{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://tatbot.ai/schemas/region-atlas-v2.json",
  "title": "InkLang SOMA region atlas",
  "description": "A deterministic mapping from the sole canonical SOMA rest surface to InkLang regions, reviewed eligibility, and default anchors.",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "atlas_schema_version",
    "inklang_version",
    "body",
    "builder",
    "frame",
    "encoding",
    "sites",
    "site_status",
    "region_meaning_count",
    "upstream_exclusions",
    "faces",
    "eligible_faces",
    "regions"
  ],
  "properties": {
    "atlas_schema_version": { "const": 2 },
    "inklang_version": { "type": "string", "minLength": 1 },
    "body": {
      "type": "object",
      "additionalProperties": false,
      "required": [
        "model_spec_id",
        "model_spec_sha256",
        "identity_sha256",
        "topology_sha256",
        "rest_surface_sha256",
        "asset_sha256"
      ],
      "properties": {
        "model_spec_id": { "const": "mhr-soma-v1" },
        "model_spec_sha256": { "$ref": "#/$defs/sha256" },
        "identity_sha256": { "$ref": "#/$defs/sha256" },
        "topology_sha256": { "$ref": "#/$defs/sha256" },
        "rest_surface_sha256": { "$ref": "#/$defs/sha256" },
        "asset_sha256": { "$ref": "#/$defs/sha256" }
      }
    },
    "builder": {
      "type": "object",
      "additionalProperties": false,
      "required": ["name", "version"],
      "properties": {
        "name": { "type": "string", "minLength": 1 },
        "version": { "type": "integer", "minimum": 1 },
        "source_revision": { "type": "string", "minLength": 1 },
        "source_sha256": { "$ref": "#/$defs/sha256" }
      }
    },
    "frame": {
      "type": "object",
      "additionalProperties": false,
      "required": ["front", "left", "up"],
      "properties": {
        "front": { "const": "-y" },
        "left": { "const": "+x" },
        "up": { "const": "+z" }
      }
    },
    "encoding": { "type": "string", "minLength": 1 },
    "sites": {
      "type": "array",
      "items": { "type": "string", "pattern": "^[a-z][a-z_]*$" },
      "minItems": 1,
      "uniqueItems": true
    },
    "site_status": {
      "type": "object",
      "minProperties": 1,
      "additionalProperties": { "$ref": "#/$defs/site_status" }
    },
    "region_meaning_count": { "const": 99 },
    "upstream_exclusions": {
      "type": "object",
      "additionalProperties": false,
      "required": ["asset_sha256", "segments", "excluded_faces"],
      "properties": {
        "asset_sha256": { "$ref": "#/$defs/sha256" },
        "segments": {
          "type": "array",
          "items": { "type": "string", "minLength": 1 },
          "uniqueItems": true
        },
        "excluded_faces": { "type": "integer", "minimum": 0 }
      }
    },
    "faces": {
      "type": "array",
      "items": { "type": "integer", "minimum": -1 },
      "minItems": 1
    },
    "eligible_faces": {
      "type": "array",
      "items": { "enum": [0, 1] },
      "minItems": 1
    },
    "regions": {
      "type": "object",
      "minProperties": 1,
      "additionalProperties": { "$ref": "#/$defs/region" }
    }
  },
  "$defs": {
    "sha256": { "type": "string", "pattern": "^[0-9a-f]{64}$" },
    "vec3": {
      "type": "array",
      "prefixItems": [{ "type": "number" }, { "type": "number" }, { "type": "number" }],
      "minItems": 3,
      "maxItems": 3
    },
    "range": {
      "type": "array",
      "prefixItems": [{ "type": "number" }, { "type": "number" }],
      "minItems": 2,
      "maxItems": 2
    },
    "site_status": {
      "type": "object",
      "additionalProperties": false,
      "required": ["status", "face_count"],
      "properties": {
        "status": {
          "enum": ["mapped_supported", "mapped_unsupported", "unsupported"]
        },
        "face_count": { "type": "integer", "minimum": 0 },
        "reason": { "type": "string", "minLength": 1 }
      }
    },
    "anchor": {
      "type": "object",
      "additionalProperties": false,
      "required": ["face", "barycentric"],
      "properties": {
        "face": { "type": "integer", "minimum": 0 },
        "barycentric": {
          "type": "array",
          "prefixItems": [
            { "type": "number", "minimum": 0, "maximum": 1 },
            { "type": "number", "minimum": 0, "maximum": 1 },
            { "type": "number", "minimum": 0, "maximum": 1 }
          ],
          "minItems": 3,
          "maxItems": 3
        }
      }
    },
    "chart": {
      "type": "object",
      "additionalProperties": false,
      "required": ["mean", "normal", "u_axis", "v_axis", "u_range", "v_range"],
      "properties": {
        "mean": { "$ref": "#/$defs/vec3" },
        "normal": { "$ref": "#/$defs/vec3" },
        "u_axis": { "$ref": "#/$defs/vec3" },
        "v_axis": { "$ref": "#/$defs/vec3" },
        "u_range": { "$ref": "#/$defs/range" },
        "v_range": { "$ref": "#/$defs/range" }
      }
    },
    "region": {
      "type": "object",
      "additionalProperties": false,
      "required": ["site_id", "laterality", "default_anchor", "chart"],
      "properties": {
        "site_id": { "type": "string", "pattern": "^[a-z][a-z_]*$" },
        "laterality": {
          "oneOf": [{ "enum": ["left", "right"] }, { "type": "null" }]
        },
        "default_anchor": { "$ref": "#/$defs/anchor" },
        "chart": { "$ref": "#/$defs/chart" }
      }
    }
  }
}