def firstArgType(method):
    return method.signatures()[0][1][0].type


def WebIDLTest(parser, harness):
    parser.parse(
        """
      // Give our dictionary a required member so we don't need to
      // mess with optional and default values.
      dictionary Dict {
        required long member;
      };
      callback interface Foo {
      };
      interface Bar {
        // Bit of a pain to get things that have dictionary types
        void passDict(Dict arg);
        void passFoo(Foo arg);
        void passNullableUnion((object? or DOMString) arg);
        void passNullable(Foo? arg);
      };
    """
    )
    results = parser.finish()

    iface = results[2]
    harness.ok(iface.isInterface(), "Should have interface")
    dictMethod = iface.members[0]
    ifaceMethod = iface.members[1]
    nullableUnionMethod = iface.members[2]
    nullableIfaceMethod = iface.members[3]

    dictType = firstArgType(dictMethod)
    ifaceType = firstArgType(ifaceMethod)

    harness.ok(dictType.isDictionary(), "Should have dictionary type")
    harness.ok(ifaceType.isInterface(), "Should have interface type")
    harness.ok(ifaceType.isCallbackInterface(), "Should have callback interface type")

    harness.ok(
        not dictType.isDistinguishableFrom(ifaceType),
        "Dictionary not distinguishable from callback interface",
    )
    harness.ok(
        not ifaceType.isDistinguishableFrom(dictType),
        "Callback interface not distinguishable from dictionary",
    )

    nullableUnionType = firstArgType(nullableUnionMethod)
    nullableIfaceType = firstArgType(nullableIfaceMethod)

    harness.ok(nullableUnionType.isUnion(), "Should have union type")
    harness.ok(nullableIfaceType.isInterface(), "Should have interface type")
    harness.ok(nullableIfaceType.nullable(), "Should have nullable type")

    harness.ok(
        not nullableUnionType.isDistinguishableFrom(nullableIfaceType),
        "Nullable type not distinguishable from union with nullable " "member type",
    )
    harness.ok(
        not nullableIfaceType.isDistinguishableFrom(nullableUnionType),
        "Union with nullable member type not distinguishable from " "nullable type",
    )

    parser = parser.reset()
    parser.parse(
        """
      interface TestIface {
        void passKid(Kid arg);
        void passParent(Parent arg);
        void passGrandparent(Grandparent arg);
        void passUnrelated1(Unrelated1 arg);
        void passUnrelated2(Unrelated2 arg);
        void passArrayBuffer(ArrayBuffer arg);
        void passArrayBuffer(ArrayBufferView arg);
      };

      interface Kid : Parent {};
      interface Parent : Grandparent {};
      interface Grandparent {};
      interface Unrelated1 {};
      interface Unrelated2 {};
    """
    )
    results = parser.finish()

    iface = results[0]
    harness.ok(iface.isInterface(), "Should have interface")
    argTypes = [firstArgType(method) for method in iface.members]
    unrelatedTypes = [firstArgType(method) for method in iface.members[-3:]]

    for type1 in argTypes:
        for type2 in argTypes:
            distinguishable = type1 is not type2 and (
                type1 in unrelatedTypes or type2 in unrelatedTypes
            )

            harness.check(
                type1.isDistinguishableFrom(type2),
                distinguishable,
                "Type %s should %sbe distinguishable from type %s"
                % (type1, "" if distinguishable else "not ", type2),
            )
            harness.check(
                type2.isDistinguishableFrom(type1),
                distinguishable,
                "Type %s should %sbe distinguishable from type %s"
                % (type2, "" if distinguishable else "not ", type1),
            )

    parser = parser.reset()
    parser.parse(
        """
      interface Dummy {};
      interface TestIface {
        void method(long arg1, TestIface arg2);
        void method(long arg1, long arg2);
        void method(long arg1, Dummy arg2);
        void method(DOMString arg1, DOMString arg2, DOMString arg3);
      };
    """
    )
    results = parser.finish()
    harness.check(len(results[1].members), 1, "Should look like we have one method")
    harness.check(
        len(results[1].members[0].signatures()), 4, "Should have four signatures"
    )

