{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://raw.githubusercontent.com/dmccreary/learning-graphs/refs/heads/main/src/schema/learning-graph-schema.json",
  "title": "Learning Graph Schema",
  "description": "JSON Schema for validating learning graph data structures used in educational dependency graphs",
  "type": "object",
  "required": ["metadata", "groups", "nodes", "edges"],
  "properties": {
    "metadata": {
      "type": "object",
      "description": "Metadata about the learning graph including title, description, and provenance information",
      "required": ["title", "description"],
      "properties": {
        "title": {
          "type": "string",
          "description": "The title of the learning graph",
          "minLength": 1
        },
        "description": {
          "type": "string",
          "description": "A detailed description of what this learning graph covers",
          "minLength": 1
        },
        "creator": {
          "type": "string",
          "description": "The person or organization that created this learning graph"
        },
        "date": {
          "type": "string",
          "description": "The creation or last modified date in YYYY-MM-DD format",
          "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
        },
        "version": {
          "type": "string",
          "description": "Version number of the learning graph content",
          "pattern": "^\\d+\\.\\d+(\\.\\d+)?$"
        },
        "format": {
          "type": "string",
          "description": "The format specification this file adheres to"
        },
        "schema": {
          "type": "string",
          "description": "URL to the JSON schema used to validate this file",
          "format": "uri"
        },
        "license": {
          "type": "string",
          "description": "The license under which this learning graph is distributed"
        }
      },
      "additionalProperties": true
    },
    "groups": {
      "type": "object",
      "description": "Taxonomy groups that categorize nodes with associated styling",
      "patternProperties": {
        "^[A-Za-z0-9_-]+$": {
          "type": "object",
          "required": ["color"],
          "properties": {
            "color": {
              "type": "string",
              "description": "CSS color value for nodes in this group",
              "pattern": "^(#[0-9A-Fa-f]{3,8}|[a-z]+|rgb\\(.*\\)|rgba\\(.*\\))$"
            },
            "font": {
              "type": "object",
              "description": "Font styling for nodes in this group",
              "properties": {
                "color": {
                  "type": "string",
                  "description": "CSS color value for text",
                  "pattern": "^(#[0-9A-Fa-f]{3,8}|[a-z]+|rgb\\(.*\\)|rgba\\(.*\\))$"
                },
                "size": {
                  "type": "number",
                  "description": "Font size in pixels",
                  "minimum": 1
                }
              }
            },
            "shape": {
              "type": "string",
              "description": "Default shape for nodes in this group",
              "enum": ["box", "circle", "ellipse", "database", "diamond", "dot", "star", "triangle", "triangleDown", "hexagon", "square"]
            }
          },
          "additionalProperties": false
        }
      },
      "additionalProperties": false,
      "minProperties": 1
    },
    "nodes": {
      "type": "array",
      "description": "Array of concept nodes in the learning graph",
      "items": {
        "type": "object",
        "required": ["id", "label", "group"],
        "properties": {
          "id": {
            "type": "integer",
            "description": "Unique identifier for the node",
            "minimum": 1
          },
          "label": {
            "type": "string",
            "description": "Display name of the concept",
            "minLength": 1
          },
          "group": {
            "type": "string",
            "description": "The taxonomy group this node belongs to"
          },
          "shape": {
            "type": "string",
            "description": "Visual shape of the node (overrides group default)",
            "enum": ["box", "circle", "ellipse", "database", "diamond", "dot", "star", "triangle", "triangleDown", "hexagon", "square"]
          },
          "color": {
            "type": "string",
            "description": "Node color (overrides group default)",
            "pattern": "^(#[0-9A-Fa-f]{3,8}|[a-z]+|rgb\\(.*\\)|rgba\\(.*\\))$"
          },
          "font": {
            "type": "object",
            "description": "Font styling for this node (overrides group default)",
            "properties": {
              "color": {
                "type": "string",
                "description": "Font color",
                "pattern": "^(#[0-9A-Fa-f]{3,8}|[a-z]+|rgb\\(.*\\)|rgba\\(.*\\))$"
              },
              "size": {
                "type": "number",
                "description": "Font size in pixels",
                "minimum": 1
              }
            }
          },
          "x": {
            "type": "number",
            "description": "X coordinate for fixed positioning"
          },
          "y": {
            "type": "number",
            "description": "Y coordinate for fixed positioning"
          },
          "fixed": {
            "type": "object",
            "description": "Controls which axes are fixed in position",
            "properties": {
              "x": {
                "type": "boolean"
              },
              "y": {
                "type": "boolean"
              }
            }
          },
          "hidden": {
            "type": "boolean",
            "description": "Whether the node is hidden from view"
          }
        },
        "additionalProperties": false
      },
      "minItems": 1
    },
    "edges": {
      "type": "array",
      "description": "Array of directed edges representing dependencies between concepts",
      "items": {
        "type": "object",
        "required": ["from", "to"],
        "properties": {
          "id": {
            "type": "integer",
            "description": "Unique identifier for the edge",
            "minimum": 1
          },
          "from": {
            "type": "integer",
            "description": "ID of the source node",
            "minimum": 1
          },
          "to": {
            "type": "integer",
            "description": "ID of the target node",
            "minimum": 1
          },
          "label": {
            "type": "string",
            "description": "Optional label for the edge relationship"
          },
          "arrows": {
            "type": "string",
            "description": "Arrow configuration",
            "enum": ["to", "from", "middle", "to,from"]
          },
          "color": {
            "type": "string",
            "description": "Edge color",
            "pattern": "^(#[0-9A-Fa-f]{3,8}|[a-z]+|rgb\\(.*\\)|rgba\\(.*\\))$"
          },
          "width": {
            "type": "number",
            "description": "Edge width in pixels",
            "minimum": 0.1
          },
          "dashes": {
            "type": "boolean",
            "description": "Whether the edge should be dashed"
          }
        },
        "additionalProperties": false
      }
    }
  },
  "additionalProperties": false
}