#!/bin/sh
#
# fetch_fio_fine.sh
#
# Fio API fine-grained account statements fetcher.
#
# ISC License
#
# Copyright 2023 Brmlab, z.s.
# Jan Hrach
# Dominik Pantůček <dominik.pantucek@trustica.cz>
#
# Permission to use, copy, modify, and/or distribute this software
# for any purpose with or without fee is hereby granted, provided
# that the above copyright notice and this permission notice appear
# in all copies.
# 
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
# WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
# AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
# CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#

# REST API endpoint
APIURI=https://www.fio.cz/ib_api/rest

# Configuration defaults - none
CONFIG_FILE="$HOME/.hackerbaserc"
CFG_BANK_DIR=
CFG_APIKEYS_FILE=
ARG_BANK_DIR=
ARG_APIKEYS_FILE=

# Argument parsing
while ! [ -z "$1" ] ; do
    case "$1" in
	-apikey)
	    ARG_APIKEYS_FILE="$2"
	    shift
	    shift
	    ;;
	-bankdir)
	    ARG_BANK_DIR="$2"
	    shift
	    shift
	    ;;
	-config)
	    CONFIG_FILE="$2"
	    shift
	    shift
	    ;;
	*)
	    echo "Usage: $0 [-config file] [-apikey file] [-bankdir dir]"
	    exit 1
	    ;;
    esac
done

# Configuration parsing - assumes "dumb" sed which cannot execute
# multiple statements
get_config_value() {
    if [ -z "$1" ] ; then
	echo "get_config_value() requires parameter name"
	exit 1
    fi
    if [ -r "$CONFIG_FILE" ] ; then
	cat "$CONFIG_FILE" \
	    | sed 's/#.*//' \
	    | sed 's/^[ \t]*//' \
	    | grep "^$1" \
	    | sed 's/^[^ \t]*//' \
	    | sed 's/^[ \t]*//' \
	    | sed 's/[ \t]*$//'
    fi
}
CFG_BANK_DIR=`get_config_value bank-dir`
CFG_APIKEYS_FILE=`get_config_value apikeys-file`

# Configuration merging
if [ -z "$ARG_BANK_DIR" ] ; then
    BANK_DIR="$CFG_BANK_DIR"
else
    BANK_DIR="$ARG_BANK_DIR"
fi
if [ -z "$ARG_APIKEYS_FILE" ] ; then
    APIKEYS_FILE="$CFG_APIKEYS_FILE"
else
    APIKEYS_FILE="$ARG_APIKEYS_FILE"
fi

# Storage for partial account statements
BANK_DIR_PARTS="$BANK_DIR/parts"
if ! [ -d "$BANK_DIR_PARTS" ] ; then
    mkdir -p "$BANK_DIR_PARTS"
fi

#
# Very simple "logging" function (stdout should be redirected to log anyway)
log() {
    echo `date '+%Y-%m-%d %H:%M:%S'` "$@"
}

#
# Returns the file modification date in YYYY-MM-DD format
get_file_date() {
    if [ -r "$1" ] ; then
	STAT=`stat -c %y "$1"`
	echo ${STAT%% *}
    else
	echo 2000-01-01
    fi
}

#
# $1 - URI
# $2 - output file
download_file() {
    url="$1"
    fname="$2"
    tmpfname="$fname.tmp"
    oldfname="$fname.old"
    for i in `seq 1 3` ; do
	if wget -q "$url" -O "$tmpfname" ; then
	    if [ -s  "$tmpfname" ] ; then
		log Download OK
		if [ -r "$fname" ] ; then
		    cp "$fname" "$oldfname"
		fi
		mv "$tmpfname" "$fname"
		log Rename OK
		break
	    else
		log Download successfull but empty or non-existing result.
		log Retrying in 5 s.
	    fi
	else
	    cat "$tmpfname"
	    log Failed download, retrying in 5 s.
	    sleep 5
	fi
    done
}

#
# Leap year?
leap_year() {
    YEAR="$1"
    ym4=`expr "$YEAR" % 4`
    ym100=`expr "$YEAR" % 100`
    ym400=`expr "$YEAR" % 400`
    if [ $ym4 = 0 ] ; then
	# Maybe
	if ! [ $ym100 = 0 ] ; then
	    # Leap
	    return 0
	else
	    # Maybe
	    if [ $ym400 = 0 ] ; then
		# Leap
		return 0
	    else
		# Not leap
		return 1
	    fi
	fi
    else
	# Not leap
	return 1
    fi
}

