/**
 * camt.025 (Receipt) and camt.054 (Bank-to-Customer Debit/Credit
 * Notification) ingestion.
 *
 * Arch §4.3 + §9.2. These are the inbound settlement-confirmation
 * messages that allow the VALIDATING phase to mark the payment leg
 * as SETTLED. The parser is intentionally minimal — just enough to
 * extract the fields the VALIDATING reconciliation compares against.
 */

export interface Camt025Receipt {
  type: "camt.025";
  messageId: string;
  originalMessageId: string;
  status: "ACCP" | "ACSC" | "ACSP" | "RJCT" | "PDNG" | string;
  reasonCode?: string;
  dateTime?: string;
}

export interface Camt054Notification {
  type: "camt.054";
  messageId: string;
  creditDebitIndicator: "CRDT" | "DBIT";
  amount: number;
  currency: string;
  endToEndId?: string;
  valueDate?: string;
  bookingDate?: string;
}

export type CamtMessage = Camt025Receipt | Camt054Notification;

function extractTag(xml: string, tag: string): string | undefined {
  const re = new RegExp(`<${tag}[^>]*>([^<]*)</${tag}>`);
  const m = re.exec(xml);
  return m ? m[1].trim() : undefined;
}

function extractAmountWithCcy(xml: string, tag: string): { amount: number; currency: string } | undefined {
  const re = new RegExp(`<${tag}[^>]*Ccy="([A-Z]{3})"[^>]*>([^<]*)</${tag}>`);
  const m = re.exec(xml);
  return m ? { currency: m[1], amount: Number(m[2]) } : undefined;
}

/**
 * Parse a camt.025 Receipt. Only fields used by the orchestrator are
 * surfaced; everything else stays in the raw XML.
 */
export function parseCamt025(xml: string): Camt025Receipt {
  if (!/xmlns="urn:iso:std:iso:20022:tech:xsd:camt\.025/.test(xml)) {
    throw new Error("camt.025: xmlns marker not found");
  }
  const messageId = extractTag(xml, "MsgId") ?? "";
  const originalMessageId = extractTag(xml, "OrgnlMsgId") ?? "";
  const status = (extractTag(xml, "Cd") ?? extractTag(xml, "ConfSts") ?? "PDNG") as Camt025Receipt["status"];
  const reasonCode = extractTag(xml, "PrtryStsRsn") ?? extractTag(xml, "Rsn");
  const dateTime = extractTag(xml, "CreDtTm");
  if (!messageId) throw new Error("camt.025: missing MsgId");
  if (!originalMessageId) throw new Error("camt.025: missing OrgnlMsgId");
  return { type: "camt.025", messageId, originalMessageId, status, reasonCode, dateTime };
}

/**
 * Parse a camt.054 Credit/Debit Notification.
 */
export function parseCamt054(xml: string): Camt054Notification {
  if (!/xmlns="urn:iso:std:iso:20022:tech:xsd:camt\.054/.test(xml)) {
    throw new Error("camt.054: xmlns marker not found");
  }
  const messageId = extractTag(xml, "MsgId") ?? "";
  const cdtDbt = (extractTag(xml, "CdtDbtInd") ?? "CRDT") as "CRDT" | "DBIT";
  const amt = extractAmountWithCcy(xml, "Amt");
  if (!amt) throw new Error("camt.054: missing Amt");
  const endToEndId = extractTag(xml, "EndToEndId");
  const valueDate = extractTag(xml, "ValDt");
  const bookingDate = extractTag(xml, "BookgDt");
  if (!messageId) throw new Error("camt.054: missing MsgId");
  return {
    type: "camt.054",
    messageId,
    creditDebitIndicator: cdtDbt,
    amount: amt.amount,
    currency: amt.currency,
    endToEndId,
    valueDate,
    bookingDate,
  };
}

/**
 * Dispatch on the xmlns marker. Throws if the document is neither
 * camt.025 nor camt.054.
 */
export function parseCamt(xml: string): CamtMessage {
  if (/xmlns="urn:iso:std:iso:20022:tech:xsd:camt\.025/.test(xml)) return parseCamt025(xml);
  if (/xmlns="urn:iso:std:iso:20022:tech:xsd:camt\.054/.test(xml)) return parseCamt054(xml);
  throw new Error("camt: unsupported or missing xmlns (expected camt.025 or camt.054)");
}

/**
 * Reconcile a camt.054 credit notification against an expected
 * (amount, currency, endToEndId). Returns the list of mismatches so
 * VALIDATING can feed them into Data.valueMismatch().
 */
export interface ReconcileExpected {
  amount: number;
  currency: string;
  endToEndId?: string;
}

export function reconcileCamt054(
  msg: Camt054Notification,
  expected: ReconcileExpected,
): Array<{ field: string; expected: unknown; actual: unknown }> {
  const mismatches: Array<{ field: string; expected: unknown; actual: unknown }> = [];
  if (msg.creditDebitIndicator !== "CRDT") {
    mismatches.push({ field: "creditDebitIndicator", expected: "CRDT", actual: msg.creditDebitIndicator });
  }
  if (msg.currency !== expected.currency) {
    mismatches.push({ field: "currency", expected: expected.currency, actual: msg.currency });
  }
  if (msg.amount !== expected.amount) {
    mismatches.push({ field: "amount", expected: expected.amount, actual: msg.amount });
  }
  if (expected.endToEndId && msg.endToEndId && msg.endToEndId !== expected.endToEndId) {
    mismatches.push({ field: "endToEndId", expected: expected.endToEndId, actual: msg.endToEndId });
  }
  return mismatches;
}