#!/bin/sh

# The MIT License (MIT)
#
# Copyright © 2024 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.


# bocler
# Bank Of Canada Latest Exchange Rates
#
# Emit the latest exchange rates against the canadian dollar 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 canadian-dollar equivalent amount.

# The full list of columns the webserver returns are shown below with their
# 1-based column indices, in case you want to change which columns this
# script picks.
#
#  1  date    # 15  RUB
#  2  AUD     # 16  SAR
#  3  BRL     # 17  SGD
#  4  CNY     # 18  ZAR
#  5  EUR     # 19  KRW
#  6  HKD     # 20  SEK
#  7  INR     # 21  CHF
#  8  IDR     # 22  TWD
#  9  JPY     # 23  THB
# 10  MYR     # 24  TRY
# 11  MXN     # 25  GBP
# 12  NZD     # 26  USD
# 13  NOK     # 27  VND
# 14  PEN


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

# keep source-code lines narrow
base='https://www.bankofcanada.ca/valet/observations/group/FX_RATES_DAILY'

# load data from website: starting from 3 days back ensures this script
# works even on weekends, while minimizing the data being transferred
wget -q -O - "${base}/csv?start_date=$(date -d '3 days ago' +'%Y-%m-%d')" |
# exclude prelude/intro lines, keeping only the header and the last line
awk '/^"date"/; END { print }' |
# ignore double quotes, and rename most column names
sed 's-"--g; s-FX--g; s-CAD--g' |
# pick a subset of the columns
awk -F "," -v OFS="\t" '{ print $1, $2, $3, $4, $5, $7, $11, $25, $26 }' |
# realign columns, turning tabs into spaces
column -t