Add Puzzle Type

Scaffold a new puzzle type across all pipeline integration points in jigsawR.

When to Use

• Adding a completely new puzzle type to the package
• Following the established integration checklist (CLAUDE.md 10-point pipeline)
• Ensuring nothing is missed when wiring a new type end-to-end

Inputs

• Required: New type name (lowercase, e.g. "triangular")
• Required: Geometry description (how pieces are shaped/arranged)
• Required: Whether the type needs external packages (add to Suggests)
• Optional: Parameter list beyond the standard (grid, size, seed, tabsize, offset)
• Optional: Reference implementation or algorithm source

Procedure

Step 1: Create Core Puzzle Module

Create R/<type>_puzzle.R with the internal generation function:

#' Generate <type> puzzle pieces (internal)
#' @noRd
generate_<type>_pieces_internal <- function(params, seed) {
  # 1. Initialize RNG state
  # 2. Generate piece geometries
  # 3. Build edge paths (SVG path data)
  # 4. Compute adjacency
  # 5. Return list: pieces, edges, adjacency, metadata
}

Follow the pattern in R/voronoi_puzzle.R or R/snic_puzzle.R for structure.

Got: Function returns a list with $pieces, $edges, $adjacency, $metadata.

If fail: Compare the return structure against generate_voronoi_pieces_internal() to identify missing list elements or incorrect types.

Step 2: Wire into jigsawR_clean.R

Edit R/jigsawR_clean.R:

1. Add "<type>" to the valid_types vector
2. Add type-specific parameter extraction in the params section
3. Add validation logic for type-specific constraints
4. Add filename prefix mapping (e.g., "<type>" -> "<type>_")

# In valid_types
valid_types <- c("rectangular", "hexagonal", "concentric", "voronoi", "snic", "<type>")

Got: generate_puzzle(type = "<type>") is accepted without "unknown type" error.

If fail: Verify the type string is added to valid_types exactly as spelled, and that parameter extraction covers all required type-specific arguments.

Step 3: Wire into unified_piece_generation.R

Edit R/unified_piece_generation.R:

1. Add dispatch case in generate_pieces_internal()
2. Add fusion handling if the type supports PILES notation

# In the switch/dispatch
"<type>" = generate_<type>_pieces_internal(params, seed)

Got: Pieces are generated when the type is dispatched.

If fail: Confirm the dispatch case string matches the type name exactly and that generate_<type>_pieces_internal is defined and exported from the puzzle module.

Step 4: Wire into piece_positioning.R

Edit R/piece_positioning.R:

Add positioning dispatch for the new type. Most types use shared positioning logic, but some need custom handling.

Got: apply_piece_positioning() handles the new type without errors and pieces are placed at correct coordinates.

If fail: Check whether the new type needs custom positioning logic or can reuse the shared positioning path. Add a dispatch case if the default path does not apply.

Step 5: Wire into unified_renderer.R

Edit R/unified_renderer.R:

1. Add rendering case in render_puzzle_svg()
2. Add edge path function: get_<type>_edge_paths()
3. Add piece name function: get_<type>_piece_name()

Got: SVG output is generated for the new type with correct piece outlines and edge paths.

If fail: Verify get_<type>_edge_paths() returns valid SVG path data and get_<type>_piece_name() produces unique identifiers for each piece.

Step 6: Wire into adjacency_api.R

Edit R/adjacency_api.R:

Add neighbor dispatch so get_neighbors() and get_adjacency() work for the new type.

Got: get_neighbors(result, piece_id) returns correct neighbors for any piece in the puzzle.

If fail: Check that the adjacency dispatch returns the correct data structure. Test with a small grid and manually verify neighbor relationships against the geometry.

Step 7: Add ggpuzzle Geom Layer

Edit R/geom_puzzle.R:

Create geom_puzzle_<type>() using the make_puzzle_layer() factory:

#' @export
geom_puzzle_<type> <- function(mapping = NULL, data = NULL, ...) {
  make_puzzle_layer(type = "<type>", mapping = mapping, data = data, ...)
}

Got: ggplot() + geom_puzzle_<type>(aes(...)) renders without error.

