/*

 * @test /nodynamiccopyright/

 * @bug 8206986

 * @summary Check expression switch works.

 * @compile/fail/ref=ExpressionSwitch-old.out -source 9 -Xlint:-options -XDrawDiagnostics ExpressionSwitch.java

 * @run main/othervm --enable-preview ExpressionSwitch

 */

import java.util.Objects;

import java.util.function.Supplier;

public class ExpressionSwitch {

    public static void main(String... args) {

        new ExpressionSwitch().run();

    }

    private void run() {

        check(T.A, "A");

        check(T.B, "B");

        check(T.C, "other");

        assertEquals(exhaustive1(T.C), "C");

        assertEquals(scopesIsolated(T.B), "B");

        assertEquals(lambdas1(T.B).get(), "B");

        assertEquals(lambdas2(T.B).get(), "B");

        assertEquals(convert1("A"), 0);

        assertEquals(convert1("B"), 0);

        assertEquals(convert1("C"), 1);

        assertEquals(convert1(""), -1);

        assertEquals(convert2("A"), 0);

        assertEquals(convert2("B"), 0);

        assertEquals(convert2("C"), 1);

        assertEquals(convert2(""), -1);

        localClass(T.A);

    }

    private String print(T t) {

        return switch (t) {

            case A -> "A";

            case B -> { break "B"; }

            default -> { break "other"; }

        };

    }

    private String exhaustive1(T t) {

        return switch (t) {

            case A -> "A";

            case B -> { break "B"; }

            case C -> "C";

            case D -> "D";

        };

    }

    private String exhaustive2(T t) {

        return switch (t) {

            case A -> "A";

            case B -> "B";

            case C -> "C";

            case D -> "D";

        };

    }

    private String scopesIsolated(T t) {

        return switch (t) {

            case A -> { String res = "A"; break res;}

            case B -> { String res = "B"; break res;}

            default -> { String res = "default"; break res;}

        };

    }

    private Supplier<String> lambdas1(T t) {

        return switch (t) {

            case A -> () -> "A";

            case B -> { break () -> "B"; }

            default -> () -> "default";

        };

    }

    private Supplier<String> lambdas2(T t) {

        return switch (t) {

            case A: break () -> "A";

            case B: { break () -> "B"; }

            default: break () -> "default";

        };

    }

    private int convert1(String s) {

        return switch (s) {

            case "A", "B" -> 0;

            case "C" -> { break 1; }

            default -> -1;

        };

    }

    private int convert2(String s) {

        return switch (s) {

            case "A", "B": break 0;

            case "C": break 1;

            default: break -1;

        };

    }

    private void localClass(T t) {

        String good = "good";

        class L {

            public String c() {

                STOP: switch (t) {

                    default: break STOP;

                }

                return switch (t) {

                    default: break good;

                };

            }

        }

        String result = new L().c();

        if (!Objects.equals(result, good)) {

            throw new AssertionError("Unexpected result: " + result);

        }

    }

    private void check(T t, String expected) {

        String result = print(t);

        assertEquals(result, expected);

    }

    private void assertEquals(Object result, Object expected) {

        if (!Objects.equals(result, expected)) {

            throw new AssertionError("Unexpected result: " + result);

        }

    }

    enum T {

        A, B, C, D;

    }

    void t() {

        Runnable r = () -> {};

        r.run();

    }

}