Cube Builder

Overview

Build cube draft configurations for GEMP-SWCCG by mapping CSV files of card names to card IDs and generating properly structured cube configuration JSON files. This skill covers the complete workflow from CSV preparation through deployment, including the critical playtesting card exclusion requirement and add-on card pack structure.

When to Use This Skill

Use this skill when:

• Creating a new cube draft configuration from card lists
• Updating an existing cube with new cards
• Troubleshooting cube draft issues (missing cards, playtesting cards appearing, etc.)
• Understanding how multi-column CSVs create add-on card packs

Workflow

CRITICAL REQUIREMENT: Unless explicitly told otherwise, you MUST use side-specific databases with defensive shields filtered out when mapping light/dark side cards. This prevents:

1. Defensive shield versions being mapped instead of effect versions (e.g., "Battle Plan" as shield vs effect)
2. Wrong-side cards appearing in drafts (e.g., DARK "Control" in LIGHT side packs)
3. Slug collision errors

See Step 3 for detailed instructions on creating filtered databases.

Step 1: Prepare CSV Files

Create three CSV files in the cube source directory:

1. default_cards.csv - Single column of card names (core cards all players start with)
2. cube_worlds_lightside.csv - Light side packs (supports multi-column for add-ons)
3. cube_worlds_darkside.csv - Dark side packs (supports multi-column for add-ons)

CSV Column Structure:

• Single column → Produces flat array: ["card1_id", "card2_id"]
• Multiple columns → Produces array of arrays: [["primary_id", "addon1_id"], ["card2_id"]]
  • Column 1 = primary card in the pack
  • Columns 2+ = add-on cards that come with the primary card
  • When a player picks a pack, they receive ALL cards in that array
  • Empty cells are skipped

Example multi-column CSV:

Admiral Ackbar,Home One
Obi-Wan Kenobi,Kenobi's Lightsaber
Luke Skywalker,,

Produces:

[
  ["admiral_ackbar_id", "home_one_id"],
  ["obi_wan_id", "lightsaber_id"],
  ["luke_id"]
]

Directory Structure:

src/gemp-swccg-server/src/main/resources/draft/cube_building/
└── <cube_name>/
    ├── default_cards.csv
    ├── cube_worlds_lightside.csv
    └── cube_worlds_darkside.csv

Step 2: Update Card Database (Critical)

The card mapping process requires an up-to-date card database that EXCLUDES playtesting cards (set 501).

./bin/gemp export-cards src/gemp-swccg-cards/src/main/resources/card_blueprint_database.json

Why this matters: The CardDataExporter automatically excludes set501 cards via a filter. If this step is skipped or uses old data, playtesting cards will appear in the cube.

Verification:

grep -c '"cardId": "501_' src/gemp-swccg-cards/src/main/resources/card_blueprint_database.json
# Must output: 0

Step 3: Create Side-Specific Databases (CRITICAL)

IMPORTANT: Unless explicitly told otherwise, you MUST filter out defensive shields from the side-specific databases to prevent slug collisions. Cards like "Battle Plan" exist as both Effect and Defensive Shield with the same slug - without filtering, the defensive shield version will be incorrectly mapped instead of the effect.

Create filtered databases excluding defensive shields:

bash <<'BASH'
cd src/gemp-swccg-cards/src/main/resources

# Create light side database without defensive shields
jq '[.[] | select(.side == "LIGHT" and .cardCategory != "DEFENSIVE_SHIELD")]' \
  card_blueprint_database.json > /tmp/card_blueprint_database_light_no_shields.json

# Create dark side database without defensive shields
jq '[.[] | select(.side == "DARK" and .cardCategory != "DEFENSIVE_SHIELD")]' \
  card_blueprint_database.json > /tmp/card_blueprint_database_dark_no_shields.json
BASH

Verify filtering worked:

bash <<'BASH'
echo "Light side defensive shields (should be 0):"
jq '[.[] | select(.cardCategory == "DEFENSIVE_SHIELD")] | length' \
  /tmp/card_blueprint_database_light_no_shields.json

echo "Dark side defensive shields (should be 0):"
jq '[.[] | select(.cardCategory == "DEFENSIVE_SHIELD")] | length' \
  /tmp/card_blueprint_database_dark_no_shields.json
BASH