If fail: Verify make_puzzle_layer() receives the correct type string and that the geom function is exported in the NAMESPACE via @export.

Step 8: Add Stat Dispatch

Edit R/stat_puzzle.R:

1. Add type-specific default parameters
2. Add dispatch case in compute_panel()

Got: The stat layer computes puzzle geometry correctly and produces the expected number of polygons.

If fail: Check that the compute_panel() dispatch case returns a data frame with the required columns (x, y, group, piece_id) and that default parameters are sensible for the new type.

Step 9: Update DESCRIPTION

Edit DESCRIPTION:

1. Add new type to the Description field text
2. Add any new packages to Suggests: (if external dependency)
3. Update Collate: to include the new R file (alphabetical order)

Got: devtools::document() succeeds. No NOTE about unlisted files.

If fail: Check that the new R file is listed in the Collate: field in alphabetical order and that any new Suggests packages are spelled correctly with version constraints.

Step 10: Update config.yml

Edit inst/config.yml:

Add defaults and constraints for the new type:

<type>:
  grid:
    default: [3, 3]
    min: [2, 2]
    max: [20, 20]
  size:
    default: [300, 300]
    min: [100, 100]
    max: [2000, 2000]
  tabsize:
    default: 20
    min: 5
    max: 50
  # Add type-specific params here

Got: Config is valid YAML. Defaults produce a working puzzle when used by generate_puzzle().

If fail: Validate YAML with yaml::yaml.load_file("inst/config.yml"). Ensure default grid and size values produce a sensible puzzle (not too small or too large).

Step 11: Extend Shiny App

Edit inst/shiny-app/app.R:

1. Add the new type to the UI type selector
2. Add conditional UI panels for type-specific parameters
3. Add server-side generation logic

Got: Shiny app shows the new type in the dropdown and generates puzzles when selected.

If fail: Check that the type is added to the choices argument of the UI selector, that the conditional panel for type-specific parameters uses conditionalPanel(condition = "input.type == '<type>'"), and that the server-side handler passes the correct parameters.

Step 12: Create Test Suite

Create tests/testthat/test-<type>-puzzles.R:

test_that("<type> puzzle generates correct piece count", { ... })
test_that("<type> puzzle respects seed reproducibility", { ... })
test_that("<type> adjacency returns valid neighbors", { ... })
test_that("<type> fusion merges pieces correctly", { ... })
test_that("<type> geom layer renders without error", { ... })
test_that("<type> SVG output is well-formed", { ... })
test_that("<type> config constraints are enforced", { ... })

If the type requires an external package, wrap tests with skip_if_not_installed().

Got: All tests pass. No skips unless external dependency is missing.

If fail: Check each integration point individually. The most common issue is missing dispatch cases — run grep -rn "switch\|valid_types" R/ to find all dispatch locations.

Validation

• generate_puzzle(type = "<type>") produces valid output
• All 10 integration points are wired correctly
• devtools::test() passes with new tests
• devtools::check() returns 0 errors, 0 warnings
• Shiny app renders the new type
• Config constraints are enforced (min/max validation)
• Adjacency and fusion work correctly
• ggpuzzle geom layer renders without error
• devtools::document() succeeds (NAMESPACE updated)

Pitfalls

• Missing dispatch case: Forgetting one of the 10+ files causes silent failure or "unknown type" errors
• strsplit with negative numbers: When creating adjacency keys with paste(a, b, sep = "-"), negative piece labels produce keys like "1--1". Use "|" separator instead and split with "\\|".
• Using cat() for output: Always use cli package logging wrappers (log_info, log_warn, etc.)
• Collate order: DESCRIPTION Collate field must be alphabetical or dependency-ordered
• Config.yml format: Ensure YAML is valid; test with yaml::yaml.load_file("inst/config.yml")

Related Skills

• generate-puzzle — test the new type after scaffolding
• run-puzzle-tests — run the full test suite to verify integration
• validate-piles-notation — test fusion with the new type
• write-testthat-tests — general test-writing patterns
• write-roxygen-docs — document the new geom function