#!/bin/sh -u
# sample answer for the CGI script exercise in CGI_script.txt
# ---
# a CGI script to fetch the weather for a given city code
# ---
# Syntax: $0 [ citycode ]
#
# If this script is run at a normal terminal, it behaves like a normal
# shell script.  If it is run without a terminal (e.g. as a CGI
# script), it outputs the CGI script headers and all messages appear
# on standard output.
# 
# NOTE: Errors must go to standard output in CGI scripts, not to standard error.
#       We test standard input to see if it is a terminal and issue
#       error messages to stderr if it is and to stdout if it is not.
#       (CGI scripts run with standard input not a terminal.)
#
# This script does not contain all the proper parts of a DAT2330 script.
# See the Notes file "script_style.txt" for the correct format.

# Set a standard shell search path and a friendly umask.
#
PATH=/bin:/usr/bin ; export PATH
umask 022

# If no terminal on standard input, assume CGI script and put out the
# CGI script header.
#
if ! tty -s ; then
	echo "Content-Type: text/plain"
	echo ""
fi

# Input section: check the argument count to assure exactly one city code.
#
if [ $# -gt 1 ] ; then
	msg="$0: expecting one city code, found $# ($*)"
	if tty -s ; then
		echo 1>&2 "$msg"
	else
		echo "$msg"
	fi	
	exit 1
fi

# A missing first argument defaults to YOW (Ottawa).
#
if [ $# -ne 1 ] ; then
	citycode=YOW
else
	citycode="$1"
fi

# Fetch the weather for the city code and remember the status.
#
echo "$0: The current '$citycode' weather is:"
lynx -dump "http://weatheroffice.ec.gc.ca/forecast/city_e.html?$citycode" \
          | grep -e 'Temp.:' -e 'Observed on'
status=$?

# Print a message if the status was not zero (on error).
#
if [ "$status" -ne 0 ] ; then
	msg="$0: Bad status lynx/grep on city '$citycode' is $status"
	if tty -s ; then
		echo 1>&2 "$msg"
	else
		echo "$msg"
 	fi
fi