/**
 * In-memory tool registry.
 *
 * Packages call `defineTool()` to create a typed ToolDef, then
 * `ToolRegistry.register()` to publish it. Transport adapters (OpenAPI,
 * MCP) consume the registry via `list()` / `get()`.
 *
 * There is no global singleton registry exported here — each server
 * instantiates its own registry so tests stay isolated.
 */

import type { ToolDef } from './types.js';

// ---------------------------------------------------------------------------
// defineTool — identity helper that preserves full generic types
// ---------------------------------------------------------------------------

/**
 * Wrap a tool definition to get TypeScript inference on `I` and `O` while
 * returning a value that satisfies `ToolDef<I, O>`.
 *
 * Usage:
 * ```ts
 * export const searchInbox = defineTool({
 *   name: 'search-inbox',
 *   tier: 'ops',
 *   requiredScope: 'gmail:self',
 *   // ...
 *   handler: async (input: SearchInboxInput, ctx) => { ... },
 * });
 * ```
 */
export function defineTool<I, O>(def: ToolDef<I, O>): ToolDef<I, O> {
  return def;
}

// ---------------------------------------------------------------------------
// ToolRegistry
// ---------------------------------------------------------------------------

/**
 * A typed, in-memory registry of tool definitions.
 *
 * Tool names must be unique across a registry instance. Attempting to
 * register a duplicate name throws synchronously so misconfigurations are
 * caught at server startup, not at request time.
 */
export class ToolRegistry {
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  private readonly tools = new Map<string, ToolDef<any, any>>();

  /**
   * Register a tool. Throws if a tool with the same name is already registered.
   */
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  register<I, O>(def: ToolDef<I, O>): this {
    if (this.tools.has(def.name)) {
      throw new Error(
        `ToolRegistry: duplicate tool name "${def.name}". ` +
          'Each tool name must be unique within a registry.',
      );
    }
    this.tools.set(def.name, def);
    return this;
  }

  /**
   * Return all registered tool definitions in insertion order.
   */
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  list(): ToolDef<any, any>[] {
    return [...this.tools.values()];
  }

  /**
   * Look up a tool by name. Returns `undefined` if not found.
   */
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  get(name: string): ToolDef<any, any> | undefined {
    return this.tools.get(name);
  }

  /**
   * The number of tools currently registered.
   */
  get size(): number {
    return this.tools.size;
  }
}