#!/bin/sh

# Defaults

PREFIX="/usr/local"
SYSCONFDIR="$PREFIX/etc/luarocks"
ROCKS_TREE="$PREFIX"

# ----------------------------------------------------------------------------
# FUNCTION DEFINITIONS
# ----------------------------------------------------------------------------

# Utility functions
# -----------------

# Resolves a full path
# - alternative to "readlink -f", which is not available on solaris
# based on https://stackoverflow.com/a/6554854/1793220
canonicalpath() {
   oldpwd="$PWD"
   if [ -d "$1" ]
   then
      if cd "$1" >/dev/null 2>&1
      then
         echo "$PWD"
      else
         echo "$1"
      fi
   else
      if cd "$(dirname "$1")" >/dev/null 2>&1
      then
         echo "$PWD/$(basename "$1")"
      else
         echo "$1"
      fi
   fi
   cd "$oldpwd" >/dev/null 2>&1 || return
}

find_program() {
   prog=$(command -v "$1" 2>/dev/null)
   if [ -n "$prog" ]
   then
      dirname "$prog"
   fi
}

die() {
   echo "$*"
   echo
   RED "configure failed."
   echo
   echo
   exit 1
}

echo_n() {
   printf "%s" "$*"
}

bold='\033[1m'
red='\033[1;31m'
green='\033[1;32m'
blue='\033[1;36m'
reset='\033[0m'

BOLD() {
   printf "$bold%s$reset" "$*"
}

RED() {
   printf "$red%s$reset" "$*"
}

GREEN() {
   printf "$green%s$reset" "$*"
}

BLUE() {
   printf "$blue%s$reset" "$*"
}

# Help
# ----

show_help() {
cat <<EOF

Configure the build process of LuaRocks.

--help                         This help.

Where to install LuaRocks:
--------------------------

--prefix=PREFIX                Directory where LuaRocks should be installed.
                               - Default is $PREFIX
--sysconfdir=SYSCONFDIR        Where the config file should be installed.
                               - Default is $SYSCONFDIR
                                 (PREFIX/etc/luarocks)

Where to install files provided by rocks:
-----------------------------------------

--rocks-tree=ROCKS_DIR         Root of the local tree of installed rocks.
                               To make files installed in this location
                               accessible to Lua and your \$PATH, see
                               "luarocks path --help" after installation.
                               Avoid using paths controlled by your
                               system's package manager, such as /usr.
                               - Default is $PREFIX
                                 (PREFIX)

Where is your Lua interpreter:
------------------------------

--lua-version=VERSION)          Use specific Lua version: 5.1, 5.2, 5.3, or 5.4
                               - Default is auto-detected.
--with-lua=LUA_DIR)             Use Lua from given directory.
                               - Default is auto-detected from your \$PATH
                                 (or the parent directory of LUA_BINDIR
                                 if --with-lua-bin is used).
--with-lua-bin=LUA_BINDIR)      You can also specify Lua's bin dir.
                               - Default is the directory of the
                                 auto-detected Lua interpreter,
                                 (or LUA_DIR/bin if --with-lua is used)
--with-lua-include=LUA_INCDIR)  Lua's includes dir.
                               - Default is LUA_DIR/include
--with-lua-lib=LUA_LIBDIR)      Lua's libraries dir.
                               - Default is LUA_DIR/lib

For specialized uses of LuaRocks:
---------------------------------

--force-config)                 Force using a single config location.
                               Do not honor the \$LUAROCKS_CONFIG_5_x
                               or \$LUAROCKS_CONFIG environment
                               variable or the user's local config.
                               Useful to avoid conflicts when LuaRocks
                               is embedded within an application.

EOF
}

# Lua detection
# -------------

detect_lua_version() {
   detected_lua=$($1 -e 'print(_VERSION:match(" (5%.[1234])$"))' 2> /dev/null)
   if [ "$detected_lua" != "nil" ]
   then
      if [ "$LUA_VERSION_SET" != "yes" ]
      then
         echo "Lua version detected: $(GREEN "$detected_lua")"
         LUA_VERSION=$detected_lua
         return 0
      elif [ "$LUA_VERSION" = "$detected_lua" ]
      then
         return 0
      fi
   fi
   return 1
}

