{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "PaperJet Annotation Schema",
  "definitions": {
    "Rect": {
      "type": "object",
      "description": "Bounding rectangle in canonical PDF-point space (top-left origin).",
      "properties": {
        "x": { "type": "number", "description": "X position in PDF points from the left edge of the page CropBox" },
        "y": { "type": "number", "description": "Y position in PDF points from the top edge of the page CropBox" },
        "width": { "type": "number", "minimum": 0 },
        "height": { "type": "number", "minimum": 0 }
      },
      "required": ["x", "y", "width", "height"]
    },
    "AnnotationBase": {
      "type": "object",
      "description": "Common envelope for all annotation types.",
      "properties": {
        "id": { "type": "string", "format": "uuid" },
        "page": { "type": "integer", "minimum": 0, "description": "0-indexed page number" },
        "type": { "type": "string", "description": "Discriminator — drives the tool/handler registries" },
        "rect": { "$ref": "#/definitions/Rect" },
        "rotation": { "type": "number", "default": 0, "description": "Degrees clockwise about rect center" },
        "z": { "type": "integer", "default": 0, "description": "Z-order within the page" },
        "props": { "type": "object", "description": "Type-specific properties, opaque to the server" },
        "createdAt": { "type": "string", "format": "date-time" },
        "updatedAt": { "type": "string", "format": "date-time" }
      },
      "required": ["id", "page", "type", "rect", "props", "createdAt", "updatedAt"]
    },
    "TextProps": {
      "type": "object",
      "properties": {
        "text": { "type": "string" },
        "fontFamily": { "type": "string", "default": "Liberation Sans" },
        "fontSize": { "type": "number", "default": 14 },
        "color": { "type": "string", "default": "#000000" },
        "align": { "type": "string", "enum": ["left", "center", "right"], "default": "left" },
        "bold": { "type": "boolean", "default": false },
        "italic": { "type": "boolean", "default": false },
        "lineHeight": { "type": "number", "default": 1.2 },
        "highlightColor": { "type": ["string", "null"] }
      },
      "required": ["text"]
    },
    "DrawProps": {
      "type": "object",
      "properties": {
        "paths": {
          "type": "array",
          "items": {
            "type": "array",
            "items": { "type": "number" },
            "minItems": 2,
            "maxItems": 2
          },
          "description": "Array of [x, y] points in rect-local space"
        },
        "strokeColor": { "type": "string", "default": "#000000" },
        "strokeWidth": { "type": "number", "default": 2 },
        "opacity": { "type": "number", "minimum": 0, "maximum": 1, "default": 1 }
      },
      "required": ["paths"]
    },
    "SignatureDrawProps": {
      "type": "object",
      "properties": {
        "mode": { "type": "string", "const": "draw" },
        "ref": { "type": "string", "description": "Asset reference for the rasterized signature" },
        "strokeColor": { "type": "string", "default": "#000000" }
      },
      "required": ["mode", "ref"]
    },
    "SignatureTypeProps": {
      "type": "object",
      "properties": {
        "mode": { "type": "string", "const": "type" },
        "text": { "type": "string" },
        "fontFamily": { "type": "string" },
        "color": { "type": "string", "default": "#000000" }
      },
      "required": ["mode", "text", "fontFamily"]
    },
    "ImageProps": {
      "type": "object",
      "properties": {
        "ref": { "type": "string", "description": "Asset reference for the uploaded image" },
        "naturalWidth": { "type": "number" },
        "naturalHeight": { "type": "number" }
      },
      "required": ["ref", "naturalWidth", "naturalHeight"]
    },
    "HighlightProps": {
      "type": "object",
      "properties": {
        "color": { "type": "string", "default": "#FFEB3B" },
        "opacity": { "type": "number", "minimum": 0, "maximum": 1, "default": 0.3 }
      }
    },
    "ShapeProps": {
      "type": "object",
      "properties": {
        "kind": { "type": "string", "enum": ["rect", "ellipse", "line", "arrow"] },
        "strokeColor": { "type": "string", "default": "#000000" },
        "fillColor": { "type": "string", "default": "transparent" },
        "strokeWidth": { "type": "number", "default": 2 }
      },
      "required": ["kind"]
    }
  },
  "allOf": [{ "$ref": "#/definitions/AnnotationBase" }]
}