#!/bin/bash
# Script to create cscope.out file for any workspace
# Script expects to see a .mkcscope.conf file in either the current working
# directory or in your $HOME. The format of the file is as follows:
#
# This is essentially a Bash script, using a structured language as follows:
# target foo bar
#   desc Description for foo
#   files <relative path to directory> <file patterns>
#
# The above segment shows a sample target 'foo', which depends on a different
# target 'bar'. The desc line is a description for use in the help, while the
# files command specifies a directory relative to the current directory and
# the file patterns to search for and add to the cscope file list. The script
# expects to run from the base folder for the project workspace, and the
# directories in the files command are relative to this base folder.
#
# Example:
# --------
# target tmux ncurses
#   desc tmux Source code
#   files tmux *.[ch] *.[cpp]
#
# target ncurses
#   desc ncurses source code
#   files ncurses *.[ch]

APP=$(basename $0)
VERSION='1.0.1'
MAKEFILE=/dev/null
CONFFILE='.mkcscope.conf'

declare -a TARGETS=()

usage()
{
    echo "$APP v$VERSION"
    echo "Usage: $APP [options] <targets>"
    echo
    echo "Options:"
    echo "--------"
    echo "      -h      Show this help screen"
    echo "      -l      List targets"
    echo "      -r      Rebuild cscope DB without regenerating files"
    echo "      -c      Create a blank config file in the current directory"
    echo
}

files()
{
    local dir=$1
    shift
    for patt in "$@"
    do
        echo -e "\t@find $PWD/$dir -name \"$patt\" -print >> $CSCOPE_FILES" >> $MAKEFILE
    done
}

desc()
{
    echo -e "\t@echo $@" >> $MAKEFILE
}

target()
{
    local tgt=$1
    shift

    echo "$tgt: $@" >> $MAKEFILE

    TARGETS=(${TARGETS[@]} $tgt)
}

list_targets()
{
    echo "Supported targets:"
    echo "------------------"
    for tgt in ${TARGETS[@]}
    do
        echo " - $tgt"
    done
}

gen_makefile()
{
    MAKEFILE=$(mktemp --tmpdir cscope-$USER-XXXXXXXX.mk)
    CSCOPE_FILES=$PWD/cscope.files
}

gen_cscope()
{
    cscope -bqv
}

gen_targets()
{
    set -f

    if [[ -r "$PWD/$CONFFILE" ]]
    then
        source "$PWD/$CONFFILE"
    elif [[ -r "$HOME/$CONFFILE" ]]
    then
        source "$HOME/$CONFFILE"
    else
        echo "Unable to find a configuration file!" >&2
        echo "Expect to find a $CONFFILE in either of:" >&2
        echo "    $PWD" >&2
        echo "    $HOME" >&2
        exit 1
    fi
}

gen_config()
{
    (cat <<-EOM
# Configuration for mkcscope
# This is essentially a Bash script, using a structured language as follows:
# target foo bar
#   desc Description for foo
#   files <relative path to directory> <file patterns>
#
# The above segment shows a sample target 'foo', which depends on a different
# target 'bar'. The desc line is a description for use in the help, while the
# files command specifies a directory relative to the current directory and
# the file patterns to search for and add to the cscope file list. The script
# expects to run from the base folder for the project workspace, and the
# directories in the files command are relative to this base folder.

# Sample configuration
# target foo bar
#     desc Target 'foo' depends on 'bar'
#     # Files are in the folder foo relative to \$PWD
#     files foo *.[ch] *.cpp
#
# target bar baz
#     desc Target 'bar' depends on 'baz'
#     # Multiple files
#     files bar/folder1 *.s
#     files bar/folder2 *.h
#
# target baz
#     desc Target 'baz' does not depend on anything
#     files baz/*.c

EOM
    ) > "$PWD/$CONFFILE"
}

cleanup()
{
    rm $MAKEFILE
}

trap cleanup "EXIT"

gen_makefile
gen_targets

while getopts "hlrc" OPTION
do
    case $OPTION in
    h)
        usage
        exit 0
        ;;

    l)
        list_targets
        exit 0
        ;;

    r)
        echo "Rebuilding existing cscope database"
        gen_cscope
        exit 0
        ;;

    c)
        echo "Creating blank configuration"
        gen_config
        exit 0
        ;;

    \?)
        echo "Invalid option -$OPTARG"
        exit 1
        ;;
    esac
done

shift $(($OPTIND - 1))

if [[ -n "$1" ]]
then
    rm -f $CSCOPE_FILES
    make -f $MAKEFILE "$@"

    if [[ ! -s $CSCOPE_FILES ]]
    then
        echo "$APP: Must specify targets to generate file list!" >&2
        exit 1
    fi

    gen_cscope
fi