{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Document Theme Component System",
  "description": "A schema for a theme that defines reusable components and their layout.",
  "type": "object",
  "properties": {
    "header": { "$ref": "#/$defs/headerObject" },
    "settings": { "$ref": "#/$defs/settingsObject" },
    "content": { "$ref": "#/$defs/contentRootObject" }
  },
  "required": ["header", "settings", "content"],
  "$defs": {
    "headerObject": {
      "type": "object",
      "properties": { "theme": { "$ref": "#/$defs/themeObject" } },
      "required": ["theme"]
    },
    "themeObject": {
      "type": "object",
      "properties": {
        "name": { "type": "string" },
        "author": { "type": "string" },
        "version": { "type": "string", "pattern": "^\\d+\\.\\d+\\.\\d+$" }
      },
      "required": ["name", "author", "version"]
    },
    "settingsObject": {
      "type": "object",
      "properties": {
        "page size": { "type": "string", "enum": ["A4", "A5", "Letter", "Legal"] },
        "margin": { "$ref": "#/$defs/marginObject" }
      },
      "required": ["page size"]
    },
    "contentRootObject": {
      "type": "object",
      "properties": {
        "settings": { "$ref": "#/$defs/contentSettingsObject" },
        "cover": { "$ref": "#/$defs/pageSection" },
        "backcover": { "$ref": "#/$defs/pageSection" },
        "interior": { "$ref": "#/$defs/pageSection" }
      },
      "additionalProperties": false
    },
    "contentSettingsObject": {
      "type": "object",
      "properties": {
        "definitions": {
          "type": "array",
          "items": { "$ref": "#/$defs/definitionObject" }
        }
      },
      "required": ["definitions"]
    },
    "definitionObject": {
      "type": "object",
      "properties": {
        "class": { "type": "string" },
        "content": {
          "type": "array",
          "items": { "$ref": "#/$defs/componentItem" }
        }
      },
      "required": ["class", "content"]
    },
    "pageSection": {
      "type": "object",
      "properties": {
        "settings": {
          "type": "object",
          "properties": {
            "paper color": { "type": "string", "pattern": "^#[0-9a-fA-F]{6}$" },
            "margin": { "$ref": "#/$defs/marginObject" }
          },
          "required": ["paper color"]
        },
        "contents": { "type": "array", "items": { "$ref": "#/$defs/contentItem" } }
      },
      "required": ["settings", "contents"]
    },
    "marginObject": {
      "type": "object",
      "properties": {
        "top": { "$ref": "#/$defs/measurementObject" },
        "bottom": { "$ref": "#/$defs/measurementObject" },
        "left": { "$ref": "#/$defs/measurementObject" },
        "right": { "$ref": "#/$defs/measurementObject" }
      },
      "required": ["top", "bottom", "left", "right"]
    },
    "measurementObject": {
      "type": "object",
      "properties": {
        "value": { "type": "number" },
        "unit": { "type": "string", "enum": ["cm", "mm", "in", "pt", "px"] }
      },
      "required": ["value", "unit"]
    },
    "contentItem": {
      "type": "object",
      "description": "An item with absolute position on a page.",
      "properties": {
        "coordinates": { "$ref": "#/$defs/coordinatesObject" },
        "information": { "$ref": "#/$defs/informationUnion" }
      },
      "required": ["coordinates", "information"]
    },
    "componentItem": {
      "type": "object",
      "description": "An item within a component definition, without absolute coordinates.",
      "properties": {
        "information": { "$ref": "#/$defs/informationUnion" }
      },
      "required": ["information"]
    },
    "informationUnion": {
      "oneOf": [
        { "$ref": "#/$defs/drawingInformation" },
        { "$ref": "#/$defs/textInformation" },
        { "$ref": "#/$defs/documentBodyInformation" },
        { "$ref": "#/$defs/imageInformation" }
      ]
    },
    "coordinatesObject": {
      "type": "object",
      "properties": {
        "x": { "$ref": "#/$defs/positionRange" },
