import { Kind } from "../language/kinds.mjs";
import { visit } from "../language/visitor.mjs";
/**
 * separateOperations accepts a single AST document which may contain many
 * operations and fragments and returns a collection of AST documents each of
 * which contains a single operation as well the fragment definitions it
 * refers to.
 */

export function separateOperations(documentAST) {
  var operations = [];
  var depGraph = Object.create(null); // Populate metadata and build a dependency graph.

  for (var _i2 = 0, _documentAST$definiti2 = documentAST.definitions; _i2 < _documentAST$definiti2.length; _i2++) {
    var definitionNode = _documentAST$definiti2[_i2];

    switch (definitionNode.kind) {
      case Kind.OPERATION_DEFINITION:
        operations.push(definitionNode);
        break;

      case Kind.FRAGMENT_DEFINITION:
        depGraph[definitionNode.name.value] = collectDependencies(definitionNode.selectionSet);
        break;
    }
  } // For each operation, produce a new synthesized AST which includes only what
  // is necessary for completing that operation.


  var separatedDocumentASTs = Object.create(null);

  var _loop = function _loop(_i4) {
    var operation = operations[_i4];
    var dependencies = new Set();

    for (var _i6 = 0, _collectDependencies2 = collectDependencies(operation.selectionSet); _i6 < _collectDependencies2.length; _i6++) {
      var fragmentName = _collectDependencies2[_i6];
      collectTransitiveDependencies(dependencies, depGraph, fragmentName);
    } // Provides the empty string for anonymous operations.


    var operationName = operation.name ? operation.name.value : ''; // The list of definition nodes to be included for this operation, sorted
    // to retain the same order as the original document.

    separatedDocumentASTs[operationName] = {
      kind: Kind.DOCUMENT,
      definitions: documentAST.definitions.filter(function (node) {
        return node === operation || node.kind === Kind.FRAGMENT_DEFINITION && dependencies.has(node.name.value);
      })
    };
  };

  for (var _i4 = 0; _i4 < operations.length; _i4++) {
    _loop(_i4);
  }

  return separatedDocumentASTs;
}

// From a dependency graph, collects a list of transitive dependencies by
// recursing through a dependency graph.
function collectTransitiveDependencies(collected, depGraph, fromName) {
  if (!collected.has(fromName)) {
    collected.add(fromName);
    var immediateDeps = depGraph[fromName];

    if (immediateDeps !== undefined) {
      for (var _i8 = 0; _i8 < immediateDeps.length; _i8++) {
        var toName = immediateDeps[_i8];
        collectTransitiveDependencies(collected, depGraph, toName);
      }
    }
  }
}

function collectDependencies(selectionSet) {
  var dependencies = [];
  visit(selectionSet, {
    FragmentSpread: function FragmentSpread(node) {
      dependencies.push(node.name.value);
    }
  });
  return dependencies;
}