{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://github.com/GBeurier/nirs4all-methods/schemas/ordered_search_space.v1.schema.json",
  "title": "n4m OrderedSearchSpaceSpec v1",
  "description": "Ordered, fingerprinted host search space. Semantic validation additionally enforces homogeneous choices, exact current-C-ABI integer bounds, domain-kind matching, unique targets, valid activations, acyclicity and constraint references.",
  "type": "object",
  "additionalProperties": false,
  "required": ["schema", "schema_version", "axes", "constraints"],
  "properties": {
    "schema": { "const": "nirs4all.ordered-search-space" },
    "schema_version": { "type": "integer", "const": 1 },
    "axes": {
      "type": "array",
      "minItems": 1,
      "items": { "$ref": "#/$defs/axis" }
    },
    "constraints": {
      "type": "array",
      "items": { "$ref": "#/$defs/constraint" }
    }
  },
  "$defs": {
    "non_empty_string": {
      "type": "string",
      "minLength": 1
    },
    "identifier": {
      "type": "string",
      "minLength": 1,
      "maxLength": 128,
      "pattern": "^[A-Za-z0-9_.:-]+$"
    },
    "i64": {
      "type": "object",
      "additionalProperties": false,
      "required": ["i64"],
      "properties": {
        "i64": {
          "type": "string",
          "pattern": "^(0|-?[1-9][0-9]*)$"
        }
      }
    },
    "f64_bits": {
      "type": "object",
      "additionalProperties": false,
      "required": ["f64_bits"],
      "properties": {
        "f64_bits": {
          "type": "string",
          "pattern": "^[0-9a-f]{16}$"
        }
      }
    },
    "string_scalar": {
      "type": "object",
      "additionalProperties": false,
      "required": ["string"],
      "properties": {
        "string": { "type": "string", "minLength": 1 }
      }
    },
    "bool_scalar": {
      "type": "object",
      "additionalProperties": false,
      "required": ["bool"],
      "properties": {
        "bool": { "type": "boolean" }
      }
    },
    "typed_scalar": {
      "oneOf": [
        { "$ref": "#/$defs/i64" },
        { "$ref": "#/$defs/f64_bits" },
        { "$ref": "#/$defs/string_scalar" },
        { "$ref": "#/$defs/bool_scalar" }
      ]
    },
    "parameter_patch_target": {
      "type": "object",
      "additionalProperties": false,
      "required": ["node_id", "namespace", "path"],
      "properties": {
        "node_id": { "$ref": "#/$defs/identifier" },
        "namespace": {
          "enum": ["operator", "fit", "control", "structural"]
        },
        "path": {
          "type": "array",
          "minItems": 1,
          "items": { "$ref": "#/$defs/non_empty_string" }
        }
      }
    },
    "activation": {
      "oneOf": [
        {
          "type": "object",
          "additionalProperties": false,
          "required": ["mode"],
          "properties": { "mode": { "const": "always" } }
        },
        {
          "type": "object",
          "additionalProperties": false,
          "required": ["mode", "parent", "choice_index"],
          "properties": {
            "mode": { "enum": ["when", "when_not"] },
            "parent": { "$ref": "#/$defs/non_empty_string" },
            "choice_index": {
              "type": "integer",
              "minimum": 0,
              "maximum": 9007199254740991
            }
          }
        }
      ]
    },
    "numeric_domain": {
      "type": "object",
      "additionalProperties": false,
      "required": ["low", "high", "step", "log"],
      "properties": {
        "low": { "$ref": "#/$defs/typed_scalar" },
        "high": { "$ref": "#/$defs/typed_scalar" },
        "step": { "$ref": "#/$defs/typed_scalar" },
        "log": { "type": "boolean" }
      }
    },
    "choice_domain": {
      "type": "object",
      "additionalProperties": false,
      "required": ["choices"],
      "description": "Choice order is semantic. All choices use one homogeneous typed-scalar kind; semantic validation rejects duplicates.",
      "properties": {
        "choices": {
          "type": "array",
          "minItems": 1,
          "items": { "$ref": "#/$defs/typed_scalar" }
        }
      }
    },
    "tuple_domain": {
      "type": "object",
      "additionalProperties": false,
      "required": ["length", "element_kind", "low", "high"],
      "properties": {
        "length": {
          "type": "integer",
          "minimum": 1,
          "maximum": 2147483647
        },
        "element_kind": { "enum": ["int", "float"] },
        "low": { "$ref": "#/$defs/typed_scalar" },
        "high": { "$ref": "#/$defs/typed_scalar" }
      }
    },
    "axis": {
      "type": "object",
      "additionalProperties": false,
      "required": [
        "name",
        "kind",
        "target",
        "domain",
        "activation",
        "inactive_policy"
      ],
      "properties": {
        "name": { "$ref": "#/$defs/non_empty_string" },
        "kind": {
          "enum": ["int", "float", "categorical", "ordinal", "sorted_tuple"]
        },
        "target": { "$ref": "#/$defs/parameter_patch_target" },
        "domain": {
          "oneOf": [
            { "$ref": "#/$defs/numeric_domain" },
            { "$ref": "#/$defs/choice_domain" },
            { "$ref": "#/$defs/tuple_domain" }
          ]
        },
        "activation": { "$ref": "#/$defs/activation" },
        "inactive_policy": { "const": "sample_then_omit" }
      }
    },
    "constraint_ref": {
      "type": "object",
      "additionalProperties": false,
      "required": ["axis"],
      "properties": {
        "axis": { "$ref": "#/$defs/non_empty_string" },
        "choice_index": {
          "type": "integer",
          "minimum": 0,
          "maximum": 9007199254740991
        }
      }
    },
    "constraint": {
      "type": "object",
      "additionalProperties": false,
      "required": ["kind", "refs"],
      "properties": {
        "kind": { "enum": ["mutex_group", "requires", "exclude"] },
        "refs": {
          "type": "array",
          "minItems": 2,
          "items": { "$ref": "#/$defs/constraint_ref" }
        }
      }
    }
  }
}