Merge pull request #38 from mdaubie/feat/35/shift-subtitles-tool

feat: add the shift subtitles tool

src/main/java/io/github/mdaubie/subtitlesparser/toolbox/ShiftSubtitles.java

@@ -0,0 +1,26 @@
+package io.github.mdaubie.subtitlesparser.toolbox;
+
+import io.github.mdaubie.subtitlesparser.model.Subtitle;
+import io.github.mdaubie.subtitlesparser.model.SubtitlesFile;
+
+import java.security.InvalidParameterException;
+
+public class ShiftSubtitles {
+    /**
+     * Shifts the subtitle timestamps by a given offset
+     *
+     * @param sf           The SubtitleFile object for which to shift the subtitles
+     * @param millisOffset The offset, from which the subtitles are shifted, can be negative
+     * @throws InvalidParameterException if the offset provided is negative and larger than the first timestamp (resulting in a negative timestamp)
+     */
+    static void shift(SubtitlesFile sf, long millisOffset) {
+        long nanosOffset = millisOffset * 1000000;
+        if (millisOffset < 0 && sf.getSubtitles().get(0).start.toNanoOfDay() + nanosOffset < 0)
+            throw new InvalidParameterException("Too large negative offset provided");
+        for (int i = 0; i < sf.getSubtitles().size() - 1; i++) {
+            Subtitle first = sf.getSubtitles().get(i);
+            first.start = first.start.plusNanos(nanosOffset);
+            first.end = first.end.plusNanos(nanosOffset);
+        }
+    }
+}

src/test/java/io/github/mdaubie/subtitlesparser/TestObjects.java

@@ -30,11 +30,24 @@ public static class SubRip {
         public static final Supplier<SubRipSubtitle> sub3FixedMerge = () -> getSubRipSubtitle(2,
                 LocalTime.of(0, 0, 56, 473 * 1000000),
                 LocalTime.of(0, 0, 59, 701 * 1000000),
-                "This is the second dialogue"+System.lineSeparator()+"This is the third dialogue");
+                "This is the second dialogue" + System.lineSeparator() + "This is the third dialogue");
+        public static final Supplier<SubRipSubtitle> sub1Shifted1000 = () -> getSubRipSubtitle(1,
+                LocalTime.of(0, 0, 52, 93 * 1000000),
+                LocalTime.of(0, 0, 53, 635 * 1000000),
+                "This is the first dialogue");
+        public static final Supplier<SubRipSubtitle> sub2Shifted1000 = () -> getSubRipSubtitle(2,
+                LocalTime.of(0, 0, 57, 473 * 1000000),
+                LocalTime.of(0, 0, 59, 266 * 1000000),
+                "This is the second dialogue");
+        public static final Supplier<SubRipSubtitle> sub3Shifted1000 = () -> getSubRipSubtitle(3,
+                LocalTime.of(0, 0, 58, 908 * 1000000),
+                LocalTime.of(0, 1, 0, 701 * 1000000),
+                "This is the third dialogue");
         public static final Supplier<SubRipFile> object1 = () -> getSubRipFile(sub1.get(), sub2.get(), sub3.get());
-        public static final Supplier<SubRipFile> object1FixedDelay = ()->getSubRipFile(sub1.get(), sub2.get(), sub3FixedDelay.get());
+        public static final Supplier<SubRipFile> object1FixedDelay = () -> getSubRipFile(sub1.get(), sub2.get(), sub3FixedDelay.get());
         public static final Supplier<SubRipFile> object2 = () -> getSubRipFile(sub2.get(), sub1.get(), sub3.get());
-        public static final Supplier<SubRipFile> object2FixedMerge = ()->getSubRipFile(sub1.get(), sub3FixedMerge.get());
+        public static final Supplier<SubRipFile> object2FixedMerge = () -> getSubRipFile(sub1.get(), sub3FixedMerge.get());
+        public static final Supplier<SubRipFile> object1Shifted1000 = () -> getSubRipFile(sub1Shifted1000.get(), sub2Shifted1000.get(), sub3Shifted1000.get());
         public static final String text1 = """
                 1
                 00:00:51,093 --> 00:00:52,635

src/test/java/io/github/mdaubie/subtitlesparser/toolbox/ShiftSubtitlesTest.java

@@ -0,0 +1,36 @@
+package io.github.mdaubie.subtitlesparser.toolbox;
+
+import io.github.mdaubie.subtitlesparser.TestObjects;
+import io.github.mdaubie.subtitlesparser.model.SubtitlesFile;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.security.InvalidParameterException;
+import java.util.function.Supplier;
+import java.util.stream.Stream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrowsExactly;
+
+class ShiftSubtitlesTest {
+    @ParameterizedTest
+    @MethodSource("shift")
+    void shift(Supplier<SubtitlesFile> sf, long millisOffset, Supplier<SubtitlesFile> expectedResult) {
+        ShiftSubtitles.shift(sf.get(), millisOffset);
+        assertThat(sf).usingRecursiveComparison().isEqualTo(expectedResult.get());
+    }
+
+    static Stream<Arguments> shift() {
+        return Stream.of(
+                Arguments.of(TestObjects.SubRip.object1, 1000, TestObjects.SubRip.object1Shifted1000)
+        );
+    }
+
+    @Test()
+    void shiftThrows() {
+        assertThrowsExactly(InvalidParameterException.class,
+                ()-> ShiftSubtitles.shift(TestObjects.SubRip.object1.get(),-52000));
+    }
+}