{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://palimpsest.info/protocol/evidence-capsule-v1.schema.json",
  "title": "Palimpsest Evidence Capsule v1",
  "type": "object",
  "additionalProperties": false,
  "required": ["content", "content_sha256", "attestations"],
  "properties": {
    "content": {"$ref": "#/$defs/content"},
    "content_sha256": {"$ref": "#/$defs/sha256"},
    "attestations": {
      "type": "array",
      "maxItems": 64,
      "items": {"$ref": "#/$defs/attestation"}
    }
  },
  "$defs": {
    "sha256": {"type": "string", "pattern": "^[0-9a-f]{64}$"},
    "identifier": {"type": "string", "pattern": "^[a-z][a-z0-9._-]{0,127}$"},
    "safeInteger": {"type": "integer", "minimum": -9007199254740991, "maximum": 9007199254740991},
    "nonnegativeSafeInteger": {"type": "integer", "minimum": 0, "maximum": 9007199254740991},
    "stringArray": {"type": "array", "maxItems": 512, "uniqueItems": true, "items": {"$ref": "#/$defs/identifier"}},
    "jsonValue": {
      "oneOf": [
        {"type": "null"},
        {"type": "boolean"},
        {"$ref": "#/$defs/safeInteger"},
        {"type": "string"},
        {"type": "array", "maxItems": 512, "items": {"$ref": "#/$defs/jsonValue"}},
        {"type": "object", "maxProperties": 512, "additionalProperties": {"$ref": "#/$defs/jsonValue"}}
      ]
    },
    "content": {
      "type": "object",
      "additionalProperties": false,
      "required": ["spec_version", "canonicalization", "created_at", "producer", "subject", "artifacts", "claims", "derivations", "intents", "bindings"],
      "properties": {
        "spec_version": {"const": "palimpsest-evidence-capsule/v1"},
        "canonicalization": {"const": "palimpsest-json-sorted-utf8-v1"},
        "created_at": {"type": "string", "format": "date-time"},
        "producer": {
          "type": "object", "additionalProperties": false,
          "required": ["name", "software"],
          "properties": {"name": {"type": "string", "minLength": 1}, "software": {"type": "string", "minLength": 1}}
        },
        "subject": {
          "type": "object", "additionalProperties": false,
          "required": ["type", "id", "title"],
          "properties": {
            "type": {"enum": ["reading", "analytical-lead", "evidence-set"]},
            "id": {"type": "string", "minLength": 1},
            "title": {"type": "string", "minLength": 1}
          }
        },
        "artifacts": {"type": "array", "minItems": 1, "maxItems": 64, "items": {"$ref": "#/$defs/artifact"}},
        "claims": {"type": "array", "minItems": 1, "maxItems": 128, "items": {"$ref": "#/$defs/claim"}},
        "derivations": {"type": "array", "maxItems": 128, "items": {"$ref": "#/$defs/derivation"}},
        "intents": {"type": "array", "maxItems": 32, "items": {"$ref": "#/$defs/intent"}},
        "bindings": {"type": "array", "maxItems": 32, "items": {"$ref": "#/$defs/binding"}}
      }
    },
    "artifact": {
      "type": "object", "additionalProperties": false,
      "required": ["id", "sha256", "size", "media_type", "source", "untrusted", "location"],
      "properties": {
        "id": {"$ref": "#/$defs/identifier"},
        "sha256": {"$ref": "#/$defs/sha256"},
        "size": {"type": "integer", "minimum": 0, "maximum": 8388608},
        "media_type": {"type": "string", "pattern": "^[A-Za-z0-9!#$&^_.+-]+/[A-Za-z0-9!#$&^_.+-]+$"},
        "source": {
          "type": "object", "additionalProperties": false,
          "required": ["uri", "captured_at", "collector"],
          "properties": {
            "uri": {"type": "string", "minLength": 1},
            "captured_at": {"type": "string", "format": "date-time"},
            "collector": {"type": "string", "minLength": 1}
          }
        },
        "untrusted": {"type": "boolean"},
        "location": {
          "oneOf": [
            {
              "type": "object", "additionalProperties": false,
              "required": ["type", "encoding", "data"],
              "properties": {"type": {"const": "inline"}, "encoding": {"const": "base64"}, "data": {"type": "string"}}
            },
            {
              "type": "object", "additionalProperties": false,
              "required": ["type", "path"],
              "properties": {"type": {"const": "path"}, "path": {"type": "string", "minLength": 1}}
            }
          ]
        }
      }
    },
    "claim": {
      "type": "object", "additionalProperties": false,
      "required": ["id", "type", "statement", "artifact_refs", "derivation_refs", "binding_refs", "evidence_level", "limitations"],
      "properties": {
        "id": {"$ref": "#/$defs/identifier"},
        "type": {"enum": ["observation", "measurement", "provenance", "integrity", "analytical-lead"]},
        "statement": {"type": "string", "minLength": 1},
        "artifact_refs": {"allOf": [{"$ref": "#/$defs/stringArray"}, {"minItems": 1}]},
        "derivation_refs": {"$ref": "#/$defs/stringArray"},
        "binding_refs": {"$ref": "#/$defs/stringArray"},
