#!/bin/sh

test_description='Test diff-highlight'

CURR_DIR=$(pwd)
TEST_OUTPUT_DIRECTORY=$(pwd)
TEST_DIRECTORY="$CURR_DIR"/../../../t
DIFF_HIGHLIGHT="$CURR_DIR"/../diff-highlight

CW="$(printf "\033[7m")"        # white
CR="$(printf "\033[27m")"       # reset

. "$TEST_DIRECTORY"/test-lib.sh

if ! test_have_prereq PERL
then
        skip_all='skipping diff-highlight tests; perl not available'
        test_done
fi

# dh_test is a test helper function which takes 3 file names as parameters. The
# first 2 files are used to generate diff and commit output, which is then
# piped through diff-highlight. The 3rd file should contain the expected output
# of diff-highlight (minus the diff/commit header, ie. everything after and
# including the first @@ line).
dh_test () {
        a="$1" b="$2" &&

        cat >patch.exp &&

        {
                cat "$a" >file &&
                git add file &&
                git commit -m "Add a file" &&

                cat "$b" >file &&
                git diff file >diff.raw &&
                git commit -a -m "Update a file" &&
                git show >commit.raw
        } >/dev/null &&

        "$DIFF_HIGHLIGHT" <diff.raw | test_strip_patch_header >diff.act &&
        "$DIFF_HIGHLIGHT" <commit.raw | test_strip_patch_header >commit.act &&
        test_cmp patch.exp diff.act &&
        test_cmp patch.exp commit.act
}

test_strip_patch_header () {
        sed -n '/^@@/,$p' $*
}

# dh_test_setup_history generates a contrived graph such that we have at least
# 1 nesting (E) and 2 nestings (F).
#
#             A branch
#            /
#       D---E---F master
#
#       git log --all --graph
#       * commit
#       |    A
#       | * commit
#       | |    F
#       | * commit
#       |/
#       |    E
#       * commit
#            D
#
dh_test_setup_history () {
        echo "file1" >file1 &&
        echo "file2" >file2 &&
        echo "file3" >file3 &&

        cat file1 >file &&
        git add file &&
        git commit -m "D" &&

        git checkout -b branch &&
        cat file2 >file &&
        git commit -a -m "A" &&

        git checkout master &&
        cat file2 >file &&
        git commit -a -m "E" &&

        cat file3 >file &&
        git commit -a -m "F"
}

left_trim () {
        "$PERL_PATH" -pe 's/^\s+//'
}

trim_graph () {
        # graphs start with * or |
        # followed by a space or / or \
        "$PERL_PATH" -pe 's@^((\*|\|)( |/|\\))+@@'
}

test_expect_success 'diff-highlight highlights the beginning of a line' '
        cat >a <<-\EOF &&
                aaa
                bbb
                ccc
        EOF

        cat >b <<-\EOF &&
                aaa
                0bb
                ccc
        EOF

        dh_test a b <<-EOF
                @@ -1,3 +1,3 @@
                 aaa
                -${CW}b${CR}bb
                +${CW}0${CR}bb
                 ccc
        EOF
'

test_expect_success 'diff-highlight highlights the end of a line' '
        cat >a <<-\EOF &&
                aaa
                bbb
                ccc
        EOF

        cat >b <<-\EOF &&
                aaa
                bb0
                ccc
        EOF

        dh_test a b <<-EOF
                @@ -1,3 +1,3 @@
                 aaa
                -bb${CW}b${CR}
                +bb${CW}0${CR}
                 ccc
        EOF
'

test_expect_success 'diff-highlight highlights the middle of a line' '
        cat >a <<-\EOF &&
                aaa
                bbb
                ccc
        EOF

        cat >b <<-\EOF &&
                aaa
                b0b
                ccc
        EOF

        dh_test a b <<-EOF
                @@ -1,3 +1,3 @@
                 aaa
                -b${CW}b${CR}b
                +b${CW}0${CR}b
                 ccc
        EOF
'

test_expect_success 'diff-highlight does not highlight whole line' '
        cat >a <<-\EOF &&
                aaa
                bbb
                ccc
        EOF

        cat >b <<-\EOF &&
                aaa
                000
                ccc
        EOF

        dh_test a b <<-EOF
                @@ -1,3 +1,3 @@
                 aaa
                -bbb
                +000
                 ccc
        EOF
'

test_expect_failure 'diff-highlight highlights mismatched hunk size' '
        cat >a <<-\EOF &&
                aaa
                bbb
        EOF

        cat >b <<-\EOF &&
                aaa
                b0b
                ccc
        EOF

        dh_test a b <<-EOF
                @@ -1,3 +1,3 @@
                 aaa
                -b${CW}b${CR}b
                +b${CW}0${CR}b
                +ccc
        EOF
'

# These two code points share the same leading byte in UTF-8 representation;
# a naive byte-wise diff would highlight only the second byte.
#
#   - U+00f3 ("o" with acute)
o_accent=$(printf '\303\263')
#   - U+00f8 ("o" with stroke)
o_stroke=$(printf '\303\270')

test_expect_success 'diff-highlight treats multibyte utf-8 as a unit' '
        echo "unic${o_accent}de" >a &&
        echo "unic${o_stroke}de" >b &&
        dh_test a b <<-EOF
                @@ -1 +1 @@
                -unic${CW}${o_accent}${CR}de
                +unic${CW}${o_stroke}${CR}de
        EOF
'

# Unlike the UTF-8 above, these are combining code points which are meant
# to modify the character preceding them:
#
#   - U+0301 (combining acute accent)
combine_accent=$(printf '\314\201')
#   - U+0302 (combining circumflex)
combine_circum=$(printf '\314\202')

test_expect_failure 'diff-highlight treats combining code points as a unit' '
        echo "unico${combine_accent}de" >a &&
        echo "unico${combine_circum}de" >b &&
        dh_test a b <<-EOF
                @@ -1 +1 @@
                -unic${CW}o${combine_accent}${CR}de
                +unic${CW}o${combine_circum}${CR}de
        EOF
'

test_expect_success 'diff-highlight works with the --graph option' '
        dh_test_setup_history &&

        # topo-order so that the order of the commits is the same as with --graph
        # trim graph elements so we can do a diff
        # trim leading space because our trim_graph is not perfect
        git log --branches -p --topo-order |
                "$DIFF_HIGHLIGHT" | left_trim >graph.exp &&
        git log --branches -p --graph |
                "$DIFF_HIGHLIGHT" | trim_graph | left_trim >graph.act &&
        test_cmp graph.exp graph.act
'

# Most combined diffs won't meet diff-highlight's line-number filter. So we
# create one here where one side drops a line and the other modifies it. That
# should result in a diff like:
#
#    - modified content
#    ++resolved content
#
# which naively looks like one side added "+resolved".
test_expect_success 'diff-highlight ignores combined diffs' '
        echo "content" >file &&
        git add file &&
        git commit -m base &&

        >file &&
        git commit -am master &&

        git checkout -b other HEAD^ &&
        echo "modified content" >file &&
        git commit -am other &&

        test_must_fail git merge master &&
        echo "resolved content" >file &&
        git commit -am resolved &&

        cat >expect <<-\EOF &&
        --- a/file
        +++ b/file
        @@@ -1,1 -1,0 +1,1 @@@
        - modified content
        ++resolved content
        EOF

        git show -c | "$DIFF_HIGHLIGHT" >actual.raw &&
        sed -n "/^---/,\$p" <actual.raw >actual &&
        test_cmp expect actual
'

test_done