search_interpreter() {
   suffix="$1"
   lua_at=""
   if [ "$LUA_BINDIR_SET" = "yes" ]
   then
      lua_at="$LUA_BINDIR"
   elif [ "$LUA_DIR_SET" = "yes" ]
   then
      LUA_BINDIR="$LUA_DIR/bin"
      if [ -f "$LUA_BINDIR/lua$suffix" ]
      then
         lua_at="$LUA_BINDIR"
      fi
   else
      lua_at=$(find_program "lua$suffix")
   fi
   if [ -n "$lua_at" ] && [ -x "$lua_at/lua$suffix" ]
   then
      if detect_lua_version "$lua_at/lua$suffix"
      then
         echo "Lua interpreter found: $(GREEN "$lua_at/lua$suffix")"
         if [ "$LUA_BINDIR_SET" != "yes" ]
         then
            LUA_BINDIR="$lua_at"
         fi
         if [ "$LUA_DIR_SET" != "yes" ]
         then
            LUA_DIR=$(dirname "$lua_at")
         fi
         LUA_INTERPRETER="lua$suffix"
         return 0
      fi
   fi
   return 1
}

# ----------------------------------------------------------------------------
# MAIN PROGRAM
# ----------------------------------------------------------------------------

# Parse options

while [ -n "$1" ]
do
   value="$(echo "$1" | sed 's/[^=]*.\(.*\)/\1/')"
   key="$(echo "$1" | sed 's/=.*//')"
   if echo "$value" | grep "~" >/dev/null 2>/dev/null
   then
      echo
      echo "$(RED WARNING:) the '~' sign is not expanded in flags."
      echo "If you mean the home directory, use \$HOME instead."
      echo
   fi
   case "$key" in

   # Help
   # ----
   --help)
      show_help
      exit 0
      ;;

   # Where to install LuaRocks:
   # --------------------------
   --prefix)
      [ -n "$value" ] || die "Missing value in flag $key."
      PREFIX="$(canonicalpath "$value")"
      PREFIX_SET=yes
      ;;
   --sysconfdir)
      [ -n "$value" ] || die "Missing value in flag $key."
      SYSCONFDIR="$(canonicalpath "$value")"
      SYSCONFDIR_SET=yes
      ;;


   # Where to install files provided by rocks:
   # -----------------------------------------
   --rocks-tree)
      [ -n "$value" ] || die "Missing value in flag $key."
      ROCKS_TREE="$(canonicalpath "$value")"
      ROCKS_TREE_SET=yes
      ;;

   # Where is your Lua interpreter:
   # ------------------------------
   --lua-version|--with-lua-version)
      [ -n "$value" ] || die "Missing value in flag $key."
      LUA_VERSION="$value"
      case "$LUA_VERSION" in
      5.1|5.2|5.3|5.4) ;;
      *) die "Invalid Lua version in flag $key."
      esac
      LUA_VERSION_SET=yes
      ;;
   --with-lua)
      [ -n "$value" ] || die "Missing value in flag $key."
      LUA_DIR="$(canonicalpath "$value")"
      [ -d "$LUA_DIR" ] || die "Bad value for --with-lua: $LUA_DIR is not a valid directory."
      LUA_DIR_SET=yes
      ;;
   --with-lua-bin)
      [ -n "$value" ] || die "Missing value in flag $key."
      LUA_BINDIR="$(canonicalpath "$value")"
      [ -d "$LUA_BINDIR" ] || die "Bad value for --with-lua-bin: $LUA_BINDIR is not a valid directory."
      LUA_BINDIR_SET=yes
      ;;
   --with-lua-include)
      [ -n "$value" ] || die "Missing value in flag $key."
      LUA_INCDIR="$(canonicalpath "$value")"
      [ -d "$LUA_INCDIR" ] || die "Bad value for --with-lua-include: $LUA_INCDIR is not a valid directory."
      ;;
   --with-lua-lib)
      [ -n "$value" ] || die "Missing value in flag $key."
      LUA_LIBDIR="$(canonicalpath "$value")"
      [ -d "$LUA_LIBDIR" ] || die "Bad value for --with-lua-lib: $LUA_LIBDIR is not a valid directory."
      ;;

   # For specialized uses of LuaRocks:
   # ---------------------------------
   --force-config)
      FORCE_CONFIG=yes
      ;;

   # Old options that no longer apply
   # --------------------------------
   --versioned-rocks-dir)
      echo "--versioned-rocks-dir is no longer necessary."
      echo "The rocks tree in LuaRocks 3.0 is always versioned."
      ;;
   --lua-suffix)
      echo "--lua-suffix is no longer necessary."
      echo "The suffix is automatically detected."
      ;;