#
# Returns the last day of given month in Fio format
# $1 - year
# $2 - month
# $3 - if non-empty, return ISO
end_of_month() {
    YEAR="$1"
    MONTH="$2"
    case $MONTH in
	01) DAY=31 ;;
	02)
	    DAY=$(
		if leap_year $YEAR ; then
		    echo 29
		else
		    echo 28
		fi
	       )
	    ;;
	03) DAY=31 ;;
	04) DAY=30 ;;
	05) DAY=31 ;;
	06) DAY=30 ;;
	07) DAY=31 ;;
	08) DAY=31 ;;
	09) DAY=30 ;;
	10) DAY=31 ;;
	11) DAY=30 ;;
	12) DAY=31 ;;
    esac
    if [ -z "$3" ] ; then
	echo "$DAY.$MONTH.$YEAR"
    else
	echo "$YEAR-$MONTH-$DAY"
    fi
}

#
# Downloads single year month
# $1 - apikey
# $2 - year
# $3 - month - must be in MM format already
# $4 - destination file name
download_year_month() {
    apikey="$1"
    year="$2"
    month="$3"
    fname="$4"
    STARTDATE="$year-$month-01"
    ENDDATE=`end_of_month $year $month 1`
    log "Downloading ${APIURI}/periods/$apikey/$STARTDATE/$ENDDATE/transactions.csv to $fname"
    download_file "${APIURI}/periods/$apikey/$STARTDATE/$ENDDATE/transactions.csv" "$fname"
}

#
# Gets the first year of the account statement.
# $1 - account number
first_acc_part() {
    accno="$1"
    ls "${BANK_DIR_PARTS}/" \
	| grep "^$accno" \
	| grep '[-][0-9][0-9][0-9][0-9].csv$' \
	| sort \
	| head -n 1
}

#
# Gets the last year of the account statement.
# $1 - account number
last_acc_part() {
    accno="$1"
    ls "${BANK_DIR_PARTS}/" \
	| grep "^$accno" \
	| grep '[-][0-9][0-9][0-9][0-9].csv$' \
	| sort -r \
	| head -n 1
}

#
# Returns all parts except for the first
# $1 - account number
all_but_first_parts() {
    accno="$1"
    first="`first_acc_part $1`"
    ls "${BANK_DIR_PARTS}/" \
	| grep "^$accno" \
	| grep '[-][0-9][0-9][0-9][0-9].csv$' \
	| sort \
	| grep -v "$first"
}

#
# Creates static header for given account
# $1 - account number
make_acc_header_static() {
    grep -B 20 '^$' "$1" \
	| grep . \
	| egrep -v 'Balance|^date|^id'
}

#
# Gets only given header
# $1 - path to file
# $2 - header name
get_header_field() {
    grep "^$2" "$1"
}

#
# Dynamic part
# $1 - account number
make_acc_header() {
    first="`first_acc_part $1`"
    last="`last_acc_part $1`"
    firstfname="$BANK_DIR_PARTS/$first"
    lastfname="$BANK_DIR_PARTS/$last"
    make_acc_header_static "$firstfname"
    get_header_field "$firstfname" openingBalance
    get_header_field "$lastfname" closingBalance
    get_header_field "$firstfname" dateStart
    get_header_field "$lastfname" dateEnd
    get_header_field "$firstfname" idFrom
    get_header_field "$lastfname" idTo
}

#
# Creates the complete merged account statement from yearly partials
# $1 - account number
merge_acc() {
    make_acc_header "$1"
    grep -A 100000 '^$' "$BANK_DIR_PARTS/`first_acc_part $1`"
    for part in `all_but_first_parts $1` ; do
	grep -A 100000 '^ID' "$BANK_DIR_PARTS/$part" \
	    | grep -v '^ID'
    done    
}

#
# Gets the first year of the account statement.
# $1 - account number
# $2 - year
first_acc_year_part() {
    accno="$1"
    ls "${BANK_DIR_PARTS}/" \
	| grep "^$accno" \
	| grep "$2-[0-9][0-9].csv$" \
	| sort \
	| head -n 1
}

#
# Gets the last year of the account statement.
# $1 - account number
# $2 - year
last_acc_year_part() {
    accno="$1"
    ls "${BANK_DIR_PARTS}/" \
	| grep "^$accno" \
	| grep "$2-[0-9][0-9].csv$" \
	| sort -r \
	| head -n 1
}

#
# Returns all parts except for the first
# $1 - account number
# $2 - year
all_but_first_year_parts() {
    accno="$1"
    first="`first_acc_year_part $1 $2`"
    ls "${BANK_DIR_PARTS}/" \
	| grep "^$accno" \
	| grep "$2-[0-9][0-9].csv$" \
	| sort \
	| grep -v "$first"
}

