feat(#64): Improve the about page

supabase/migrations/20260110120000_create_stats_cache.sql

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+-- Create stats_cache table to store cached statistics
+-- This table will be updated once per day to improve performance
+
+CREATE TABLE stats_cache (
+  id BIGSERIAL PRIMARY KEY,
+  pokemon_caught BIGINT NOT NULL DEFAULT 0,
+  total_users BIGINT NOT NULL DEFAULT 0,
+  completed_pokedexes BIGINT NOT NULL DEFAULT 0,
+  updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+-- Create index for faster lookups
+CREATE INDEX idx_stats_cache_updated_at ON stats_cache(updated_at DESC);
+
+-- Enable RLS
+ALTER TABLE stats_cache ENABLE ROW LEVEL SECURITY;
+
+-- RLS policies: Only allow reads (stats are public)
+CREATE POLICY "Anyone can view stats cache" ON stats_cache
+  FOR SELECT USING (true);
+
+-- No insert/update/delete policies - only database functions can modify this table

supabase/migrations/20260110120001_create_update_stats_function.sql

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+-- Create function to calculate and update stats in the cache table
+-- This function runs the expensive queries and stores the results
+
+CREATE OR REPLACE FUNCTION update_and_get_stats()
+RETURNS TABLE (
+  pokemon_caught BIGINT,
+  total_users BIGINT,
+  completed_pokedexes BIGINT,
+  updated_at TIMESTAMPTZ
+)
+SECURITY DEFINER
+LANGUAGE plpgsql
+AS $$
+DECLARE
+  v_pokemon_caught BIGINT;
+  v_total_users BIGINT;
+  v_completed_pokedexes BIGINT;
+BEGIN
+  -- Calculate current stats: count of caught Pokémon
+  SELECT COUNT(*) INTO v_pokemon_caught
+  FROM catch_records
+  WHERE caught = true;
+
+  -- Calculate current stats: count of total users
+  SELECT COUNT(*) INTO v_total_users
+  FROM auth.users;
+
+  -- Calculate current stats: count of completed pokedexes
+  -- A pokedex is completed when all its entries have caught = true
+  SELECT COUNT(*) INTO v_completed_pokedexes
+  FROM (
+    SELECT pokedexId
+    FROM catch_records
+    GROUP BY pokedexId
+    HAVING COUNT(*) = COUNT(*) FILTER (WHERE caught = true)
+  ) completed;
+
+  -- Update cache using UPSERT pattern
+  INSERT INTO stats_cache (pokemon_caught, total_users, completed_pokedexes, updated_at)
+  VALUES (v_pokemon_caught, v_total_users, v_completed_pokedexes, NOW())
+  ON CONFLICT (id) DO UPDATE
+  SET pokemon_caught = EXCLUDED.pokemon_caught,
+      total_users = EXCLUDED.total_users,
+      completed_pokedexes = EXCLUDED.completed_pokedexes,
+      updated_at = NOW();
+
+  -- Return the stats
+  RETURN QUERY
+  SELECT v_pokemon_caught, v_total_users, v_completed_pokedexes, NOW() AS updated_at;
+END;
+$$;

supabase/migrations/20260110120002_create_get_stats_function.sql

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+-- Create function to get public stats with caching
+-- Returns cached stats if fresh (within 24 hours), otherwise refreshes cache
+
+CREATE OR REPLACE FUNCTION get_public_stats()
+RETURNS TABLE (
+  pokemon_caught BIGINT,
+  total_users BIGINT,
+  completed_pokedexes BIGINT,
+  updated_at TIMESTAMPTZ
+)
+SECURITY DEFINER
+LANGUAGE plpgsql
+AS $$
+DECLARE
+  v_cache_exists BOOLEAN;
+BEGIN
+  -- Check if cache exists and is fresh (within 24 hours)
+  SELECT EXISTS(
+    SELECT 1 FROM stats_cache
+    WHERE stats_cache.updated_at > NOW() - INTERVAL '24 hours'
+  ) INTO v_cache_exists;
+
+  IF v_cache_exists THEN
+    -- Return cached stats
+    RETURN QUERY
+    SELECT sc.pokemon_caught, sc.total_users, sc.completed_pokedexes, sc.updated_at
+    FROM stats_cache sc
+    ORDER BY sc.updated_at DESC
+    LIMIT 1;
+  ELSE
+    -- Cache is stale or doesn't exist, update it
+    RETURN QUERY
+    SELECT * FROM update_and_get_stats();
+  END IF;
+END;
+$$;

