use std::net::TcpStream;
use std::process::Stdio;
use std::time::Duration;

use anyhow::Context;
use async_trait::async_trait;
use base64::Engine;
use fantoccini::actions::{InputSource, MOUSE_BUTTON_LEFT, MouseActions, PointerAction};
use fantoccini::key::Key;
use fantoccini::{Client, ClientBuilder, Locator};
use serde::{Deserialize, Serialize};
use serde_json::{Map, Value, json};
use tracing;

use crate::config::BrowserConfig;
use crate::tools::traits::{Tool, ToolResult};

const CHROME_CANDIDATES: &[&str] = &[
    "google-chrome",
    "chromium-browser",
    "chromium",
    "google-chrome-stable",
    "chrome",
];

const CHROMEDRIVER_CANDIDATES: &[&str] = &["chromedriver"];

pub struct BrowserTool {
    webdriver_url: String,
    headless: bool,
    chrome_path: Option<String>,
    state: tokio::sync::Mutex<BrowserState>,
    driver: std::sync::Mutex<Option<tokio::process::Child>>,
}

struct BrowserState {
    client: Option<Client>,
}

impl Drop for BrowserTool {
    fn drop(&mut self) {
        if let Ok(mut driver) = self.driver.lock()
            && let Some(ref mut child) = driver.take()
        {
            tracing::debug!("Stopping chromedriver process");
            let _ = child.start_kill();
        }
    }
}

impl BrowserTool {
    pub fn new(config: &BrowserConfig) -> Self {
        Self {
            webdriver_url: config.webdriver_url.clone(),
            headless: config.headless,
            chrome_path: config.chrome_path.clone(),
            state: tokio::sync::Mutex::new(BrowserState { client: None }),
            driver: std::sync::Mutex::new(None),
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum BrowserAction {
    Open {
        url: String,
    },
    Snapshot {
        #[serde(default)]
        interactive_only: bool,
        #[serde(default)]
        compact: bool,
        #[serde(default)]
        depth: Option<i64>,
    },
    Click {
        selector: String,
    },
    Fill {
        selector: String,
        value: String,
    },
    Type {
        selector: Option<String>,
        text: String,
    },
    GetText {
        selector: String,
    },
    GetTitle,
    GetUrl,
    Screenshot {
        #[serde(default)]
        path: Option<String>,
        #[serde(default)]
        return_base64: bool,
    },
    Focus {
        selector: String,
    },
    Wait {
        #[serde(default)]
        selector: Option<String>,
        #[serde(default)]
        ms: Option<u64>,
        #[serde(default)]
        text: Option<String>,
    },
    Press {
        key: String,
    },
    Hover {
        selector: String,
    },
    ClickAt {
        x: u32,
        y: u32,
    },
    Scroll {
        direction: String,
        #[serde(default)]
        pixels: Option<u32>,
    },
    Close,
}

