Add Elo rating system with match entry and CSV upload

- Implement EloCalculator service for 2v2 Euchre matches
- Create background job processing with GoodJob
- Add single match entry form
- Add CSV upload for batch match entry
- Create player rankings view
- Add database schema for matches and elo snapshots

app/actions/admin/matches/create.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Actions
+    module Admin
+      module Matches
+        class Create < EuchreCamp::Action
+          include Deps[repo: 'repositories.matches']
+
+          def handle(request, response)
+            match_params = request.params.to_h
+            match_params[:played_at] = Time.parse(match_params[:played_at]) if match_params[:played_at]
+
+            # Create the match
+            match = repo.create(match_params)
+
+            # Enqueue background job to calculate Elo
+            EuchreCamp::Jobs::CalculateEloJob.perform_later(match[:id])
+
+            response.redirect_to("/admin/matches")
+          rescue StandardError => e
+            # Handle validation errors or other issues
+            puts "Error: #{e.message}"
+            puts e.backtrace.join("\n")
+            response.redirect_to("/admin/matches/new")
+          end
+        end
+      end
+    end
+  end
+end

app/actions/admin/matches/index.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Actions
+    module Admin
+      module Matches
+        class Index < EuchreCamp::Action
+          include Deps[repo: 'repositories.matches']
+
+          def handle(_request, response)
+            matches = repo.all
+            response.render(view, matches: matches)
+          end
+        end
+      end
+    end
+  end
+end

app/actions/admin/matches/new.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Actions
+    module Admin
+      module Matches
+        class New < EuchreCamp::Action
+          include Deps[repo: 'repositories.players']
+
+          def handle(_request, response)
+            players = repo.all
+            response.render(view, players: players)
+          end
+        end
+      end
+    end
+  end
+end

app/actions/admin/matches/process_upload.rb

@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+require "csv"
+
+module EuchreCamp
+  module Actions
+    module Admin
+      module Matches
+        class ProcessUpload < EuchreCamp::Action
+          include Deps[repo: 'repositories.matches']
+
+          def handle(request, response)
+            # In Hanami, file uploads are in request.params
+            file = request.params[:csv_file]
+            
+            unless file && file[:tempfile]
+              response.redirect_to("/admin/matches/upload")
+              return
+            end
+
+            matches_created = 0
+            errors = []
+
+            # Parse CSV
+            CSV.foreach(file[:tempfile].path, headers: true, header_converters: :symbol) do |row|
+              begin
+                # Map CSV columns to our database structure
+                # Expected columns: played_at, team_1_p1_name, team_1_p2_name, team_1_score, team_2_p1_name, team_2_p2_name, team_2_score
+                
+                # Find or create players by name
+                player_1 = find_or_create_player(row[:team_1_p1_name])
+                player_2 = find_or_create_player(row[:team_1_p2_name])
+                player_3 = find_or_create_player(row[:team_2_p1_name])
+                player_4 = find_or_create_player(row[:team_2_p2_name])
+                
+                played_at = begin
+                  Time.parse(row[:played_at])
+                rescue
+                  Time.now
+                end
+                
+                match_data = {
+                  played_at: played_at,
+                  team_1_p1_id: player_1[:id],
+                  team_1_p2_id: player_2[:id],
+                  team_1_score: row[:team_1_score].to_i,
+                  team_2_p1_id: player_3[:id],
+                  team_2_p2_id: player_4[:id],
+                  team_2_score: row[:team_2_score].to_i,
+                  status: 'completed'
+                }
+
+                match = repo.create(match_data)
+                EuchreCamp::Jobs::CalculateEloJob.perform_later(match[:id])
+                matches_created += 1
+                
+              rescue => e
+                errors << "Row #{row}: #{e.message}"
+              end
+            end
+
+            response.flash[:message] = "Created #{matches_created} matches.#{' Errors: ' + errors.join(', ') if errors.any?}"
+            response.redirect_to("/admin/matches")
+          end
+
+          private
+
+          def find_or_create_player(name)
+            rom = EuchreCamp::App["persistence.rom"]
+            return nil unless name
+            
+            name = name.strip
+            player = rom.relations[:players].where(name: name).one
+            
+            if player
+              player
+            else
+              rom.relations[:players].insert(name: name, rating: 0, current_elo: 1000)
+              rom.relations[:players].where(name: name).one
+            end
+          end
+        end
+      end
+    end
+  end
+end

