widget rects for the headed verifier (wasm only).
    #[cfg(target_arch = "wasm32")]
    hits: std::collections::HashMap<String, egui::Rect>,
}

impl BugReportPanel {
    pub fn new() -> Self {
        Self {
            phase: Phase::Idle,
            description: String::new(),
            email: String::new(),
            status: String::new(),
            screenshot_png: None,
            thumb: None,
            model_json: String::new(),
            response_rx: None,
            #[cfg(target_arch = "wasm32")]
            hits: std::collections::HashMap::new(),
        }
    }

    /// Toolbar entry point: snapshot the model, request a screenshot of THIS
    /// frame (before the dialog exists), and begin capturing. Ignored if a
    /// report flow is already in progress.
    pub fn request(&mut self, ctx: &egui::Context, state: &EngineState) {
        if self.phase != Phase::Idle {
            return;
        }
        self.description.clear();
        self.email.clear();
        self.status.clear();
        self.screenshot_png = None;
        self.thumb = None;
        self.response_rx = None;
        // The model can't change while the modal is open, but snapshot it now so
        // the report reflects exactly the state the user was looking at.
        self.model_json = state.history_request_json();
        ctx.send_viewport_cmd(egui::ViewportCommand::Screenshot(egui::UserData::default()));
        self.phase = Phase::Capturing { frames: 0 };
        ctx.request_repaint();
    }

    /// Draw + drive the flow. Called once per frame at ctx level (like the file
    /// dialog). Idempotent while [`Phase::Idle`].
    pub fn show(&mut self, ctx: &egui::Context, state: &mut EngineState) {
        #[cfg(target_arch = "wasm32")]
        self.hits.clear();

        self.poll_capture(ctx);
        self.drain_response(state);

        if !matches!(self.phase, Phase::Editing | Phase::Sending) {
            return;
        }

        let sending = self.phase == Phase::Sending;
        let mut submit = false;
        let mut cancel = false;
        let modal = egui::Modal::new(egui::Id::new("brep-bug-report")).show(ctx, |ui| {
            ui.set_width(560.0);
            ui.heading("\u{1F41E}  Submit a bug report");
            ui.add_space(4.0);
            ui.label(
                "Describe what went wrong. Your current model and a screenshot of \
                 the app (UI + 3D view) are attached automatically.",
            );
            ui.add_space(2.0);
            ui.weak("Your report and its screenshot may be shown publicly on the bug list.");
            ui.add_space(8.0);

            ui.label("What happened?");
            let desc = ui.add(
                egui::TextEdit::multiline(&mut self.description)
                    .desired_rows(5)
                    .desired_width(f32::INFINITY)
                    .hint_text("Steps, what you expected, and what actually happened"),
            );
            self.hit("field:description", &desc);

            ui.add_space(6.0);
            ui.label("Email (optional)");
            let email = ui.add(
                egui::TextEdit::singleline(&mut self.email)
                    .desired_width(f32::INFINITY)
                    .hint_text("so we can follow up — optional"),
            );
            self.hit("field:email", &email);

            ui.add_space(8.0);
            if let Some(tex) = &self.thumb {
                ui.label("Attached screenshot:");
                ui.add_space(2.0);
                // Fit the preview to the dialog width, keeping aspect.
                let size = tex.size_vec2();
                let scale = (520.0 / size.x).min(1.0);
                ui.add(
                    egui::Image::new((tex.id(), size * scale))
                        .corner_radius(4.0)
                        .bg_fill(egui::Color32::from_gray(20)),
                );
            } else {
                ui.weak("(screenshot unavailable — the model + description will still be sent)");
            }

            ui.add_space(10.0);
            ui.horizontal(|ui| {
                let can_submit = !self.description.trim().is_empty() && !sending;
                let label = if sending { "Sending\u{2026}" } else { "Submit report" };
                let submit_btn = ui.add_enabled(can_submit, egui::Button::new(label));
                self.hit("submit", &submit_btn);
                if submit_btn.clicked() {
                    submit = true;
                }
                let cancel_btn = ui.add_enabled(!sending, egui::Button::new("Cancel"));
                self.hit("cancel", &cancel_btn);
                if cancel_btn.clicked() {
                    cancel = true;
                }
            });
            if !self.status.is_empty() {
                ui.add_space(6.0);
                ui.weak(&self.status);
            }
        });

        if submit {
            self.send(ctx);
        } else if cancel || (modal.should_close() && !sending) {
            self.reset();
        }
    }