fn parse_browser_action(action_str: &str, args: &Value) -> anyhow::Result<BrowserAction> {
    match action_str {
        "open" => {
            let url = args
                .get("url")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'url' for open action"))?;
            Ok(BrowserAction::Open {
                url: url.to_string(),
            })
        }
        "snapshot" => Ok(BrowserAction::Snapshot {
            interactive_only: args
                .get("interactive_only")
                .and_then(Value::as_bool)
                .unwrap_or(true),
            compact: args.get("compact").and_then(Value::as_bool).unwrap_or(true),
            depth: args.get("depth").and_then(|v| v.as_i64()),
        }),
        "click" => {
            let selector = args
                .get("selector")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'selector' for click"))?;
            Ok(BrowserAction::Click {
                selector: selector.to_string(),
            })
        }
        "fill" => {
            let selector = args
                .get("selector")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'selector' for fill"))?;
            let value = args
                .get("value")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'value' for fill"))?;
            Ok(BrowserAction::Fill {
                selector: selector.to_string(),
                value: value.to_string(),
            })
        }
        "type" => {
            let selector = args
                .get("selector")
                .and_then(|v| v.as_str())
                .map(|s| s.to_string());
            let text = args
                .get("text")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'text' for type"))?;
            Ok(BrowserAction::Type {
                selector,
                text: text.to_string(),
            })
        }
        "get_text" => {
            let selector = args
                .get("selector")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'selector' for get_text"))?;
            Ok(BrowserAction::GetText {
                selector: selector.to_string(),
            })
        }
        "get_title" => Ok(BrowserAction::GetTitle),
        "get_url" => Ok(BrowserAction::GetUrl),
        "screenshot" => Ok(BrowserAction::Screenshot {
            path: args.get("path").and_then(|v| v.as_str()).map(String::from),
            return_base64: args
                .get("return_base64")
                .and_then(Value::as_bool)
                .unwrap_or(false),
        }),
        "focus" => {
            let selector = args
                .get("selector")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'selector' for focus"))?;
            Ok(BrowserAction::Focus {
                selector: selector.to_string(),
            })
        }
        "wait" => Ok(BrowserAction::Wait {
            selector: args
                .get("selector")
                .and_then(|v| v.as_str())
                .map(String::from),
            ms: args.get("ms").and_then(|v| v.as_u64()),
            text: args.get("text").and_then(|v| v.as_str()).map(String::from),
        }),
        "press" => {
            let key = args
                .get("key")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'key' for press"))?;
            Ok(BrowserAction::Press {
                key: key.to_string(),
            })
        }
        "hover" => {
            let selector = args
                .get("selector")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'selector' for hover"))?;
            Ok(BrowserAction::Hover {
                selector: selector.to_string(),
            })
        }
        "scroll" => {
            let direction = args
                .get("direction")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("Missing 'direction' for scroll"))?;
            Ok(BrowserAction::Scroll {
                direction: direction.to_string(),
                pixels: args
                    .get("pixels")
                    .and_then(|v| v.as_u64())
                    .map(|p| u32::try_from(p).unwrap_or(u32::MAX)),
            })
        }
        "close" => Ok(BrowserAction::Close),
        "click_at" => {
            let x = args
                .get("x")
                .and_then(|v| v.as_u64())
                .ok_or_else(|| anyhow::anyhow!("Missing 'x' for click_at"))?
                as u32;
            let y = args
                .get("y")
                .and_then(|v| v.as_u64())
                .ok_or_else(|| anyhow::anyhow!("Missing 'y' for click_at"))?
                as u32;
            Ok(BrowserAction::ClickAt { x, y })
        }
        other => anyhow::bail!("Unsupported browser action: {}", other),
    }
}

#[async_trait]
impl Tool for BrowserTool {
    fn name(&self) -> &str {
        "browser"
    }

    fn description(&self) -> &str {
        "Automate browser interactions via WebDriver. \
        Actions: open, snapshot, click, fill, type, get_text, get_title, \
        get_url, screenshot, wait, press, hover, scroll, close, focus, click_at. \
        Each session holds a single page; calling open again navigates \
        the current page (does not open a new tab). \
        Selectors: CSS, @e1 refs (from snapshot), text=... for text content, \
        label=... for <label> association. \
        Use focus to set focus on an element before typing or filling. \
        After click_at focuses an element, use type without selector \
        to type into the active element. \
        Limitations: press supports single keys only (no Ctrl+/Shift+ combos); \
        screenshot captures the visible viewport only."
    }

    fn parameters_schema(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "action": {
                    "type": "string",
                    "description": "Browser action to perform",
                    "enum": [
                        "open", "snapshot", "click", "fill", "type",
                        "get_text", "get_title", "get_url", "screenshot",
                        "wait", "press", "hover", "scroll", "close", "focus", "click_at"
                    ]
                },
                "url": {
                    "type": "string",
                    "description": "(open) URL to navigate to"
                },
                "selector": {
                    "type": "string",
                    "description": "(click/fill/type/get_text/hover/wait/focus) CSS selector, @e1 ref, text=..., or label=... Omit for type to target active element after click_at."
                },
                "value": {
                    "type": "string",
                    "description": "(fill) Value to fill. On dynamic sites, try click or focus first to make element interactable."
                },
                "text": {
                    "type": "string",
                    "description": "(type/wait) Text to append or wait for. For type, selector optional — if omitted, types into active element."
                },
                "key": {
                    "type": "string",
                    "description": "(press) Key to press. Single keys only: Enter, Tab, Escape, Backspace, Delete, ArrowUp, ArrowDown, Space, etc."
                },
                "direction": {
                    "type": "string",
                    "description": "(scroll) Scroll direction",
                    "enum": ["up", "down", "left", "right"]
                },
                "pixels": {
                    "type": "integer",
                    "description": "(scroll) Pixels to scroll (default 600)"
                },
                "ms": {
                    "type": "integer",
                    "description": "(wait) Milliseconds to wait"
                },
                "path": {
                    "type": "string",
                    "description": "(screenshot) File path to save screenshot. Omit to auto-save to /tmp/picobot_screenshot_<ts>.png"
                },
                "return_base64": {
                    "type": "boolean",
                    "description": "(screenshot) Also return image as base64 data URI"
                },
                "interactive_only": {
                    "type": "boolean",
                    "description": "(snapshot) Only show interactive elements (default true)"
                },
                "compact": {
                    "type": "boolean",
                    "description": "(snapshot) Compact output mode (default true)"
                },
                "depth": {
                    "type": "integer",
                    "description": "(snapshot) Max DOM depth for traversal"
                },
                "x": {
                    "type": "integer",
                    "description": "(click_at) X coordinate in viewport pixels"
                },
                "y": {
                    "type": "integer",
                    "description": "(click_at) Y coordinate in viewport pixels"
                }
            },
            "required": ["action"]
        })
    }

