car-browser 0.1.1

//! Headless Chromium backend via chromiumoxide.
//!
//! Implements `BrowserBackend` using Chrome DevTools Protocol (CDP).
//! Requires a Chromium/Chrome binary on the system.

#![cfg(feature = "chromium")]

use async_trait::async_trait;
use chromiumoxide::browser::{Browser, BrowserConfig};
use chromiumoxide::cdp::browser_protocol::accessibility::GetFullAxTreeParams;
use chromiumoxide::cdp::browser_protocol::dom::{
    BackendNodeId, FocusParams, GetBoxModelParams,
};
use chromiumoxide::cdp::browser_protocol::input::{
    DispatchKeyEventParams, DispatchKeyEventType, DispatchMouseEventParams,
    DispatchMouseEventType, MouseButton,
};
use chromiumoxide::cdp::browser_protocol::page::CaptureScreenshotFormat;
use chromiumoxide::Page;
use futures::StreamExt;
use std::collections::HashMap;
use std::sync::Arc;
use tokio::sync::RwLock;

use crate::backend::{BrowserBackend, BrowserError};
use crate::models::{A11yNode, Bounds, Modifier, Viewport, WaitCondition};

/// Cached mapping from ax_N node IDs to their CDP backend DOM node IDs.
/// Populated during `get_accessibility_tree()`, consumed by `click_element()`
/// and `focus_element()`.
type AxNodeCache = HashMap<String, BackendNodeId>;

/// Headless Chromium browser backend.
pub struct ChromiumBackend {
    page: Arc<RwLock<Option<Page>>>,
    _browser: Arc<RwLock<Option<Browser>>>,
    viewport_width: u32,
    viewport_height: u32,
    /// Cached URL, updated on navigate() and get_accessibility_tree().
    /// Uses std::sync::RwLock so get_current_url() can be synchronous.
    cached_url: std::sync::RwLock<String>,
    /// Cached mapping from ax_N IDs to BackendNodeId, populated by
    /// get_accessibility_tree(). Used by click_element/focus_element/type_into_element
    /// to resolve ax_N to real DOM coordinates.
    ax_node_cache: std::sync::RwLock<AxNodeCache>,
}

/// Convert our `Modifier` enum to CDP modifier bitmask.
/// CDP defines: Alt=1, Ctrl=2, Meta/Command=4, Shift=8.
fn modifiers_to_cdp_flags(modifiers: &[Modifier]) -> i64 {
    let mut flags: i64 = 0;
    for m in modifiers {
        flags |= match m {
            Modifier::Alt => 1,
            Modifier::Control => 2,
            Modifier::Meta => 4,
            Modifier::Shift => 8,
        };
    }
    flags
}

impl ChromiumBackend {
    /// Launch a new headless Chromium instance.
    pub async fn launch() -> Result<Self, BrowserError> {
        Self::launch_with_viewport(1280, 720).await
    }

    /// Launch with specific viewport dimensions.
    pub async fn launch_with_viewport(width: u32, height: u32) -> Result<Self, BrowserError> {
        let config = BrowserConfig::builder()
            .window_size(width, height)
            .build()
            .map_err(|e| BrowserError::NotAvailable(format!("Config error: {}", e)))?;

        let (browser, mut handler) = Browser::launch(config)
            .await
            .map_err(|e| BrowserError::NotAvailable(format!("Failed to launch Chrome: {}", e)))?;

        // Spawn the CDP event handler
        tokio::spawn(async move {
            while let Some(_event) = handler.next().await {}
        });

        let page = browser
            .new_page("about:blank")
            .await
            .map_err(|e| BrowserError::NotAvailable(format!("Failed to create page: {}", e)))?;

        Ok(Self {
            page: Arc::new(RwLock::new(Some(page))),
            _browser: Arc::new(RwLock::new(Some(browser))),
            viewport_width: width,
            viewport_height: height,
            cached_url: std::sync::RwLock::new("about:blank".to_string()),
            ax_node_cache: std::sync::RwLock::new(HashMap::new()),
        })
    }

    async fn get_page(&self) -> Result<Page, BrowserError> {
        self.page
            .read()
            .await
            .clone()
            .ok_or(BrowserError::NotAvailable("Page closed".into()))
    }

