import type { XOTemplate, XOTemplateTransactionOutput } from '@xo-cash/types';
import type { Invitation } from '../services/invitation.js';

export interface SelectableUtxoLike {
  outpointTransactionHash: string;
  outpointIndex: number;
  valueSatoshis: bigint;
  lockingBytecode?: string;
  selected: boolean;
}

export const hasMissingRequirements = (missingRequirements: {
  variables?: string[];
  inputs?: string[];
  outputs?: string[];
  roles?: Record<string, unknown>;
}): boolean => {
  return (
    (missingRequirements.variables?.length ?? 0) > 0
    || (missingRequirements.inputs?.length ?? 0) > 0
    || (missingRequirements.outputs?.length ?? 0) > 0
    || (missingRequirements.roles !== undefined && Object.keys(missingRequirements.roles).length > 0)
  );
};

export const isInvitationRequirementsComplete = async (invitation: Invitation): Promise<boolean> => {
  const missingRequirements = await invitation.getMissingRequirements();
  return !hasMissingRequirements(missingRequirements);
};

export const resolveActionRoles = (
  template: XOTemplate | undefined,
  actionIdentifier: string | undefined,
  rolesFromNavigation?: string[],
): string[] => {
  if (rolesFromNavigation && rolesFromNavigation.length > 0) {
    return [ ...new Set(rolesFromNavigation) ];
  }

  if (!template || !actionIdentifier) return [];
  const starts = template.start ?? [];
  const roleIds = starts
    .filter((entry) => entry.action === actionIdentifier)
    .map((entry) => entry.role);

  return [ ...new Set(roleIds) ];
};

export const roleRequiresInputs = (
  template: XOTemplate | undefined,
  actionIdentifier: string | undefined,
  roleIdentifier: string | undefined,
): boolean => {
  if (!template || !actionIdentifier || !roleIdentifier) return false;
  const action = template.actions?.[actionIdentifier];
  if (!action) return false;

  const actionRole = action.roles?.[roleIdentifier];
  const roleSlotsMin = actionRole?.requirements?.slots?.min ?? 0;
  if (roleSlotsMin > 0) return true;

  // Some templates specify slot/input requirements at action.requirements.roles
  // instead of role.requirements. Respect those as well.
  const roleRequirement = action.requirements?.roles?.find((requirement) => requirement.role === roleIdentifier);
  const actionLevelSlotsMin = roleRequirement?.slots?.min ?? 0;
  if (actionLevelSlotsMin > 0) return true;

  const transactionIdentifier = action.transaction;
  const transaction = transactionIdentifier ? template.transactions?.[transactionIdentifier] : undefined;
  const roleInputs = transaction?.roles?.[roleIdentifier]?.inputs;

  return (roleInputs?.length ?? 0) > 0;
};

export const getTransactionOutputIdentifier = (output: XOTemplateTransactionOutput): string | undefined => {
  if (typeof output === 'string') return output;
  if (output && typeof output === 'object' && 'output' in output && typeof output.output === 'string') {
    return output.output;
  }
  return undefined;
};

export const normalizeLockingBytecodeHex = (value: string): string => value.trim().replace(/^0x/i, '');

export const resolveProvidedLockingBytecodeHex = (
  template: XOTemplate,
  outputIdentifier: string,
  variableValues: Record<string, string>,
): string | undefined => {
  const outputDefinition = template.outputs?.[outputIdentifier];
  if (!outputDefinition || typeof outputDefinition.lockscript !== 'string') return undefined;

  const lockingScriptDefinition = (template.lockingScripts as Record<string, unknown> | undefined)?.[outputDefinition.lockscript] as
    | { lockingScript?: string }
    | undefined;
  const scriptIdentifier = lockingScriptDefinition?.lockingScript;
  if (!scriptIdentifier) return undefined;

  const scriptExpression = (template.scripts as Record<string, unknown> | undefined)?.[scriptIdentifier];
  if (typeof scriptExpression !== 'string') return undefined;

  const directVariableMatch = scriptExpression.match(/^<\s*([A-Za-z0-9_]+)\s*>$/);
  if (!directVariableMatch) return undefined;

  const variableIdentifier = directVariableMatch[1];
  if (!variableIdentifier) return undefined;

  const providedValue = variableValues[variableIdentifier];
  if (!providedValue) return undefined;

  return normalizeLockingBytecodeHex(providedValue);
};

export const mapUnspentOutputsToSelectable = (unspentOutputs: any[]): SelectableUtxoLike[] => {
  return unspentOutputs.map((utxo: any) => ({
    outpointTransactionHash: utxo.outpointTransactionHash,
    outpointIndex: utxo.outpointIndex,
    valueSatoshis: BigInt(utxo.valueSatoshis),
    lockingBytecode: utxo.lockingBytecode
      ? typeof utxo.lockingBytecode === 'string'
        ? utxo.lockingBytecode
        : Buffer.from(utxo.lockingBytecode).toString('hex')
      : undefined,
    selected: false,
  }));
};

export const autoSelectGreedyUtxos = (
  utxos: SelectableUtxoLike[],
  requiredWithFee: bigint,
): SelectableUtxoLike[] => {
  let accumulated = 0n;
  const seenLockingBytecodes = new Set<string>();

  for (const utxo of utxos) {
    if (utxo.lockingBytecode && seenLockingBytecodes.has(utxo.lockingBytecode)) {
      continue;
    }
    if (utxo.lockingBytecode) {
      seenLockingBytecodes.add(utxo.lockingBytecode);
    }

    utxo.selected = true;
    accumulated += utxo.valueSatoshis;

    if (accumulated >= requiredWithFee) {
      break;
    }
  }

  return utxos;
};