app/actions/admin/matches/upload.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require "csv"
+
+module EuchreCamp
+  module Actions
+    module Admin
+      module Matches
+        class Upload < EuchreCamp::Action
+          def handle(request, response)
+            response.render(view)
+          end
+        end
+      end
+    end
+  end
+end

app/actions/players/rankings.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Actions
+    module Players
+      class Rankings < EuchreCamp::Action
+        include Deps[repo: 'repositories.players']
+
+        def handle(_request, response)
+          # Get all players and sort by current Elo
+          players = repo.all.sort_by { |p| -p.current_elo }
+          response.render(view, players: players)
+        end
+      end
+    end
+  end
+end

app/jobs/calculate_elo_job.rb

@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Jobs
+    class CalculateEloJob
+      def self.perform_later(match_id)
+        # Enqueue job using GoodJob's database directly
+        rom = EuchreCamp::App["persistence.rom"]
+        
+        job_params = {
+          queue_name: "default",
+          priority: 0,
+          serialized_params: { "match_id" => match_id }.to_json,
+          scheduled_at: Time.now,
+          created_at: Time.now,
+          updated_at: Time.now,
+          job_class: "EuchreCamp::Jobs::CalculateEloJob",
+          executions_count: 0
+        }
+        
+        rom.relations[:good_jobs].insert(job_params)
+      end
+
+      def self.perform(match_id)
+        # This is the actual job execution
+        match = find_match(match_id)
+        return unless match
+
+        # Get current player ratings
+        player_ratings = fetch_player_ratings(match)
+
+        # Calculate new ratings
+        calculation_results = EuchreCamp::Services::EloCalculator.calculate(
+          player_ratings: player_ratings,
+          team_1_players: [match[:team_1_p1_id], match[:team_1_p2_id]],
+          team_2_players: [match[:team_2_p1_id], match[:team_2_p2_id]],
+          team_1_score: match[:team_1_score],
+          team_2_score: match[:team_2_score]
+        )
+
+        # Update player ratings and create snapshots
+        update_player_ratings(calculation_results, match_id)
+      end
+
+      private
+
+      def self.find_match(match_id)
+        rom = EuchreCamp::App["persistence.rom"]
+        rom.relations[:matches].by_pk(match_id).one
+      end
+
+      def self.fetch_player_ratings(match)
+        rom = EuchreCamp::App["persistence.rom"]
+        player_ids = [
+          match[:team_1_p1_id],
+          match[:team_1_p2_id],
+          match[:team_2_p1_id],
+          match[:team_2_p2_id]
+        ]
+
+        players = rom.relations[:players].where(id: player_ids).to_a
+        players.each_with_object({}) do |player, hash|
+          hash[player[:id]] = player[:current_elo] || 1000
+        end
+      end
+
+      def self.update_player_ratings(results, match_id)
+        rom = EuchreCamp::App["persistence.rom"]
+
+        results.each do |player_id, data|
+          # Update player's current Elo
+          rom.relations[:players].where(id: player_id).update(current_elo: data[:rating_after])
+
+          # Create Elo snapshot record
+          rom.relations[:elo_snapshots].insert(
+            player_id: player_id,
+            match_id: match_id,
+            rating_before: data[:rating_before],
+            rating_after: data[:rating_after],
+            rating_change: data[:rating_change]
+          )
+        end
+      end
+    end
+  end
+end

app/repositories/matches.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require 'rom-repository'
+
+module EuchreCamp
+  module Repositories
+    class Matches < ::EuchreCamp::Repository[:matches]
+      commands :create, update: :by_pk, delete: :by_pk
+
+      def all
+        matches.to_a
+      end
+
+      def by_id(id)
+        matches.by_pk(id).one!
+      end
+    end
+  end
+end

