#!/bin/sh
set -eu

if [ "$#" -ne 1 ]; then
    echo "usage: cli_week_start_test.sh /path/to/nocal" >&2
    exit 2
fi

nocal=$1
tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/nocal-cli-week-start.XXXXXX")
trap 'rm -rf "$tmpdir"' EXIT HUP INT TERM

fail()
{
    echo "$1" >&2
    exit 1
}

expect_failure()
{
    description=$1
    shift
    if "$@" >"$tmpdir/out" 2>"$tmpdir/err"; then
        fail "$description unexpectedly succeeded"
    fi
}

help=$("$nocal" --help)
case $help in
    *"--week-start DAY"*"monday through sunday"*) ;;
    *) fail "help does not document --week-start and its accepted range" ;;
esac

"$nocal" --print --demo >"$tmpdir/default"
"$nocal" --print --demo --week-start monday >"$tmpdir/monday"
cmp "$tmpdir/default" "$tmpdir/monday" >/dev/null ||
    fail "default frame is not Monday-first"

header=$(sed -n '2p' "$tmpdir/monday" | tr -d ' ')
case $header in
    *MondayTuesdayWednesdayThursdayFridaySaturdaySunday*) ;;
    *) fail "Monday-first header is not in weekday order" ;;
esac

"$nocal" --print --demo --week-start sunday >"$tmpdir/sunday"
header=$(sed -n '2p' "$tmpdir/sunday" | tr -d ' ')
case $header in
    *SundayMondayTuesdayWednesdayThursdayFridaySaturday*) ;;
    *) fail "Sunday-first header was not rotated" ;;
esac

"$nocal" --print --demo --week-start wednesday >"$tmpdir/wednesday"
header=$(sed -n '2p' "$tmpdir/wednesday" | tr -d ' ')
case $header in
    *WednesdayThursdayFridaySaturdaySundayMondayTuesday*) ;;
    *) fail "Wednesday-first header was not rotated" ;;
esac

# The first numbered cell must be the correct spill date for each selected
# week start. Nocal is Linux-only, so GNU date is available in its test setup.
month_start=$(date +%Y-%m-01)
month_weekday=$(date -d "$month_start" +%w)
for selection in sunday:0 wednesday:3; do
    name=${selection%%:*}
    weekday=${selection##*:}
    offset=$(( (month_weekday - weekday + 7) % 7 ))
    expected=$(date -d "$month_start -$offset days" +%-d)
    first_row=$(sed -n '4p' "$tmpdir/$name")
    actual=$(printf '%s\n' "$first_row" | sed 's/[^0-9]/ /g' | awk '{print $1}')
    [ "$actual" = "$expected" ] ||
        fail "$name-first grid began on $actual instead of spill date $expected"
done

# Option parsing finishes before the calendar is loaded or any write mode can
# run. Invalid, missing, and repeated values therefore leave the target exact.
calendar=$tmpdir/calendar.ics
printf '%s\n' 'sentinel calendar bytes' >"$calendar"
cp "$calendar" "$tmpdir/calendar-before"

expect_failure "invalid week-start value" \
    "$nocal" --calendar "$calendar" --week-start MONDAY
grep -F -- "invalid --week-start day" "$tmpdir/err" >/dev/null ||
    fail "invalid week-start value did not report its parse error"

expect_failure "missing week-start value" \
    "$nocal" --calendar "$calendar" --week-start
grep -F -- "--week-start requires a day" "$tmpdir/err" >/dev/null ||
    fail "missing week-start value did not report its parse error"

expect_failure "repeated week-start option" \
    "$nocal" --calendar "$calendar" --week-start sunday --week-start monday
grep -F -- "--week-start may only be supplied once" "$tmpdir/err" >/dev/null ||
    fail "repeated week-start did not report its parse error"

cmp "$calendar" "$tmpdir/calendar-before" >/dev/null ||
    fail "week-start parse failure changed the calendar"
[ ! -e "$calendar.bak" ] ||
    fail "week-start parse failure created a calendar backup"