    fn exclusive(&self) -> bool {
        true
    }

    async fn execute(&self, args: Value) -> anyhow::Result<ToolResult> {
        let action_str = args
            .get("action")
            .and_then(|v| v.as_str())
            .ok_or_else(|| anyhow::anyhow!("Missing required parameter: action"))?;

        let action = parse_browser_action(action_str, &args)?;

        let mut state = self.state.lock().await;
        state
            .execute_action(
                action,
                self.headless,
                &self.webdriver_url,
                self.chrome_path.as_deref(),
                &self.driver,
            )
            .await
    }
}

impl BrowserState {
    async fn execute_action(
        &mut self,
        action: BrowserAction,
        headless: bool,
        webdriver_url: &str,
        chrome_path: Option<&str>,
        driver: &std::sync::Mutex<Option<tokio::process::Child>>,
    ) -> anyhow::Result<ToolResult> {
        let action_clone = action.clone();
        let result = self
            .try_execute(action, headless, webdriver_url, chrome_path, driver)
            .await;

        match result {
            Ok(r) => Ok(r),
            Err(e) => {
                if is_recoverable_error(&e) {
                    tracing::warn!("Recoverable browser session error, retrying: {:#}", e);
                    self.reset_session(driver).await;
                    self.try_execute(action_clone, headless, webdriver_url, chrome_path, driver)
                        .await
                } else {
                    Err(e)
                }
            }
        }
    }

