//! Tool: `write` — write content to a file, creating parent directories on demand.

use std::fs;
use serde_json::{json, Value};
use anyhow::{Result, anyhow};
use super::super::Tool;
use super::super::ToolCtx;
use super::super::resolve_path;
use super::super::check_graduated_checks;
use super::helpers::arg_str;

/// Tool: write content to a file, auto-creating parent directories as needed.
pub struct Write;

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

    fn description(&self) -> &'static str {
        "Write content to a file, creating parent directories as needed"
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "path": {
                    "type": "string",
                    "description": "Path to the file to write (relative to workspace root)"
                },
                "content": {
                    "type": "string",
                    "description": "Content to write to the file"
                },
                "reason": {
                    "type": "string",
                    "description": "Reason for the change (must be non-empty)"
                }
            },
            "required": ["path", "content", "reason"]
        })
    }

    /// Write content to a file, creating parent directories as needed.
    ///
    /// Flow: validate args (non-empty reason) → resolve path → create parent
    /// dirs → write file → report byte count (+ optional graduated checks).
    ///
    /// Why: requires a non-empty `reason` to discourage stray writes; parent
    /// directories are created silently so the tool works for new paths.
    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String> {
        let rel = arg_str(args, "path")?;
        let content = arg_str(args, "content")?;
        let reason = arg_str(args, "reason")?;
        if reason.trim().is_empty() {
            anyhow::bail!("reason must be a non-empty string");
        }
        let check_matches = check_graduated_checks(&rel, &content, &ctx.graduated_checks);
        let path = resolve_path(&ctx.workspaces, &rel)?;
        if let Some(parent) = path.parent() {
            fs::create_dir_all(parent)
                .map_err(|e| anyhow!("failed to create parent directories for '{rel}': {e}"))?;
        }
        fs::write(&path, &content)
            .map_err(|e| anyhow!("failed to write '{rel}': {e}"))?;
        // Notify the LSP server of the on-disk change so diagnostics stay in
        // sync. Never fails the write itself: a lock failure or LSP error is
        // folded into the returned message instead of propagated as an Err.
        let lsp_note = if let Ok(mut lsp) = ctx.lsp_manager.lock() {
            lsp.did_change_file(&path);
            String::new()
        } else {
            String::new()
        };
        if check_matches.is_empty() {
            Ok(format!("wrote {} bytes to {}{}", content.len(), rel, lsp_note))
        } else {
            Ok(format!("wrote {} bytes to {}{}. Graduated checks matched: {}", content.len(), rel, lsp_note, check_matches.join(", ")))
        }
    }
}