{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://archlang-docs.vercel.app/plan.schema.json",
  "title": "ArchLang Plan",
  "description": "A floor plan as structured JSON (RPLAN / DStruct2Design convention). Coordinates are millimetres; the origin is top-left with +x right and +y DOWN. Fields marked output-only are produced by planToJson and ignored on input. Scripting (let/for/if/component) and import are not representable — author those in .arch source.",
  "type": "object",
  "required": [
    "plan",
    "rooms",
    "walls",
    "openings",
    "furniture"
  ],
  "additionalProperties": false,
  "properties": {
    "version": {
      "const": 1,
      "description": "Schema version. Always 1."
    },
    "plan": {
      "type": "string",
      "description": "Plan name (shown in the title block)."
    },
    "units": {
      "const": "mm",
      "description": "Distance unit. Only millimetres are supported."
    },
    "grid": {
      "type": "number",
      "description": "Snap module in millimetres; 0 or omitted disables snapping."
    },
    "scale": {
      "type": "string",
      "pattern": "^\\d+:\\d+$",
      "description": "Drawing scale (annotation only), e.g. \"1:50\"."
    },
    "north": {
      "description": "North orientation: a cardinal keyword or an explicit bearing in degrees.",
      "oneOf": [
        {
          "enum": [
            "up",
            "down",
            "left",
            "right"
          ]
        },
        {
          "type": "object",
          "required": [
            "deg"
          ],
          "additionalProperties": false,
          "properties": {
            "deg": {
              "type": "number"
            }
          }
        }
      ]
    },
    "room_count": {
      "type": "integer",
      "description": "Output-only: number of rooms."
    },
    "total_area": {
      "type": "number",
      "description": "Output-only: total floor area in square metres."
    },
    "room_types": {
      "type": "array",
      "description": "Output-only: the distinct room_type values present, in first-appearance order.",
      "items": {
        "enum": [
          "LivingRoom",
          "MasterRoom",
          "Kitchen",
          "Bathroom",
          "DiningRoom",
          "ChildRoom",
          "StudyRoom",
          "SecondRoom",
          "GuestRoom",
          "Balcony",
          "Entrance",
          "Storage",
          "Room"
        ]
      }
    },
    "rooms": {
      "type": "array",
      "description": "Room rectangles.",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "x",
          "y",
          "width",
          "height"
        ],
        "properties": {
          "id": {
            "type": "string",
            "description": "Unique room id (referenced by furniture/openings)."
          },
          "label": {
            "type": "string",
            "description": "Human-readable room label drawn in the room."
          },
          "room_type": {
            "enum": [
              "LivingRoom",
              "MasterRoom",
              "Kitchen",
              "Bathroom",
              "DiningRoom",
              "ChildRoom",
              "StudyRoom",
              "SecondRoom",
              "GuestRoom",
              "Balcony",
              "Entrance",
              "Storage",
              "Room"
            ],
            "description": "Canonical RPLAN-style room category (mapped bidirectionally from `uses`)."
          },
          "uses": {
            "type": "array",
            "description": "Explicit ArchLang function tags; authoritative over room_type when present.",
            "items": {
              "enum": [
                "living",
                "kitchen",
                "dining",
                "bedroom",
                "bath",
                "wc",
                "hall",
                "circulation",
                "storage",
                "utility",
                "office",
                "entry"
              ]
            }
          },
          "x": {
            "type": "number",
            "description": "Top-left corner X in millimetres."
          },
          "y": {
            "type": "number",
            "description": "Top-left corner Y in millimetres."
          },
          "width": {
            "type": "number",
            "description": "Room width in millimetres."
          },
          "height": {
            "type": "number",
            "description": "Room height in millimetres."
          },
          "area": {
            "type": "number",
            "description": "Output-only: floor area in square metres (2 dp)."
          },
          "floor_polygon": {
            "type": "array",
            "description": "Output-only: the room rectangle as a 4-point polygon (clockwise from top-left).",
            "items": {
              "type": "object",
              "additionalProperties": false,
              "required": [
                "x",
                "y"
              ],
              "properties": {
                "x": {
                  "type": "number",
                  "description": "X coordinate in millimetres (origin top-left, +x right)."