    #[allow(clippy::too_many_lines)]
    async fn try_execute(
        &mut self,
        action: BrowserAction,
        headless: bool,
        webdriver_url: &str,
        chrome_path: Option<&str>,
        driver: &std::sync::Mutex<Option<tokio::process::Child>>,
    ) -> anyhow::Result<ToolResult> {
        match action {
            BrowserAction::Open { url } => {
                self.ensure_session(headless, webdriver_url, chrome_path, driver)
                    .await?;
                let client = self.active_client()?;
                client.goto(&url).await?;
                let _ = client
                    .execute(
                        "Object.defineProperty(navigator,'webdriver',{get:()=>undefined})",
                        Vec::<Value>::new(),
                    )
                    .await;
                let current = client.current_url().await?;
                Ok(ToolResult {
                    success: true,
                    output: format!("Opened {}", current),
                    error: None,
                })
            }
            BrowserAction::Snapshot {
                interactive_only,
                compact,
                depth,
            } => {
                let client = self.active_client()?;
                let result: Value = client
                    .execute(&snapshot_script(interactive_only, compact, depth), vec![])
                    .await?;
                let output = serde_json::to_string_pretty(&result)?;
                Ok(ToolResult {
                    success: true,
                    output,
                    error: None,
                })
            }
            BrowserAction::Click { selector } => {
                let client = self.active_client()?;
                find_element(client, &selector).await?.click().await?;
                Ok(ToolResult {
                    success: true,
                    output: format!("Clicked {}", selector),
                    error: None,
                })
            }
            BrowserAction::Fill { selector, value } => {
                let client = self.active_client()?;
                let el = find_element(client, &selector).await?;
                let fill_result = async {
                    let _ = el.clear().await;
                    tokio::time::sleep(Duration::from_millis(300)).await;
                    el.send_keys(&value).await
                }
                .await;
                match fill_result {
                    Ok(()) => {}
                    Err(ref e) if format!("{e}").to_lowercase().contains("not interactable") => {
                        tracing::debug!("Fill via WebDriver failed, falling back to JS: {e}");
                        let escaped = value
                            .replace('\\', "\\\\")
                            .replace('\'', "\\'")
                            .replace('\n', "\\n");
                        client
                            .execute(
                                &format!(
                                    "arguments[0].value='{escaped}';arguments[0].dispatchEvent(new Event('input',{{bubbles:true}}));arguments[0].dispatchEvent(new Event('change',{{bubbles:true}}));"
                                ),
                                vec![serde_json::to_value(&el)?],
                            )
                            .await?;
                    }
                    Err(e) => return Err(e.into()),
                }
                tracing::debug!(
                    action = "fill",
                    output_len = value.len(),
                    "Browser action completed"
                );
                Ok(ToolResult {
                    success: true,
                    output: format!("Filled {} with {}", selector, value),
                    error: None,
                })
            }
            BrowserAction::Type { selector, text } => {
                let client = self.active_client()?;
                let type_result = match selector {
                    Some(ref sel) => {
                        let el = find_element(client, sel).await?;
                        el.send_keys(&text).await
                    }
                    None => {
                        // Type into active element (useful after click_at)
                        let el = client.active_element().await?;
                        el.send_keys(&text).await
                    }
                };
                match type_result {
                    Ok(()) => {}
                    Err(ref e) if format!("{e}").to_lowercase().contains("not interactable") => {
                        tracing::debug!("Type via WebDriver failed, falling back to JS: {e}");
                        let escaped = text
                            .replace('\\', "\\\\")
                            .replace('\'', "\\'")
                            .replace('\n', "\\n");
                        if let Some(ref sel) = selector {
                            let el = find_element(client, sel).await?;
                            client
                                .execute(
                                    &format!(
                                        "arguments[0].value='{escaped}';arguments[0].dispatchEvent(new Event('input',{{bubbles:true}}));arguments[0].dispatchEvent(new Event('change',{{bubbles:true}}));"
                                    ),
                                    vec![serde_json::to_value(&el)?],
                                )
                                .await?;
                        } else {
                            client
                                .execute(
                                    &format!(
                                        "var el=document.activeElement;el.value='{escaped}';el.dispatchEvent(new Event('input',{{bubbles:true}}));el.dispatchEvent(new Event('change',{{bubbles:true}}));"
                                    ),
                                    Vec::<Value>::new(),
                                )
                                .await?;
                        }
                    }
                    Err(e) => return Err(e.into()),
                }
                let target = selector.as_deref().unwrap_or("activeElement");
                Ok(ToolResult {
                    success: true,
                    output: format!("Typed {} chars into {}", text.len(), target),
                    error: None,
                })
            }
            BrowserAction::GetText { selector } => {
                let client = self.active_client()?;
                let text = find_element(client, &selector).await?.text().await?;
                Ok(ToolResult {
                    success: true,
                    output: text,
                    error: None,
                })
            }
            BrowserAction::GetTitle => {
                let client = self.active_client()?;
                let title = client.title().await?;
                Ok(ToolResult {
                    success: true,
                    output: title,
                    error: None,
                })
            }
            BrowserAction::GetUrl => {
                let client = self.active_client()?;
                let url = client.current_url().await?;
                Ok(ToolResult {
                    success: true,
                    output: url.to_string(),
                    error: None,
                })
            }
            BrowserAction::Screenshot {
                path,
                return_base64,
            } => {
                let client = self.active_client()?;
                let png = client.screenshot().await?;
                let save_path = path.unwrap_or_else(|| {
                    format!(
                        "/tmp/picobot_screenshot_{}.png",
                        std::time::SystemTime::now()
                            .duration_since(std::time::UNIX_EPOCH)
                            .unwrap_or_default()
                            .as_secs()
                    )
                });
                tokio::fs::write(&save_path, &png).await?;
                if return_base64 {
                    let b64 = base64::engine::general_purpose::STANDARD.encode(&png);
                    tracing::debug!(
                        action = "screenshot",
                        output_len = b64.len(),
                        "Browser action completed"
                    );
                    return Ok(ToolResult {
                        success: true,
                        output: format!(
