{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://buildchain.libkungfu.dev/schema/v4-canonical-contracts-v1.schema.json",
  "title": "Buildchain v4 canonical contract suite",
  "description": "Closed provider-free contracts for canonical JSON, content roots, explicit clocks, events, receipts, and typed faults.",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "schemaVersion",
    "canonicalization",
    "root",
    "clock",
    "event",
    "receipt",
    "fault"
  ],
  "properties": {
    "schemaVersion": { "const": 1 },
    "canonicalization": {
      "type": "object",
      "additionalProperties": false,
      "required": [
        "id",
        "keyPattern",
        "minimumInteger",
        "maximumInteger",
        "terminator"
      ],
      "properties": {
        "id": { "const": "buildchain-canonical-json/v1" },
        "keyPattern": { "const": "^[ -~]+$" },
        "minimumInteger": { "const": -9007199254740991 },
        "maximumInteger": { "const": 9007199254740991 },
        "terminator": { "const": "LF" }
      }
    },
    "root": { "$ref": "#/$defs/root" },
    "clock": { "$ref": "#/$defs/clock" },
    "event": { "$ref": "#/$defs/event" },
    "receipt": { "$ref": "#/$defs/receipt" },
    "fault": { "$ref": "#/$defs/fault" }
  },
  "$defs": {
    "root": {
      "type": "object",
      "additionalProperties": false,
      "required": ["algorithm", "encoding", "domainSeparator", "domains"],
      "properties": {
        "algorithm": { "const": "sha256" },
        "encoding": { "const": "sha256:<lowercase-hex>" },
        "domainSeparator": { "const": "domain + NUL + canonical-bytes" },
        "domains": {
          "const": [
            "queue-state",
            "candidate-identity",
            "fencing-token",
            "transition-receipt",
            "observation",
            "semantic-diff",
            "bootstrap-evidence",
            "stage-capsule-identity",
            "stage-capsule",
            "stage-capsule-availability",
            "stage-capsule-output-manifest",
            "stage-capsule-retention-promise",
            "stage-capsule-retention-state",
            "stage-capsule-transport",
            "stage-capsule-store-receipt",
            "stage-capsule-quarantine",
            "stage-capsule-resume-observation",
            "stage-capsule-resume-plan",
            "stage-capsule-artifact-manifest",
            "stage-capsule-artifact-content",
            "stage-capsule-fault-campaign",
            "stage-capsule-seed-evidence",
            "stage-capsule-resume-evidence",
            "stage-capsule-platform-qualification",
            "stage-capsule-qualification",
            "stage-capsule-wave-reconciliation",
            "provider-operation-identity",
            "provider-operation-intent",
            "provider-operation-attempt",
            "provider-operation-observation",
            "provider-operation-confirmation",
            "provider-operation-reconciliation",
            "provider-operation-journal",
            "provider-operation-journal-state"
          ]
        }
      }
    },
    "clock": {
      "type": "object",
      "additionalProperties": false,
      "required": ["mode", "format", "pattern"],
      "properties": {
        "mode": { "const": "explicit-input-only" },
        "format": { "const": "RFC3339 UTC with millisecond precision" },
        "pattern": {
          "const": "^(?!0000)\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.\\d{3}Z$"
        }
      }
    },
    "sha256Root": {
      "type": "string",
      "pattern": "^sha256:[0-9a-f]{64}$"
    },
    "asciiToken": {
      "type": "string",
      "pattern": "^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$"
    },
    "event": {
      "type": "object",
      "additionalProperties": false,
      "required": [
        "schema",
        "eventId",
        "eventType",
        "occurredAt",
        "subjectRoot",
        "payload"
      ],
      "properties": {
        "schema": { "const": "buildchain-v4-event-envelope/v1" },
        "eventId": { "$ref": "#/$defs/sha256Root" },
        "eventType": { "$ref": "#/$defs/asciiToken" },
        "occurredAt": {
          "type": "string",
          "pattern": "^(?!0000)\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.\\d{3}Z$"
        },
        "subjectRoot": { "$ref": "#/$defs/sha256Root" },
        "payload": true
      }
    },
    "fault": {
      "type": "object",
      "additionalProperties": false,
      "required": ["schema", "code", "class", "path", "message", "retry"],
      "properties": {
        "schema": { "const": "buildchain-v4-contract-fault/v1" },
        "code": { "$ref": "#/$defs/asciiToken" },
        "class": {
          "enum": ["validation", "concurrency", "authority", "idempotence"]
        },
        "path": { "type": "string", "pattern": "^\\$" },
        "message": { "type": "string", "minLength": 1 },
        "retry": { "enum": ["stop", "reread", "redecide", "reselect"] }
      }
    },
    "receipt": {
      "type": "object",
      "additionalProperties": false,
      "required": [
        "schema",
        "receiptType",
        "recordedAt",
        "eventRoot",
        "priorStateRoot",
        "nextStateRoot",
        "outcome",
        "fault"
      ],
      "properties": {
        "schema": { "const": "buildchain-v4-receipt-envelope/v1" },
        "receiptType": { "$ref": "#/$defs/asciiToken" },
        "recordedAt": {
          "type": "string",
          "pattern": "^(?!0000)\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.\\d{3}Z$"
        },
        "eventRoot": { "$ref": "#/$defs/sha256Root" },
        "priorStateRoot": {
          "oneOf": [{ "$ref": "#/$defs/sha256Root" }, { "type": "null" }]
        },
        "nextStateRoot": {
          "oneOf": [{ "$ref": "#/$defs/sha256Root" }, { "type": "null" }]
        },
        "outcome": { "enum": ["accepted", "rejected", "noop"] },
        "fault": { "oneOf": [{ "$ref": "#/$defs/fault" }, { "type": "null" }] }
      }
    }
  }
}