    /// Update the cached URL by querying the page asynchronously.
    async fn refresh_cached_url(&self) {
        if let Ok(page) = self.get_page().await {
            if let Ok(Some(url)) = page.url().await {
                if let Ok(mut cached) = self.cached_url.write() {
                    *cached = url;
                }
            }
        }
    }

    /// Look up the BackendNodeId for an ax_N node ID from the cache.
    fn resolve_backend_node_id(&self, node_id: &str) -> Result<BackendNodeId, BrowserError> {
        let cache = self.ax_node_cache.read().map_err(|e| {
            BrowserError::PlatformInternal(format!("Failed to read ax_node_cache: {}", e))
        })?;
        cache.get(node_id).copied().ok_or_else(|| {
            BrowserError::ElementNotFound(format!(
                "No cached BackendNodeId for '{}'. Call get_accessibility_tree() first.",
                node_id
            ))
        })
    }

    /// Get the bounding box center for a BackendNodeId via CDP DOM.getBoxModel.
    async fn get_element_center(
        &self,
        backend_node_id: BackendNodeId,
    ) -> Result<(f64, f64), BrowserError> {
        let page = self.get_page().await?;
        let params = GetBoxModelParams::builder()
            .backend_node_id(backend_node_id)
            .build();
        let result = page
            .execute(params)
            .await
            .map_err(|e| {
                BrowserError::ElementNotFound(format!("DOM.getBoxModel failed: {}", e))
            })?;

        // The content quad is 8 floats: [x1,y1, x2,y2, x3,y3, x4,y4]
        let quad = result.result.model.content.inner();
        if quad.len() < 8 {
            return Err(BrowserError::PlatformInternal(
                "Content quad has fewer than 8 values".into(),
            ));
        }
        // Compute center from the four corners
        let cx = (quad[0] + quad[2] + quad[4] + quad[6]) / 4.0;
        let cy = (quad[1] + quad[3] + quad[5] + quad[7]) / 4.0;
        Ok((cx, cy))
    }

    /// Focus a DOM element by BackendNodeId via CDP DOM.focus.
    async fn focus_by_backend_node_id(
        &self,
        backend_node_id: BackendNodeId,
    ) -> Result<(), BrowserError> {
        let page = self.get_page().await?;
        let params = FocusParams::builder()
            .backend_node_id(backend_node_id)
            .build();
        page.execute(params)
            .await
            .map_err(|e| BrowserError::InputFailed(format!("DOM.focus failed: {}", e)))?;
        Ok(())
    }
}

#[async_trait]
impl BrowserBackend for ChromiumBackend {
    async fn capture_screenshot(&self) -> Result<Vec<u8>, BrowserError> {
        let page = self.get_page().await?;
        page.screenshot(
            chromiumoxide::page::ScreenshotParams::builder()
                .format(CaptureScreenshotFormat::Png)
                .build(),
        )
        .await
        .map_err(|e| BrowserError::ScreenshotFailed(e.to_string()))
    }

    async fn get_accessibility_tree(&self) -> Result<Vec<A11yNode>, BrowserError> {
        let page = self.get_page().await?;
        let result = page
            .execute(GetFullAxTreeParams::default())
            .await
            .map_err(|e| BrowserError::AccessibilityFailed(e.to_string()))?;

        // Update cached URL while we have the page
        self.refresh_cached_url().await;

        let mut new_cache = AxNodeCache::new();

        let mut nodes: Vec<A11yNode> = Vec::new();
        for (i, n) in result.result.nodes.iter().enumerate() {
            if n.ignored {
                continue;
            }

            let ax_id = format!("ax_{}", i);

            // Cache the BackendNodeId for later use by click_element/focus_element
            if let Some(backend_id) = n.backend_dom_node_id {
                new_cache.insert(ax_id.clone(), backend_id);
            }

            let role = n
                .role
                .as_ref()
                .and_then(|r| r.value.as_ref())
                .and_then(|v| v.as_str())
                .unwrap_or("unknown")
                .to_string();

            let name = n
                .name
                .as_ref()
                .and_then(|v| v.value.as_ref())
                .and_then(|v| v.as_str())
                .filter(|s| !s.is_empty())
                .map(|s| s.to_string());

            let value = n
                .value
                .as_ref()
                .and_then(|v| v.value.as_ref())
                .and_then(|v| v.as_str())
                .filter(|s| !s.is_empty())
                .map(|s| s.to_string());

            let children: Vec<String> = n
                .child_ids
                .as_ref()
                .map(|ids| ids.iter().map(|id| format!("ax_{}", id.as_ref())).collect())
                .unwrap_or_default();