    /// While capturing, look for the delivered screenshot; time out gracefully.
    fn poll_capture(&mut self, ctx: &egui::Context) {
        let frames = match &mut self.phase {
            Phase::Capturing { frames } => {
                *frames += 1;
                *frames
            }
            _ => return,
        };
        // eframe injects `Event::Screenshot` into the frame's raw input once the
        // async framebuffer readback completes. Take the newest one.
        let shot = ctx.input(|i| {
            i.raw.events.iter().rev().find_map(|e| match e {
                egui::Event::Screenshot { image, .. } => Some(image.clone()),
                _ => None,
            })
        });
        if let Some(img) = shot {
            self.screenshot_png = encode_png(&img);
            self.thumb = Some(ctx.load_texture(
                "brep-bug-shot",
                (*img).clone(),
                egui::TextureOptions::LINEAR,
            ));
            self.phase = Phase::Editing;
        } else if frames > CAPTURE_TIMEOUT_FRAMES {
            self.status = "(screenshot unavailable)".into();
            self.phase = Phase::Editing;
        } else {
            ctx.request_repaint();
        }
    }

    /// Drain the POST reply: success closes the dialog with a toast; an error
    /// stays open so the user can retry.
    fn drain_response(&mut self, state: &mut EngineState) {
        let Some(rx) = &self.response_rx else { return };
        let Ok(result) = rx.try_recv() else { return };
        self.response_rx = None;
        match result {
            Ok(()) => {
                state.push_notice("Bug report submitted — thank you!".to_string());
                self.reset();
            }
            Err(e) => {
                self.status = format!("Submit failed: {e}");
                self.phase = Phase::Editing;
            }
        }
    }

    /// Build the multipart body and fire the POST (native + wasm via ehttp).
    fn send(&mut self, ctx: &egui::Context) {
        self.status = "Submitting\u{2026}".into();
        self.phase = Phase::Sending;

        let (content_type, body) = build_multipart(
            &self.description,
            &self.email,
            &self.model_json,
            self.screenshot_png.as_deref(),
        );
        let mut req = ehttp::Request::post(REPORT_URL, body);
        // `Request::post` sets text/plain; replace it with our multipart type.
        req.headers
            .headers
            .retain(|(k, _)| !k.eq_ignore_ascii_case("content-type"));
        req.headers.headers.push(("Content-Type".to_string(), content_type));

        let (tx, rx) = std::sync::mpsc::channel();
        let ctx = ctx.clone();
        ehttp::fetch(req, move |result| {
            let out = match result {
                Ok(resp) if resp.ok => Ok(()),
                Ok(resp) => Err(format!("HTTP {} {}", resp.status, resp.status_text)),
                Err(err) => Err(err),
            };
            let _ = tx.send(out);
            ctx.request_repaint();
        });
        self.response_rx = Some(rx);
    }

    /// Back to idle, dropping the screenshot + preview texture.
    fn reset(&mut self) {
        self.phase = Phase::Idle;
        self.description.clear();
        self.email.clear();
        self.status.clear();
        self.screenshot_png = None;
        self.thumb = None;
        self.response_rx = None;
    }

    /// Record a widget's screen rect for the headed verifier (wasm only; a no-op
    /// on native).
    #[cfg(target_arch = "wasm32")]
    fn hit(&mut self, key: &str, resp: &egui::Response) {
        self.hits.insert(key.to_string(), resp.rect);
    }
    #[cfg(not(target_arch = "wasm32"))]
    #[inline]
    fn hit(&mut self, _key: &str, _resp: &egui::Response) {}

