#!/bin/sh

# The MIT License (MIT)
#
# Copyright © 2020-2025 pacman64
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the “Software”), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.


# ecbler
# European Central Bank Latest Exchange Rates
#
# Emit the latest exchange rates against the euro as 2 lines, the first line
# being a header with the column names.
#
# The numbers in the second line are what you multiply each foreign currency
# to get its equivalent amount in euros.


# handle leading options
case "$1" in
    -h|--h|-help|--help)
        awk '/^# +ecbler/, /^$/ { gsub(/^# ?/, ""); print }' "$0"
        exit 0
    ;;
esac

# load data from website
wget -q -O - 'https://www.ecb.europa.eu/stats/eurofxref/eurofxref.zip' |
# decompress payload
gzip -d |
# turn CSV into TSV, ignoring trailing empty fields
sed -E 's- *\r$--; s-,$--; s-, *-\t-g; s-\t+$--' |
# reciprocate dividers into multipliers
awk -F "\t" '
NR == 1 { print }
NR == 2 {
    printf "%s", $1
    for (i = 2; i <= NF; i++) printf("\t%.6f", 1.0 / $i)
    printf "\n"
}'

# extending the pipe-chain to a step calling `column -t` realigns columns,
# turning tabs into spaces