supabase/migrations/20260110144000_fix_stats_functions_ambiguity.sql

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+-- Fix ambiguous column reference errors in stats functions.
+--
+-- If earlier migrations have already been applied, editing them will not update
+-- the deployed database. This migration re-defines the functions using
+-- CREATE OR REPLACE so the corrected definitions take effect.
+
+CREATE OR REPLACE FUNCTION update_and_get_stats()
+RETURNS TABLE (
+  pokemon_caught BIGINT,
+  total_users BIGINT,
+  completed_pokedexes BIGINT,
+  updated_at TIMESTAMPTZ
+)
+SECURITY DEFINER
+LANGUAGE plpgsql
+AS $$
+DECLARE
+  v_pokemon_caught BIGINT;
+  v_total_users BIGINT;
+  v_completed_pokedexes BIGINT;
+BEGIN
+  -- Calculate current stats: count of caught Pokémon
+  SELECT COUNT(*) INTO v_pokemon_caught
+  FROM catch_records
+  WHERE caught = true;
+
+  -- Calculate current stats: count of total users
+  SELECT COUNT(*) INTO v_total_users
+  FROM auth.users;
+
+  -- Calculate current stats: count of completed pokedexes
+  -- A pokedex is completed when all its entries have caught = true
+  SELECT COUNT(*) INTO v_completed_pokedexes
+  FROM (
+    SELECT "pokedexId"
+    FROM catch_records
+    GROUP BY "pokedexId"
+    HAVING COUNT(*) = COUNT(*) FILTER (WHERE caught = true)
+  ) completed;
+
+  -- Update cache using UPSERT pattern
+  INSERT INTO stats_cache (pokemon_caught, total_users, completed_pokedexes, updated_at)
+  VALUES (v_pokemon_caught, v_total_users, v_completed_pokedexes, NOW())
+  ON CONFLICT (id) DO UPDATE
+  SET pokemon_caught = EXCLUDED.pokemon_caught,
+      total_users = EXCLUDED.total_users,
+      completed_pokedexes = EXCLUDED.completed_pokedexes,
+      updated_at = NOW();
+
+  -- Return stats
+  RETURN QUERY
+  SELECT v_pokemon_caught, v_total_users, v_completed_pokedexes, NOW() AS updated_at;
+END;
+$$;
+
+
+CREATE OR REPLACE FUNCTION get_public_stats()
+RETURNS TABLE (
+  pokemon_caught BIGINT,
+  total_users BIGINT,
+  completed_pokedexes BIGINT,
+  updated_at TIMESTAMPTZ
+)
+SECURITY DEFINER
+LANGUAGE plpgsql
+AS $$
+DECLARE
+  v_cache_exists BOOLEAN;
+BEGIN
+  -- Check if cache exists and is fresh (within 24 hours)
+  SELECT EXISTS(
+    SELECT 1 FROM stats_cache
+    WHERE stats_cache.updated_at > NOW() - INTERVAL '24 hours'
+  ) INTO v_cache_exists;
+
+  IF v_cache_exists THEN
+    -- Return cached stats (qualify updated_at to avoid ambiguity with output parameter)
+    RETURN QUERY
+    SELECT sc.pokemon_caught, sc.total_users, sc.completed_pokedexes, sc.updated_at
+    FROM stats_cache sc
+    ORDER BY sc.updated_at DESC
+    LIMIT 1;
+  ELSE
+    -- Cache is stale or doesn't exist, update it
+    RETURN QUERY
+    SELECT * FROM update_and_get_stats();
+  END IF;
+END;
+$$;