import type { FastifyInstance } from 'fastify';
import { query } from '../db/client.js';
import { logger } from '../observability/logger.js';

interface RtkStatsBody {
  host: string;
  commands: Array<{
    rtk_id: number;
    timestamp: string;
    original_cmd: string;
    rtk_cmd: string;
    input_tokens: number;
    output_tokens: number;
    saved_tokens: number;
    savings_pct: number;
    exec_time_ms: number;
    project_path: string;
  }>;
}

export async function rtkRoutes(app: FastifyInstance): Promise<void> {
  // ─── Ingest RTK stats from client machines ───────────────────────────
  app.post<{ Body: RtkStatsBody }>('/v1/rtk/stats', async (req, reply) => {
    const { host, commands } = req.body;

    if (!host || !Array.isArray(commands)) {
      reply.code(400);
      return { error: 'host and commands array required' };
    }

    let inserted = 0;
    for (const cmd of commands) {
      try {
        const result = await query(
          `INSERT INTO rtk_commands (
            rtk_id, host, timestamp, original_cmd, rtk_cmd,
            input_tokens, output_tokens, saved_tokens, savings_pct,
            exec_time_ms, project_path
          ) VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11)
          ON CONFLICT (host, rtk_id) DO NOTHING`,
          [
            cmd.rtk_id, host, cmd.timestamp, cmd.original_cmd, cmd.rtk_cmd,
            cmd.input_tokens, cmd.output_tokens, cmd.saved_tokens, cmd.savings_pct,
            cmd.exec_time_ms, cmd.project_path,
          ],
        );
        if (result.rowCount && result.rowCount > 0) inserted += 1;
      } catch (err) {
        logger.warn({ err, rtk_id: cmd.rtk_id }, 'Failed to insert RTK command');
      }
    }

    logger.info({ host, received: commands.length, inserted }, 'RTK stats ingested');
    return { received: commands.length, inserted };
  });

  // ─── Aggregate stats (all hosts) ──────────────────────────────────────
  app.get<{ Querystring: { period?: string } }>('/v1/rtk/stats', async (req) => {
    const intervals: Record<string, string> = {
      today: "timestamp >= CURRENT_DATE",
      week: "timestamp >= CURRENT_DATE - INTERVAL '7 days'",
      month: "timestamp >= CURRENT_DATE - INTERVAL '30 days'",
      all: '1=1',
    };
    const where = intervals[req.query.period ?? 'all'] ?? intervals['all']!;

    const result = await query<{
      total_commands: string; total_input: string; total_output: string;
      total_saved: string; avg_savings: string; hosts: string; projects: string;
    }>(`SELECT
      COUNT(*) as total_commands,
      COALESCE(SUM(input_tokens), 0) as total_input,
      COALESCE(SUM(output_tokens), 0) as total_output,
      COALESCE(SUM(saved_tokens), 0) as total_saved,
      COALESCE(AVG(savings_pct), 0) as avg_savings,
      COUNT(DISTINCT host) as hosts,
      COUNT(DISTINCT project_path) as projects
     FROM rtk_commands WHERE ${where}`);

    const row = result.rows[0]!;
    return {
      period: req.query.period ?? 'all',
      total_commands: parseInt(row.total_commands, 10),
      total_input_tokens: parseInt(row.total_input, 10),
      total_output_tokens: parseInt(row.total_output, 10),
      total_saved_tokens: parseInt(row.total_saved, 10),
      avg_savings_pct: parseFloat(row.avg_savings),
      unique_hosts: parseInt(row.hosts, 10),
      unique_projects: parseInt(row.projects, 10),
    };
  });

  // ─── Top commands by savings ──────────────────────────────────────────
  app.get('/v1/rtk/commands', async () => {
    const result = await query<{
      cmd: string; count: string; saved: string; avg_pct: string;
    }>(`SELECT
      split_part(rtk_cmd, ' ', 1) || ' ' || split_part(rtk_cmd, ' ', 2) as cmd,
      COUNT(*) as count,
      COALESCE(SUM(saved_tokens), 0) as saved,
      COALESCE(AVG(savings_pct), 0) as avg_pct
     FROM rtk_commands
     WHERE timestamp >= CURRENT_DATE - INTERVAL '30 days'
     GROUP BY cmd
     ORDER BY saved DESC
     LIMIT 20`);

    return {
      commands: result.rows.map(r => ({
        cmd: r.cmd,
        count: parseInt(r.count, 10),
        saved_tokens: parseInt(r.saved, 10),
        avg_savings_pct: parseFloat(r.avg_pct),
      })),
    };
  });

  // ─── Per-host breakdown ───────────────────────────────────────────────
  app.get('/v1/rtk/hosts', async () => {
    const result = await query<{
      host: string; count: string; saved: string; last_seen: string;
    }>(`SELECT
      host,
      COUNT(*) as count,
      COALESCE(SUM(saved_tokens), 0) as saved,
      MAX(timestamp) as last_seen
     FROM rtk_commands
     GROUP BY host
     ORDER BY saved DESC`);

    return {
      hosts: result.rows.map(r => ({
        host: r.host,
        commands: parseInt(r.count, 10),
        saved_tokens: parseInt(r.saved, 10),
        last_seen: r.last_seen,
      })),
    };
  });
}