                            "Screenshot saved to {}. Base64: data:image/png;base64,{}",
                            save_path, b64
                        ),
                        error: None,
                    });
                }
                tracing::debug!(
                    action = "screenshot",
                    output_len = save_path.len(),
                    "Browser action completed"
                );
                Ok(ToolResult {
                    success: true,
                    output: format!("Screenshot saved to {}", save_path),
                    error: None,
                })
            }
            BrowserAction::Focus { selector } => {
                let client = self.active_client()?;
                let el = find_element(client, &selector).await?;
                client
                    .execute(
                        "arguments[0].focus(); arguments[0].scrollIntoView({block:'center'});",
                        vec![serde_json::to_value(el)?],
                    )
                    .await?;
                tracing::debug!(
                    action = "focus",
                    output_len = selector.len(),
                    "Browser action completed"
                );
                Ok(ToolResult {
                    success: true,
                    output: format!("Focused {}", selector),
                    error: None,
                })
            }
            BrowserAction::Wait { selector, ms, text } => {
                if let Some(sel) = selector {
                    let client = self.active_client()?;
                    wait_for_selector(client, &sel).await?;
                    Ok(ToolResult {
                        success: true,
                        output: format!("Element found: {}", sel),
                        error: None,
                    })
                } else if let Some(duration_ms) = ms {
                    tokio::time::sleep(Duration::from_millis(duration_ms)).await;
                    Ok(ToolResult {
                        success: true,
                        output: format!("Waited {} ms", duration_ms),
                        error: None,
                    })
                } else if let Some(needle) = text {
                    let client = self.active_client()?;
                    let xpath = xpath_contains_text(&needle);
                    client.wait().for_element(Locator::XPath(&xpath)).await?;
                    Ok(ToolResult {
                        success: true,
                        output: format!("Text appeared: {}", needle),
                        error: None,
                    })
                } else {
                    tokio::time::sleep(Duration::from_millis(250)).await;
                    Ok(ToolResult {
                        success: true,
                        output: "Waited 250 ms".to_string(),
                        error: None,
                    })
                }
            }
            BrowserAction::Press { key } => {
                let client = self.active_client()?;
                let key_input = webdriver_key(&key);
                match client.active_element().await {
                    Ok(el) => {
                        el.send_keys(&key_input).await?;
                    }
                    Err(_) => {
                        find_element(client, "body")
                            .await?
                            .send_keys(&key_input)
                            .await?;
                    }
                }
                Ok(ToolResult {
                    success: true,
                    output: format!("Pressed {}", key),
                    error: None,
                })
            }
            BrowserAction::Hover { selector } => {
                let client = self.active_client()?;
                let el = find_element(client, &selector).await?;
                hover_element(client, &el).await?;
                Ok(ToolResult {
                    success: true,
                    output: format!("Hovered {}", selector),
                    error: None,
                })
            }
            BrowserAction::ClickAt { x, y } => {
                let client = self.active_client()?;
                let actions = MouseActions::new("mouse".to_string())
                    .then(PointerAction::MoveTo {
                        duration: Some(Duration::from_millis(100)),
                        x: x as f64,
                        y: y as f64,
                    })
                    .then(PointerAction::Down {
                        button: MOUSE_BUTTON_LEFT,
                    })
                    .then(PointerAction::Up {
                        button: MOUSE_BUTTON_LEFT,
                    });
                client.perform_actions(actions).await?;
                let _ = client.release_actions().await;
                // Get info about the clicked element
                let element_info: Value = client
                    .execute(
                        &format!(
                            "(()=>{{var e=document.elementFromPoint({},{x});if(!e)return null;return{{tag:e.tagName.toLowerCase(),id:e.id||null,type:e.type||null,text:(e.value||e.placeholder||e.innerText||'').slice(0,80)}}}})()",
                            x
                        ),
                        Vec::<Value>::new(),
                    )
                    .await
                    .unwrap_or_default();
                let desc = match element_info.as_object() {
                    Some(info) => {
                        let tag = info.get("tag").and_then(|v| v.as_str()).unwrap_or("?");
                        let id = info.get("id").and_then(|v| v.as_str()).unwrap_or("");
                        let el_type = info.get("type").and_then(|v| v.as_str()).unwrap_or("");
                        let text = info.get("text").and_then(|v| v.as_str()).unwrap_or("");
                        let id_str = if id.is_empty() {
                            String::new()
                        } else {
                            format!("#{id}")
                        };
                        let type_str = if el_type.is_empty() {
                            String::new()
                        } else {
                            format!("[type={el_type}]")
                        };
                        let text_str = if text.is_empty() {
                            String::new()
                        } else {
                            format!(" ({text})")
                        };
                        format!("Clicked at ({x},{y}) on <{tag}{id_str}{type_str}>{text_str}")
                    }
                    None => format!("Clicked at ({}, {})", x, y),
                };
                Ok(ToolResult {
                    success: true,
                    output: desc,
                    error: None,
                })
            }
            BrowserAction::Scroll { direction, pixels } => {
                let client = self.active_client()?;
                let amount = i64::from(pixels.unwrap_or(600));
                let (dx, dy) = match direction.as_str() {
                    "up" => (0, -amount),
                    "down" => (0, amount),
                    "left" => (-amount, 0),
                    "right" => (amount, 0),
                    _ => anyhow::bail!(
                        "Unsupported scroll direction '{}'. Use up/down/left/right",
                        direction
                    ),
                };
                let position: Value = client
                    .execute(
                        "window.scrollBy(arguments[0], arguments[1]); \
                         return { x: window.scrollX, y: window.scrollY };",
                        vec![json!(dx), json!(dy)],
                    )
                    .await?;
                Ok(ToolResult {
                    success: true,
                    output: format!(
                        "Scrolled {} by {} -> {}",
                        direction,
                        amount,
                        serde_json::to_string(&position).unwrap_or_default()
                    ),
                    error: None,
                })
            }
            BrowserAction::Close => {
                self.reset_session(driver).await;
                Ok(ToolResult {
                    success: true,
                    output: "Browser session closed".to_string(),
                    error: None,
                })
            }
        }
    }

