// Tool handler for the review_code MCP tool.

import { validateToolInput } from "./schemas.js";
import { checkContextBudget } from "../utils/context-budget.js";
import { buildReviewCodePrompt } from "../prompts/review-code.js";

/**
 * Handle the review_code MCP tool.
 *
 * Orchestration order: validate -> config -> budget -> prompt -> client -> response.
 * All external dependencies injected via deps. Internal utilities imported directly.
 * No throws escape — all paths return structured results.
 *
 * @param {unknown} input
 *   Raw tool input per ARCHITECTURE.md §7 schema.
 * @param {{
 *   loadConfig: () => object,
 *   createProvider: (config: object) => { send: (request: ProviderRequest, cfg: object) => Promise<{ content: string }> }
 *     ProviderRequest = { prompt?: string, input?: object }
 * }} deps
 *   Injected external dependencies.
 * @returns {Promise<{ ok: true, answer: string, warnings: string[] } | { ok: false, error: string, warnings: string[] }>}
 */
export async function handleReviewCode(input, deps) {
  // --- 1. Validate input (before anything else) ---

  const validation = validateToolInput(input);
  if (!validation.ok) {
    return { ok: false, error: validation.errors.join(" | "), warnings: [] };
  }

  // --- 2. Load config ---

  let config;
  try {
    config = deps.loadConfig();
  } catch (err) {
    return { ok: false, error: String(err), warnings: [] };
  }

  // --- 3. Context budget check ---

  const budget = checkContextBudget(validation.data, config);
  if (!budget.ok) {
    return { ok: false, error: budget.error, warnings: budget.warnings };
  }

  // --- 4. Build prompt ---

  const promptMessages = buildReviewCodePrompt(budget.input);

  // --- 5. Create chat provider ---

  let provider;
  try {
    provider = deps.createProvider(config);
  } catch (err) {
    return { ok: false, error: String(err), warnings: [] };
  }

  // --- 5b. Package shared data for provider ---

  const reviewRequest = { prompt: promptMessages, input: budget.input };

  // --- 6. Send via provider ---

  let aiResult;
  try {
    aiResult = await provider.send(reviewRequest, config);
  } catch (err) {
    return { ok: false, error: String(err), warnings: [] };
  }

  // --- 7. Success ---

  return { ok: true, answer: aiResult.content, warnings: budget.warnings };
}