{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://stac-extensions.github.io/view/v1.1.0/schema.json",
  "title": "View Geometry Extension",
  "description": "STAC View Geometry for STAC Items and STAC Collections.",
  "type": "object",
  "required": ["stac_extensions"],
  "properties": {
    "stac_extensions": {
      "type": "array",
      "contains": {
        "const": "https://stac-extensions.github.io/view/v1.1.0/schema.json"
      }
    }
  },
  "oneOf": [
    {
      "$comment": "This is the schema for STAC Items.",
      "type": "object",
      "required": ["type"],
      "properties": {
        "type": {
          "const": "Feature"
        }
      },
      "anyOf": [
        {
          "required": ["properties"],
          "properties": {
            "properties": {
              "$ref": "#/definitions/requirements_and_fields"
            }
          }
        },
        {
          "$ref": "#/definitions/assets"
        }
      ]
    },
    {
      "$comment": "This is the schema for STAC Collections.",
      "type": "object",
      "required": ["type"],
      "properties": {
        "type": {
          "const": "Collection"
        }
      },
      "anyOf": [
        {
          "$ref": "#/definitions/assets"
        },
        {
          "required": ["item_assets"],
          "properties": {
            "item_assets": {
              "$ref": "#/definitions/asset_contains"
            }
          }
        },
        {
          "$comment": "This is the schema for the fields in Summaries. By default, only checks the existence of the properties, but not the schema of the summaries.",
          "required": ["summaries"],
          "properties": {
            "summaries": {
              "$ref": "#/definitions/require_any_field"
            }
          }
        }
      ]
    }
  ],
  "definitions": {
    "assets": {
      "required": ["assets"],
      "properties": {
        "assets": {
          "$ref": "#/definitions/asset_contains"
        }
      }
    },
    "asset_contains": {
      "type": "object",
      "not": {
        "additionalProperties": {
          "not": {
            "$ref": "#/definitions/requirements_and_fields"
          }
        }
      }
    },
    "requirements_and_fields": {
      "allOf": [
        {
          "$ref": "#/definitions/require_any_field"
        },
        {
          "$ref": "#/definitions/fields"
        }
      ]
    },
    "require_any_field": {
      "$comment": "Please list all fields here so that we can force the existence of one of them in other parts of the schemas.",
      "anyOf": [
        { "required": ["view:off_nadir"] },
        { "required": ["view:incidence_angle"] },
        { "required": ["view:azimuth"] },
        { "required": ["view:sun_azimuth"] },
        { "required": ["view:sun_elevation"] },
        { "required": ["view:moon_azimuth"] },
        { "required": ["view:moon_elevation"] }
      ]
    },
    "fields": {
      "$comment": "Add your new fields here. Don't require them here, do that above in the item schema.",
      "type": "object",
      "properties": {
        "view:off_nadir": {
          "title": "Off Nadir",
          "type": "number",
          "minimum": 0,
          "maximum": 90
        },
        "view:incidence_angle": {
          "title": "Center incidence angle",
          "type": "number",
          "minimum": 0,
          "maximum": 90
        },
        "view:azimuth": {
          "title": "Azimuth angle",
          "type": "number",
          "minimum": 0,
          "maximum": 360
        },
        "view:sun_azimuth": {
          "title": "Sun Azimuth",
          "type": "number",
          "minimum": 0,
          "maximum": 360
        },
        "view:sun_elevation": {
          "title": "Sun Elevation",
          "type": "number",
          "minimum": -90,
          "maximum": 90
        },
        "view:moon_azimuth": {
          "title": "Moon Azimuth",
          "type": "number",
          "minimum": 0,
          "maximum": 360
        },
        "view:moon_elevation": {
          "title": "Moon Elevation",
          "type": "number",
          "minimum": 0,
          "maximum": 90
        }
      },
      "patternProperties": {
        "^(?!view:)": {
          "$comment": "Do not allow unspecified fields prefixed with view:"
        }
      },
      "additionalProperties": false
    }
  }
}