Why this matters:

• Prevents defensive shields from being mapped when effect versions exist
• Prevents side-mixing (e.g., DARK "Control" appearing in LIGHT side packs)
• Resolves slug collisions for cards with same names on both sides

Step 4: Map Card Names to IDs

Map each CSV file to card IDs using the map_card_names_to_ids script with side-specific, defensive-shield-filtered databases:

CUBE_DIR="src/gemp-swccg-server/src/main/resources/draft/cube_building/<cube_name>"

# Map default/core cards (use main database)
./bin/map_card_names_to_ids \
  $CUBE_DIR/default_cards.csv \
  $CUBE_DIR/default_cards_mapped.json \
  src/gemp-swccg-cards/src/main/resources/card_blueprint_database.json

# Map light side packs (use light-only, no shields)
./bin/map_card_names_to_ids \
  $CUBE_DIR/cube_worlds_lightside.csv \
  $CUBE_DIR/cube_worlds_lightside_mapped.json \
  /tmp/card_blueprint_database_light_no_shields.json

# Map dark side packs (use dark-only, no shields)
./bin/map_card_names_to_ids \
  $CUBE_DIR/cube_worlds_darkside.csv \
  $CUBE_DIR/cube_worlds_darkside_mapped.json \
  /tmp/card_blueprint_database_dark_no_shields.json

Output Files:

• *_mapped.json - Card ID arrays (flat or nested based on CSV structure)
• *_mapped_log.json - Processing logs with missing cards and warnings

Review the logs for:

• Missing cards (slug shown for debugging)
• Multiple matches (script auto-selects first match)
• Success rate (should be >95%)

Script Behavior:

• Detects single vs multi-column by checking for non-empty columns
• Slugifies card names (lowercase, special chars → -)
• Tries exact slug match, then slug + set name, then slug with -v suffix (virtual fallback)
• Logs all issues for review

Step 5: Generate Cube Configuration

Use create_cube to build the final configuration:

python3 bin/create_cube \
  src/gemp-swccg-server/src/main/resources/draft/cube_building/<cube_name> \
  src/gemp-swccg-server/src/main/resources/draft/<outputFile>.json

Required Files in Cube Directory:

• default_cards_mapped.json
• cube_worlds_lightside_mapped.json
• cube_worlds_darkside_mapped.json

Configuration Parameters (hardcoded in script):

• count: 9 - Pack choices shown per round
• repeat: 56 - Number of draft rounds
• objChoiceCountPerSide: 0 - No objective picks (standard cube)

Output Structure:

{
  "format": "cube",
  "fixedCount": 0,
  "objChoiceCountPerSide": 0,
  "choiceCountPerSide": 56,
  "lightObjCards": [],
  "darkObjCards": [],
  "startingPool": {
    "type": "cubeDraftRun",
    "data": {
      "coreCards": ["5_164", "12_164", ...]
    }
  },
  "choices": [
    {
      "type": "cubePackObjPick",
      "repeat": 56,
      "data": {
        "count": 9,
        "packs": [
          ["110_6", "107_5"],
          ["213_31"],
          ...
        ]
      }
    },
    { /* dark side choice with same structure */ }
  ]
}

Step 6: Register Draft Format

Add the cube to the draft registry:

File: src/gemp-swccg-server/src/main/resources/swccgDrafts.json

[
  {
    "type": "c7_draft",
    "location": "/draft/cube7Draft.json"
  },
  {
    "type": "<cube_identifier>_draft",
    "location": "/draft/<outputFile>.json"
  }
]

Important:

• type - Format identifier (used in code and database)
• location - Path relative to resources directory

Step 7: Update Frontend

Add the cube to the league admin dropdown:

File: src/gemp-swccg-async/src/main/web/includes/admin/leagueAdmin.html

Location: Around line 459 in the solo draft form

<select name="format">
  <option value="c7_draft">Cube v7 Draft</option>
  <option value="c7obj_draft">Cube v7 Draft + Obj</option>
  <option value="<cube_identifier>_draft">Your Cube Name</option>
</select>

