{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://geocourse.org/schema/0.1/geocourse.schema.json",
  "title": "GeoCourse 0.1",
  "description": "Structure, types, patterns and value ranges of a GeoCourse 0.1 file (spec sections 3 to 8). Sample counts, coverage and other cross-references are checked by the reference validator only. A draft may change until it is declared released; after that it is frozen.",
  "type": "object",
  "required": ["type", "format", "id", "version", "name", "length", "closed", "profile", "ranges"],
  "properties": {
    "$schema": { "type": "string" },
    "type": { "const": "Course" },
    "format": { "type": "string", "pattern": "^\\d+\\.\\d+$" },
    "id": { "type": "string", "pattern": "^[a-z0-9-]{1,64}$" },
    "version": { "type": "integer", "minimum": 1 },
    "name": { "type": "string" },
    "description": { "type": "string" },
    "length": { "type": "number", "exclusiveMinimum": 0 },
    "closed": { "type": "boolean" },
    "created": { "$ref": "#/$defs/timestamp" },
    "authors": { "type": "array", "items": { "type": "string" } },
    "licence": { "type": "string" },
    "attribution": { "type": "array", "items": { "type": "string" } },
    "sources": { "type": "array", "items": { "$ref": "#/$defs/source" } },
    "summary": {
      "type": "object",
      "properties": {
        "elevationGain": { "type": "number", "minimum": 0 },
        "elevationLoss": { "type": "number", "minimum": 0 },
        "maxGrade": { "type": "number" }
      }
    },
    "geometry": { "$ref": "#/$defs/geometry" },
    "profile": { "$ref": "#/$defs/profile" },
    "ranges": { "type": "array", "items": { "$ref": "#/$defs/range" } },
    "osm": {
      "type": "object",
      "properties": {
        "snapshot": { "$ref": "#/$defs/timestamp" },
        "relation": { "type": "integer", "minimum": 1 }
      }
    },
    "extensionsUsed": { "type": "array", "uniqueItems": true, "items": { "$ref": "#/$defs/extensionName" } },
    "extensionsRequired": { "type": "array", "uniqueItems": true, "items": { "$ref": "#/$defs/extensionName" } },
    "extensions": { "$ref": "#/$defs/extensions" }
  },
  "anyOf": [
    { "required": ["geometry"] },
    { "required": ["profile"], "properties": { "profile": { "required": ["heading"] } } }
  ],
  "$defs": {
    "timestamp": { "type": "string", "format": "date-time" },
    "extensionName": { "type": "string", "pattern": "^[a-z0-9]+_[a-z0-9_]+$" },
    "vendorValue": { "type": "string", "pattern": "^[a-z0-9]+:[a-z0-9_]+$" },
    "extensions": {
      "type": "object",
      "propertyNames": { "$ref": "#/$defs/extensionName" },
      "additionalProperties": { "type": "object" }
    },
    "source": {
      "type": "object",
      "required": ["kind", "name", "licence"],
      "properties": {
        "kind": { "enum": ["geometry", "elevation", "road"] },
        "name": { "type": "string" },
        "licence": { "type": "string" },
        "url": { "type": "string" },
        "retrieved": { "$ref": "#/$defs/timestamp" }
      }
    },
    "channel": {
      "type": "object",
      "required": ["scale", "values"],
      "properties": {
        "scale": { "type": "number", "exclusiveMinimum": 0 },
        "values": { "type": "array", "items": { "type": "integer" } }
      }
    },
    "geometry": {
      "type": "object",
      "required": ["frame", "step", "scale", "positions"],
      "properties": {
        "frame": { "enum": ["wgs84", "local"] },
        "step": { "type": "number", "exclusiveMinimum": 0 },
        "scale": { "type": "number", "exclusiveMinimum": 0 },
        "positions": { "type": "array", "minItems": 4, "items": { "type": "integer" } },
        "origin": {
          "type": "object",
          "required": ["lon", "lat"],
          "properties": {
            "lon": { "type": "number", "minimum": -180, "maximum": 180 },
            "lat": { "type": "number", "minimum": -90, "maximum": 90 }
          }
        },
        "extensions": { "$ref": "#/$defs/extensions" }
      },
      "if": { "properties": { "frame": { "const": "wgs84" } } },
      "then": { "not": { "required": ["origin"] } }
    },
    "profile": {
      "type": "object",
      "required": ["step", "elevation"],
      "properties": {
        "step": { "type": "number", "exclusiveMinimum": 0, "maximum": 50 },
        "elevation": { "$ref": "#/$defs/channel" },
        "grade": { "$ref": "#/$defs/channel" },
        "heading": { "$ref": "#/$defs/channel" },
        "bendRadiusLimit": { "type": "number", "exclusiveMinimum": 0 },
        "extensions": { "$ref": "#/$defs/extensions" }
      }
    },
    "osmRef": {
      "type": "object",
      "required": ["type", "id"],
      "properties": {
        "type": { "enum": ["way", "node", "relation"] },
