feat: daily coding challenge system (#52)

config.json

@@ -151,6 +151,7 @@
       "rank": "everyone",
       "leaderboard": "everyone",
       "profile": "everyone",
+      "challenge": "everyone",
       "review": "everyone",
       "showcase": "everyone"
     }
@@ -206,6 +207,12 @@
     "levelThresholds": [100, 300, 600, 1000, 1500, 2500, 4000, 6000, 8500, 12000],
     "roleRewards": {}
   },
+  "challenges": {
+    "enabled": false,
+    "channelId": null,
+    "postTime": "09:00",
+    "timezone": "America/New_York"
+  },
   "review": {
     "enabled": false,
     "channelId": null,

migrations/011_challenges.cjs

@@ -0,0 +1,35 @@
+/**
+ * Migration 011 — Daily Coding Challenges
+ * Creates the challenge_solves table for tracking user solve history.
+ *
+ * Uses challenge_date (DATE) as part of the PK so users can re-solve the same
+ * challenge index when the cycle repeats on a different day. This also enables
+ * simple date-based consecutive-day streak calculation.
+ *
+ * @see https://github.com/VolvoxLLC/volvox-bot/issues/52
+ */
+
+'use strict';
+
+/**
+ * @param {import('pg').Pool} pool
+ */
+async function up(pool) {
+  await pool.query(`
+    CREATE TABLE IF NOT EXISTS challenge_solves (
+      guild_id TEXT NOT NULL,
+      challenge_date DATE NOT NULL,
+      challenge_index INTEGER NOT NULL,
+      user_id TEXT NOT NULL,
+      solved_at TIMESTAMPTZ DEFAULT NOW(),
+      PRIMARY KEY (guild_id, challenge_date, user_id)
+    );
+  `);
+
+  await pool.query(`
+    CREATE INDEX IF NOT EXISTS idx_challenge_solves_guild
+      ON challenge_solves(guild_id);
+  `);
+}
+
+module.exports = { up };

src/api/utils/configAllowlist.js

@@ -23,6 +23,7 @@ export const SAFE_CONFIG_KEYS = new Set([
   'reputation',
   'engagement',
   'github',
+  'challenges',
   'review',
 ]);
 

