/**
 * Pipedrive MCP Server Class
 * Implements lazy-loaded tool modules for optimal performance
 */

import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import {
  CallToolRequestSchema,
  ListToolsRequestSchema,
} from '@modelcontextprotocol/sdk/types.js';
import { PipedriveClient } from './client.js';
import type { ToolDefinition, ToolResult } from './types.js';

interface ToolModule {
  tools: ToolDefinition[];
  handle: (
    client: PipedriveClient,
    name: string,
    args: Record<string, unknown>
  ) => Promise<ToolResult>;
}

interface LazyGroup {
  path: string;
  module?: ToolModule;
  toolNames: string[];
}

export class PipedriveMCPServer {
  private server: Server;
  private client: PipedriveClient;
  private groups: LazyGroup[] = [];
  private toolToGroup: Map<string, number> = new Map();
  private allTools: ToolDefinition[] = [];

  constructor(client: PipedriveClient) {
    this.client = client;

    this.server = new Server(
      {
        name: 'pipedrive-mcp',
        version: '1.0.0',
      },
      {
        capabilities: {
          tools: {},
        },
      }
    );

    this.setupToolModules();
    this.setupHandlers();
  }

  private setupToolModules() {
    // Tool groups — metadata loaded eagerly, handlers loaded lazily
    this.groups = [
      // Core tools
      { path: './tools/deals-tools.js', toolNames: [] },
      { path: './tools/persons-tools.js', toolNames: [] },
      { path: './tools/organizations-tools.js', toolNames: [] },
      { path: './tools/activities-tools.js', toolNames: [] },
      { path: './tools/pipelines-tools.js', toolNames: [] },
      { path: './tools/stages-tools.js', toolNames: [] },
      { path: './tools/products-tools.js', toolNames: [] },
      { path: './tools/leads-tools.js', toolNames: [] },
      { path: './tools/notes-tools.js', toolNames: [] },
      { path: './tools/files-tools.js', toolNames: [] },
      { path: './tools/filters-tools.js', toolNames: [] },
      { path: './tools/goals-tools.js', toolNames: [] },
      { path: './tools/webhooks-tools.js', toolNames: [] },
      { path: './tools/users-tools.js', toolNames: [] },
      { path: './tools/mail-tools.js', toolNames: [] },
      { path: './tools/subscriptions-tools.js', toolNames: [] },

      // UI apps
      { path: './apps/deal-dashboard.js', toolNames: [] },
      { path: './apps/deal-detail.js', toolNames: [] },
      { path: './apps/deal-grid.js', toolNames: [] },
      { path: './apps/pipeline-kanban.js', toolNames: [] },
      { path: './apps/pipeline-analytics.js', toolNames: [] },
      { path: './apps/pipeline-funnel.js', toolNames: [] },
      { path: './apps/person-detail.js', toolNames: [] },
      { path: './apps/person-grid.js', toolNames: [] },
      { path: './apps/org-detail.js', toolNames: [] },
      { path: './apps/org-grid.js', toolNames: [] },
      { path: './apps/activity-dashboard.js', toolNames: [] },
      { path: './apps/activity-calendar.js', toolNames: [] },
      { path: './apps/lead-inbox.js', toolNames: [] },
      { path: './apps/lead-detail.js', toolNames: [] },
      { path: './apps/product-catalog.js', toolNames: [] },
      { path: './apps/product-detail.js', toolNames: [] },
      { path: './apps/note-manager.js', toolNames: [] },
      { path: './apps/file-manager.js', toolNames: [] },
      { path: './apps/goal-tracker.js', toolNames: [] },
      { path: './apps/revenue-dashboard.js', toolNames: [] },
      { path: './apps/email-inbox.js', toolNames: [] },
      { path: './apps/filter-manager.js', toolNames: [] },
      { path: './apps/user-stats.js', toolNames: [] },
      { path: './apps/deals-timeline.js', toolNames: [] },
      { path: './apps/subscription-manager.js', toolNames: [] },
      { path: './apps/search-results.js', toolNames: [] },
      { path: './apps/won-deals.js', toolNames: [] },
    ];
  }

  private async loadGroupMetadata(): Promise<void> {
    const toolDefs: ToolDefinition[] = [];
    for (let i = 0; i < this.groups.length; i++) {
      const mod = (await import(this.groups[i].path)) as ToolModule;
      this.groups[i].module = mod;
      this.groups[i].toolNames = mod.tools.map((t) => t.name);
      for (const tool of mod.tools) {
        this.toolToGroup.set(tool.name, i);
        toolDefs.push(tool);
      }
    }
    this.allTools = toolDefs;
  }

  private async getHandler(
    toolName: string
  ): Promise<ToolModule['handle'] | null> {
    const idx = this.toolToGroup.get(toolName);
    if (idx === undefined) return null;
    const group = this.groups[idx];
    if (!group.module) {
      group.module = (await import(group.path)) as ToolModule;
    }
    return group.module.handle;
  }

  private setupHandlers() {
    // List Tools
    this.server.setRequestHandler(ListToolsRequestSchema, async () => {
      // Load metadata on first request
      if (this.allTools.length === 0) {
        await this.loadGroupMetadata();
      }

      return {
        tools: this.allTools.map((t) => ({
          name: t.name,
          description: t.description,
          inputSchema: t.inputSchema,
        })),
      };
    });

    // Call Tool
    this.server.setRequestHandler(CallToolRequestSchema, async (request) => {
      // Ensure metadata is loaded
      if (this.allTools.length === 0) {
        await this.loadGroupMetadata();
      }

      const { name, arguments: args } = request.params;
      const handler = await this.getHandler(name);
      
      if (!handler) {
        return {
          content: [{ type: 'text' as const, text: `Unknown tool: ${name}` }],
          isError: true,
        } as Record<string, unknown>;
      }

      const result = await handler(
        this.client,
        name,
        (args as Record<string, unknown>) || {}
      );
      
      return result as unknown as Record<string, unknown>;
    });
  }

  async connect(transport: any) {
    await this.server.connect(transport);
    
    // Load metadata after connection
    await this.loadGroupMetadata();
    console.error(
      `Pipedrive MCP server — ${this.allTools.length} tools loaded across ${this.groups.length} modules`
    );
  }
}