Critical: The value attribute MUST match the type field in swccgDrafts.json

Step 8: Deploy and Verify

# Rebuild server module (contains cube config)
./bin/gemp reload-fast

# Verify in browser
# 1. Access http://localhost:17001/gemp-swccg/
# 2. Login as admin
# 3. Navigate to League Admin → Add Solo Draft League
# 4. Verify cube appears in format dropdown
# 5. Create test league and access draft to confirm no errors

Verification Checklist

Before finalizing:

• Card database excludes playtesting cards (grep check shows 0)
• Cube configuration excludes playtesting cards (grep check shows 0)
• All CSVs mapped with >95% success rate
• Cube config has correct structure (coreCards flat, packs nested)
• Draft registered in swccgDrafts.json with correct type/location
• Frontend dropdown includes cube with matching value attribute
• Server rebuilt and restarted
• Draft loads without errors in browser

Troubleshooting

Issue: Playtesting Cards Appear in Draft

Root Cause: Old card database contains set 501 cards

Solution:

1. Regenerate card database (Step 2)
2. Re-run all mapping scripts (Step 3)
3. Regenerate cube config (Step 4)
4. Verify with grep: grep '"501_' <cube_config>.json

Issue: "Card database not found"

Solution: Run card export command from Step 2

Issue: Multiple Cards Found (Warnings)

Cause: Card name matches multiple versions/sets

Solution: Script auto-selects first match. Review *_mapped_log.json to verify correct card. If wrong, update CSV with more specific name or set identifier.

Issue: Missing Cards in Log

Cause: Card doesn't exist or is misspelled

Solution:

1. Check log for attempted slug
2. Search card database for correct name
3. Update CSV and re-run mapping

Issue: Draft Doesn't Appear in Dropdown

Cause: Registration mismatch or cache issue

Solution:

1. Verify type in swccgDrafts.json matches value in leagueAdmin.html
2. Rebuild: ./bin/gemp reload-fast
3. Hard refresh browser (Cmd+Shift+R)

Issue: Division by Zero Error

Symptom: java.lang.ArithmeticException: / by zero at DefaultSoloDraft.java:66

Cause: Missing null check for objChoiceCountPerSide

Solution: Verify line 66 has:

if (_objChoiceCountPerSide > 0 && offset % _objChoiceCountPerSide == 0) {

If missing > 0 check, apply fix and rebuild.

File Locations

gemp-swccg/
├── bin/
│   ├── gemp                          # CLI helper
│   ├── map_card_names_to_ids         # CSV → IDs mapper
│   └── create_cube                   # Cube config generator
│
├── src/gemp-swccg-cards/src/main/resources/
│   └── card_blueprint_database.json  # Card database (no set501)
│
├── src/gemp-swccg-server/src/main/resources/
│   ├── draft/
│   │   ├── <outputFile>.json        # Your cube config
│   │   └── cube_building/
│   │       └── <cube_name>/         # Source files
│   │           ├── default_cards.csv
│   │           ├── default_cards_mapped.json
│   │           ├── cube_worlds_lightside.csv
│   │           ├── cube_worlds_lightside_mapped.json
│   │           ├── cube_worlds_darkside.csv
│   │           └── cube_worlds_darkside_mapped.json
│   │
│   └── swccgDrafts.json              # Draft registry
│
├── src/gemp-swccg-server/src/main/java/.../draft2/
│   └── DefaultSoloDraft.java         # Draft logic (line 66 fix)
│
└── src/gemp-swccg-async/src/main/web/includes/admin/
    └── leagueAdmin.html              # Frontend admin UI

Technical Details

Pack Structure

Single card pack:

["card_id"]

Pack with add-ons:

["primary_card_id", "addon1_id", "addon2_id"]

Player receives ALL cards when picking the pack.

Draft Flow

1. Players start with all coreCards from startingPool
2. Alternates between light/dark for 56 rounds (choiceCountPerSide)
3. Each round shows 9 random packs (count: 9)
4. Player picks 1 pack, receives all cards in that array
5. Packs support add-ons via array-of-arrays structure

Choice Types

• cubePackObjPick - Pack-based (supports add-ons)
• cubePick - Single card (no add-ons)

Always use cubePackObjPick for consistency, even without objectives.

