import type { Context } from 'telegraf';
import type { Database } from 'better-sqlite3';

function getStreaks(db: Database): { current: number; longest: number } {
  const rows = db.prepare(
    "SELECT date FROM schedule WHERE status = 'completed' ORDER BY date ASC"
  ).all() as Array<{ date: string }>;

  if (rows.length === 0) return { current: 0, longest: 0 };

  let current = 1, longest = 1, streak = 1;

  for (let i = 1; i < rows.length; i++) {
    const prev = new Date(rows[i - 1]!.date + 'T12:00:00');
    const curr = new Date(rows[i]!.date + 'T12:00:00');
    const diff = Math.round((curr.getTime() - prev.getTime()) / 86400000);
    if (diff <= 2) {
      streak++;
      if (streak > longest) longest = streak;
    } else {
      streak = 1;
    }
  }

  current = streak;
  return { current, longest };
}

export function handleStreak(db: Database) {
  return async (ctx: Context) => {
    const { current, longest } = getStreaks(db);
    await ctx.reply(`🔥 Current streak: ${current} sessions\n🏆 Longest streak: ${longest} sessions`);
  };
}