package com.google.gson;

import static com.google.common.truth.Truth.assertThat;
import static org.junit.Assert.fail;

import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import java.io.IOException;
import java.io.StringReader;
import org.junit.Test;

public class TypeAdapterTest {
  @Test
  public void testNullSafe() throws IOException {
    TypeAdapter<String> adapter = new TypeAdapter<String>() {
      @Override public void write(JsonWriter out, String value) {
        throw new AssertionError("unexpected call");
      }

      @Override public String read(JsonReader in) {
        throw new AssertionError("unexpected call");
      }
    }.nullSafe();

    assertThat(adapter.toJson(null)).isEqualTo("null");
    assertThat(adapter.fromJson("null")).isNull();
  }

  /**
   * Tests behavior when {@link TypeAdapter#write(JsonWriter, Object)} manually throws
   * {@link IOException} which is not caused by writer usage.
   */
  @Test
  public void testToJson_ThrowingIOException() {
    final IOException exception = new IOException("test");
    TypeAdapter<Integer> adapter = new TypeAdapter<Integer>() {
      @Override public void write(JsonWriter out, Integer value) throws IOException {
        throw exception;
      }

      @Override public Integer read(JsonReader in) {
        throw new AssertionError("not needed by this test");
      }
    };

    try {
      adapter.toJson(1);
      fail();
    } catch (JsonIOException e) {
      assertThat(e.getCause()).isEqualTo(exception);
    }

    try {
      adapter.toJsonTree(1);
      fail();
    } catch (JsonIOException e) {
      assertThat(e.getCause()).isEqualTo(exception);
    }
  }

  private static final TypeAdapter<String> adapter = new TypeAdapter<String>() {
    @Override public void write(JsonWriter out, String value) throws IOException {
      out.value(value);
    }

    @Override public String read(JsonReader in) throws IOException {
      return in.nextString();
    }
  };

  // Note: This test just verifies the current behavior; it is a bit questionable
  // whether that behavior is actually desired
  @Test
  public void testFromJson_Reader_TrailingData() throws IOException {
    assertThat(adapter.fromJson(new StringReader("\"a\"1"))).isEqualTo("a");
  }

  // Note: This test just verifies the current behavior; it is a bit questionable
  // whether that behavior is actually desired
  @Test
  public void testFromJson_String_TrailingData() throws IOException {
    assertThat(adapter.fromJson("\"a\"1")).isEqualTo("a");
  }
}