Add czkrates, a shellfu script to get CZK rates

README.md

@@ -34,6 +34,17 @@ Example:
     00000008  01110010 01101100 01100100 00001010  |rld.|
     $
 
+### czkrates ###
+
+    czkrates [-d] [-v] [-D DATE] [AMOUNT] [CURRENCY]
+    czkrates [-d] [-v] [-D DATE] [CURRENCY] [AMOUNT]
+
+Show CZK rate for currency CURRENCY. If AMOUNT is given, multiply by
+that number.  Use `-D` to get rate for past day, the DATE format is
+the same as for *date* utility from coreutils.  `-d` and `-v` turn on
+debugging and verbosity, respectively.
+
+
 ### dissect\_url ###
 
 Split URLs into components and arguments.  Output is useful to see more easily

bin/czkrates

@@ -0,0 +1,132 @@
+#!/bin/bash
+#shellcheck disable=SC1090
+
+. "$(shellfu-get path)" || exit 3
+
+shellfu import pretty
+
+
+#
+# Currency to use when not specified
+#
+CZKRATES_DEFAULT_CURRENCY=${CZKRATES_DEFAULT_CURRENCY:-USD}
+
+
+#
+# URL to daily table from
+#
+# The real URL is formed by appending current date.
+#
+CZKRATES_URL=${CZKRATES_URL:-http://www.cnb.cz/en/financial_markets/foreign_exchange_market/exchange_rate_fixing/daily.txt}
+
+usage() {
+    mkusage "[options] [CURRENCY] [MULTIPLIER]" \
+            "[options] [MULTIPLIER] [CURRENCY]" \
+            "" \
+        -o \
+            "-D DATE, --date DATE   Use currency rate from DATE instead"    \
+            "       of today.  DATEs like 'last sun' work, see section DATE"\
+            "       STRING of date(1) for more info."                       \
+            "-d, --debug    Turn on debbugging output"                      \
+            "-v, --verbose  Be more verbose"
+}
+
+type_of() {
+    #
+    # Print 'int' if $1 is an integer, 'nil' if empty; 'str' otherwise
+    #
+    local es_p es_n
+    test -z "$1" && echo nil && return
+    test "$1" -ge 0 2>/dev/null; es_p=$?    # assuming positive
+    test "$1" -lt 0 2>/dev/null; es_n=$?    # assuming negative
+    test $es_p -eq 2 && echo str && return
+    test $es_n -eq 2 && echo str && return
+    echo int
+}
+
+parse_rate1() {
+    #
+    # Parse field $2 from currency $1 data
+    #
+    local wntcur=$1
+    local wntfld=${2:-Rate}
+    case "$wntfld" in
+        Country|Currency|Amount|Code|Rate) true;;
+        *) mkusage "code Country|Currency|Amount|Code|Rate" ;;
+    esac
+    local date head
+    read -r date
+    debug "got: date=$date"
+    read -r head
+    debug "got: head=$head"
+    while IFS='|' read -r Country Currency Amount Code Rate;
+    do
+        debug "got: Country=$Country Currency=$Currency Amount=$Amount Code=$Code Rate=$Rate"
+        test "$wntcur" = "$Code" || continue
+        case $Amount in
+            1) echo "${!wntfld}" ;;
+            *) python -c "print(float($Rate)/$Amount)" ;;
+        esac
+    done
+}
+
+get_unit_price() {
+    #
+    # Get price of 1 unit of $currrency
+    #
+    local table     # table with rate data
+    think "getting currrency for: $Curr"
+    table=$(curl -f --insecure --silent "$Uri") \
+     || die "failed to download rates: $Uri"
+    parse_rate1 "$Curr" Rate <<<"$table" | grep .
+}
+
+maybe_multiply() {
+    #
+    # Multiply if needed
+    #
+    local price
+    read -r price
+    if test "$Mult" = 1;
+    then
+        echo "$price"
+    else
+        think "multiplying by: $Mult"
+        python -c "print(float($price) * $Mult)"
+    fi
+}
+
+
+main() {
+    local Uri
+    local Curr
+    local Mult
+    local Date=now
+    Uri=$CZKRATES_URL
+    Uri+="?date=$(date +%d.%m.%Y)"
+    #shellcheck disable=SC2034
+    while true; do case "$1" in
+        -D|--date)    Date=$2;  shift 2 || usage ;;
+        -d|--debug)   PRETTY_DEBUG=true;   shift ;;
+        -v|--verbose) PRETTY_VERBOSE=true; shift ;;
+        -*)           usage ;;
+        *)            break ;;
+    esac done
+    Uri+="?date=$(date -d "$Date" +%d.%m.%Y)"
+    case "$(type_of "$1"):$(type_of "$2")" in
+        int:int|str:str)    usage ;;
+        int:nil|nil:int)    Mult="$1$2"          ;;
+        str:nil|nil:str)    Curr="$1$2"          ;;
+        str:int)            Curr="$1"; Mult="$2" ;;
+        int:str)            Curr="$2"; Mult="$1" ;;
+    esac
+    Curr="${Curr:-$CZKRATES_DEFAULT_CURRENCY}"
+    Curr="${Curr^^}"
+    Mult="${Mult:-1}"
+    debug -v Uri Curr Mult
+    get_unit_price | maybe_multiply
+}
+
+debug -v CZKRATES_DEFAULT_CURRENCY
+
+main "$@"