package ch2;

import org.junit.jupiter.api.Test;
import static ch2.StringUtils.substringsBetween;
import static org.assertj.core.api.Assertions.assertThat;

public class StringUtilsTest {

    @Test void strIsNullOrEmpty() {
        assertThat(substringsBetween(null, "a", "b")).isEqualTo(null);
        assertThat(substringsBetween("", "a", "b")).isEqualTo(new String[]{});
    }

    @Test
    void openIsNullOrEmpty() {
        assertThat(substringsBetween("abc", null, "b")).isEqualTo(null);
        assertThat(substringsBetween("abc", "", "b")).isEqualTo(null);
    }

    @Test
    void closeIsNullOrEmpty() {
        assertThat(substringsBetween("abc", "a", null)).isEqualTo(null);
        assertThat(substringsBetween("abc", "a", null)).isEqualTo(null);
    }

    @Test
    void strOfLength1() {
        assertThat(substringsBetween("a", "a", "b")).isEqualTo(null);
        assertThat(substringsBetween("a", "b", "a")).isEqualTo(null);
        assertThat(substringsBetween("a", "b", "b")).isEqualTo(null);
        assertThat(substringsBetween("a", "a", "a")).isEqualTo(null);
    }

    @Test
    void openAndCloseOfLength1() {
        assertThat(substringsBetween("abc", "x", "y")).isEqualTo(null);
        assertThat(substringsBetween("abc", "a", "y")).isEqualTo(null);
        assertThat(substringsBetween("abc", "x", "c")).isEqualTo(null);
        assertThat(substringsBetween("abc", "a", "c")).isEqualTo(new String[] {"b"});
        assertThat(substringsBetween("abcabc", "a", "c")).isEqualTo(new String[] {"b", "b"});
        assertThat(substringsBetween("abcabyt byrc", "a", "c")).isEqualTo(new String[] {"b", "byt byr"});
    }

    @Test
    void openAndCloseTagsOfDifferentSizes() {
        assertThat(substringsBetween("aabcc", "xx", "yy")).isEqualTo(null);
        assertThat(substringsBetween("aabcc", "aa", "yy")).isEqualTo(null);
        assertThat(substringsBetween("aabcc", "xx", "cc")).isEqualTo(null);
        assertThat(substringsBetween("aabbcc", "aa", "cc")).isEqualTo(new String[] {"bb"});
        assertThat(substringsBetween("aabbccaaeecc", "aa", "cc")).isEqualTo(new String[] {"bb", "ee"});
        assertThat(substringsBetween("a abb ddc ca abbcc", "a a", "c c")).isEqualTo(new String[] {"bb dd"});
    }

    @Test
    void noSubstringBetweenOpenAndCloseTags() {
        assertThat(substringsBetween("aabb", "aa", "bb")).isEqualTo(new String[] {""});
    }

    @Test
    void closeTagAppearingMultipleTimes() {
        assertThat(substringsBetween("aabcddaabeddaab", "aa", "d")).isEqualTo(new String[] {"bc", "be"});
        assertThat(substringsBetween("aabcddabeddaab", "aa", "d")).isEqualTo(new String[] {"bc"});
    }
}