app/services/elo_calculator.rb

@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Services
+    class EloCalculator
+      # Standard Elo K-factor
+      K_FACTOR = 32
+
+      # Calculate Elo ratings for a 2v2 Euchre match
+      #
+      # @param player_ratings [Hash] player_id => current_rating
+      # @param team_1_players [Array<Integer>] player IDs for team 1
+      # @param team_2_players [Array<Integer>] player IDs for team 2
+      # @param team_1_score [Integer] score for team 1
+      # @param team_2_score [Integer] score for team 2
+      # @return [Hash] player_id => { rating_before:, rating_after:, rating_change: }
+      def self.calculate(player_ratings:, team_1_players:, team_2_players:, team_1_score:, team_2_score:)
+        # Validate inputs
+        raise ArgumentError, "Team 1 must have exactly 2 players" unless team_1_players.length == 2
+        raise ArgumentError, "Team 2 must have exactly 2 players" unless team_2_players.length == 2
+
+        # Determine winner (first to 10 points)
+        team_1_wins = team_1_score >= 10
+        team_2_wins = team_2_score >= 10
+
+        unless team_1_wins || team_2_wins
+          raise ArgumentError, "One team must reach 10 points to win"
+        end
+
+        if team_1_wins && team_2_wins
+          raise ArgumentError, "Only one team can win (both reached 10 points)"
+        end
+
+        winner = team_1_wins ? :team_1 : :team_2
+
+        # Calculate average ratings for each team
+        team_1_avg = team_1_players.map { |id| player_ratings[id] }.sum / 2.0
+        team_2_avg = team_2_players.map { |id| player_ratings[id] }.sum / 2.0
+
+        # Calculate expected scores using Elo formula
+        # E = 1 / (1 + 10^((R_opp - R_team) / 400))
+        expected_team_1 = 1.0 / (1.0 + 10.0**((team_2_avg - team_1_avg) / 400.0))
+        expected_team_2 = 1.0 / (1.0 + 10.0**((team_1_avg - team_2_avg) / 400.0))
+
+        # Actual scores (1 for win, 0 for loss)
+        actual_team_1 = team_1_wins ? 1.0 : 0.0
+        actual_team_2 = team_2_wins ? 1.0 : 0.0
+
+        # Calculate rating changes for each player
+        results = {}
+
+        # Team 1 players
+        team_1_players.each do |player_id|
+          old_rating = player_ratings[player_id]
+          rating_change = K_FACTOR * (actual_team_1 - expected_team_1)
+          new_rating = (old_rating + rating_change).round
+          results[player_id] = {
+            rating_before: old_rating,
+            rating_after: new_rating,
+            rating_change: rating_change.round
+          }
+        end
+
+        # Team 2 players
+        team_2_players.each do |player_id|
+          old_rating = player_ratings[player_id]
+          rating_change = K_FACTOR * (actual_team_2 - expected_team_2)
+          new_rating = (old_rating + rating_change).round
+          results[player_id] = {
+            rating_before: old_rating,
+            rating_after: new_rating,
+            rating_change: rating_change.round
+          }
+        end
+
+        results
+      end
+    end
+  end
+end

app/templates/admin/matches/index.html.erb

@@ -0,0 +1,36 @@
+<h1>Match Administration</h1>
+
+<p><a href="/admin/matches/new">Enter New Match</a> | <a href="/admin/matches/upload">Upload CSV</a></p>
+
+<% if matches.any? %>
+  <table>
+    <thead>
+      <tr>
+        <th>ID</th>
+        <th>Date</th>
+        <th>Team 1</th>
+        <th>Score</th>
+        <th>Team 2</th>
+        <th>Score</th>
+        <th>Status</th>
+      </tr>
+    </thead>
+    <tbody>
+      <% matches.each do |match| %>
+        <tr>
+          <td><%= match.id %></td>
+          <td><%= match.played_at&.strftime('%Y-%m-%d %H:%M') %></td>
+          <td><%= match.team_1_p1_id %>/<%= match.team_1_p2_id %></td>
+          <td><%= match.team_1_score %></td>
+          <td><%= match.team_2_p1_id %>/<%= match.team_2_p2_id %></td>
+          <td><%= match.team_2_score %></td>
+          <td><%= match.status %></td>
+        </tr>
+      <% end %>
+    </tbody>
+  </table>
+<% else %>
+  <p>No matches entered yet.</p>
+<% end %>
+
+<p><a href="/admin/players">Manage Players</a></p>