    parser = parser.reset()
    threw = False
    try:
        parser.parse(
            """
          interface Dummy {};
          interface TestIface {
            void method(long arg1, TestIface arg2);
            void method(long arg1, long arg2);
            void method(any arg1,  Dummy arg2);
            void method(DOMString arg1, DOMString arg2, DOMString arg3);
          };
        """
        )
        results = parser.finish()
    except:
        threw = True

    harness.ok(
        threw,
        "Should throw when args before the distinguishing arg are not "
        "all the same type",
    )

    parser = parser.reset()
    threw = False
    try:
        parser.parse(
            """
          interface Dummy {};
          interface TestIface {
            void method(long arg1, TestIface arg2);
            void method(long arg1, long arg2);
            void method(any arg1,  DOMString arg2);
            void method(DOMString arg1, DOMString arg2, DOMString arg3);
          };
        """
        )
        results = parser.finish()
    except:
        threw = True

    harness.ok(threw, "Should throw when there is no distinguishing index")

    # Now let's test our whole distinguishability table
    argTypes = [
        "long",
        "short",
        "long?",
        "short?",
        "boolean",
        "boolean?",
        "DOMString",
        "ByteString",
        "UTF8String",
        "Enum",
        "Enum2",
        "Interface",
        "Interface?",
        "AncestorInterface",
        "UnrelatedInterface",
        "CallbackInterface",
        "CallbackInterface?",
        "CallbackInterface2",
        "object",
        "Callback",
        "Callback2",
        "Dict",
        "Dict2",
        "sequence<long>",
        "sequence<short>",
        "record<DOMString, object>",
        "record<USVString, Dict>",
        "record<ByteString, long>",
        "record<UTF8String, long>",
        "any",
        "Promise<any>",
        "Promise<any>?",
        "USVString",
        "JSString",
        "ArrayBuffer",
        "ArrayBufferView",
        "Uint8Array",
        "Uint16Array",
        "(long or Callback)",
        "(long or Dict)",
    ]

    # Try to categorize things a bit to keep list lengths down
    def allBut(list1, list2):
        return [
            a
            for a in list1
            if a not in list2
            and (a != "any" and a != "Promise<any>" and a != "Promise<any>?")
        ]

    unions = ["(long or Callback)", "(long or Dict)"]
    numerics = ["long", "short", "long?", "short?"]
    booleans = ["boolean", "boolean?"]
    primitives = numerics + booleans
    nonNumerics = allBut(argTypes, numerics + unions)
    nonBooleans = allBut(argTypes, booleans)
    strings = [
        "DOMString",
        "ByteString",
        "Enum",
        "Enum2",
        "USVString",
        "JSString",
        "UTF8String",
    ]
    nonStrings = allBut(argTypes, strings)
    nonObjects = primitives + strings
    objects = allBut(argTypes, nonObjects)
    bufferSourceTypes = ["ArrayBuffer", "ArrayBufferView", "Uint8Array", "Uint16Array"]
    interfaces = [
        "Interface",
        "Interface?",
        "AncestorInterface",
        "UnrelatedInterface",
    ] + bufferSourceTypes
    nullables = [
        "long?",
        "short?",
        "boolean?",
        "Interface?",
        "CallbackInterface?",
        "Dict",
        "Dict2",
        "Date?",
        "any",
        "Promise<any>?",
    ] + allBut(unions, ["(long or Callback)"])
    sequences = ["sequence<long>", "sequence<short>"]
    nonUserObjects = nonObjects + interfaces + sequences
    otherObjects = allBut(argTypes, nonUserObjects + ["object"])
    notRelatedInterfaces = (
        nonObjects
        + ["UnrelatedInterface"]
        + otherObjects
        + sequences
        + bufferSourceTypes
    )
    records = [
        "record<DOMString, object>",
        "record<USVString, Dict>",
        "record<ByteString, long>",
        "record<UTF8String, long>",
    ]  # JSString not supported in records