Complete Example

# 1. Create directory
mkdir -p src/gemp-swccg-server/src/main/resources/draft/cube_building/my_cube

# 2. Add CSV files (user provides)
# - default_cards.csv
# - cube_worlds_lightside.csv
# - cube_worlds_darkside.csv

# 3. Update card database
./bin/gemp export-cards src/gemp-swccg-cards/src/main/resources/card_blueprint_database.json

# 4. Create side-specific databases WITHOUT defensive shields
bash <<'BASH'
cd src/gemp-swccg-cards/src/main/resources

# Light side without defensive shields
jq '[.[] | select(.side == "LIGHT" and .cardCategory != "DEFENSIVE_SHIELD")]' \
  card_blueprint_database.json > /tmp/card_blueprint_database_light_no_shields.json

# Dark side without defensive shields
jq '[.[] | select(.side == "DARK" and .cardCategory != "DEFENSIVE_SHIELD")]' \
  card_blueprint_database.json > /tmp/card_blueprint_database_dark_no_shields.json

# Verify filtering
echo "Light side shields (should be 0):"
jq '[.[] | select(.cardCategory == "DEFENSIVE_SHIELD")] | length' \
  /tmp/card_blueprint_database_light_no_shields.json

echo "Dark side shields (should be 0):"
jq '[.[] | select(.cardCategory == "DEFENSIVE_SHIELD")] | length' \
  /tmp/card_blueprint_database_dark_no_shields.json
BASH

# 5. Map all cards with side-specific databases
CUBE_DIR="src/gemp-swccg-server/src/main/resources/draft/cube_building/my_cube"

# Default cards - use main database
./bin/map_card_names_to_ids \
  $CUBE_DIR/default_cards.csv \
  $CUBE_DIR/default_cards_mapped.json \
  src/gemp-swccg-cards/src/main/resources/card_blueprint_database.json

# Light side - use filtered light-only database
./bin/map_card_names_to_ids \
  $CUBE_DIR/cube_worlds_lightside.csv \
  $CUBE_DIR/cube_worlds_lightside_mapped.json \
  /tmp/card_blueprint_database_light_no_shields.json

# Dark side - use filtered dark-only database
./bin/map_card_names_to_ids \
  $CUBE_DIR/cube_worlds_darkside.csv \
  $CUBE_DIR/cube_worlds_darkside_mapped.json \
  /tmp/card_blueprint_database_dark_no_shields.json

# 6. Generate config
python3 bin/create_cube $CUBE_DIR src/gemp-swccg-server/src/main/resources/draft/cubeMyCube.json

# 7. Verify no playtesting or defensive shields
echo "Playtesting cards (should be 0):"
grep -c '"501_' src/gemp-swccg-server/src/main/resources/draft/cubeMyCube.json || echo "0"

echo "Checking defensive shields are not in cube..."
# This checks a sample defensive shield - expand as needed
bash <<'BASH'
CUBE_FILE="src/gemp-swccg-server/src/main/resources/draft/cubeMyCube.json"
SHIELD_COUNT=0
for id in $(jq -r '.[] | select(.cardCategory == "DEFENSIVE_SHIELD") | .cardId' \
  src/gemp-swccg-cards/src/main/resources/card_blueprint_database.json | head -10); do
  if grep -q "\"$id\"" "$CUBE_FILE"; then
    SHIELD_COUNT=$((SHIELD_COUNT + 1))
  fi
done
echo "Defensive shields found: $SHIELD_COUNT (should be 0)"
BASH

# 8. Register in swccgDrafts.json
# Add: {"type": "my_cube_draft", "location": "/draft/cubeMyCube.json"}

# 9. Add to leagueAdmin.html
# Add: <option value="my_cube_draft">My Cube Draft</option>

# 10. Deploy
./bin/gemp reload-fast

Resources

See references/ directory for additional documentation on cube draft mechanics and troubleshooting scenarios.