app/templates/admin/matches/new.html.erb

@@ -0,0 +1,66 @@
+<h1>Enter New Match</h1>
+
+<form action="/admin/matches" method="post">
+  <input type="hidden" name="_csrf_token" value="<%= csrf_token %>">
+
+  <div>
+    <label for="played_at">Date/Time:</label>
+    <input type="datetime-local" id="played_at" name="played_at" required value="<%= Time.now.strftime('%Y-%m-%dT%H:%M') %>">
+  </div>
+
+  <fieldset>
+    <legend>Team 1</legend>
+    <div>
+      <label for="team_1_p1_id">Player 1:</label>
+      <select id="team_1_p1_id" name="team_1_p1_id" required>
+        <option value="">Select player...</option>
+        <% players.each do |player| %>
+          <option value="<%= player.id %>"><%= player.name %></option>
+        <% end %>
+      </select>
+    </div>
+    <div>
+      <label for="team_1_p2_id">Player 2:</label>
+      <select id="team_1_p2_id" name="team_1_p2_id" required>
+        <option value="">Select player...</option>
+        <% players.each do |player| %>
+          <option value="<%= player.id %>"><%= player.name %></option>
+        <% end %>
+      </select>
+    </div>
+    <div>
+      <label for="team_1_score">Score:</label>
+      <input type="number" id="team_1_score" name="team_1_score" min="0" max="10" required value="10">
+    </div>
+  </fieldset>
+
+  <fieldset>
+    <legend>Team 2</legend>
+    <div>
+      <label for="team_2_p1_id">Player 1:</label>
+      <select id="team_2_p1_id" name="team_2_p1_id" required>
+        <option value="">Select player...</option>
+        <% players.each do |player| %>
+          <option value="<%= player.id %>"><%= player.name %></option>
+        <% end %>
+      </select>
+    </div>
+    <div>
+      <label for="team_2_p2_id">Player 2:</label>
+      <select id="team_2_p2_id" name="team_2_p2_id" required>
+        <option value="">Select player...</option>
+        <% players.each do |player| %>
+          <option value="<%= player.id %>"><%= player.name %></option>
+        <% end %>
+      </select>
+    </div>
+    <div>
+      <label for="team_2_score">Score:</label>
+      <input type="number" id="team_2_score" name="team_2_score" min="0" max="10" required value="7">
+    </div>
+  </fieldset>
+
+  <button type="submit">Save Match</button>
+</form>
+
+<p><a href="/admin/matches">Back to Matches</a></p>

app/templates/admin/matches/upload.html.erb

@@ -0,0 +1,26 @@
+<h1>Upload Matches (CSV)</h1>
+
+<p>Upload a CSV file with the following columns:</p>
+<pre>
+played_at, team_1_p1_name, team_1_p2_name, team_1_score, team_2_p1_name, team_2_p2_name, team_2_score
+</pre>
+
+<form action="/admin/matches/process_upload" method="post" enctype="multipart/form-data">
+  <input type="hidden" name="_csrf_token" value="<%= csrf_token %>">
+  
+  <div>
+    <label for="csv_file">CSV File:</label>
+    <input type="file" id="csv_file" name="csv_file" accept=".csv" required>
+  </div>
+
+  <button type="submit">Upload</button>
+</form>
+
+<p><a href="/admin/matches">Back to Matches</a></p>
+
+<h2>Example CSV:</h2>
+<pre>
+played_at,team_1_p1_name,team_1_p2_name,team_1_score,team_2_p1_name,team_2_p2_name,team_2_score
+2026-03-26 10:00,Alice,Bob,10,Charlie,David,7
+2026-03-26 10:30,Alice,Bob,10,Charlie,David,7
+</pre>

app/templates/players/rankings.html.erb

@@ -0,0 +1,28 @@
+<h1>Player Rankings</h1>
+
+<% if players.any? %>
+  <table>
+    <thead>
+      <tr>
+        <th>Rank</th>
+        <th>Player</th>
+        <th>Elo Rating</th>
+        <th>Original Rating</th>
+      </tr>
+    </thead>
+    <tbody>
+      <% players.each_with_index do |player, index| %>
+        <tr>
+          <td><%= index + 1 %></td>
+          <td><%= player.name %></td>
+          <td><strong><%= player.current_elo %></strong></td>
+          <td><%= player.rating %></td>
+        </tr>
+      <% end %>
+    </tbody>
+  </table>
+<% else %>
+  <p>No players found.</p>
+<% end %>
+
+<p><a href="/admin/players">Admin</a></p>

app/views/admin/matches/index.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Views
+    module Admin
+      module Matches
+        class Index < EuchreCamp::View
+          expose :matches
+        end
+      end
+    end
+  end
+end

app/views/admin/matches/new.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Views
+    module Admin
+      module Matches
+        class New < EuchreCamp::View
+          expose :players
+        end
+      end
+    end
+  end
+end

app/views/admin/matches/upload.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Views
+    module Admin
+      module Matches
+        class Upload < EuchreCamp::View
+        end
+      end
+    end
+  end
+end

app/views/players/rankings.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Views
+    module Players
+      class Rankings < EuchreCamp::View
+        expose :players
+      end
+    end
+  end
+end