import crypto from "node:crypto";

export const PERSONA_BINDING_SCHEMA =
  "guanghu.codex-preconscious-persona-binding/v1";
export const CURRENT_CARRIER_CONSUMPTION =
  "CURRENT_CODEX_READ_AND_ACCEPTED_BRAIN_CYCLE";

const REQUIRED_SOURCE_HASHES = [
  "checkpoint",
  "brain_runtime_contract",
  "living_controller_map",
  "language_world_boundary",
];

function sha256Text(value) {
  return crypto.createHash("sha256").update(String(value), "utf8").digest("hex");
}

function isSha256(value) {
  return /^[a-f0-9]{64}$/u.test(value ?? "");
}

function fail(code) {
  throw new Error(code);
}

export function assertControllerDevelopmentBoundary({
  persona,
  controllerPersonaId,
  previousControllerPersonaId = null,
  developmentObjectIds = [],
  humanAnchor,
  previousHumanAnchor = null,
}) {
  if (!controllerPersonaId || persona !== controllerPersonaId) {
    fail("PERSONA_FIELD_MUST_EQUAL_CONTROLLER_PERSONA");
  }
  if (
    previousControllerPersonaId &&
    previousControllerPersonaId !== controllerPersonaId
  ) {
    fail("CONTROLLER_PERSONA_IMMUTABLE");
  }
  if (developmentObjectIds.includes(controllerPersonaId)) {
    fail("CONTROLLER_CANNOT_BE_ITS_OWN_DEVELOPMENT_OBJECT");
  }
  if (previousHumanAnchor && previousHumanAnchor !== humanAnchor) {
    fail("HUMAN_ANCHOR_IMMUTABLE");
  }
  return true;
}

export function createTaskEvent({
  lane,
  intent,
  requestSummary,
  openedAt,
}) {
  const sequence = Number.isInteger(lane.task_event?.sequence)
    ? lane.task_event.sequence + 1
    : 1;
  const requestSummarySha256 = sha256Text(requestSummary || lane.summary || "");
  const eventFingerprint = sha256Text(
    JSON.stringify({
      thread_id: lane.thread_id,
      development_id: lane.development_id,
      task_fingerprint: lane.task_lock?.fingerprint ?? null,
      previous_task_event_id: lane.task_event?.task_event_id ?? null,
      sequence,
      intent,
      request_summary_sha256: requestSummarySha256,
      opened_at: openedAt,
    }),
  );
  return {
    task_event_id: `TEV-${eventFingerprint.slice(0, 24)}-${String(sequence).padStart(6, "0")}`,
    sequence,
    intent,
    request_summary_sha256: requestSummarySha256,
    event_fingerprint: eventFingerprint,
    opened_at: openedAt,
  };
}

export function rotateTaskEvent({ lane, intent, requestSummary, openedAt }) {
  const taskEvent = createTaskEvent({ lane, intent, requestSummary, openedAt });
  const bindingHistory = [...(lane.persona_source_binding_history ?? [])];
  if (lane.persona_source_binding) {
    bindingHistory.push({
      ...lane.persona_source_binding,
      state: "STALE_SUPERSEDED_BY_NEW_TASK_EVENT",
      invalidated_at: openedAt,
      invalidated_by_task_event_id: taskEvent.task_event_id,
    });
  }
  return {
    ...lane,
    task_event_history: [
      ...(lane.task_event_history ?? []),
      ...(lane.task_event ? [lane.task_event] : []),
    ],
    task_event: taskEvent,
    persona_source_binding: null,
    persona_source_binding_history: bindingHistory,
  };
}