    pub async fn reset_session(
        &mut self,
        driver: &std::sync::Mutex<Option<tokio::process::Child>>,
    ) {
        if let Some(client) = self.client.take() {
            let _ = client.close().await;
        }
        if let Ok(mut guard) = driver.lock()
            && let Some(ref mut child) = guard.take()
        {
            tracing::debug!("Stopping chromedriver process");
            let _ = child.start_kill();
        }
    }

    async fn ensure_session(
        &mut self,
        headless: bool,
        webdriver_url: &str,
        chrome_path: Option<&str>,
        driver: &std::sync::Mutex<Option<tokio::process::Child>>,
    ) -> anyhow::Result<()> {
        if self.client.is_some() {
            return Ok(());
        }

        let chrome_binary = match chrome_path {
            Some(path) if !path.trim().is_empty() => Some(path.trim().to_string()),
            _ => {
                verify_chrome_installed()?;
                None
            }
        };

        let chromedriver_binary = find_chromedriver_binary()?;

        let port = extract_port(webdriver_url);

        let launched = if !webdriver_endpoint_reachable(webdriver_url) {
            tracing::info!(
                "chromedriver not running at {}, launching: {} --port={}",
                webdriver_url,
                chromedriver_binary,
                port
            );
            launch_chromedriver(driver, &chromedriver_binary, port)?;
            true
        } else {
            false
        };

        if launched {
            wait_for_webdriver_ready(webdriver_url).await
                .map_err(|e| {
                    kill_driver_guard(driver);
                    e.context("chromedriver failed to start. Is Chrome installed? Check browser.chrome_path in config.json")
                })?;
        }

        let mut capabilities: Map<String, Value> = Map::new();
        let mut chrome_options: Map<String, Value> = Map::new();
        let mut args: Vec<Value> = Vec::new();

        if headless {
            args.push(Value::String("--headless=new".to_string()));
            args.push(Value::String("--disable-gpu".to_string()));
            args.push(Value::String("--no-sandbox".to_string()));
            args.push(Value::String("--disable-dev-shm-usage".to_string()));
        }

        args.push(Value::String("--window-size=1920,1080".to_string()));

        // Anti-bot detection
        args.push(Value::String(
            "--disable-blink-features=AutomationControlled".to_string(),
        ));
        args.push(Value::String(
            "--user-agent=Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/147.0.0.0 Safari/537.36".to_string(),
        ));

        if let Some(ref binary) = chrome_binary {
            chrome_options.insert("binary".to_string(), Value::String(binary.clone()));
        }

        if !args.is_empty() {
            chrome_options.insert("args".to_string(), Value::Array(args));
        }

        chrome_options.insert(
            "excludeSwitches".to_string(),
            serde_json::json!(["enable-automation"]),
        );

        capabilities.insert(
            "goog:chromeOptions".to_string(),
            Value::Object(chrome_options),
        );

        let client = ClientBuilder::rustls()?
            .capabilities(capabilities)
            .connect(webdriver_url)
            .await
            .with_context(|| {
                format!(
                    "Failed to connect to WebDriver at {}. \
                     Make sure chromedriver is installed and running.",
                    webdriver_url
                )
            })?;

        self.client = Some(client);
        Ok(())
    }

    fn active_client(&self) -> anyhow::Result<&Client> {
        self.client
            .as_ref()
            .ok_or_else(|| anyhow::anyhow!("No active browser session. Run action='open' first"))
    }
}

fn launch_chromedriver(
    driver: &std::sync::Mutex<Option<tokio::process::Child>>,
    chromedriver_binary: &str,
    port: u16,
) -> anyhow::Result<()> {
    let child = tokio::process::Command::new(chromedriver_binary)
        .arg(format!("--port={}", port))
        .stdout(Stdio::null())
        .stderr(Stdio::null())
        .spawn()
        .with_context(|| format!("Failed to launch chromedriver: {}", chromedriver_binary))?;

