import type { FastifyInstance } from 'fastify';
import type { Sql } from '../db.js';

// token-analyzer-ui: aggregate token/cost analytics across all agent_sessions.
// v1 — global view only (no per-project or per-user filtering).

export interface AnalyticsSummary {
  total_input_tokens: number;
  total_output_tokens: number;
  total_cost: number;
  session_count: number;
}

export interface SessionAnalyticsRow {
  session_id: string;
  session_name: string;
  total_input_tokens: number;
  total_output_tokens: number;
  total_cost: number;
  last_active_at: string | null;
}

export interface TokenBreakdownAgg {
  category: string;
  total_tokens: number;
}

export function registerAnalyticsRoutes(app: FastifyInstance, sql: Sql): void {
  // GET /api/analytics/summary — aggregate totals across all agent_sessions.
  app.get('/api/analytics/summary', async () => {
    const [row] = await sql<AnalyticsSummary[]>`
      SELECT
        COALESCE(SUM(a.input_tokens), 0)::BIGINT AS total_input_tokens,
        COALESCE(SUM(a.output_tokens), 0)::BIGINT AS total_output_tokens,
        COALESCE(SUM(a.cost), 0)::DOUBLE PRECISION AS total_cost,
        COUNT(DISTINCT c.session_id)::INT AS session_count
      FROM agent_sessions a
      JOIN chats c ON c.id = a.chat_id
    `;
    return row ?? { total_input_tokens: 0, total_output_tokens: 0, total_cost: 0, session_count: 0 };
  });

  // GET /api/analytics/sessions — per-session token/cost breakdown.
  app.get('/api/analytics/sessions', async () => {
    const rows = await sql<SessionAnalyticsRow[]>`
      SELECT
        c.session_id AS session_id,
        s.name AS session_name,
        COALESCE(SUM(a.input_tokens), 0)::BIGINT AS total_input_tokens,
        COALESCE(SUM(a.output_tokens), 0)::BIGINT AS total_output_tokens,
        COALESCE(SUM(a.cost), 0)::DOUBLE PRECISION AS total_cost,
        MAX(a.last_active_at) AS last_active_at
      FROM agent_sessions a
      JOIN chats c ON c.id = a.chat_id
      JOIN sessions s ON s.id = c.session_id
      GROUP BY c.session_id, s.name
      ORDER BY MAX(a.last_active_at) DESC NULLS LAST
    `;
    return { sessions: rows };
  });

  // GET /api/analytics/token-breakdown — aggregate token_breakdown categories
  // across all tasks that carry the JSONB field.
  app.get('/api/analytics/token-breakdown', async () => {
    const rows = await sql<{ category: string; total_tokens: number }[]>`
      SELECT
        key AS category,
        SUM((value->>0)::BIGINT)::BIGINT AS total_tokens
      FROM tasks,
      LATERAL jsonb_each(token_breakdown)
      WHERE token_breakdown IS NOT NULL
        AND jsonb_typeof(token_breakdown) = 'object'
      GROUP BY key
      ORDER BY total_tokens DESC
    `;
    return { categories: rows };
  });
}