src/commands/challenge.js

@@ -0,0 +1,239 @@
+/**
+ * Challenge Command
+ * View today's coding challenge, check your streak, or see the leaderboard.
+ *
+ * @see https://github.com/VolvoxLLC/volvox-bot/issues/52
+ */
+
+import { EmbedBuilder, SlashCommandBuilder } from 'discord.js';
+import { getPool } from '../db.js';
+import { info } from '../logger.js';
+import {
+  buildChallengeButtons,
+  buildChallengeEmbed,
+  getLocalDateString,
+  selectTodaysChallenge,
+} from '../modules/challengeScheduler.js';
+import { getConfig } from '../modules/config.js';
+import { safeEditReply } from '../utils/safeSend.js';
+
+export const data = new SlashCommandBuilder()
+  .setName('challenge')
+  .setDescription('Daily coding challenges')
+  .addSubcommand((sub) => sub.setName('today').setDescription("Show today's coding challenge"))
+  .addSubcommand((sub) =>
+    sub.setName('streak').setDescription('Show your solve streak and total solves'),
+  )
+  .addSubcommand((sub) =>
+    sub.setName('leaderboard').setDescription('Top 10 solvers this week and all-time'),
+  );
+
+/**
+ * Execute the /challenge command.
+ *
+ * @param {import('discord.js').ChatInputCommandInteraction} interaction
+ */
+export async function execute(interaction) {
+  await interaction.deferReply({ ephemeral: false });
+
+  const subcommand = interaction.options.getSubcommand();
+  const config = getConfig(interaction.guildId);
+  const challengesCfg = config.challenges ?? {};
+
+  if (!challengesCfg.enabled) {
+    await safeEditReply(interaction, {
+      content: '❌ Daily coding challenges are not enabled on this server.',
+    });
+    return;
+  }
+
+  if (subcommand === 'today') {
+    await handleToday(interaction, challengesCfg);
+  } else if (subcommand === 'streak') {
+    await handleStreak(interaction);
+  } else if (subcommand === 'leaderboard') {
+    await handleLeaderboard(interaction);
+  }
+}
+
+/**
+ * Handle /challenge today
+ *
+ * @param {import('discord.js').ChatInputCommandInteraction} interaction
+ * @param {Object} challengesCfg
+ */
+async function handleToday(interaction, challengesCfg) {
+  const pool = getPool();
+  const timezone = challengesCfg.timezone ?? 'America/New_York';
+  const now = new Date();
+  const { challenge, index, dayNumber } = selectTodaysChallenge(now, timezone);
+
+  // Get current solve count for today's challenge
+  let solveCount = 0;
+  if (pool) {
+    const dateStr = getLocalDateString(now, timezone);
+    const { rows } = await pool.query(
+      'SELECT COUNT(*) AS total FROM challenge_solves WHERE guild_id = $1 AND challenge_date = $2',
+      [interaction.guildId, dateStr],
+    );
+    // COUNT(*) returns bigint → pg driver serialises as string; cast explicitly
+    solveCount = Number(rows[0].total);
+  }
+
+  const embed = buildChallengeEmbed(challenge, dayNumber, solveCount);
+  const buttons = buildChallengeButtons(index);
+
+  await safeEditReply(interaction, { embeds: [embed], components: [buttons] });
+
+  info('/challenge today used', {
+    userId: interaction.user.id,
+    guildId: interaction.guildId,
+    dayNumber,
+    challengeTitle: challenge.title,
+  });
+}
+
+/**
+ * Handle /challenge streak
+ *
+ * @param {import('discord.js').ChatInputCommandInteraction} interaction
+ */
+async function handleStreak(interaction) {
+  const pool = getPool();
+  if (!pool) {
+    await safeEditReply(interaction, { content: '❌ Database unavailable.' });
+    return;
+  }
+
+  const { guildId } = interaction;
+  const userId = interaction.user.id;
+
+  // Total solves
+  const { rows: totalRows } = await pool.query(
+    'SELECT COUNT(*) AS total FROM challenge_solves WHERE guild_id = $1 AND user_id = $2',
+    [guildId, userId],
+  );
+  // COUNT(*) returns bigint → pg driver serialises as string; cast explicitly
+  const totalSolves = Number(totalRows[0].total);
+
+  // Get all solved dates ordered newest-first to compute consecutive-day streak
+  const { rows: solvedRows } = await pool.query(
+    `SELECT challenge_date FROM challenge_solves
+     WHERE guild_id = $1 AND user_id = $2
+     ORDER BY challenge_date DESC`,
+    [guildId, userId],
+  );
+
+  // Compute streak: count consecutive days backwards from today (or yesterday).
+  // pg returns DATE columns as JS Date objects at UTC midnight.
+  let streak = 0;
+  if (solvedRows.length > 0) {
+    const todayUTC = new Date();
+    const todayStr = todayUTC.toISOString().slice(0, 10);
+    const yesterdayUTC = new Date(todayUTC);
+    yesterdayUTC.setUTCDate(yesterdayUTC.getUTCDate() - 1);
+    const yesterdayStr = yesterdayUTC.toISOString().slice(0, 10);
+
+    const dates = solvedRows.map((r) => new Date(r.challenge_date).toISOString().slice(0, 10));
+    const mostRecent = dates[0];
+
+    // Only count a streak if the user solved today or yesterday
+    if (mostRecent === todayStr || mostRecent === yesterdayStr) {
+      streak = 1;
+      for (let i = 1; i < dates.length; i++) {
+        const prevDate = new Date(dates[i - 1]);
+        prevDate.setUTCDate(prevDate.getUTCDate() - 1);
+        if (dates[i] === prevDate.toISOString().slice(0, 10)) {
+          streak++;
+        } else {
+          break;
+        }
+      }
+    }
+  }
+
+  const embed = new EmbedBuilder()
+    .setColor(0x5865f2)
+    .setTitle(`📊 Challenge Stats — ${interaction.user.displayName}`)
+    .setThumbnail(interaction.user.displayAvatarURL())
+    .addFields(
+      {
+        name: '🔥 Current Streak',
+        value: `**${streak}** challenge${streak !== 1 ? 's' : ''}`,
+        inline: true,
+      },
+      {
+        name: '✅ Total Solved',
+        value: `**${totalSolves}** challenge${totalSolves !== 1 ? 's' : ''}`,
+        inline: true,
+      },
+    )
+    .setFooter({ text: 'Keep solving to grow your streak!' })
+    .setTimestamp();
+
+  await safeEditReply(interaction, { embeds: [embed] });
+}
+
+/**
+ * Handle /challenge leaderboard
+ *
+ * @param {import('discord.js').ChatInputCommandInteraction} interaction
+ */
+async function handleLeaderboard(interaction) {
+  const pool = getPool();
+  if (!pool) {
+    await safeEditReply(interaction, { content: '❌ Database unavailable.' });
+    return;
+  }
+
+  const { guildId } = interaction;
+
+  // All-time top 10
+  const { rows: allTimeRows } = await pool.query(
+    `SELECT user_id, COUNT(*) AS total
+     FROM challenge_solves
+     WHERE guild_id = $1
+     GROUP BY user_id
+     ORDER BY total DESC
+     LIMIT 10`,
+    [guildId],
+  );
+
+  // This week top 10 (last 7 days)
+  const { rows: weekRows } = await pool.query(
+    `SELECT user_id, COUNT(*) AS total
+     FROM challenge_solves
+     WHERE guild_id = $1 AND solved_at >= NOW() - INTERVAL '7 days'
+     GROUP BY user_id
+     ORDER BY total DESC
+     LIMIT 10`,
+    [guildId],
+  );
+
+  const medals = ['🥇', '🥈', '🥉'];
+
+  const formatBoard = (rows) => {
+    if (rows.length === 0) return '_No solves yet — be the first!_';
+    return rows
+      .map((row, i) => {
+        const prefix = medals[i] ?? `**${i + 1}.**`;
+        const total = Number(row.total);
+        return `${prefix} <@${row.user_id}> — **${total}** solve${total !== 1 ? 's' : ''}`;
+      })
+      .join('\n');
+  };
+
+  const embed = new EmbedBuilder()
+    .setColor(0xfee75c)
+    .setTitle('🏆 Challenge Leaderboard')
+    .addFields(
+      { name: '📅 This Week', value: formatBoard(weekRows) },
+      { name: '🌟 All-Time', value: formatBoard(allTimeRows) },
+    )
+    .setFooter({ text: 'Solve daily challenges to climb the ranks!' })
+    .setTimestamp();
+
+  await safeEditReply(interaction, { embeds: [embed] });
+
+  info('/challenge leaderboard used', { userId: interaction.user.id, guildId });
+}