{
	"$schema": "https://json-schema.org/draft/2020-12/schema",
	"title": "Foldnano design file, format version 1",
	"description": "Shape of a Foldnano .fn.json document at formatVersion 1, including files saved before versioning (no header). Field meanings, units and conventions: Foldnano docs, Contributors > File Format.",
	"type": "object",
	"required": ["id", "name", "parts"],
	"additionalProperties": false,
	"properties": {
		"format": { "const": "foldnano" },
		"formatVersion": { "const": 1 },
		"savedWith": {
			"type": "object",
			"required": ["app", "commit"],
			"additionalProperties": false,
			"properties": {
				"app": { "type": "string" },
				"commit": { "type": "string" }
			}
		},
		"id": { "type": "string" },
		"name": { "type": "string" },
		"parts": { "type": "array", "items": { "$ref": "#/$defs/part" } }
	},
	"$defs": {
		"vec3": {
			"type": "object",
			"required": ["x", "y", "z"],
			"additionalProperties": false,
			"properties": {
				"x": { "type": "number" },
				"y": { "type": "number" },
				"z": { "type": "number" }
			}
		},
		"bpIndex": { "type": "integer", "minimum": 0 },
		"part": {
			"type": "object",
			"required": ["name", "id", "planes", "regions", "virtualHelices", "oligos"],
			"additionalProperties": false,
			"properties": {
				"name": { "type": "string" },
				"id": { "type": "string" },
				"planes": { "type": "array", "items": { "$ref": "#/$defs/plane" } },
				"regions": { "type": "array", "items": { "$ref": "#/$defs/region" } },
				"virtualHelices": { "type": "array", "items": { "$ref": "#/$defs/virtualHelix" } },
				"oligos": { "type": "array", "items": { "$ref": "#/$defs/oligo" } },
				"customModifications": {
					"type": "array",
					"items": { "$ref": "#/$defs/modificationDef" }
				},
				"overlayPlacements": {
					"type": "array",
					"items": { "$ref": "#/$defs/overlayPlacement" }
				},
				"repeatGroups": { "type": "array", "items": { "$ref": "#/$defs/repeatGroup" } }
			}
		},
		"plane": {
			"type": "object",
			"required": ["id", "name", "origin", "u", "v", "normal"],
			"additionalProperties": false,
			"properties": {
				"id": { "type": "string" },
				"name": { "type": "string" },
				"origin": { "$ref": "#/$defs/vec3" },
				"u": { "$ref": "#/$defs/vec3" },
				"v": { "$ref": "#/$defs/vec3" },
				"normal": { "$ref": "#/$defs/vec3" }
			}
		},
		"region": {
			"type": "object",
			"required": [
				"id",
				"name",
				"kind",
				"planeId",
				"vhOrder",
				"step",
				"turnsPerStep",
				"subStepSize",
				"twistOffset"
			],
			"anyOf": [{ "required": ["maxBase"] }, { "required": ["defaultMaxBase"] }],
			"additionalProperties": false,
			"properties": {
				"id": { "type": "string" },
				"name": { "type": "string" },
				"kind": { "enum": ["HONEYCOMB", "SQUARE", "FREEFORM"] },
				"planeId": { "type": "string" },
				"vhOrder": { "type": "array", "items": { "type": "string" } },
				"step": { "type": "integer", "minimum": 1 },
				"turnsPerStep": { "type": "number", "exclusiveMinimum": 0 },
				"subStepSize": { "type": "integer", "minimum": 1 },
				"twistOffset": { "type": "number" },
				"minBase": {
					"$ref": "#/$defs/bpIndex",
					"description": "Always written; older files may lack it and it defaults to 0."
				},
				"maxBase": { "$ref": "#/$defs/bpIndex" },
				"defaultMaxBase": {
					"$ref": "#/$defs/bpIndex",
					"description": "Legacy name for maxBase; read only when maxBase is absent."
				}
			}
		},
		"virtualHelix": {
			"type": "object",
			"required": ["index", "listRow", "regionId", "length", "strandSets"],
			"additionalProperties": false,
			"properties": {
				"id": {
					"type": "string",
					"description": "Always written; files from early development may lack it and get a new id on load."
