#!/usr/bin/env node
/**
 * MCP server: NestJS module/controller validator (read-only).
 *
 * Tools:
 *   - validate_module_source    : assert a TypeScript source string is a
 *                                 well-formed Nest module
 *   - check_app_registration    : verify that server/src/app.module.ts
 *                                 imports and registers a given module class
 *
 * Purely lexical — we do not use the TypeScript compiler API (that would
 * add a dependency). Regex-level checks are sufficient for the structural
 * invariants the orchestrator cares about.
 */

import fs from "node:fs";
import path from "node:path";
import { runMCPServer } from "./lib/mcp-server.mjs";
import { getProjectRoot } from "../lib/project-root.mjs";

const projectRoot = getProjectRoot();

// Regex constants for NestJS module validation
const DECORATOR_KEYS_RE = /(?:^|[,{\s])(imports|controllers|providers|exports)\s*:/g;
const IMPORTS_BLOCK_RE = /imports\s*:\s*\[([\s\S]*?)\]/;

const tools = [
  {
    name: "validate_module_source",
    description:
      "Validate that a TypeScript source string declares a well-formed NestJS module: imports @Module from @nestjs/common, applies the @Module decorator with an object argument, and exports a class. Returns the class name and the decorator keys it declares.",
    inputSchema: {
      type: "object",
      properties: {
        source: { type: "string", description: "Contents of a *.module.ts file" },
      },
      required: ["source"],
    },
    execute: async ({ source }) => {
      if (typeof source !== "string" || source.length === 0) {
        return { success: false, error: "source must be a non-empty string" };
      }

      const issues = [];

      if (!/from ['"]@nestjs\/common['"]/.test(source)) {
        issues.push("does not import from @nestjs/common");
      }
      if (!/\bModule\b/.test(source)) {
        issues.push("does not reference the Module symbol");
      }

      const decoratorMatch = source.match(/@Module\s*\(\s*\{([\s\S]*?)\}\s*\)/);
      if (!decoratorMatch) {
        issues.push("no @Module({...}) decorator found");
      }

      const classMatch = source.match(/export\s+class\s+(\w+)/);
      if (!classMatch) {
        issues.push("no `export class <Name>` declaration");
      }

      // Extract the top-level keys inside the decorator object so callers
      // can sanity-check providers/controllers/imports presence.
      const declaredKeys = [];
      if (decoratorMatch) {
        const body = decoratorMatch[1];
        let m;
        while ((m = DECORATOR_KEYS_RE.exec(body)) !== null) {
          declaredKeys.push(m[1]);
        }
      }

      return {
        success: issues.length === 0,
        result: {
          className: classMatch?.[1] ?? null,
          declaredKeys,
          issues,
        },
      };
    },
  },
  {
    name: "check_app_registration",
    description:
      "Check whether server/src/app.module.ts imports and registers a given Nest module class. Useful after generator_nest_resources produces a module, to verify the orchestrator has wired it into the parent-owned app.module.ts.",
    inputSchema: {
      type: "object",
      properties: {
        moduleClass: {
          type: "string",
          description: "e.g. `ChangeEquipmentStatusModule`",
        },
        appModulePath: {
          type: "string",
          description:
            "Optional override for the app.module.ts path (relative to project root). Defaults to server/src/app.module.ts.",
        },
      },
      required: ["moduleClass"],
    },
    execute: async ({ moduleClass, appModulePath }) => {
      if (typeof moduleClass !== "string" || !/^[A-Z]\w*Module$/.test(moduleClass)) {
        return {
          success: false,
          error: "moduleClass must be a PascalCase class name ending in Module",
        };
      }

      const relPath = appModulePath ?? "server/src/app.module.ts";
      const absPath = path.isAbsolute(relPath)
        ? relPath
        : path.join(projectRoot, relPath);

      let source: string;
      try {
        source = fs.readFileSync(absPath, "utf8");
      } catch (err) {
        return {
          success: false,
          error: `failed to read ${relPath}: ${err instanceof Error ? err.message : String(err)}`,
        };
      }

      const importRe = new RegExp(
        `import\\s*\\{[^}]*\\b${moduleClass}\\b[^}]*\\}\\s*from\\s*['"]([^'"]+)['"]`
      );
      const importMatch = source.match(importRe);

      const decoratorMatch = source.match(/@Module\s*\(\s*\{([\s\S]*?)\}\s*\)/);
      let registered = false;
      if (decoratorMatch) {
        const importsBlock = decoratorMatch[1].match(IMPORTS_BLOCK_RE);
        if (importsBlock) {
          const importedModules = importsBlock[1]
            .split(",")
            .map((s) => s.trim())
            .filter(Boolean);
          registered = importedModules.includes(moduleClass);
        }
      }

      return {
        success: Boolean(importMatch) && registered,
        result: {
          moduleClass,
          appModulePath: relPath,
          imported: Boolean(importMatch),
          importedFrom: importMatch?.[1] ?? null,
          registered,
        },
      };
    },
  },
];

runMCPServer({ name: "kis-toir-nest-validator", version: "0.1.0", tools });