//! Toolsets module - registry of dynamically loadable tool collections.
//!
//! Toolsets are groups of related tools that can be loaded on-demand via the
//! `load_toolset` tool. This keeps the default tool set lean while allowing
//! access to specialized tools when needed.
//!
//! The agent sees a concise registry in the system prompt and can load
//! toolsets as needed. The tool definitions are returned so the agent
//! learns how to call the newly available tools.

use g3_providers::Tool;
use serde_json::json;

/// A toolset that can be dynamically loaded.
#[derive(Debug, Clone)]
pub struct Toolset {
    /// Unique identifier for the toolset (e.g., "webdriver")
    pub name: &'static str,
    /// Brief description of what the toolset provides
    pub description: &'static str,
    /// Function that returns the tool definitions for this toolset
    tool_definitions_fn: fn() -> Vec<Tool>,
}

impl Toolset {
    /// Get the tool definitions for this toolset.
    pub fn get_tools(&self) -> Vec<Tool> {
        (self.tool_definitions_fn)()
    }
}

/// Registry of all available toolsets.
/// Add new toolsets here as they are created.
const TOOLSET_REGISTRY: &[Toolset] = &[
    Toolset {
        name: "webdriver",
        description: "Browser automation via Safari WebDriver. Start sessions, navigate, find elements, click, type, execute JavaScript, take screenshots.",
        tool_definitions_fn: create_webdriver_tools,
    },
];

/// Get a toolset by name.
///
/// Returns `Ok(Toolset)` if found, or `Err` with a helpful message listing
/// available toolsets if not found.
pub fn get_toolset(name: &str) -> Result<&'static Toolset, String> {
    let name = name.trim();
    
    if name.is_empty() {
        return Err(format!(
            "Toolset name cannot be empty. Available toolsets: {}",
            list_toolset_names().join(", ")
        ));
    }
    
    TOOLSET_REGISTRY
        .iter()
        .find(|t| t.name == name)
        .ok_or_else(|| {
            format!(
                "Unknown toolset '{}'. Available toolsets: {}",
                name,
                list_toolset_names().join(", ")
            )
        })
}

/// List all available toolset names.
pub fn list_toolset_names() -> Vec<&'static str> {
    TOOLSET_REGISTRY.iter().map(|t| t.name).collect()
}

/// Get all available toolsets.
pub fn get_all_toolsets() -> &'static [Toolset] {
    TOOLSET_REGISTRY
}

/// Generate the prompt section describing available toolsets.
///
/// This is injected into the system prompt so the agent knows what
/// toolsets are available to load.
pub fn generate_toolsets_prompt() -> String {
    if TOOLSET_REGISTRY.is_empty() {
        return String::new();
    }
    
    let mut prompt = String::new();
    prompt.push_str("# Available Toolsets\n\n");
    prompt.push_str("You can dynamically load additional tools using `load_toolset`. ");
    prompt.push_str("The tool will return the full definitions so you learn how to use them.\n\n");
    prompt.push_str("<available_toolsets>\n");
    
    for toolset in TOOLSET_REGISTRY {
        prompt.push_str("  <toolset>\n");
        prompt.push_str(&format!("    <name>{}</name>\n", escape_xml(toolset.name)));
        prompt.push_str(&format!("    <description>{}</description>\n", escape_xml(toolset.description)));
        prompt.push_str("  </toolset>\n");
    }
    
    prompt.push_str("</available_toolsets>\n");
    prompt
}

/// Escape special XML characters.
fn escape_xml(s: &str) -> String {
    s.replace('&', "&amp;")
        .replace('<', "&lt;")
        .replace('>', "&gt;")
        .replace('"', "&quot;")
        .replace('\'', "&apos;")
}

// =============================================================================
// TOOLSET DEFINITIONS
// =============================================================================