				},
				"index": { "type": "integer", "minimum": 0 },
				"listRow": { "type": "integer" },
				"regionId": { "type": "string" },
				"latticeCoords": {
					"type": "object",
					"required": ["row", "col"],
					"additionalProperties": false,
					"properties": {
						"row": { "type": "integer" },
						"col": { "type": "integer" }
					}
				},
				"localFrame": {
					"type": "object",
					"required": ["origin", "axis", "radial0"],
					"additionalProperties": false,
					"properties": {
						"origin": { "$ref": "#/$defs/vec3" },
						"axis": { "$ref": "#/$defs/vec3" },
						"radial0": { "$ref": "#/$defs/vec3" }
					}
				},
				"length": { "type": "integer", "minimum": 0 },
				"strandSets": {
					"type": "array",
					"minItems": 2,
					"maxItems": 2,
					"items": { "$ref": "#/$defs/strandSet" }
				}
			}
		},
		"strandSet": {
			"type": "object",
			"required": ["strandIndex", "segmentIds"],
			"additionalProperties": false,
			"properties": {
				"strandIndex": { "enum": [0, 1] },
				"segmentIds": { "type": "array", "items": { "type": "string" } }
			}
		},
		"oligo": {
			"type": "object",
			"required": ["id", "segments", "color", "isScaffold", "isSequenceLocked", "name"],
			"additionalProperties": false,
			"properties": {
				"id": { "type": "string" },
				"segments": {
					"type": "array",
					"minItems": 1,
					"items": { "$ref": "#/$defs/oligoSegment" }
				},
				"color": { "type": "string" },
				"isScaffold": { "type": "boolean" },
				"isSequenceLocked": { "type": "boolean" },
				"name": { "type": "string" },
				"repeatGroupId": { "type": "string" },
				"mirrorOf": {
					"type": "object",
					"required": ["groupId", "instanceId", "sourceOligoId", "structure"],
					"additionalProperties": false,
					"properties": {
						"groupId": { "type": "string" },
						"instanceId": { "type": "string" },
						"sourceOligoId": { "type": "string" },
						"structure": { "type": "string" }
					}
				}
			}
		},
		"oligoSegment": {
			"type": "object",
			"required": ["id", "inVirtualHelixIndex", "fivePrime", "threePrime"],
			"additionalProperties": false,
			"properties": {
				"id": { "type": "string" },
				"inVirtualHelixIndex": { "type": "integer", "minimum": 0 },
				"fivePrime": { "$ref": "#/$defs/segmentEnd" },
				"threePrime": { "$ref": "#/$defs/segmentEnd" },
				"sequence": { "type": "string" },
				"slots": {
					"type": "array",
					"items": {
						"type": "object",
						"required": ["bpIndex", "seq"],
						"additionalProperties": false,
						"properties": {
							"bpIndex": { "$ref": "#/$defs/bpIndex" },
							"seq": { "type": "string" }
						}
					}
				}
			}
		},
		"segmentEnd": {
			"type": "object",
			"required": ["segmentId", "isThreePrime", "index", "connectedSegmentId"],
			"additionalProperties": false,
			"properties": {
				"segmentId": { "type": "string" },
				"isThreePrime": { "type": "boolean" },
				"index": { "$ref": "#/$defs/bpIndex" },
				"connectedSegmentId": { "type": ["string", "null"] },
				"modification": { "type": ["string", "null"] },
				"isConstrained": {
					"type": "boolean",
					"description": "Derived from the design; written for reference and recomputed on load."
				}
			}
		},
		"modificationDef": {
			"type": "object",
			"required": ["name"],
			"additionalProperties": false,
			"properties": {
				"name": { "type": "string" },
				"color": { "type": "string" },
				"symbol": {
					"type": "string",
					"description": "Legacy; files saved before modifications had colors. Ignored on load."
				}
			}
		},
		"overlayPlacement": {
			"type": "object",
			"required": ["id", "transform"],
			"additionalProperties": false,
			"properties": {
				"id": { "type": "string" },
				"sourceKey": { "type": "string" },
				"transform": {
					"type": "object",
					"required": ["position", "quaternion"],
					"additionalProperties": false,
					"properties": {
						"position": { "$ref": "#/$defs/vec3" },
						"quaternion": {
							"type": "array",
							"minItems": 4,
							"maxItems": 4,
							"items": { "type": "number" }
						}
					}
				}
			}
		},
		"repeatGroup": {
			"type": "object",
			"required": ["id", "name", "instances"],
			"additionalProperties": false,
			"properties": {
				"id": { "type": "string" },
				"name": { "type": "string" },
				"instances": {
					"type": "array",
					"items": {
						"type": "object",
						"required": ["id", "bpOffset"],
						"additionalProperties": false,
						"properties": {
							"id": { "type": "string" },
							"bpOffset": { "type": "integer" },
							"vhMap": {
								"type": "object",
								"additionalProperties": { "type": "string" }
							}
						}
					}
				}
			}
		}
	}
}