#!/usr/bin/env bats

setup() {
  set -euo pipefail

  bats_load_library bats-support
  bats_load_library bats-assert

  DIR="$(cd "$(dirname "$BATS_TEST_FILENAME")" >/dev/null 2>&1 && pwd)"
  PATH="$DIR/../bin:$PATH"
}

@test "keeps hunk when replacement matches" {
  printf "%s\n" "foo" >"$BATS_TEST_TMPDIR/old"
  printf "%s\n" "bar" >"$BATS_TEST_TMPDIR/new"
  diff_output="$(git diff --no-index "$BATS_TEST_TMPDIR/old" \
    "$BATS_TEST_TMPDIR/new" || true)"
  run mechanicaldiff.py foo bar <<<"$diff_output"
  assert_success
  assert_output "$diff_output"
}

@test "drops diff when replacement does not match" {
  printf "%s\n" "foo" >"$BATS_TEST_TMPDIR/old"
  printf "%s\n" "baz" >"$BATS_TEST_TMPDIR/new"
  git diff --no-index "$BATS_TEST_TMPDIR/old" "$BATS_TEST_TMPDIR/new" \
    >"$BATS_TEST_TMPDIR/diff" || true
  run mechanicaldiff.py foo bar <"$BATS_TEST_TMPDIR/diff"
  assert_failure
  assert_output ""
}

@test "keeps diff with only mode change" {
  printf "%s\n" "foo" >"$BATS_TEST_TMPDIR/old"
  printf "%s\n" "foo" >"$BATS_TEST_TMPDIR/new"
  chmod 0644 "$BATS_TEST_TMPDIR/old"
  chmod 0755 "$BATS_TEST_TMPDIR/new"

  diff_output="$(git diff --no-index "$BATS_TEST_TMPDIR/old" \
    "$BATS_TEST_TMPDIR/new" || true)"

  run mechanicaldiff.py foo bar <<<"$diff_output"
  assert_success
  assert_output "$diff_output"
}

@test "drops one hunk and keeps another" {
  cat >"$BATS_TEST_TMPDIR/old" <<-'EOF'
	alpha
	beta
	gamma
	one
	two
	three
	four
	five
	six
	seven
	eight
	nine
	ten
	delta
	EOF
  sed \
    -e 's/beta/beta_changed/' \
    -e 's/delta/delta_changed/' \
    "$BATS_TEST_TMPDIR/old" >"$BATS_TEST_TMPDIR/new"
  sed 's/beta/beta_changed/' "$BATS_TEST_TMPDIR/old" \
    >"$BATS_TEST_TMPDIR/new_kept"

  git diff --no-index "$BATS_TEST_TMPDIR/old" \
    "$BATS_TEST_TMPDIR/new" \
    >"$BATS_TEST_TMPDIR/diff_full" || true
  git diff --no-index "$BATS_TEST_TMPDIR/old" \
    "$BATS_TEST_TMPDIR/new_kept" \
    >"$BATS_TEST_TMPDIR/diff_expected" || true

  run mechanicaldiff.py "beta" "beta_changed" <"$BATS_TEST_TMPDIR/diff_full"
  assert_failure
  assert_output --partial "-beta"
  assert_output --partial "+beta_changed"
  refute_output --partial "delta_changed"
}

@test "handles multiple files" {
  printf "%s\n" "foo" >"$BATS_TEST_TMPDIR/old1"
  printf "%s\n" "bar" >"$BATS_TEST_TMPDIR/new1"
  printf "%s\n" "alpha" >"$BATS_TEST_TMPDIR/old2"
  printf "%s\n" "beta" >"$BATS_TEST_TMPDIR/new2"

  git diff --no-index "$BATS_TEST_TMPDIR/old1" "$BATS_TEST_TMPDIR/new1" \
    >"$BATS_TEST_TMPDIR/diff_one" || true
  git diff --no-index "$BATS_TEST_TMPDIR/old2" "$BATS_TEST_TMPDIR/new2" \
    >"$BATS_TEST_TMPDIR/diff_two" || true