        "y": { "$ref": "#/$defs/positionRange" },
        "layer": { "type": "integer" }
      },
      "required": ["x", "y", "layer"]
    },
    "positionRange": {
      "type": "object",
      "properties": {
        "start": { "type": "number" },
        "end": { "type": "number" }
      },
      "required": ["start"]
    },
    "drawingInformation": {
      "type": "object",
      "properties": {
        "type": { "const": "drawing" },
        "dimension": { "$ref": "#/$defs/dimensionObject" },
        "relative position": { "$ref": "#/$defs/relativePositionObject" },
        "rotation": { "type": "number" },
        "shape": {
          "oneOf": [
            { "$ref": "#/$defs/rectangleShape" },
            { "$ref": "#/$defs/lineShape" }
          ]
        },
        "line": { "$ref": "#/$defs/lineObject" },
        "fill": { "$ref": "#/$defs/fillObject" },
        "settings": {
          "type": "object",
          "properties": {
            "padding": { "$ref": "#/$defs/marginObject" },
            "skip margin": { "type": "boolean" }
          }
        }
      },
      "required": ["type", "shape"]
    },
    "textInformation": {
      "type": "object",
      "properties": {
        "type": { "const": "text" },
        "font": { "$ref": "#/$defs/fontObject" },
        "variable": { "type": "string", "pattern": "^\\$.+" }
      },
      "required": ["type", "font", "variable"]
    },
    "documentBodyInformation": {
      "type": "object",
      "properties": {
        "type": { "const": "document body" },
        "font": { "$ref": "#/$defs/fontObject" },
        "variable": { "type": "string", "pattern": "^\\$.+" }
      },
      "required": ["type", "font", "variable"]
    },
    "imageInformation": {
      "type": "object",
      "properties": {
        "type": { "const": "image" },
        "dimension": { "$ref": "#/$defs/dimensionObject" },
        "relative position": { "$ref": "#/$defs/relativePositionObject" }
      },
      "required": ["type", "dimension"]
    },
    "dimensionObject": {
      "type": "object",
      "properties": {
        "width": { "$ref": "#/$defs/measurementObject" },
        "height": { "$ref": "#/$defs/measurementObject" },
        "layer": { "type": "integer" }
      },
      "required": ["width", "height", "layer"]
    },
    "relativePositionObject": {
      "type": "object",
      "properties": {
        "horizontal": { "type": "string", "enum": ["left", "center", "right"] },
        "vertical": { "type": "string", "enum": ["top", "center", "bottom"] }
      },
      "required": ["horizontal", "vertical"]
    },
    "fontObject": {
      "type": "object",
      "properties": {
        "size": { "type": "number" },
        "name": { "type": "string" }
      },
      "required": ["size", "name"]
    },
    "rectangleShape": {
      "type": "object",
      "properties": {
        "type": { "const": "rectangle" },
        "corner radius": { "$ref": "#/$defs/cornerRadiusObject" }
      },
      "required": ["type"]
    },
    "lineShape": {
      "type": "object",
      "properties": { "type": { "const": "line" } },
      "required": ["type"]
    },
    "cornerRadiusObject": {
      "type": "object",
      "properties": {
        "top left": { "type": "number" },
        "top right": { "type": "number" },
        "bottom left": { "type": "number" },
        "bottom right": { "type": "number" }
      },
      "required": ["top left", "top right", "bottom left", "bottom right"]
    },
    "lineObject": {
      "type": "object",
      "properties": {
        "stroke": { "type": "string", "enum": ["solid", "dashed", "dotted"] },
        "width": { "type": "number" },
        "color": { "type": "string", "pattern": "^#[0-9a-fA-F]{6}$" }
      },
      "required": ["stroke", "width", "color"]
    },
    "fillObject": {
      "type": "object",
      "properties": {
        "color": { "type": "string", "pattern": "^#[0-9a-fA-F]{6}$" },
        "opacity": { "type": "number", "minimum": 0, "maximum": 1 }
      },
      "required": ["color"]
    }
  }
}