import crypto from "node:crypto";

export const COMMAND_BUDGET = Object.freeze({
  maxCommands: 48,
  maxReadCommands: 16,
});

/** Return the explicit source/RNA record IDs selected for one module batch. */
export function selectedRecordIds(module = {}) {
  const values = module.selectedRecordIds ?? module.coverageBindings ?? module.sourceUnits ?? [];
  return [...new Set((Array.isArray(values) ? values : []).filter((value) => typeof value === "string" && value.length > 0))];
}

/** A batch identity is stable across retries and changes when selection changes. */
export function batchIdFor(task, module = {}) {
  const ids = selectedRecordIds(module);
  const moduleId = module.moduleId ?? "UNKNOWN_MODULE";
  const digest = crypto.createHash("sha256").update(JSON.stringify(ids)).digest("hex").slice(0, 16);
  return module.batchId ?? `${task}:${moduleId}:${digest}`;
}

export function batchContract(task, module = {}) {
  const selected = selectedRecordIds(module);
  return {
    batchId: batchIdFor(task, module),
    selectedRecordIds: selected,
    selectedCount: selected.length,
  };
}

export function completedBatch(manifest, task, module = {}) {
  const expected = batchContract(task, module);
  return manifest?.status === "done"
    && manifest.batchId === expected.batchId
    && JSON.stringify(manifest.selectedRecordIds ?? []) === JSON.stringify(expected.selectedRecordIds);
}

export function commandBudget(commands = []) {
  const values = Array.isArray(commands) ? commands.filter((value) => typeof value === "string") : [];
  const readCommands = values.filter((value) => /\b(?:cat|head|tail|sed|rg|find|ls|stat)\b/u.test(value));
  return {
    maxCommands: COMMAND_BUDGET.maxCommands,
    maxReadCommands: COMMAND_BUDGET.maxReadCommands,
    commandCount: values.length,
    readCommandCount: readCommands.length,
    withinBudget: values.length <= COMMAND_BUDGET.maxCommands && readCommands.length <= COMMAND_BUDGET.maxReadCommands,
  };
}

export function adaptiveBatchSize({ currentSize, history = [], minSize = 1, maxSize = currentSize, remaining = Number.MAX_SAFE_INTEGER }) {
  const size = Math.max(minSize, Math.min(maxSize, currentSize));
  const recent = history.filter((item) => Number.isFinite(item.durationMs) && Number.isFinite(item.commands)).slice(-3);
  let next = size;
  if (recent.some((item) => item.timeout === true || item.durationMs > 900_000 || item.commands > COMMAND_BUDGET.maxCommands)) {
    next = Math.floor(size / 2);
  } else if (recent.length > 0 && recent.every((item) => item.durationMs < 300_000 && item.commands < 24 && item.focusedGateFailure !== true)) {
    next = size + 4;
  }
  return Math.max(minSize, Math.min(maxSize, remaining, next));
}