    /// Logical state for the headed verifier: which phase + whether a shot was
    /// captured.
    #[cfg(target_arch = "wasm32")]
    pub fn state_json(&self) -> String {
        let phase = match self.phase {
            Phase::Idle => "idle",
            Phase::Capturing { .. } => "capturing",
            Phase::Editing => "editing",
            Phase::Sending => "sending",
        };
        serde_json::json!({
            "phase": phase,
            "hasScreenshot": self.screenshot_png.is_some(),
            "status": self.status,
        })
        .to_string()
    }

    /// The published widget hit-rects (egui points) for the headed verifier.
    #[cfg(target_arch = "wasm32")]
    pub fn hits_json(&self) -> String {
        let map: serde_json::Map<String, serde_json::Value> = self
            .hits
            .iter()
            .map(|(k, r)| {
                (
                    k.clone(),
                    serde_json::json!([r.center().x, r.center().y, r.width(), r.height()]),
                )
            })
            .collect();
        serde_json::Value::Object(map).to_string()
    }
}

/// Encode an egui `ColorImage` (the screenshot) to PNG bytes via the pure-Rust
/// `image` crate (wasm-safe). `None` on a zero-size image or encode error.
fn encode_png(color: &egui::ColorImage) -> Option<Vec<u8>> {
    use image::ImageEncoder;
    let [w, h] = color.size;
    if w == 0 || h == 0 {
        return None;
    }
    let mut rgba = Vec::with_capacity(w * h * 4);
    for px in &color.pixels {
        // Straight (un-premultiplied) sRGBA, matching a normal PNG.
        rgba.extend_from_slice(&px.to_srgba_unmultiplied());
    }
    let mut png = Vec::new();
    image::codecs::png::PngEncoder::new(&mut png)
        .write_image(&rgba, w as u32, h as u32, image::ExtendedColorType::Rgba8)
        .ok()?;
    Some(png)
}

/// Hand-build a `multipart/form-data` body (avoids ehttp's `multipart` feature,
/// which pulls `rand`→`getrandom` and would need the wasm `js` feature). The
/// boundary carries a distinctive ASCII prefix plus the payload lengths so it
/// can't collide with the (text) model JSON or the PNG bytes.
fn build_multipart(
    description: &str,
    email: &str,
    model: &str,
    screenshot: Option<&[u8]>,
) -> (String, Vec<u8>) {
    let boundary = format!(
        "----BREPBugReport{:x}x{:x}Boundary",
        model.len(),
        screenshot.map(|s| s.len()).unwrap_or(0)
    );
    let mut body = Vec::new();
    push_text_field(&mut body, &boundary, "description", description);
    push_text_field(&mut body, &boundary, "email", email);
    push_file_field(
        &mut body,
        &boundary,
        "model",
        "model.BREP.json",
        "application/json",
        model.as_bytes(),
    );
    if let Some(png) = screenshot {
        push_file_field(&mut body, &boundary, "screenshot", "screenshot.png", "image/png", png);
    }
    body.extend_from_slice(format!("--{boundary}--\r\n").as_bytes());
    (format!("multipart/form-data; boundary={boundary}"), body)
}

fn push_text_field(body: &mut Vec<u8>, boundary: &str, name: &str, value: &str) {
    body.extend_from_slice(
        format!("--{boundary}\r\nContent-Disposition: form-data; name=\"{name}\"\r\n\r\n")
            .as_bytes(),
    );
    body.extend_from_slice(value.as_bytes());
    body.extend_from_slice(b"\r\n");
}

fn push_file_field(
    body: &mut Vec<u8>,
    boundary: &str,
    name: &str,
    filename: &str,
    content_type: &str,
    bytes: &[u8],
) {
    body.extend_from_slice(
        format!(
            "--{boundary}\r\nContent-Disposition: form-data; name=\"{name}\"; \
             filename=\"{filename}\"\r\nContent-Type: {content_type}\r\n\r\n"
        )
        .as_bytes(),
    );
    body.extend_from_slice(bytes);
    body.extend_from_slice(b"\r\n");
}