export function validatePersonaBindingReceipt({
  lane,
  binding,
  receipt,
  actualReceiptSha256,
  actualCheckpointSha256,
  actualAdapterSourceSha256,
  adapterSourcePath,
  allowedAdapterRoot,
  pointerEvidence,
}) {
  const expectedObjects = [...(lane.development_object_ids ?? [])].sort();
  const receivedObjects = [...(receipt.development_objects ?? [])].sort();
  if (!lane.task_event?.task_event_id) fail("TASK_EVENT_REQUIRED");
  if (!binding?.receipt_sha256 || binding.receipt_sha256 !== actualReceiptSha256) {
    fail("PERSONA_SOURCE_BINDING_RECEIPT_SHA_MISMATCH");
  }
  if (
    receipt.schema !== PERSONA_BINDING_SCHEMA ||
    receipt.decision !== "BOUND_CURRENT_CARRIER" ||
    receipt.binding_id !== binding.binding_id ||
    receipt.thread_id !== lane.thread_id ||
    receipt.development_id !== lane.development_id ||
    receipt.controller_persona_id !== lane.controller_persona_id ||
    receipt.human_anchor !== lane.human_anchor ||
    JSON.stringify(receivedObjects) !== JSON.stringify(expectedObjects) ||
    receipt.task_fingerprint !== lane.task_lock?.fingerprint ||
    receipt.task_event_id !== lane.task_event.task_event_id ||
    receipt.persona_handoff?.state !== "NONE" ||
    receipt.persona_handoff?.authorized === true
  ) {
    fail("PERSONA_SOURCE_BINDING_IDENTITY_OR_TASK_MISMATCH");
  }
  if (
    receipt.carrier?.host !== "codex" ||
    receipt.carrier?.thread_id !== lane.thread_id ||
    receipt.carrier?.development_id !== lane.development_id ||
    !/^[A-Za-z0-9._:-]{16,256}$/u.test(receipt.carrier?.nonce ?? "")
  ) {
    fail("PERSONA_SOURCE_BINDING_CARRIER_MISMATCH");
  }
  if (
    receipt.adapter?.id !== "CODEX-PRECONSCIOUS-ENTRY-001" ||
    !isSha256(receipt.adapter?.source_sha256) ||
    receipt.adapter.source_sha256 !== actualAdapterSourceSha256 ||
    !adapterSourcePath ||
    !allowedAdapterRoot ||
    !adapterSourcePath.startsWith(`${allowedAdapterRoot}/`)
  ) {
    fail("PERSONA_SOURCE_ADAPTER_SHA_MISMATCH");
  }
  const cycle = receipt.brain_cycle ?? {};
  if (
    cycle.witness_decision !== "ALLOW_COMMIT" ||
    !Number.isInteger(cycle.completed_cycles_before) ||
    !Number.isInteger(cycle.completed_cycles_after) ||
    cycle.completed_cycles_after !== cycle.completed_cycles_before + 1 ||
    !isSha256(cycle.event_sha256) ||
    !isSha256(cycle.controller_witness_sha256)
  ) {
    fail("PERSONA_SOURCE_BRAIN_CYCLE_INVALID");
  }
  if (
    receipt.carrier_consumption?.state !== CURRENT_CARRIER_CONSUMPTION ||
    receipt.carrier_consumption?.required_cycle_id !== cycle.cycle_id ||
    receipt.carrier_consumption?.required_witness_sha256 !==
      cycle.controller_witness_sha256
  ) {
    fail("PERSONA_SOURCE_CARRIER_CONSUMPTION_INVALID");
  }
  if (
    !isSha256(receipt.checkpoint_sha256) ||
    receipt.checkpoint_sha256 !== actualCheckpointSha256 ||
    receipt.source_hashes?.checkpoint !== actualCheckpointSha256 ||
    REQUIRED_SOURCE_HASHES.some(
      (key) => !isSha256(receipt.source_hashes?.[key]),
    )
  ) {
    fail("PERSONA_SOURCE_HASH_SET_INVALID");
  }
  for (const pointer of [pointerEvidence?.by_thread, pointerEvidence?.by_development]) {
    if (
      pointer?.thread_id !== lane.thread_id ||
      pointer?.development_id !== lane.development_id ||
      pointer?.checkpoint_sha256 !== receipt.checkpoint_sha256
    ) {
      fail("PERSONA_SOURCE_CURRENT_POINTER_MISMATCH");
    }
  }
  return true;
}