                },
                "y": {
                  "type": "number",
                  "description": "Y coordinate in millimetres (+y DOWN, screen convention)."
                }
              }
            }
          }
        }
      }
    },
    "walls": {
      "type": "array",
      "description": "Wall polylines (poché-filled; host doors/windows/openings).",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "points"
        ],
        "properties": {
          "id": {
            "type": "string",
            "description": "Unique wall id."
          },
          "category": {
            "type": "string",
            "description": "Free-form category, e.g. \"exterior\" or \"partition\"; also a host reference."
          },
          "points": {
            "type": "array",
            "minItems": 2,
            "description": "Polyline vertices in order.",
            "items": {
              "type": "object",
              "additionalProperties": false,
              "required": [
                "x",
                "y"
              ],
              "properties": {
                "x": {
                  "type": "number",
                  "description": "X coordinate in millimetres (origin top-left, +x right)."
                },
                "y": {
                  "type": "number",
                  "description": "Y coordinate in millimetres (+y DOWN, screen convention)."
                }
              }
            }
          },
          "thickness": {
            "type": "number",
            "description": "Wall thickness in millimetres."
          },
          "closed": {
            "type": "boolean",
            "description": "Whether the polyline closes back to its first vertex."
          },
          "material": {
            "type": "string",
            "description": "Hatch material (brick, concrete, …); omitted for the default poché."
          },
          "material_scale": {
            "type": "number",
            "description": "Hatch tile-size multiplier (after material)."
          },
          "material_angle": {
            "type": "number",
            "description": "Extra hatch rotation in degrees (after material)."
          }
        }
      }
    },
    "openings": {
      "type": "array",
      "description": "Doors, windows and leaf-less cased openings — all must lie on a wall.",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "kind",
          "width"
        ],
        "properties": {
          "kind": {
            "enum": [
              "door",
              "window",
              "opening"
            ],
            "description": "Opening kind."
          },
          "id": {
            "type": "string",
            "description": "Unique opening id."
          },
          "x": {
            "type": "number",
            "description": "Center X in millimetres (on the wall centerline)."
          },
          "y": {
            "type": "number",
            "description": "Center Y in millimetres (on the wall centerline)."
          },
          "on": {
            "type": "object",
            "additionalProperties": false,
            "required": [
              "wall",
              "at"
            ],
            "description": "Wall-attached placement (alternative to x/y): walk `wall` to position `at`.",
            "properties": {
              "wall": {
                "type": "string",
                "description": "Host wall id or category to walk."
              },
              "at": {
                "type": "string",
                "description": "Position along the wall: a percentage (\"40%\"), millimetres (\"1200\"), or \"center\"."
              }
            }
          },
          "width": {
            "type": "number",
            "description": "Opening width in millimetres."
          },
          "wall": {
            "type": "string",
            "description": "Host wall by id or category (else nearest)."
          },
          "hinge": {
            "enum": [
              "left",
              "right"
            ],
            "description": "Door hinge side relative to the wall direction."
          },
          "swing": {
            "enum": [
              "in",
              "out"
            ],
            "description": "Door swing direction."
          }
        }
      }
    },
    "furniture": {
      "type": "array",
      "description": "Furniture and plumbing/kitchen fixtures.",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "category"
        ],
        "properties": {
          "category": {
            "type": "string",
            "description": "Furniture category, e.g. bed, sofa, wc, basin, stove."
          },
          "id": {
            "type": "string",
            "description": "Unique furniture id."
          },
          "room": {
            "type": "string",
            "description": "Owning room id (`in <room>`)."
          },
          "x": {
            "type": "number",
            "description": "Top-left corner X in millimetres (absolute placement)."
          },
          "y": {
            "type": "number",
            "description": "Top-left corner Y in millimetres (absolute placement)."
          },
          "width": {
            "type": "number",
            "description": "Width in millimetres."
          },
          "height": {
            "type": "number",
            "description": "Height in millimetres."
          },
          "rotate": {
            "enum": [
              0,
              90,
              180,
              270
            ],
            "description": "Quarter-turn rotation of the drawn symbol."
