//! Get diagnostics from LSP.
//!
//! Sends a `textDocument/diagnostic` request to the connected language
//! server for a given file and returns errors, warnings, and other
//! diagnostics.

use crate::tools::{Tool, ToolCtx};
use anyhow::Result;
use serde_json::{json, Value};
use tracing::{error, info, instrument};

/// Tool that retrieves diagnostics (errors, warnings) from the LSP for a file.
///
/// Flow: parse language/path → lock LSP manager → find client
/// → send `textDocument/diagnostic` → return pretty-printed JSON response.
pub struct LspDiagnostics;

impl Tool for LspDiagnostics {
    fn name(&self) -> &'static str {
        "lsp_diagnostics"
    }

    fn description(&self) -> &'static str {
        "Get diagnostics (errors, warnings) from the LSP for a file"
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "language": {
                    "type": "string",
                    "description": "Language identifier"
                },
                "path": {
                    "type": "string",
                    "description": "File path to get diagnostics for"
                }
            },
            "required": ["language", "path"]
        })
    }

    #[instrument(skip(self, ctx, args))]
    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String> {
        let language = crate::tools::arg_str(args, "language")?;
        let path = crate::tools::arg_str(args, "path")?;

        info!(language, path, "LSP diagnostics requested");

        let manager = match ctx.lsp_manager.lock() {
            Ok(g) => g,
            Err(poisoned) => {
                error!("LSP manager mutex poisoned, recovering");
                poisoned.into_inner()
            }
        };
        if let Some(client) = manager.get_client(&language) {
            let result = client.send_request(
                "textDocument/diagnostic",
                &json!({
                    "textDocument": { "uri": format!("file://{}", path) }
                }),
            )?;
            Ok(serde_json::to_string_pretty(&result)?)
        } else {
            anyhow::bail!("no LSP client connected for '{language}'")
        }
    }
}