    # Build a representation of the distinguishability table as a dict
    # of dicts, holding True values where needed, holes elsewhere.
    data = dict()
    for type in argTypes:
        data[type] = dict()

    def setDistinguishable(type, types):
        for other in types:
            data[type][other] = True

    setDistinguishable("long", nonNumerics)
    setDistinguishable("short", nonNumerics)
    setDistinguishable("long?", allBut(nonNumerics, nullables))
    setDistinguishable("short?", allBut(nonNumerics, nullables))
    setDistinguishable("boolean", nonBooleans)
    setDistinguishable("boolean?", allBut(nonBooleans, nullables))
    setDistinguishable("DOMString", nonStrings)
    setDistinguishable("ByteString", nonStrings)
    setDistinguishable("UTF8String", nonStrings)
    setDistinguishable("USVString", nonStrings)
    setDistinguishable("JSString", nonStrings)
    setDistinguishable("Enum", nonStrings)
    setDistinguishable("Enum2", nonStrings)
    setDistinguishable("Interface", notRelatedInterfaces)
    setDistinguishable("Interface?", allBut(notRelatedInterfaces, nullables))
    setDistinguishable("AncestorInterface", notRelatedInterfaces)
    setDistinguishable(
        "UnrelatedInterface", allBut(argTypes, ["object", "UnrelatedInterface"])
    )
    setDistinguishable("CallbackInterface", nonUserObjects)
    setDistinguishable("CallbackInterface?", allBut(nonUserObjects, nullables))
    setDistinguishable("CallbackInterface2", nonUserObjects)
    setDistinguishable("object", nonObjects)
    setDistinguishable("Callback", nonUserObjects)
    setDistinguishable("Callback2", nonUserObjects)
    setDistinguishable("Dict", allBut(nonUserObjects, nullables))
    setDistinguishable("Dict2", allBut(nonUserObjects, nullables))
    setDistinguishable("sequence<long>", allBut(argTypes, sequences + ["object"]))
    setDistinguishable("sequence<short>", allBut(argTypes, sequences + ["object"]))
    setDistinguishable("record<DOMString, object>", nonUserObjects)
    setDistinguishable("record<USVString, Dict>", nonUserObjects)
    # JSString not supported in records
    setDistinguishable("record<ByteString, long>", nonUserObjects)
    setDistinguishable("record<UTF8String, long>", nonUserObjects)
    setDistinguishable("any", [])
    setDistinguishable("Promise<any>", [])
    setDistinguishable("Promise<any>?", [])
    setDistinguishable("ArrayBuffer", allBut(argTypes, ["ArrayBuffer", "object"]))
    setDistinguishable(
        "ArrayBufferView",
        allBut(argTypes, ["ArrayBufferView", "Uint8Array", "Uint16Array", "object"]),
    )
    setDistinguishable(
        "Uint8Array", allBut(argTypes, ["ArrayBufferView", "Uint8Array", "object"])
    )
    setDistinguishable(
        "Uint16Array", allBut(argTypes, ["ArrayBufferView", "Uint16Array", "object"])
    )
    setDistinguishable("(long or Callback)", allBut(nonUserObjects, numerics))
    setDistinguishable("(long or Dict)", allBut(nonUserObjects, numerics + nullables))

    def areDistinguishable(type1, type2):
        return data[type1].get(type2, False)

    def checkDistinguishability(parser, type1, type2):
        idlTemplate = """
          enum Enum { "a", "b" };
          enum Enum2 { "c", "d" };
          interface Interface : AncestorInterface {};
          interface AncestorInterface {};
          interface UnrelatedInterface {};
          callback interface CallbackInterface {};
          callback interface CallbackInterface2 {};
          callback Callback = any();
          callback Callback2 = long(short arg);
          // Give our dictionaries required members so we don't need to
          // mess with optional and default values.
          dictionary Dict { required long member; };
          dictionary Dict2 { required long member; };
          interface TestInterface {%s
          };
        """
        methodTemplate = """
            void myMethod(%s arg);"""
        methods = (methodTemplate % type1) + (methodTemplate % type2)
        idl = idlTemplate % methods
        parser = parser.reset()
        threw = False
        try:
            parser.parse(idl)
            results = parser.finish()
        except:
            threw = True

        if areDistinguishable(type1, type2):
            harness.ok(
                not threw,
                "Should not throw for '%s' and '%s' because they are distinguishable"
                % (type1, type2),
            )
        else:
            harness.ok(
                threw,
                "Should throw for '%s' and '%s' because they are not distinguishable"
                % (type1, type2),
            )

    # Enumerate over everything in both orders, since order matters in
    # terms of our implementation of distinguishability checks
    for type1 in argTypes:
        for type2 in argTypes:
            checkDistinguishability(parser, type1, type2)