{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://meshnotes.org/spec/annotation/v1/schema.json",
  "title": "MeshNotes Annotation Format v1.0",
  "description": "Schema for a MeshNotes W3C Web Annotation Collection (https://meshnotes.org/spec/annotation/v1/). Forward-compatible: required core members are validated, known members are shape-checked, and additional properties are permitted throughout.",
  "type": "object",
  "required": ["@context", "type", "id", "dcterms:conformsTo", "total", "first"],
  "additionalProperties": true,
  "properties": {
    "@context": {
      "oneOf": [
        { "type": "string" },
        { "type": "array", "minItems": 1, "items": { "type": ["string", "object"] } }
      ]
    },
    "type": { "const": "AnnotationCollection" },
    "id": { "type": "string" },
    "label": { "type": "string" },
    "dcterms:conformsTo": { "const": "https://meshnotes.org/spec/annotation/v1/" },
    "generator": { "type": "object" },
    "generated": { "type": "string" },
    "modelSource": { "$ref": "#/$defs/modelSource" },
    "stylesheet": { "type": "object" },
    "meshnotes:groups": { "type": "array", "items": { "$ref": "#/$defs/group" } },
    "modelInfo": { "type": "object" },
    "metadata": { "type": "object" },
    "total": { "type": "integer", "minimum": 0 },
    "first": {
      "type": "object",
      "required": ["items"],
      "additionalProperties": true,
      "properties": {
        "type": { "const": "AnnotationPage" },
        "items": { "type": "array", "items": { "$ref": "#/$defs/annotation" } }
      }
    }
  },
  "$defs": {
    "modelSource": {
      "type": "object",
      "required": ["id"],
      "additionalProperties": true,
      "properties": {
        "id": { "type": "string" },
        "type": { "type": "string" },
        "schema:name": { "type": "string" },
        "format": { "type": "string" },
        "upAxis": { "type": "string" },
        "unit": { "type": "string" },
        "meshnotes:crs": { "type": "string" },
        "schema:sha256": { "type": "string", "pattern": "^[A-Fa-f0-9]{64}$" }
      }
    },
    "group": {
      "type": "object",
      "additionalProperties": true,
      "properties": {
        "id": { "type": "number" },
        "meshnotes:uuid": { "type": "string" },
        "schema:name": { "type": "string" },
        "schema:color": { "type": "string" },
        "meshnotes:visible": { "type": "boolean" },
        "meshnotes:opacity": { "type": "number" }
      }
    },
    "annotation": {
      "type": "object",
      "required": ["type", "target"],
      "additionalProperties": true,
      "properties": {
        "type": { "const": "Annotation" },
        "id": { "type": "string" },
        "motivation": { "type": "string" },
        "schema:name": { "type": "string" },
        "created": { "type": "string" },
        "modified": { "type": "string" },
        "annotationType": { "enum": ["point", "line", "polygon", "surface", "box"] },
        "meshnotes:groupUuid": { "type": "string" },
        "surfaceProjection": { "type": "boolean" },
        "target": { "$ref": "#/$defs/target" },
        "body": {
          "oneOf": [
            { "$ref": "#/$defs/textualBody" },
            { "type": "array", "items": { "$ref": "#/$defs/textualBody" } }
          ]
        },
        "meshnotes:nameVersions": { "type": "array" },
        "meshnotes:groupVersions": { "type": "array" }
      }
    },
    "target": {
      "type": "object",
      "required": ["type", "selector"],
      "additionalProperties": true,
      "properties": {
        "type": { "const": "SpecificResource" },
        "source": { "type": ["object", "string"] },
        "styleClass": { "type": "string" },
        "selector": { "$ref": "#/$defs/selector" }
      }
    },
    "selector": {
      "type": "object",
      "required": ["type"],
      "additionalProperties": true,
      "properties": {
        "type": {
          "enum": [
            "meshnotes:PointSelector",
            "meshnotes:PolylineSelector",
            "meshnotes:PolygonSelector",
            "meshnotes:SurfaceSelector",
            "meshnotes:BoxSelector"
          ]
        },
        "dcterms:conformsTo": { "type": "string" },
        "meshnotes:wkt": { "type": "string", "pattern": "^(POINT|LINESTRING|POLYGON) Z \\(.*\\)$" },
        "geo:asWKT": { "type": "string" },
        "meshnotes:centroid": { "$ref": "#/$defs/wktPointZ" },
        "meshnotes:normal": { "$ref": "#/$defs/wktPointZ" },
        "meshnotes:faces": { "type": "array", "items": { "type": "string" } },
        "meshnotes:center": { "$ref": "#/$defs/wktPointZ" },
        "meshnotes:size": { "$ref": "#/$defs/wktPointZ" },
        "meshnotes:rotation": { "type": "array", "minItems": 4, "maxItems": 4, "items": { "type": "number" } }
      },
      "allOf": [
        {
          "if": { "properties": { "type": { "const": "meshnotes:SurfaceSelector" } }, "required": ["type"] },
          "then": { "required": ["meshnotes:faces"] }
        },
        {
          "if": { "properties": { "type": { "const": "meshnotes:BoxSelector" } }, "required": ["type"] },
          "then": { "required": ["meshnotes:center", "meshnotes:size", "meshnotes:rotation"] }
        }
      ]
    },
    "wktPointZ": { "type": "string", "pattern": "^POINT Z \\([^()]*\\)$" },
    "textualBody": {
      "type": "object",
      "additionalProperties": true,
      "properties": {
        "type": { "const": "TextualBody" },
        "value": { "type": "string" },
        "format": { "type": "string" },
        "language": { "type": "string" },
        "creator": { "$ref": "#/$defs/creator" },
        "created": { "type": "string" },
        "modified": { "type": "string" },
        "schema:url": { "type": "array", "items": { "type": "string" } },
        "meshnotes:entryUuid": { "type": "string" },
        "meshnotes:versions": { "type": "array" }
      }
    },
    "creator": {
      "type": "object",
      "additionalProperties": true,
      "properties": {
        "type": { "type": "string" },
        "name": { "type": "string" },
        "id": { "type": "string" }
      }
    }
  }
}