//! Types representing accessibility tree snapshots from camofox-browser.

use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// A page snapshot returned by the camofox-browser API.
///
/// The snapshot is an accessibility tree with stable element refs
/// (e.g., `e1`, `e2`) that can be used for clicking and typing.
/// This format is ~90% more token-efficient than raw HTML.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PageSnapshot {
    /// Accessibility tree text with element refs.
    pub snapshot: String,
    /// Optional URL of the page.
    #[serde(default)]
    pub url: String,
    /// Optional page title.
    #[serde(default)]
    pub title: String,
    /// Optional screenshot as base64 PNG.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub screenshot: Option<String>,
    /// Element reference map: ref -> element info.
    #[serde(default)]
    pub elements: HashMap<String, ElementInfo>,
}

/// Information about a single element in the snapshot.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ElementInfo {
    /// The element's tag name (e.g., "a", "button", "input").
    #[serde(default)]
    pub tag: String,
    /// Visible text content.
    #[serde(default)]
    pub text: String,
    /// URL for links.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub href: Option<String>,
    /// Whether the element is interactive.
    #[serde(default)]
    pub interactive: bool,
}

impl PageSnapshot {
    /// Create a new snapshot from raw text.
    pub fn new(snapshot: String) -> Self {
        Self {
            snapshot,
            url: String::new(),
            title: String::new(),
            screenshot: None,
            elements: HashMap::new(),
        }
    }

    /// Whether the snapshot is empty (no content).
    pub fn is_empty(&self) -> bool {
        self.snapshot.is_empty()
    }

    /// Number of characters in the snapshot text.
    pub fn len(&self) -> usize {
        self.snapshot.len()
    }

    /// Extract all element refs from the snapshot text.
    ///
    /// Refs look like `[e1]`, `[e2]` in the accessibility tree.
    pub fn extract_refs(&self) -> Vec<String> {
        let mut refs = Vec::new();
        for line in self.snapshot.lines() {
            // Pattern: [eN] or eN
            if let Some(start) = line.find("[e") {
                let end = line[start + 2..].find(']').map(|i| start + 2 + i);
                if let Some(end_pos) = end {
                    let ref_str = &line[start + 1..start + 1 + end_pos + 1];
                    refs.push(ref_str.to_string());
                }
            }
        }
        refs.sort();
        refs.dedup();
        refs
    }
}

/// Links extracted from a page.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PageLinks {
    /// List of links on the page.
    pub links: Vec<LinkItem>,
    /// Total count of links.
    pub total: usize,
}

/// A single link item.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LinkItem {
    /// Link text.
    pub text: String,
    /// Target URL.
    pub href: String,
    /// Optional title attribute.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub title: Option<String>,
}

/// Response from page navigation.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct NavigationResult {
    /// Final URL after navigation.
    pub url: String,
    /// Page title.
    pub title: String,
    /// Whether navigation succeeded.
    pub ok: bool,
}

/// Response from element interaction (click/type).
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InteractionResult {
    /// Whether the interaction succeeded.
    pub ok: bool,
    /// New snapshot after interaction (if available).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub snapshot: Option<PageSnapshot>,
}

/// Health check response from camofox-browser.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HealthResponse {
    /// Server is OK.
    pub ok: bool,
    /// Engine type (e.g., "camoufox").
    pub engine: String,
    /// Whether browser is connected.
    #[serde(default)]
    pub browser_connected: bool,
    /// Whether browser is running.
    #[serde(default)]
    pub browser_running: bool,
    /// Number of active tabs.
    #[serde(default)]
    pub active_tabs: u32,
    /// Number of active sessions.
    #[serde(default)]
    pub active_sessions: u32,
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_extract_refs_from_snapshot() {
        let snap = PageSnapshot::new(
            "- heading \"Example\" [level=1]\n- link \"Click\" [e1]:\n  - /url: https://example.com\n- paragraph: text [e2]\n".into(),
        );
        let refs = snap.extract_refs();
        assert!(refs.contains(&"[e1]".to_string()));
        assert!(refs.contains(&"[e2]".to_string()));
    }

    #[test]
    fn test_empty_snapshot() {
        let snap = PageSnapshot::new(String::new());
        assert!(snap.is_empty());
        assert_eq!(snap.len(), 0);
    }

    #[test]
    fn test_health_response_deserialize() {
        let json = r#"{"ok":true,"engine":"camoufox","browserConnected":true,"browserRunning":true,"activeTabs":3,"activeSessions":2}"#;
        let health: HealthResponse = serde_json::from_str(json).unwrap();
        assert!(health.ok);
        assert_eq!(health.active_tabs, 3);
    }
}