        "evidence_level": {"enum": ["direct", "derived", "sampled", "reported"]},
        "limitations": {"type": "array", "items": {"type": "string", "minLength": 1}}
      }
    },
    "derivation": {
      "type": "object", "additionalProperties": false,
      "required": ["id", "type", "description", "input_artifact_refs", "supports_claim_refs", "proof"],
      "properties": {
        "id": {"$ref": "#/$defs/identifier"},
        "type": {"enum": ["extraction", "calculation", "ranking", "analyst-judgment"]},
        "description": {"type": "string", "minLength": 1},
        "input_artifact_refs": {"allOf": [{"$ref": "#/$defs/stringArray"}, {"minItems": 1}]},
        "supports_claim_refs": {"allOf": [{"$ref": "#/$defs/stringArray"}, {"minItems": 1}]},
        "proof": {
          "oneOf": [
            {
              "type": "object", "additionalProperties": false,
              "required": ["type", "artifact_ref", "pointer", "expected"],
              "properties": {
                "type": {"const": "json-pointer-equals-v1"},
                "artifact_ref": {"$ref": "#/$defs/identifier"},
                "pointer": {"type": "string", "pattern": "^(|/.*)$"},
                "expected": {"$ref": "#/$defs/jsonValue"}
              }
            },
            {
              "type": "object", "additionalProperties": false,
              "required": ["type", "reason"],
              "properties": {"type": {"const": "declared-nonrecomputable-v1"}, "reason": {"type": "string", "minLength": 1}}
            }
          ]
        }
      }
    },
    "intent": {
      "type": "object", "additionalProperties": false,
      "required": ["type", "summary", "advisory"],
      "properties": {
        "type": {"enum": ["human-review", "investigate", "preserve", "compare", "cite"]},
        "summary": {"type": "string", "minLength": 1},
        "advisory": {"const": true}
      }
    },
    "ledgerEntry": {
      "type": "object", "additionalProperties": false,
      "required": ["seq", "ts", "source", "payload_sha256", "prev_hash", "entry_hash"],
      "properties": {
        "seq": {"$ref": "#/$defs/nonnegativeSafeInteger"}, "ts": {"type": "string", "format": "date-time"},
        "source": {"type": "string", "minLength": 1}, "payload_sha256": {"$ref": "#/$defs/sha256"},
        "prev_hash": {"$ref": "#/$defs/sha256"}, "entry_hash": {"$ref": "#/$defs/sha256"}
      }
    },
    "inclusionProof": {
      "type": "object", "additionalProperties": false,
      "required": ["type", "seq", "entry_hash", "n_entries", "path", "merkle_root"],
      "properties": {
        "type": {"const": "palimpsest-merkle-duplicate-last-v1"},
        "seq": {"$ref": "#/$defs/nonnegativeSafeInteger"}, "entry_hash": {"$ref": "#/$defs/sha256"},
        "n_entries": {"type": "integer", "minimum": 1, "maximum": 9007199254740991}, "merkle_root": {"$ref": "#/$defs/sha256"},
        "path": {"type": "array", "maxItems": 64, "items": {"type": "object", "additionalProperties": false, "required": ["side", "hash"], "properties": {"side": {"enum": ["left", "right"]}, "hash": {"$ref": "#/$defs/sha256"}}}}
      }
    },
    "anchor": {
      "type": "object", "additionalProperties": false,
      "required": ["type", "ledger", "prefix_entries", "head_hash", "merkle_root", "anchored_at", "input_artifact_ref", "proof_artifact_ref", "proof_type"],
      "properties": {
        "type": {"const": "palimpsest-prefix-anchor-v1"}, "ledger": {"type": "string", "pattern": "^[a-z][a-z0-9_]*$"},
        "prefix_entries": {"type": "integer", "minimum": 1, "maximum": 9007199254740991}, "head_hash": {"$ref": "#/$defs/sha256"},
        "merkle_root": {"$ref": "#/$defs/sha256"}, "anchored_at": {"type": "string", "format": "date-time"},
        "input_artifact_ref": {"$ref": "#/$defs/identifier"}, "proof_artifact_ref": {"$ref": "#/$defs/identifier"},
        "proof_type": {"const": "opentimestamps-detached-envelope-v1"}
      }
    },
    "binding": {
      "type": "object", "additionalProperties": false,
      "required": ["id", "type", "artifact_ref", "payload_canonicalization", "entry", "inclusion_proof", "anchor"],
      "properties": {
        "id": {"$ref": "#/$defs/identifier"},
        "type": {"const": "palimpsest-ledger-anchor-v1"},
        "artifact_ref": {"$ref": "#/$defs/identifier"},
        "payload_canonicalization": {"const": "palimpsest-ledger-python-json-v1"},
        "entry": {"$ref": "#/$defs/ledgerEntry"},
        "inclusion_proof": {"$ref": "#/$defs/inclusionProof"},
        "anchor": {"$ref": "#/$defs/anchor"}
      }
    },
    "attestation": {
      "type": "object", "additionalProperties": false,
      "required": ["type", "content_sha256", "actor", "issued_at", "statement"],
      "properties": {
        "type": {"const": "statement-v1"}, "content_sha256": {"$ref": "#/$defs/sha256"},
        "actor": {"type": "string", "minLength": 1}, "issued_at": {"type": "string", "format": "date-time"},
        "statement": {"type": "string", "minLength": 1}
      }
    }
  }
}