/// Create WebDriver browser automation tools.
///
/// These tools enable browser automation via Safari WebDriver.
fn create_webdriver_tools() -> Vec<Tool> {
    vec![
        Tool {
            name: "webdriver_start".to_string(),
            description: "Start a Safari WebDriver session for browser automation. Must be called before any other webdriver tools. Requires Safari's 'Allow Remote Automation' to be enabled in Develop menu.".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {},
                "required": []
            }),
        },
        Tool {
            name: "webdriver_navigate".to_string(),
            description: "Navigate to a URL in the browser".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {
                    "url": {
                        "type": "string",
                        "description": "The URL to navigate to (must include protocol, e.g., https://)"
                    }
                },
                "required": ["url"]
            }),
        },
        Tool {
            name: "webdriver_get_url".to_string(),
            description: "Get the current URL of the browser".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {},
                "required": []
            }),
        },
        Tool {
            name: "webdriver_get_title".to_string(),
            description: "Get the title of the current page".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {},
                "required": []
            }),
        },
        Tool {
            name: "webdriver_find_element".to_string(),
            description: "Find an element on the page by CSS selector and return its text content".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {
                    "selector": {
                        "type": "string",
                        "description": "CSS selector to find the element (e.g., 'h1', '.class-name', '#id')"
                    }
                },
                "required": ["selector"]
            }),
        },
        Tool {
            name: "webdriver_find_elements".to_string(),
            description: "Find all elements matching a CSS selector and return their text content".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {
                    "selector": {
                        "type": "string",
                        "description": "CSS selector to find elements"
                    }
                },
                "required": ["selector"]
            }),
        },
        Tool {
            name: "webdriver_click".to_string(),
            description: "Click an element on the page".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {
                    "selector": {
                        "type": "string",
                        "description": "CSS selector for the element to click"
                    }
                },
                "required": ["selector"]
            }),
        },
        Tool {
            name: "webdriver_send_keys".to_string(),
            description: "Type text into an input element".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {
                    "selector": {
                        "type": "string",
                        "description": "CSS selector for the input element"
                    },
                    "text": {
                        "type": "string",
                        "description": "Text to type into the element"
                    },
                    "clear_first": {
                        "type": "boolean",
                        "description": "Whether to clear the element before typing (default: true)"
                    }
                },
                "required": ["selector", "text"]
            }),
        },
        Tool {
            name: "webdriver_execute_script".to_string(),
            description: "Execute JavaScript code in the browser and return the result".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {
                    "script": {
                        "type": "string",
                        "description": "JavaScript code to execute (use 'return' to return a value)"
                    }
                },
                "required": ["script"]
            }),
        },
        Tool {
            name: "webdriver_get_page_source".to_string(),
            description: "Get the rendered HTML source of the current page. Returns the current DOM state after JavaScript execution.".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {
                    "max_length": {
                        "type": "integer",
                        "description": "Maximum length of HTML to return (default: 10000, use 0 for no truncation)"
                    },
                    "save_to_file": {
                        "type": "string",
                        "description": "Optional file path to save the HTML instead of returning it inline"
                    }
                },
                "required": []
            }),
        },
        Tool {
            name: "webdriver_screenshot".to_string(),
            description: "Take a screenshot of the browser window".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {
                    "path": {
                        "type": "string",
                        "description": "Path where to save the screenshot (e.g., '/tmp/screenshot.png')"
                    }
                },
                "required": ["path"]
            }),
        },
        Tool {
            name: "webdriver_back".to_string(),
            description: "Navigate back in browser history".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {},
                "required": []
            }),
        },
        Tool {
            name: "webdriver_forward".to_string(),
            description: "Navigate forward in browser history".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {},
                "required": []
            }),
        },
        Tool {
            name: "webdriver_refresh".to_string(),
            description: "Refresh the current page".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {},
                "required": []
            }),
        },
        Tool {
            name: "webdriver_quit".to_string(),
            description: "Close the browser and end the WebDriver session".to_string(),
            input_schema: json!({
                "type": "object",
                "properties": {},
                "required": []
            }),
        },
    ]
}

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

    #[test]
    fn test_get_toolset_webdriver() {
        let toolset = get_toolset("webdriver").unwrap();
        assert_eq!(toolset.name, "webdriver");
        assert!(!toolset.description.is_empty());
        
        let tools = toolset.get_tools();
        assert!(!tools.is_empty());
        assert!(tools.iter().any(|t| t.name == "webdriver_start"));
    }

    #[test]
    fn test_get_toolset_unknown() {
        let result = get_toolset("nonexistent");
        assert!(result.is_err());
        let err = result.unwrap_err();
        assert!(err.contains("Unknown toolset"));
        assert!(err.contains("webdriver")); // Should list available toolsets
    }

    #[test]
    fn test_get_toolset_empty_name() {
        let result = get_toolset("");
        assert!(result.is_err());
        let err = result.unwrap_err();
        assert!(err.contains("cannot be empty"));
    }

    #[test]
    fn test_get_toolset_whitespace_trimmed() {
        let toolset = get_toolset("  webdriver  ").unwrap();
        assert_eq!(toolset.name, "webdriver");
    }

    #[test]
    fn test_list_toolset_names() {
        let names = list_toolset_names();
        assert!(names.contains(&"webdriver"));
    }

    #[test]
    fn test_generate_toolsets_prompt() {
        let prompt = generate_toolsets_prompt();
        assert!(prompt.contains("<available_toolsets>"));
        assert!(prompt.contains("</available_toolsets>"));
        assert!(prompt.contains("<name>webdriver</name>"));
        assert!(prompt.contains("load_toolset"));
    }

    #[test]
    fn test_xml_escaping() {
        // The current toolsets don't have special chars, but test the function
        assert_eq!(escape_xml("<test>"), "&lt;test&gt;");
        assert_eq!(escape_xml("a & b"), "a &amp; b");
    }

    #[test]
    fn test_webdriver_tools_complete() {
        let tools = create_webdriver_tools();
        let tool_names: Vec<_> = tools.iter().map(|t| t.name.as_str()).collect();
        
        // Verify all expected webdriver tools are present
        assert!(tool_names.contains(&"webdriver_start"));
        assert!(tool_names.contains(&"webdriver_navigate"));
        assert!(tool_names.contains(&"webdriver_get_url"));
        assert!(tool_names.contains(&"webdriver_get_title"));
        assert!(tool_names.contains(&"webdriver_find_element"));
        assert!(tool_names.contains(&"webdriver_find_elements"));
        assert!(tool_names.contains(&"webdriver_click"));
        assert!(tool_names.contains(&"webdriver_send_keys"));
        assert!(tool_names.contains(&"webdriver_execute_script"));
        assert!(tool_names.contains(&"webdriver_get_page_source"));
        assert!(tool_names.contains(&"webdriver_screenshot"));
        assert!(tool_names.contains(&"webdriver_back"));
        assert!(tool_names.contains(&"webdriver_forward"));
        assert!(tool_names.contains(&"webdriver_refresh"));
        assert!(tool_names.contains(&"webdriver_quit"));
    }
}