#
# Dynamic part
# $1 - account number
# $2 - year
make_acc_year_header() {
    first="`first_acc_year_part $1 $2`"
    last="`last_acc_year_part $1 $2`"
    firstfname="$BANK_DIR_PARTS/$first"
    lastfname="$BANK_DIR_PARTS/$last"
    make_acc_header_static "$firstfname"
    get_header_field "$firstfname" openingBalance
    get_header_field "$lastfname" closingBalance
    get_header_field "$firstfname" dateStart
    get_header_field "$lastfname" dateEnd
    get_header_field "$firstfname" idFrom
    get_header_field "$lastfname" idTo
}

#
# Single year merged
# $1 - account number
# $2 - year
merge_acc_year() {
    make_acc_year_header "$1" "$2"
    grep -A 100000 '^$' "$BANK_DIR_PARTS/`first_acc_year_part $1 $2`"
    for part in `all_but_first_year_parts $1 $2` ; do
	grep -A 100000 '^ID' "$BANK_DIR_PARTS/$part" \
	    | grep -v '^ID'
    done
}

# Current year and month
CYEAR=`date +%Y`
CMONTH=`date +%m|sed s/^0//`
MONTHLIMIT=2

# Mark
log "$0" ======== started ========

# Each line should contain account number and Fio API token as first
# two non-whitespace strings. Third token is the starting year for
# this account. The rest of each line is ignored. There must be no
# leading whitespace.
while read accnt ; do
    # Extract account number, Fio token and starting year
    ACCNO=${accnt%% *}
    accrest=${accnt#* }
    APIKEY=${accrest%% *}
    accrest2=${accrest#* }
    YEAR=${accrest2%% *}

    # Check starting year before attempting partial downloads -
    # doesn't matter much anymore, but kept as sanity check.
    if [ -z "$YEAR" ] ; then
	log "Missing start year for account $ACCNO"
	continue
    fi
    if [ "$YEAR" -gt "$CYEAR" ] ; then
	log "Start year for account $ACCNO in the future: $YEAR"
	continue
    fi
    if [ "$YEAR" -lt "2010" ] ; then
	log "Start year for account $ACCNO before Brmlab existence: $YEAR"
	continue
    fi
    
    # Iterate over the months
    monthsleft=$MONTHLIMIT
    currentmonth=$CMONTH
    currentyear=$CYEAR
    while [ $monthsleft -gt 0 ] ; do
	if ! [ "$currentmonth" = "$CMONTH" -a "$currentyear" = "$CYEAR" ] ; then
	    log "Sleeping for 30s before next API usage"
	    sleep 30
	fi
	# Proces unconditionally
	currentmonthStr=$currentmonth
	if [ $currentmonth -lt 10 ] ; then
	    currentmonthStr=0$currentmonth
	fi
	CSVNAME="$BANK_DIR_PARTS/$ACCNO-$currentyear-$currentmonthStr.csv"
	log "Update $ACCNO in $currentyear $currentmonth ($currentmonthStr)"
	download_year_month "$APIKEY" "$currentyear" "$currentmonthStr" "$CSVNAME"
	monthsleft=`expr $monthsleft - 1`
	if [ $currentmonth = 1 ] ; then
	    currentmonth=12
	    currentyear=`expr $currentyear - 1`
	else
	    currentmonth=`expr $currentmonth - 1`
	fi
    done

    # Merge the account
    for year in `seq $currentyear $CYEAR` ; do
	log "Merging $ACCNO $year"
	merge_acc_year "$ACCNO" "$year" >"$BANK_DIR_PARTS/$ACCNO-$year.csv.tmp"
	if [ -r "$BANK_DIR_PARTS/$ACCNO-$year.csv" ] ; then
	    cp "$BANK_DIR_PARTS/$ACCNO-$year.csv" "$BANK_DIR_PARTS/$ACCNO-$year.csv.old"
	fi
	mv "$BANK_DIR_PARTS/$ACCNO-$year.csv.tmp" "$BANK_DIR_PARTS/$ACCNO-$year.csv"
    done
    log "FINAL Merging $ACCNO"
    merge_acc "$ACCNO" >"$BANK_DIR/$ACCNO.csv.tmp"
    log "Renaming $ACCNO"
    if [ -r "$BANK_DIR/$ACCNO.csv" ] ; then
	cp "$BANK_DIR/$ACCNO.csv" "$BANK_DIR/$ACCNO.csv.old"
    fi
    mv "$BANK_DIR/$ACCNO.csv.tmp" "$BANK_DIR/$ACCNO.csv"
done < "$APIKEYS_FILE"

# Mark
log "$0" ======== finished ========