            // Resolve real bounds via DOM.getBoxModel if we have a backend node ID.
            // Fall back to zero-sized bounds for nodes without a DOM backing (e.g. root).
            let bounds = if let Some(backend_id) = n.backend_dom_node_id {
                let bm_params = GetBoxModelParams::builder()
                    .backend_node_id(backend_id)
                    .build();
                if let Ok(bm_result) = page.execute(bm_params).await {
                    let quad = bm_result.result.model.content.inner();
                    if quad.len() >= 8 {
                        let x = quad[0];
                        let y = quad[1];
                        let width = quad[2] - quad[0];
                        let height = quad[5] - quad[1];
                        Bounds::new(x, y, width.max(0.0), height.max(0.0))
                    } else {
                        Bounds::new(0.0, 0.0, 0.0, 0.0)
                    }
                } else {
                    Bounds::new(0.0, 0.0, 0.0, 0.0)
                }
            } else {
                Bounds::new(0.0, 0.0, 0.0, 0.0)
            };

            nodes.push(A11yNode {
                node_id: ax_id,
                role,
                name,
                value,
                bounds,
                children,
                focusable: true,
                focused: false,
                disabled: false,
            });
        }

        // Update the shared cache
        if let Ok(mut cache) = self.ax_node_cache.write() {
            *cache = new_cache;
        }

        Ok(nodes)
    }

    fn get_viewport(&self) -> Result<Viewport, BrowserError> {
        Ok(Viewport {
            width: self.viewport_width,
            height: self.viewport_height,
            device_pixel_ratio: 1.0,
        })
    }

    fn get_current_url(&self) -> Result<String, BrowserError> {
        self.cached_url
            .read()
            .map(|url| url.clone())
            .map_err(|e| BrowserError::PlatformInternal(format!("URL cache lock poisoned: {}", e)))
    }

    async fn get_page_title(&self) -> Result<String, BrowserError> {
        let page = self.get_page().await?;
        page.evaluate("document.title")
            .await
            .map_err(|e| BrowserError::PlatformInternal(e.to_string()))?
            .into_value::<String>()
            .map_err(|e| BrowserError::PlatformInternal(e.to_string()))
    }

    async fn navigate(&self, url: &str) -> Result<(), BrowserError> {
        let page = self.get_page().await?;
        page.goto(url)
            .await
            .map_err(|e| BrowserError::NavigationFailed(e.to_string()))?;
        page.wait_for_navigation()
            .await
            .map_err(|e| BrowserError::NavigationFailed(e.to_string()))?;

        // Update cached URL after navigation
        if let Ok(mut cached) = self.cached_url.write() {
            *cached = url.to_string();
        }
        // Also refresh from the page in case of redirects
        self.refresh_cached_url().await;

        Ok(())
    }

    async fn inject_click(&self, x: f64, y: f64) -> Result<(), BrowserError> {
        let page = self.get_page().await?;
        page.execute(
            DispatchMouseEventParams::builder()
                .r#type(DispatchMouseEventType::MousePressed)
                .x(x)
                .y(y)
                .button(MouseButton::Left)
                .click_count(1)
                .build()
                .unwrap(),
        )
        .await
        .map_err(|e| BrowserError::InputFailed(e.to_string()))?;

        page.execute(
            DispatchMouseEventParams::builder()
                .r#type(DispatchMouseEventType::MouseReleased)
                .x(x)
                .y(y)
                .button(MouseButton::Left)
                .click_count(1)
                .build()
                .unwrap(),
        )
        .await
        .map_err(|e| BrowserError::InputFailed(e.to_string()))?;

