#!/bin/bash
function do_help() {
    printf "Options:
  --help (-h)   Display this message
  --prefix      Path to install MOOG
  --bindir      Path to install MOOG binaries (default: PREFIX/bin)
  --datadir     Path to install MOOG data files (default: PREFIX/share/moog)
  --with-x11    Path to X11 lib directory
  --with-sm     Path to SM lib directory\n"
}

dummy_c='#include <stdio.h>
int main(int argc, char *argv[]) { return 0; }'

function check_lib() {
    # Purpose:
    #   Link a dummy C program to a library
    #
    # Invocation:
    #   check_lib X11 /usr/X11/lib
    #   check_lib X11
    #
    # Returns:
    #   "yes" and 0 on linkage success
    #   "no" and 1 on linkage failure
    if [[ $# < 1 ]]; then
        echo "ERROR: ${FUNCNAME[0]}: Missing library name" >&2
        return 2
    fi

    local name="$(mktemp)"
    local lib="${1}"
    local libdirs=""
    for libdir in "${@:2}"; do
        libdirs+="-L$libdir "
    done

    echo "$dummy_c" > "$name".c
    if ! "$CC" -o "${name}" -l"${lib}" $libdirs "${name}".c; then
        echo "no"
        rm -f "$name"
        rm -f "$name".c
        return 1
    fi
    echo "yes"
    rm -f "$name"
    rm -f "$name".c
    return 0
}

# Determine C compiler's absolute path
CC=${CC:-gcc}
CC="$(command -v $CC 2>/dev/null)"
if [[ ! -f "$CC" ]]; then
    echo "$CC could not be found" >&2
    exit 1
fi
if [[ -L "$CC" ]]; then
    CC="$(readlink $CC)"
fi

# Determine fortran compiler's absolute path
FC=${FC:-gfortran}
FC="$(command -v $FC 2>/dev/null)"
if [[ ! -f "$FC" ]]; then
    echo "$FC could not be found" >&2
    exit 1
fi
if [[ -L "$FC" ]]; then
    FC="$(readlink $FC)"
fi

with_x11="/usr/X11/lib"
with_sm="/usr/local/sm"
fflags=(
    -Wall
    -Wextra
    -ff2c
    -fdefault-double-8
    -fdefault-real-8
)
gcc_version="$($FC -v 2>&1 | tail -n 1 | sed -E -n 's/gcc\ version\ ([0-9]+.[0-9]+.[0-9]+).*/\1/p')"
gcc_major="${gcc_version%%\.*}"

# Handle GCC 10 requirements
if (( $gcc_major >= 10 )); then
    fflags+=(--allow-argument-mismatch)
fi

# Generate new argv list, with elements split on '=' or ' '
argv=()
for x in $@; do
    if [[ "$x" =~ .*=.* ]]; then
        key="${x%=*}"
        value="${x#*=}"
        argv+=($key)
        argv+=($value)
    else
        argv+=($x)
    fi
done


# Parse arguments
i=0
nargs=${#argv[@]}
while [[ $i < $nargs ]]; do
    key="${argv[$i]}"
    value="${argv[$i+1]}"
    case "$key" in
        --help|-h)
            do_help
            exit 0
            ;;
        --prefix)
            prefix="$value"
            (( i++ ))
            ;;
        --bindir)
            bindir="$value"
            (( i++ ))
            ;;
        --datadir)
            datadir="$value"
            (( i++ ))
            ;;
        --with-x11)
            with_x11="$value"
            (( i++ ))
            ;;
        --with-sm)
            with_sm="$value"
            (( i++ ))
            ;;
    esac
    (( i++ ))
done

# Assign default paths if not modified by the user
[[ -z "${prefix}" ]] && prefix="/usr/local"
[[ -z "${bindir}" ]] && bindir="${prefix}/bin"
[[ -z "${datadir}" ]] && datadir="${prefix}/share/moog"

# Convert fortran flag array to string
fflags="${fflags[@]}"

# Populate build templates
sed "s|@PREFIX@|${prefix}|g;\
    s|@BINDIR@|${bindir}|g;\
    s|@DATADIR@|${datadir}|g;\
    s|@FFLAGS@|${fflags}|g;\
    s|@WITH_X11@|${with_x11}|g;\
    s|@WITH_SM@|${with_sm}|g;\
    s|@FC@|${FC}|g;\
    " Makefile.in > Makefile
sed "s|@MOOGPATH_DEFAULT@|${datadir}/|" Moog.f.in > Moog.f

state_tcl=$(check_lib tcl)
state_tk=$(check_lib tk)
state_x11=$(check_lib X11 $with_x11)
state_sm_plotsub=$(check_lib plotsub $with_sm)
state_sm_devices=$(check_lib devices $with_sm)
state_sm_utils=$(check_lib utils $with_sm)

# Dump information
printf "
Configured with:

GCC version ........... $gcc_version
Fortran compiler ...... $FC
Installation prefix ... $prefix
X11 library ........... $with_x11
X11 works ............. $state_x11
TCL works ............. $state_tcl
TK works .............. $state_tk
SM library ............ $with_sm
SM (plotsub) works .... $state_sm_plotsub
SM (devices) works .... $state_sm_devices
SM (utils) works ...... $state_sm_utils

Run 'make' to compile
Run 'make install' to install
"