#!/bin/ksh
# ed
# William Robertson - www.williamrobertson.net

# More convenient way to invoke editor from command line, influenced by Oracle
# SQL*Plus where e.g. "ed myscript" invokes your chosen editor for myscript.sql.
# (Especially if you sometimes type "ed somescript" at the Unix prompt, and find
# yourself looking at a blank screen with a cryptic number at the bottom.)
# Syntax:
#     ed filename
#     ed FileName
#     ed filename.ext filename2 filename3...
# If filename not found, ed tries filename.extension for standard extensions:
file_extensions="java html htm sql lst lis txt log ctl pls sps spb spp sjf"
# The first matching filename.ext is added to the list of filenames for editing.
# Case-insensitive, so e.g. 'ed swingcolortest' will find SwingColorTest.java.
# 
# Setting optional environment variable DEBUG=TRUE allows printing of debug info
# during running, and suppresses actual 'vi' command at end. Most convenient form is
# probably "DEBUG=TRUE ed filename".

typeset -i arguments=$#
file_list=$*

# Substitute your favourite editor here:
alias edit='/applications/application_folders/vim/Vim.app/Contents/MacOS/Vim -g'
# alias edit=/usr/bin/vi

function debug
{
	# Display message if DEBUG set to TRUE:
	[[ ${DEBUG:=FALSE} = TRUE ]] && print -u2 "$*"
}

function resolve_filename
{
	# For specified filename parameter, find a matching file and echo its name,
	# supplying extension if unspecified, using case-insensitive match.
	# In Mac ksh, file names are interpreted case-insensitively, or almost...
	# e.g. say a file exists named 'SwingColorTest.java':
	# 'ls swingcolortest.java' returns 'swingcolortest.java'
	# 'ls SWINGCOLORTEST.JAVA' returns 'SWINGCOLORTEST.JAVA'
	# 'ls swingcolortest.*' returns failure.
	# 'javac swingcolortest.java' can fail because the file is treated as
	# 'swingcolortest.java' which does not match the class name specified in it.
	# (Seems to be more to it though as sometimes works...)
	# Attempt to find the real capitalisation using 'ls | grep -i filename'.

	original_filename=$1
	filename_no_path=$1
	if [[ -n ${ORACLE_PATH} ]]
	then
		# Add path elements here in standard:path:format (searched left to right):
		filepath=${ORACLE_PATH}:.
	else
		filepath=.
	fi

	debug "$0 resolving filename $*"

	if [[ ${original_filename} = */* ]]; then
		filepath=${original_filename%/*}
		debug "Specified path is '${filepath}'"

		filename_no_path=${original_filename##*/}
	fi

	if [[ ${original_filename} != ${filename_no_path} ]]; then
		debug "Filename without path component is '${filename_no_path}'"
	fi

	searchpath=$(print ${filepath} |sed 's/:/ /g')
	debug Search path is ${searchpath}

	for dir in ${searchpath}
	do
		debug Searching in directory $dir

		debug about to look for  ${dir}/${filename_no_path}, so long as ${dir}/${filename_no_path} is not a directory:
		if [[ -f ${dir}/${filename_no_path} ]] && [[ ! -d ${dir}/${filename_no_path} ]]; then
			debug "Case-insensitive check found file '${dir}/${filename_no_path}'"
			debug "Checking case by listing files named '${filename_no_path}' in directory '${dir}':"

			# Assignment and test for success combined into one crypric command line:
			# TRUE if 'ls | grep' command is successful: this will also populate 'resolved_filename'.
			if resolved_filename=${dir}/$(ls -aC1 ${dir} | grep -i "^${filename_no_path}$")
			then
				resolved_filename=${resolved_filename#./}
				debug "Check for '${filename_no_path}' in '${dir}' found '${resolved_filename}'"
			else
				debug \
				"File '${original_filename}' confirmed by -f test, but mysteriously absent for ls"
			fi
		elif [[ ${filename_no_path} != *.* ]]
		then
			debug "Did not find file '${original_filename}' as specified. Trying with standard extensions:"
			for extension in ${file_extensions}
			do
				debug "Extension '.${extension}':"
				if [[ -f ${dir}/${filename_no_path}.${extension} ]]
				then
					# Assignment and test for success combined into one crypric command line:
					# TRUE if 'ls | grep' command is successful; the result of this will also
					# populate 'resolved_filename' variable.
					if resolved_filename=${dir:-.}/$(ls -aC1 ${dir} | grep -i "^${filename_no_path}.${extension}$")
					then
						resolved_filename=${resolved_filename#./}
						debug \
						"Found file named '${resolved_filename}' in directory '${dir}'"

						break
					else
						print -u2 \
						Case of filename ${original_filename}.${extension} in question
					fi
				else
					debug \
					"Checking possible extensions: ${original_filename}.${extension} not found"
				fi
			done
		fi
	done  # end file path loop

	if [[ -n ${resolved_filename} ]]
	then
		print ${resolved_filename}
	else
		print -u2 "$0: No file found matching ${original_filename}"
		return 1
	fi
}

# End of function definitions; start of processing:

debug print Debug mode - displaying diagnostics only:
[[ ${DEBUG} = TRUE ]] && alias edit

if (( arguments > 0 )); then
	for filename in $@
	do
		filelist="${filelist} $(resolve_filename ${filename})"
	done

	# Strip trailing spaces:
	while [[ ${filelist} != ${filelist%% } ]]
	do
		filelist=${filelist%% }
	done

	debug "filelist is '${filelist}'"
fi

debug "Number of arguments = $arguments"

if (( arguments > 0 )) && [[ -z ${filelist} ]]
then
	typeset -uL1 yesno

	read yesno?"No files found. Continue? [Y/N] "

	if [[ ${yesno} = Y ]]; then
		[[ ${DEBUG} = TRUE ]] && alias edit
		edit ${file_list}
	else
		exit 0
	fi
else
	debug "Editing file list: '${filelist}'"
	
	if [[ ${DEBUG:=TRUE} = TRUE ]]; then
		debug edit ${filelist}
	else
		[[ ${DEBUG} = TRUE ]] &&  set -vx
		edit ${filelist}
	fi
fi