{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://openhydro.org/schemas/v1/coupling_1d2d.schema.json",
  "title": "Benchmark1d2d 1D/2D Coupling Map",
  "description": "Minimal SWMM (or other 1D) node ↔ 2D cell/face exchange map for coupled urban inundation tests.",
  "type": "object",
  "additionalProperties": false,
  "required": ["schema_version", "network_ref", "terrain_ref", "exchanges"],
  "properties": {
    "schema_version": {
      "type": "string",
      "pattern": "^(0|[1-9]\\d*)\\.(0|[1-9]\\d*)\\.(0|[1-9]\\d*)(?:-[0-9A-Za-z-]+(?:\\.[0-9A-Za-z-]+)*)?(?:\\+[0-9A-Za-z-]+(?:\\.[0-9A-Za-z-]+)*)?$"
    },
    "network_ref": {
      "type": "object",
      "additionalProperties": false,
      "required": ["path"],
      "properties": {
        "path": { "type": "string", "minLength": 1 },
        "format": {
          "type": "string",
          "enum": ["network_1d_json", "swmm_inp", "other"]
        },
        "sha256": {
          "type": "string",
          "pattern": "^[a-fA-F0-9]{64}$"
        }
      }
    },
    "terrain_ref": {
      "type": "object",
      "additionalProperties": false,
      "required": ["path"],
      "properties": {
        "path": { "type": "string", "minLength": 1 },
        "format": {
          "type": "string",
          "enum": ["terrain_2d_json", "geotiff", "ugrid", "other"]
        },
        "sha256": {
          "type": "string",
          "pattern": "^[a-fA-F0-9]{64}$"
        }
      }
    },
    "exchange_model": {
      "type": "string",
      "enum": [
        "weir",
        "orifice",
        "free_discharge",
        "head_difference",
        "custom"
      ],
      "description": "Default exchange formulation for all links unless overridden."
    },
    "exchanges": {
      "type": "array",
      "minItems": 1,
      "items": { "$ref": "#/$defs/exchange" }
    }
  },
  "$defs": {
    "exchange": {
      "type": "object",
      "additionalProperties": false,
      "required": ["id", "node_id", "surface"],
      "properties": {
        "id": { "type": "string", "minLength": 1 },
        "node_id": {
          "type": "string",
          "minLength": 1,
          "description": "1D network node (e.g. SWMM manhole/junction) id."
        },
        "surface": {
          "type": "object",
          "additionalProperties": false,
          "required": ["kind"],
          "properties": {
            "kind": {
              "type": "string",
              "enum": ["cell", "face", "point"]
            },
            "cell_id": { "type": "string" },
            "face_id": { "type": "string" },
            "x": { "type": "number" },
            "y": { "type": "number" }
          },
          "allOf": [
            {
              "if": {
                "properties": { "kind": { "const": "cell" } },
                "required": ["kind"]
              },
              "then": { "required": ["cell_id"] }
            },
            {
              "if": {
                "properties": { "kind": { "const": "face" } },
                "required": ["kind"]
              },
              "then": { "required": ["face_id"] }
            },
            {
              "if": {
                "properties": { "kind": { "const": "point" } },
                "required": ["kind"]
              },
              "then": { "required": ["x", "y"] }
            }
          ]
        },
        "crest_elevation": { "type": "number" },
        "exchange_width": {
          "type": "number",
          "exclusiveMinimum": 0
        },
        "discharge_coefficient": {
          "type": "number",
          "exclusiveMinimum": 0
        },
        "exchange_model": {
          "type": "string",
          "enum": [
            "weir",
            "orifice",
            "free_discharge",
            "head_difference",
            "custom"
          ]
        },
        "bidirectional": {
          "type": "boolean",
          "default": true
        },
        "attributes": {
          "type": "object",
          "additionalProperties": true
        }
      }
    }
  }
}