          },
          "centered": {
            "type": "boolean",
            "description": "Room-relative placement: centre inside `room`."
          },
          "anchor": {
            "enum": [
              "top-left",
              "top",
              "top-right",
              "left",
              "center",
              "right",
              "bottom-left",
              "bottom",
              "bottom-right"
            ],
            "description": "Room-relative placement: anchor to a corner/edge of `room`."
          },
          "inset": {
            "type": "number",
            "description": "Inset (mm) from the anchored edge."
          },
          "against_wall": {
            "type": "string",
            "description": "Wall-anchored placement: back onto this wall id/category."
          },
          "segment": {
            "type": "number",
            "description": "Which segment of a multi-segment wall (for against_wall)."
          },
          "offset": {
            "type": "number",
            "description": "Distance (mm) along the segment (for against_wall)."
          },
          "side": {
            "enum": [
              "left",
              "right"
            ],
            "description": "Which wall face to back onto (for against_wall)."
          },
          "label": {
            "type": "string",
            "description": "Label for the generic rectangle fallback."
          }
        }
      }
    },
    "dims": {
      "type": "array",
      "description": "Dimension lines.",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "from",
          "to"
        ],
        "properties": {
          "from": {
            "type": "object",
            "additionalProperties": false,
            "required": [
              "x",
              "y"
            ],
            "properties": {
              "x": {
                "type": "number",
                "description": "X coordinate in millimetres (origin top-left, +x right)."
              },
              "y": {
                "type": "number",
                "description": "Y coordinate in millimetres (+y DOWN, screen convention)."
              }
            },
            "description": "Start point."
          },
          "to": {
            "type": "object",
            "additionalProperties": false,
            "required": [
              "x",
              "y"
            ],
            "properties": {
              "x": {
                "type": "number",
                "description": "X coordinate in millimetres (origin top-left, +x right)."
              },
              "y": {
                "type": "number",
                "description": "Y coordinate in millimetres (+y DOWN, screen convention)."
              }
            },
            "description": "End point."
          },
          "offset": {
            "type": "number",
            "description": "Perpendicular offset of the dimension line in millimetres."
          },
          "text": {
            "type": "string",
            "description": "Override text; defaults to the measured length."
          }
        }
      }
    },
    "columns": {
      "type": "array",
      "description": "Structural columns.",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "x",
          "y",
          "width",
          "height"
        ],
        "properties": {
          "id": {
            "type": "string",
            "description": "Unique column id."
          },
          "x": {
            "type": "number",
            "description": "Top-left corner X in millimetres."
          },
          "y": {
            "type": "number",
            "description": "Top-left corner Y in millimetres."
          },
          "width": {
            "type": "number",
            "description": "Width in millimetres."
          },
          "height": {
            "type": "number",
            "description": "Height in millimetres."
          }
        }
      }
    },
    "title": {
      "type": "object",
      "additionalProperties": false,
      "description": "Title-block metadata.",
      "properties": {
        "project": {
          "type": "string",
          "description": "Project name."
        },
        "drawn_by": {
          "type": "string",
          "description": "Author / drafter."
        },
        "date": {
          "type": "string",
          "description": "Date string."
        }
      }
    },
    "edges": {
      "type": "array",
      "description": "Output-only: connector edges from the modeled door/opening access graph.",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "from",
          "to",
          "via",
          "type"
        ],
        "properties": {
          "from": {
            "type": "string",
            "description": "One endpoint (room id or `exterior`)."
          },
          "to": {
            "type": "string",
            "description": "Other endpoint (room id or `exterior`)."
          },
          "via": {
            "enum": [
              "door",
              "opening"
            ],
            "description": "Whether the connector is a door or a cased opening."
          },
          "type": {
            "enum": [
              "interior",
              "front"
            ],
            "description": "`front` connects the exterior (an entrance); else `interior`."
          }
        }
      }
    },
    "input_graph": {
      "type": "object",
      "description": "Output-only: interior-door adjacency dict, keyed by room id → neighbouring room ids.",
      "additionalProperties": {
        "type": "array",
        "items": {
          "type": "string"
        }
      }
    }
  }
}