  cat "$BATS_TEST_TMPDIR/diff_one" "$BATS_TEST_TMPDIR/diff_two" \
    >"$BATS_TEST_TMPDIR/diff_all"

  run mechanicaldiff.py foo bar <"$BATS_TEST_TMPDIR/diff_one"
  assert_success
  output_one="$output"

  run mechanicaldiff.py foo bar <"$BATS_TEST_TMPDIR/diff_two"
  assert_failure
  output_two="$output"

  run mechanicaldiff.py foo bar <"$BATS_TEST_TMPDIR/diff_all"
  assert_failure
  assert_output "${output_one}${output_two}"
}

@test "supports regex group substitutions" {
  cat >"$BATS_TEST_TMPDIR/old" <<-'EOF'
	foo(123)
	bar
	EOF
  cat >"$BATS_TEST_TMPDIR/new" <<-'EOF'
	foo-123
	bar
	EOF

  git diff --no-index "$BATS_TEST_TMPDIR/old" "$BATS_TEST_TMPDIR/new" \
    >"$BATS_TEST_TMPDIR/diff" || true

  run mechanicaldiff.py 'foo\((\d+)\)' 'foo-\1' <"$BATS_TEST_TMPDIR/diff"
  assert_success
  assert_output "$(cat "$BATS_TEST_TMPDIR/diff")"
}

@test "replaces a substring within a line" {
  cat >"$BATS_TEST_TMPDIR/old" <<-'EOF'
	prefix foo suffix
	EOF
  cat >"$BATS_TEST_TMPDIR/new" <<-'EOF'
	prefix bar suffix
	EOF

  git diff --no-index "$BATS_TEST_TMPDIR/old" "$BATS_TEST_TMPDIR/new" \
    >"$BATS_TEST_TMPDIR/diff" || true

  run mechanicaldiff.py foo bar <"$BATS_TEST_TMPDIR/diff"
  assert_success
  assert_output "$(cat "$BATS_TEST_TMPDIR/diff")"
}

@test "keeps only matching line in a consecutive change block" {
  cat >"$BATS_TEST_TMPDIR/old" <<-'EOF'
	foo
	bar
	baz
	EOF
  sed \
    -e 's/foo/foo_changed/' \
    -e 's/bar/bar_changed/' \
    "$BATS_TEST_TMPDIR/old" >"$BATS_TEST_TMPDIR/new"
  sed 's/foo/foo_changed/' "$BATS_TEST_TMPDIR/old" \
    >"$BATS_TEST_TMPDIR/new_kept"

  git diff --no-index "$BATS_TEST_TMPDIR/old" "$BATS_TEST_TMPDIR/new" \
    >"$BATS_TEST_TMPDIR/diff_full" || true
  git diff --no-index "$BATS_TEST_TMPDIR/old" "$BATS_TEST_TMPDIR/new_kept" \
    >"$BATS_TEST_TMPDIR/diff_expected" || true

  run mechanicaldiff.py foo foo_changed <"$BATS_TEST_TMPDIR/diff_full"
  assert_failure
  expected="$(sed \
    -e 's/new_kept/new/g' \
    -e '/^index /d' \
    "$BATS_TEST_TMPDIR/diff_expected")"
  output_normalized="$(printf '%s\n' "$output" | sed -e '/^index /d')"
  assert_equal "$expected" "$output_normalized"
}

@test "drops hunk when all pairs become context" {
  cat >"$BATS_TEST_TMPDIR/old" <<-'EOF'
	foo
	bar
	baz
	EOF
  sed \
    -e 's/foo/foo_changed/' \
    -e 's/bar/bar_changed/' \
    "$BATS_TEST_TMPDIR/old" >"$BATS_TEST_TMPDIR/new"

  git diff --no-index "$BATS_TEST_TMPDIR/old" "$BATS_TEST_TMPDIR/new" \
    >"$BATS_TEST_TMPDIR/diff_full" || true

  run mechanicaldiff.py qux quux <"$BATS_TEST_TMPDIR/diff_full"
  assert_failure
  assert_output ""
}