        "id": { "type": "integer", "minimum": 1 },
        "version": { "type": "integer", "minimum": 1 },
        "from": { "type": "number", "minimum": 0 },
        "to": { "type": "number", "minimum": 0 }
      }
    },
    "range": {
      "type": "object",
      "required": ["type", "from", "to"],
      "properties": {
        "type": { "type": "string", "minLength": 1 },
        "from": { "type": "number", "minimum": 0 },
        "to": { "type": "number", "minimum": 0 },
        "id": { "type": "string", "minLength": 1 },
        "properties": {
          "type": "object",
          "properties": {
            "tags": { "type": "object", "additionalProperties": { "type": "string" } }
          }
        },
        "osm": { "type": "array", "items": { "$ref": "#/$defs/osmRef" } },
        "extensions": { "$ref": "#/$defs/extensions" }
      },
      "allOf": [
        {
          "if": { "properties": { "type": { "const": "surface" } } },
          "then": {
            "required": ["properties"],
            "properties": {
              "properties": {
                "required": ["crr", "grip"],
                "properties": {
                  "crr": { "type": "number", "minimum": 0 },
                  "grip": { "type": "number", "exclusiveMinimum": 0 },
                  "surface": { "type": "string" },
                  "smoothness": { "type": "string" },
                  "tracktype": { "type": "string" },
                  "name": { "type": "string" }
                }
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "road" } } },
          "then": {
            "properties": {
              "properties": {
                "properties": {
                  "width": { "type": "number", "exclusiveMinimum": 0 },
                  "widthSource": { "enum": ["osm", "survey", "estimated", "design"] },
                  "highway": { "type": "string" },
                  "lanes": { "type": "integer", "minimum": 1 },
                  "name": { "type": "string" },
                  "ref": { "type": "string" },
                  "lit": { "type": "string" },
                  "cycleway": { "type": "string" }
                }
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "bend" } } },
          "then": {
            "required": ["properties"],
            "properties": {
              "properties": {
                "required": ["radius", "direction", "apex"],
                "properties": {
                  "radius": { "type": "number", "exclusiveMinimum": 0 },
                  "direction": { "enum": ["left", "right"] },
                  "apex": { "type": "number", "minimum": 0 }
                }
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "climb" } } },
          "then": {
            "properties": {
              "properties": {
                "properties": {
                  "name": { "type": "string" },
                  "category": { "enum": ["4", "3", "2", "1", "HC"] }
                }
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "segment" } } },
          "then": {
            "required": ["id"],
            "properties": { "properties": { "properties": { "name": { "type": "string" } } } }
          }
        },
        {
          "if": { "properties": { "type": { "const": "structure" } } },
          "then": {
            "required": ["properties"],
            "properties": {
              "properties": {
                "required": ["kind"],
                "properties": {
                  "kind": { "anyOf": [{ "enum": ["bridge", "tunnel", "building_passage"] }, { "$ref": "#/$defs/vendorValue" }] },
                  "name": { "type": "string" }
                }
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "hazard" } } },
          "then": {
            "required": ["properties"],
            "properties": {
              "properties": {
                "required": ["kind"],
                "properties": {
                  "kind": { "anyOf": [{ "enum": ["cattle_grid", "speed_bump", "railway_crossing", "ford", "gate"] }, { "$ref": "#/$defs/vendorValue" }] }
                }
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "marker" } } },
          "then": {
            "required": ["properties"],
            "properties": {
              "properties": {
                "required": ["kind"],
                "properties": {
                  "kind": { "anyOf": [{ "enum": ["start", "finish", "summit", "sprint", "feed", "town", "viewpoint", "sign", "info"] }, { "$ref": "#/$defs/vendorValue" }] },
                  "name": { "type": "string" },
                  "text": { "type": "string" }
                }
              }
            }
          }
        }
      ]
    }
  }
}