    *driver.lock().unwrap() = Some(child);
    Ok(())
}

fn kill_driver_guard(driver: &std::sync::Mutex<Option<tokio::process::Child>>) {
    if let Ok(mut guard) = driver.lock()
        && let Some(ref mut child) = guard.take()
    {
        let _ = child.start_kill();
    }
}

async fn wait_for_webdriver_ready(webdriver_url: &str) -> anyhow::Result<()> {
    let deadline = tokio::time::Instant::now() + Duration::from_secs(10);

    loop {
        if webdriver_endpoint_reachable(webdriver_url) {
            return Ok(());
        }

        if tokio::time::Instant::now() >= deadline {
            anyhow::bail!(
                "Timed out waiting for chromedriver to start listening on {}",
                webdriver_url
            );
        }

        tokio::time::sleep(Duration::from_millis(200)).await;
    }
}

fn verify_chrome_installed() -> anyhow::Result<()> {
    for name in CHROME_CANDIDATES {
        if which::which(name).is_ok() {
            return Ok(());
        }
    }

    anyhow::bail!(
        "Chrome/Chromium not found. Install with:\n\
           Ubuntu/Debian: apt install chromium-browser\n\
           macOS: brew install chromium\n\
         Or set browser.chrome_path in config.json"
    )
}

fn find_chromedriver_binary() -> anyhow::Result<String> {
    for name in CHROMEDRIVER_CANDIDATES {
        if let Ok(path) = which::which(name) {
            return Ok(path.to_string_lossy().to_string());
        }
    }

    anyhow::bail!(
        "chromedriver not found. Install with:\n\
           Ubuntu/Debian: apt install chromium-chromedriver\n\
           macOS: brew install chromedriver\n\
         Or download from https://chromedriver.chromium.org/"
    )
}

fn extract_port(webdriver_url: &str) -> u16 {
    reqwest::Url::parse(webdriver_url)
        .ok()
        .and_then(|u| u.port())
        .unwrap_or(9515)
}

fn webdriver_endpoint_reachable(webdriver_url: &str) -> bool {
    let parsed = match reqwest::Url::parse(webdriver_url) {
        Ok(url) => url,
        Err(_) => return false,
    };

    if parsed.scheme() != "http" && parsed.scheme() != "https" {
        return false;
    }

    let host = match parsed.host_str() {
        Some(h) if !h.is_empty() => h,
        _ => return false,
    };

    let port = parsed.port_or_known_default().unwrap_or(9515);
    let addr = format!("{}:{}", host, port);

    TcpStream::connect_timeout(
        &addr
            .parse::<std::net::SocketAddr>()
            .unwrap_or_else(|_| ([127, 0, 0, 1], port).into()),
        Duration::from_millis(500),
    )
    .is_ok()
}

fn is_recoverable_error(err: &anyhow::Error) -> bool {
    let message = format!("{:#}", err).to_ascii_lowercase();

    message.contains("invalid session id")
        || message.contains("no such window")
        || message.contains("session not created")
        || message.contains("connection reset")
        || message.contains("broken pipe")
        || (message.contains("webdriver")
            && (message.contains("timed out") || message.contains("timeout")))
}

enum SelectorKind {
    Css(String),
    XPath(String),
}

fn parse_selector(selector: &str) -> SelectorKind {
    let trimmed = selector.trim();

    if let Some(text_query) = trimmed.strip_prefix("text=") {
        return SelectorKind::XPath(xpath_contains_text(text_query));
    }

    if let Some(label_query) = trimmed.strip_prefix("label=") {
        let literal = xpath_literal(label_query);
        return SelectorKind::XPath(format!(
            "(//label[contains(normalize-space(.), {literal})] \
             /following::*[self::input or self::textarea or self::select][1] \
             | //*[@aria-label and contains(normalize-space(@aria-label), {literal})] \
             | //label[contains(normalize-space(.), {literal})])"
        ));
    }

    if trimmed.starts_with('@') {
        let escaped = css_attr_escape(trimmed);
        return SelectorKind::Css(format!(r#"[data-zc-ref="{escaped}"]"#));
    }

    SelectorKind::Css(trimmed.to_string())
}

async fn find_element(
    client: &Client,
    selector: &str,
) -> anyhow::Result<fantoccini::elements::Element> {
    match parse_selector(selector) {
        SelectorKind::Css(css) => Ok(client.find(Locator::Css(&css)).await?),
        SelectorKind::XPath(xpath) => Ok(client.find(Locator::XPath(&xpath)).await?),
    }
}

async fn wait_for_selector(client: &Client, selector: &str) -> anyhow::Result<()> {
    match parse_selector(selector) {
        SelectorKind::Css(css) => {
            client.wait().for_element(Locator::Css(&css)).await?;
        }
        SelectorKind::XPath(xpath) => {
            client.wait().for_element(Locator::XPath(&xpath)).await?;
        }
    }
    Ok(())
}

