use crate::router::McpTool;
use crate::state::MemoryState;
use crate::tools::FetchUrlTool;
use async_trait::async_trait;
use reqwest::Client;
use serde_json::Value;
use std::sync::Arc;

pub struct FetchUrlHandler;

#[async_trait]
impl McpTool for FetchUrlHandler {
    fn name(&self) -> &'static str {
        "fetch_url"
    }

    fn schema(&self) -> Value {
        crate::mcp::tool_def::<FetchUrlTool>(
            "fetch_url",
            "Fetch content from a URL via an HTTP GET request natively (supports proxy config via environment variables: HTTP_PROXY, HTTPS_PROXY, NO_PROXY)",
        )
    }

    async fn execute(&self, args: Value, _state: Arc<MemoryState>) -> crate::error::Result<String> {
        let req: FetchUrlTool = serde_json::from_value(args).map_err(|e| {
            crate::error::AppError::BadRequest(format!(
                "Schema validation failed. Your JSON arguments do not match the expected tool schema: {}",
                e
            ))
        })?;

        let mut client_builder = Client::builder();

        // Add optional user agent
        if let Some(ua) = req.user_agent {
            client_builder = client_builder.user_agent(ua);
        } else {
            client_builder = client_builder.user_agent("mcp-memory-server/1.0");
        }

        // Allow bypassing SSL validation for self-signed certificates
        if req.ignore_ssl_errors.unwrap_or(false) {
            client_builder = client_builder.danger_accept_invalid_certs(true);
        }

        // Reqwest automatically uses HTTP_PROXY, HTTPS_PROXY, NO_PROXY 
        // environment variables by default, so we don't need to manually
        // extract and apply them, the builder handles it.

        let client = client_builder.build().map_err(|e| {
            crate::error::AppError::Internal(format!("Failed to build HTTP client: {}", e))
        })?;

        let res = client.get(&req.url).send().await.map_err(|e| {
            crate::error::AppError::Internal(format!("HTTP request to {} failed: {}", req.url, e))
        })?;

        let status = res.status();
        let content = res.text().await.map_err(|e| {
            crate::error::AppError::Internal(format!("Failed to read response body: {}", e))
        })?;

        if !status.is_success() {
            return Ok(format!(
                "HTTP Error: {} {}\n\nResponse Body:\n{}",
                status.as_u16(),
                status.canonical_reason().unwrap_or("Unknown"),
                content
            ));
        }

        Ok(content)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use axum::{routing::get, Router};
    use tokio::net::TcpListener;

    async fn spawn_test_server() -> String {
        let app = Router::new()
            .route("/test", get(|| async { "Hello, World!" }))
            .route(
                "/not_found",
                get(|| async {
                    (
                        axum::http::StatusCode::NOT_FOUND,
                        "Not Found Error",
                    )
                }),
            );

        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
        let port = listener.local_addr().unwrap().port();
        
        tokio::spawn(async move {
            axum::serve(listener, app).await.unwrap();
        });

        format!("http://127.0.0.1:{}", port)
    }

    #[tokio::test]
    async fn test_fetch_url_success() {
        let base_url = spawn_test_server().await;
        let handler = FetchUrlHandler;
        let url = format!("{}/test", base_url);

        let res = handler
            .execute(
                serde_json::json!({
                    "url": url
                }),
                Arc::new(MemoryState::new("")),
            )
            .await
            .unwrap();

        assert_eq!(res, "Hello, World!");
    }

    #[tokio::test]
    async fn test_fetch_url_not_found() {
        let base_url = spawn_test_server().await;
        let handler = FetchUrlHandler;
        let url = format!("{}/not_found", base_url);

        let res = handler
            .execute(
                serde_json::json!({
                    "url": url
                }),
                Arc::new(MemoryState::new("")),
            )
            .await
            .unwrap();

        assert!(res.contains("HTTP Error: 404 Not Found"));
        assert!(res.contains("Not Found Error"));
    }
}