{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://target-revenue.example/schemas/ledger_entry.schema.json",
  "title": "Target Ledger Entry",
  "description": "Stage 0 schema per specs/TechnicalSpecificationDocument.md §3.2 and specs/OpenQuestions-WorkingDefaults.md Q6/Q10/Q14. Append-only; corrections are new compensating entries, never mutation.",
  "type": "object",
  "required": [
    "id",
    "phase",
    "type",
    "amount",
    "currency",
    "recognized_at",
    "evidence_reference",
    "previous_entry_hash"
  ],
  "additionalProperties": false,
  "properties": {
    "id": {
      "type": "string",
      "pattern": "^trsl:entry:[a-zA-Z0-9]+$",
      "description": "Globally unique, monotonically orderable (ULID or equivalent)."
    },
    "phase": {
      "type": "string",
      "pattern": "^trsl:phase:[a-zA-Z0-9._-]+$"
    },
    "type": {
      "type": "string",
      "enum": [
        "development-credit",
        "remission-credit",
        "credit-reversal",
        "remission-correction",
        "administrative-correction-development",
        "administrative-correction-remission",
        "conversion-checkpoint"
      ],
      "description": "Closed set per TSD §3.2; not extensible per-project. administrative-correction-development/-remission split 2026-07-29 to make the corrected target side explicit in the type name (specs/TargetLedgerSpecification.md §2)."
    },
    "amount": {
      "type": "number",
      "description": "Positive for credits; the fold interprets sign by entry type (see fold.py). Reversal/correction entries reduce their target's cumulative total."
    },
    "currency": {
      "type": "string",
      "pattern": "^[A-Z]{3}$",
      "description": "Must match the Phase's initial_target.currency (working default Q6). No FX conversion in the pure fold."
    },
    "recognized_at": {
      "type": "string",
      "format": "date-time",
      "description": "Settlement time, not invoice time (Rule 4 / working default Q10 payment-settled)."
    },
    "extension": {
      "type": "object",
      "description": "Required for development-credit/remission-credit entries.",
      "required": ["id", "version"],
      "additionalProperties": false,
      "properties": {
        "id": {
          "type": "string",
          "pattern": "^trsl:(extension|policy):[a-zA-Z0-9._-]+$"
        },
        "version": { "type": "string" }
      }
    },
    "evidence_reference": {
      "type": "string",
      "description": "URI, may use the confidential: scheme. Tiering per working default Q10 (E0/E1/E2)."
    },
    "previous_entry_hash": {
      "type": "string",
      "pattern": "^[a-f0-9]{64}$|^GENESIS$",
      "description": "SHA-256 hex digest of the previous entry's canonical serialization for this Phase, or the literal GENESIS for the first entry."
    },
    "signature": {
      "type": "string",
      "description": "Ed25519 signature over the canonical serialization (working default Q14). Optional in Stage 0 fixtures, required for any public claim."
    },
    "reverses": {
      "type": "string",
      "pattern": "^trsl:entry:[a-zA-Z0-9]+$",
      "description": "Required on credit-reversal and remission-correction entries: the entry id being reversed or corrected."
    }
  },
  "allOf": [
    {
      "if": {
        "properties": { "type": { "const": "credit-reversal" } }
      },
      "then": { "required": ["reverses"] }
    },
    {
      "if": {
        "properties": { "type": { "const": "remission-correction" } }
      },
      "then": { "required": ["reverses"] }
    },
    {
      "if": {
        "properties": {
          "type": { "enum": ["development-credit", "remission-credit"] }
        }
      },
      "then": { "required": ["extension"] }
    }
  ]
}