async fn hover_element(
    client: &Client,
    element: &fantoccini::elements::Element,
) -> anyhow::Result<()> {
    let actions = MouseActions::new("mouse".to_string()).then(PointerAction::MoveToElement {
        element: element.clone(),
        duration: Some(Duration::from_millis(150)),
        x: 0.0,
        y: 0.0,
    });

    client.perform_actions(actions).await?;
    let _ = client.release_actions().await;
    Ok(())
}

fn css_attr_escape(input: &str) -> String {
    input
        .replace('\\', "\\\\")
        .replace('"', "\\\"")
        .replace('\n', " ")
}

fn xpath_contains_text(text: &str) -> String {
    format!("//*[contains(normalize-space(.), {})]", xpath_literal(text))
}

fn xpath_literal(input: &str) -> String {
    if !input.contains('"') {
        return format!("\"{}\"", input);
    }
    if !input.contains('\'') {
        return format!("'{}'", input);
    }

    let segments: Vec<&str> = input.split('"').collect();
    let mut parts: Vec<String> = Vec::new();
    for (index, part) in segments.iter().enumerate() {
        if !part.is_empty() {
            parts.push(format!("\"{}\"", part));
        }
        if index + 1 < segments.len() {
            parts.push("'\"'".to_string());
        }
    }

    if parts.is_empty() {
        "\"\"".to_string()
    } else {
        format!("concat({})", parts.join(","))
    }
}

fn webdriver_key(key: &str) -> String {
    match key.trim().to_ascii_lowercase().as_str() {
        "enter" => Key::Enter.to_string(),
        "return" => Key::Return.to_string(),
        "tab" => Key::Tab.to_string(),
        "escape" | "esc" => Key::Escape.to_string(),
        "backspace" => Key::Backspace.to_string(),
        "delete" => Key::Delete.to_string(),
        "arrowup" => Key::Up.to_string(),
        "arrowdown" => Key::Down.to_string(),
        "arrowleft" => Key::Left.to_string(),
        "arrowright" => Key::Right.to_string(),
        "home" => Key::Home.to_string(),
        "end" => Key::End.to_string(),
        "pageup" => Key::PageUp.to_string(),
        "pagedown" => Key::PageDown.to_string(),
        "space" => " ".to_string(),
        other => {
            tracing::warn!(
                "Unrecognized key '{}', this will have no effect (press only supports single named keys)",
                other
            );
            other.to_string()
        }
    }
}

fn snapshot_script(interactive_only: bool, compact: bool, depth: Option<i64>) -> String {
    let depth_literal = depth
        .map(|level| level.to_string())
        .unwrap_or_else(|| "null".to_string());

    format!(
        r#"(() => {{
  const interactiveOnly = {interactive_only};
  const compact = {compact};
  const maxDepth = {depth_literal};
  const nodes = [];
  const root = document.body || document.documentElement;
  let counter = 0;

  const isVisible = (el) => {{
    const style = window.getComputedStyle(el);
    if (style.display === 'none' || style.visibility === 'hidden' || Number(style.opacity || 1) === 0) {{
      return false;
    }}
    const rect = el.getBoundingClientRect();
    return rect.width > 0 && rect.height > 0;
  }};

   const isInteractive = (el) => {{
    if (el.disabled || el.readOnly) return false;
    if (!isVisible(el)) return false;
    if (el.matches('a,button,input,select,textarea,summary,[role],*[tabindex]')) return true;
    return typeof el.onclick === 'function';
  }};

  const describe = (el, depth) => {{
    const interactive = isInteractive(el);
    const text = (el.innerText || el.textContent || '').trim().replace(/\s+/g, ' ').slice(0, 140);
    if (interactiveOnly && !interactive) return;
    if (compact && !interactive && !text) return;

    const ref = '@e' + (++counter);
    el.setAttribute('data-zc-ref', ref);
    const rect = el.getBoundingClientRect();
    nodes.push({{
      ref,
      depth,
      tag: el.tagName.toLowerCase(),
      id: el.id || null,
      role: el.getAttribute('role'),
      text,
      interactive,
      x: Math.round(rect.x),
      y: Math.round(rect.y),
      w: Math.round(rect.width),
      h: Math.round(rect.height),
    }});
  }};

  const walk = (el, depth) => {{
    if (!(el instanceof Element)) return;
    if (maxDepth !== null && depth > maxDepth) return;
    if (isVisible(el)) {{
      describe(el, depth);
    }}
    for (const child of el.children) {{
      walk(child, depth + 1);
      if (nodes.length >= 400) return;
    }}
  }};

  if (root) walk(root, 0);

  return JSON.stringify({{
    title: document.title,
    url: window.location.href,
    count: nodes.length,
    nodes,
  }});
}})();"#
    )
}