import { type NextRequest, NextResponse } from 'next/server';

import { withAuth, buildItemFilter } from '@/lib/apiHelpers';
import pool from '@/lib/db';

export const GET = withAuth(async (req: NextRequest) => {
  const p = req.nextUrl.searchParams;
  const combinators = p.getAll('combinator');
  const itemsWhitelist = p.getAll('item');
  const itemsBlacklist = p.getAll('exclude');
  const signalType = p.get('signal') ?? 'both';
  const from = p.get('from');
  const to = p.get('to');
  const useRegex = p.get('regex') === 'true';
  const orderBy = p.get('order_by') ?? 'value_asc';
  const limitStr = p.get('limit');
  const limit = limitStr ? parseInt(limitStr, 10) : null;

  const conditions: string[] = [];
  const values: unknown[] = [];
  const param = { current: 1 };

  if (combinators.length > 0) {
    conditions.push(`combinator = ANY($${param.current++})`);
    values.push(combinators);
  }

  const wlClause = buildItemFilter(itemsWhitelist, useRegex, true, values, param);
  if (wlClause) conditions.push(wlClause);

  const blClause = buildItemFilter(itemsBlacklist, useRegex, false, values, param);
  if (blClause) conditions.push(blClause);

  if (from) {
    conditions.push(`real_time >= $${param.current++}`);
    values.push(new Date(from));
  }
  if (to) {
    conditions.push(`real_time <= $${param.current++}`);
    values.push(new Date(to));
  }

  const where = conditions.length > 0 ? `WHERE ${conditions.join(' AND ')}` : '';

  const valueCol = signalType === 'red' ? 'red' : 'green';
  const selectCols =
    signalType === 'green'
      ? 'real_time, game_tick, combinator, item_key, green'
      : signalType === 'red'
        ? 'real_time, game_tick, combinator, item_key, red'
        : 'real_time, game_tick, combinator, item_key, green, red';

  if ((orderBy === 'delta_asc' || orderBy === 'delta_desc') && limit !== null) {
    const baseConditions: string[] = [];
    const baseValues: unknown[] = [];
    const baseParam = { current: 1 };

    if (combinators.length > 0) {
      baseConditions.push(`combinator = ANY($${baseParam.current++})`);
      baseValues.push(combinators);
    }

    const wlBase = buildItemFilter(itemsWhitelist, useRegex, true, baseValues, baseParam);
    if (wlBase) baseConditions.push(wlBase);

    const blBase = buildItemFilter(itemsBlacklist, useRegex, false, baseValues, baseParam);
    if (blBase) baseConditions.push(blBase);

    const baseWhere = baseConditions.length > 0 ? `WHERE ${baseConditions.join(' AND ')}` : '';
    const baseWhereAnd = baseConditions.length > 0 ? `AND ${baseConditions.join(' AND ')}` : '';

    const deltaQuery = `
      WITH snap_now AS (
        SELECT DISTINCT ON (combinator, item_key)
          combinator, item_key, ${valueCol} AS val, real_time AS ref_time
        FROM signals
        ${baseWhere}
        ORDER BY combinator, item_key, real_time DESC
      ),
      snap_then AS (
        SELECT DISTINCT ON (s.combinator, s.item_key)
          s.combinator, s.item_key, s.${valueCol} AS val
        FROM signals s
        JOIN snap_now n USING (combinator, item_key)
        WHERE s.real_time <= n.ref_time - INTERVAL '10 minutes'
          ${baseWhereAnd}
        ORDER BY s.combinator, s.item_key, s.real_time DESC
      ),
      deltas AS (
        SELECT
          snap_now.combinator,
          snap_now.item_key,
          (snap_now.val - COALESCE(snap_then.val, snap_now.val)) AS delta
        FROM snap_now
        LEFT JOIN snap_then USING (combinator, item_key)
      )
      SELECT combinator, item_key, delta
      FROM deltas
      ORDER BY delta ${orderBy === 'delta_asc' ? 'ASC' : 'DESC'}
      LIMIT $${baseParam.current}
    `;

    const deltaResult = await pool.query<{
      combinator: string;
      item_key: string;
      delta: number;
    }>(deltaQuery, [...baseValues, limit]);

    const top = deltaResult.rows;
    if (top.length === 0) return NextResponse.json([]);

    const seriesConditions = top.map(
      (_, idx) =>
        `(combinator = $${param.current + idx * 2} AND item_key = $${param.current + idx * 2 + 1})`,
    );
    const fullWhere = `${where ? where + ' AND' : 'WHERE'} (${seriesConditions.join(' OR ')})`;
    const orderCase = top
      .map(
        (_, idx) =>
          `WHEN combinator = $${param.current + idx * 2} AND item_key = $${param.current + idx * 2 + 1} THEN ${idx}`,
      )
      .join(' ');
    const result = await pool.query(
      `SELECT ${selectCols} FROM signals ${fullWhere} ORDER BY CASE ${orderCase} ELSE ${top.length} END, real_time ASC`,
      [...values, ...top.flatMap((r) => [r.combinator, r.item_key])],
    );
    return NextResponse.json(result.rows);
  }

  if (
    (orderBy === 'value_asc' || orderBy === 'value_desc' || orderBy === 'abs_desc') &&
    limit !== null
  ) {
    const latestVals = await pool.query<{
      combinator: string;
      item_key: string;
      val: number;
    }>(
      `SELECT DISTINCT ON (combinator, item_key)
         combinator, item_key, ${valueCol} AS val
       FROM signals ${where}
       ORDER BY combinator, item_key, real_time DESC`,
      values,
    );

    let sorted = latestVals.rows;
    if (orderBy === 'value_asc') sorted = [...sorted].sort((a, b) => a.val - b.val);
    if (orderBy === 'value_desc') sorted = [...sorted].sort((a, b) => b.val - a.val);
    if (orderBy === 'abs_desc')
      sorted = [...sorted].sort((a, b) => Math.abs(b.val) - Math.abs(a.val));

    const top = sorted.slice(0, limit);
    if (top.length === 0) return NextResponse.json([]);

    const seriesConditions = top.map(
      (_, idx) =>
        `(combinator = $${param.current + idx * 2} AND item_key = $${param.current + idx * 2 + 1})`,
    );
    const fullWhere = `${where ? where + ' AND' : 'WHERE'} (${seriesConditions.join(' OR ')})`;
    const orderCase = top
      .map(
        (_, idx) =>
          `WHEN combinator = $${param.current + idx * 2} AND item_key = $${param.current + idx * 2 + 1} THEN ${idx}`,
      )
      .join(' ');
    const result = await pool.query(
      `SELECT ${selectCols} FROM signals ${fullWhere} ORDER BY CASE ${orderCase} ELSE ${top.length} END, real_time ASC`,
      [...values, ...top.flatMap((r) => [r.combinator, r.item_key])],
    );
    return NextResponse.json(result.rows);
  }

  const rowLimit = orderBy === 'time' && limit ? `LIMIT ${limit}` : '';
  const result = await pool.query(
    `SELECT ${selectCols} FROM signals ${where} ORDER BY real_time ASC ${rowLimit}`,
    values,
  );
  return NextResponse.json(result.rows);
});