//! Read a file from the workspace.

use crate::tools::{resolve_path, Tool, ToolCtx};
use anyhow::Result;
use serde_json::{json, Value};
use std::fs;
use tracing::{info, instrument, warn};

/// Read the contents of a file.
///
/// Flow: resolve path → check existence and type → read file content → return.
pub struct Read;

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

    fn description(&self) -> &'static str {
        "Read the contents of a file"
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "path": {
                    "type": "string",
                    "description": "Path to the file to read (relative to workspace root)"
                }
            },
            "required": ["path"]
        })
    }

    #[instrument(skip(self, ctx, args))]
    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String> {
        let rel = crate::tools::arg_str(args, "path")?;
        let path = resolve_path(&ctx.workspaces, &rel)?;
        if !path.exists() {
            warn!(rel = %rel, "read target does not exist");
            anyhow::bail!("file '{rel}' does not exist");
        }
        if !path.is_file() {
            warn!(rel = %rel, "read target is not a file");
            anyhow::bail!("'{rel}' is not a file");
        }
        let content = fs::read_to_string(&path)?;
        info!(rel = %rel, bytes = content.len(), "file read");
        Ok(content)
    }
}