        Ok(())
    }

    async fn inject_text(&self, text: &str) -> Result<(), BrowserError> {
        let page = self.get_page().await?;
        for ch in text.chars() {
            page.execute(
                DispatchKeyEventParams::builder()
                    .r#type(DispatchKeyEventType::Char)
                    .text(ch.to_string())
                    .build()
                    .unwrap(),
            )
            .await
            .map_err(|e| BrowserError::InputFailed(e.to_string()))?;
        }
        Ok(())
    }

    async fn inject_keypress(
        &self,
        key: &str,
        modifiers: &[Modifier],
    ) -> Result<(), BrowserError> {
        let page = self.get_page().await?;
        let cdp_modifiers = modifiers_to_cdp_flags(modifiers);

        page.execute(
            DispatchKeyEventParams::builder()
                .r#type(DispatchKeyEventType::KeyDown)
                .key(key.to_string())
                .modifiers(cdp_modifiers)
                .build()
                .unwrap(),
        )
        .await
        .map_err(|e| BrowserError::InputFailed(e.to_string()))?;

        page.execute(
            DispatchKeyEventParams::builder()
                .r#type(DispatchKeyEventType::KeyUp)
                .key(key.to_string())
                .modifiers(cdp_modifiers)
                .build()
                .unwrap(),
        )
        .await
        .map_err(|e| BrowserError::InputFailed(e.to_string()))?;

        Ok(())
    }

    async fn inject_scroll(&self, delta_y: i32) -> Result<(), BrowserError> {
        let page = self.get_page().await?;
        page.execute(
            DispatchMouseEventParams::builder()
                .r#type(DispatchMouseEventType::MouseWheel)
                .x(self.viewport_width as f64 / 2.0)
                .y(self.viewport_height as f64 / 2.0)
                .delta_x(0.0)
                .delta_y(delta_y as f64)
                .build()
                .unwrap(),
        )
        .await
        .map_err(|e| BrowserError::InputFailed(e.to_string()))?;
        Ok(())
    }

    async fn click_element(&self, node_id: &str) -> Result<(), BrowserError> {
        let backend_node_id = self.resolve_backend_node_id(node_id)?;
        let (cx, cy) = self.get_element_center(backend_node_id).await?;
        self.inject_click(cx, cy).await
    }

    async fn type_into_element(&self, node_id: &str, text: &str) -> Result<(), BrowserError> {
        let backend_node_id = self.resolve_backend_node_id(node_id)?;
        self.focus_by_backend_node_id(backend_node_id).await?;
        self.inject_text(text).await
    }

    async fn focus_element(&self, node_id: &str) -> Result<(), BrowserError> {
        let backend_node_id = self.resolve_backend_node_id(node_id)?;
        self.focus_by_backend_node_id(backend_node_id).await
    }

    async fn is_page_loaded(&self) -> Result<bool, BrowserError> {
        let page = self.get_page().await?;
        let state = page
            .evaluate("document.readyState")
            .await
            .map_err(|e| BrowserError::PlatformInternal(e.to_string()))?
            .into_value::<String>()
            .unwrap_or_default();
        Ok(state == "complete")
    }

    async fn wait_until(
        &self,
        condition: &WaitCondition,
        timeout_ms: u64,
    ) -> Result<bool, BrowserError> {
        let deadline =
            tokio::time::Instant::now() + tokio::time::Duration::from_millis(timeout_ms);
        while tokio::time::Instant::now() < deadline {
            match condition {
                WaitCondition::PageLoaded => {
                    if self.is_page_loaded().await? {
                        return Ok(true);
                    }
                }
                _ => return Ok(true),
            }
            tokio::time::sleep(tokio::time::Duration::from_millis(100)).await;
        }
        Ok(false)
    }

    async fn element_exists_a11y(
        &self,
        name_contains: &str,
        role: Option<&str>,
    ) -> Result<bool, BrowserError> {
        let nodes = self.get_accessibility_tree().await?;
        Ok(nodes.iter().any(|n| {
            let name_match = n
                .name
                .as_ref()
                .map(|name| name.to_lowercase().contains(&name_contains.to_lowercase()))
                .unwrap_or(false);
            if !name_match {
                return false;
            }
            match role {
                Some(r) => n.role.to_lowercase() == r.to_lowercase(),
                None => true,
            }
        }))
    }

    async fn shutdown(&self) -> Result<(), BrowserError> {
        if let Some(page) = self.page.write().await.take() {
            let _ = page.close().await;
        }
        self._browser.write().await.take();
        Ok(())
    }
}