   *)
      die "Error: Unknown flag: $1"
      ;;
   esac
   shift
done

echo
BLUE "Configuring LuaRocks..."
echo
echo

# ----------------------------------------
# Derive options from the ones given
# ----------------------------------------

if [ "$PREFIX_SET" = "yes" ] && [ ! "$SYSCONFDIR_SET" = "yes" ]
then
   if [ "$PREFIX" = "/usr" ]
   then SYSCONFDIR=/etc/luarocks
   else SYSCONFDIR=$PREFIX/etc/luarocks
   fi
fi

if [ "$PREFIX_SET" = "yes" ] && [ ! "$ROCKS_TREE_SET" = "yes" ]
then
   ROCKS_TREE=$PREFIX
fi

# ----------------------------------------
# Search for Lua
# ----------------------------------------

lua_interp_found=no

case "$LUA_VERSION" in
5.1)
   suffixes="5.1 51 -5.1 -51 jit"
   ;;
5.2)
   suffixes="5.2 52 -5.2 -52"
   ;;
5.3)
   suffixes="5.3 53 -5.3 -53"
   ;;
5.4)
   suffixes="5.4 54 -5.4 -54"
   ;;
*)
   suffixes="5.4 54 -5.4 -54 5.3 53 -5.3 -53 5.2 52 -5.2 -52 5.1 51 -5.1 -51 jit"
   ;;
esac

for suffix in $suffixes ""
do
   search_interpreter "$suffix" && {
      lua_interp_found=yes
      break
   }
done

if [ "$lua_interp_found" != "yes" ]
then
   if [ "$LUA_VERSION_SET" ]
   then
      interp="Lua $LUA_VERSION"
   else
      interp="Lua"
   fi
   if [ "$LUA_DIR_SET" ] || [ "$LUA_BINDIR_SET" ]
   then
      where="$LUA_BINDIR"
   else
      where="\$PATH"
   fi
   echo "$(RED $interp interpreter not found) in $where"
   echo "You may want to use the flags $(BOLD --with-lua), $(BOLD --with-lua-bin) and/or $(BOLD --lua-version)"
   die "Run $(BOLD ./configure --help) for details."
fi

if [ "$LUA_VERSION_SET" = "yes" ]
then
   echo_n "Checking if $LUA_BINDIR/$LUA_INTERPRETER is Lua version $LUA_VERSION... "
   if detect_lua_version "$LUA_BINDIR/$LUA_INTERPRETER"
   then
      echo "yes"
   else
      echo "no"
      die "You may want to use the flags --with-lua, --with-lua-bin and/or --lua-version. See --help."
   fi
fi

unzip_found=$(find_program "unzip")
if [ -n "$unzip_found" ]
then
   echo "unzip found in PATH: $(GREEN "$unzip_found")"
else
   RED "Could not find 'unzip'."
   die "Make sure it is installed and available in your PATH."
fi

# Write config

make clean > /dev/null 2> /dev/null

rm -f built
cat <<EOF > config.unix
# This file was automatically generated by the configure script.
# Run "./configure --help" for details.

PREFIX=$PREFIX
SYSCONFDIR=$SYSCONFDIR
ROCKS_TREE=$ROCKS_TREE
LUA_VERSION=$LUA_VERSION
LUA_INTERPRETER=$LUA_INTERPRETER
LUA_DIR=$LUA_DIR
LUA_BINDIR=$LUA_BINDIR
LUA_INCDIR=$LUA_INCDIR
LUA_LIBDIR=$LUA_LIBDIR
FORCE_CONFIG=$FORCE_CONFIG
EOF

{
   echo '-- LuaRocks configuration'
   echo
   echo 'rocks_trees = {'
   echo '   { name = "user", root = home .. "/.luarocks" },'
   echo '   { name = "system", root = "'"$ROCKS_TREE"'" },'
   echo '}'
   if [ -n "$LUA_INTERPRETER" ]; then echo 'lua_interpreter = "'"$LUA_INTERPRETER"'"' ; fi
   if [ -n "$LUA_DIR" ]; then echo 'variables.LUA_DIR = "'"$LUA_DIR"'"' ; fi
   if [ -n "$LUA_INCDIR" ]; then echo 'variables.LUA_INCDIR = "'"$LUA_INCDIR"'"' ; fi
   if [ -n "$LUA_BINDIR" ]; then echo 'variables.LUA_BINDIR = "'"$LUA_BINDIR"'"' ; fi
   if [ -n "$LUA_LIBDIR" ]; then echo 'variables.LUA_LIBDIR = "'"$LUA_LIBDIR"'"' ; fi
} > "config-$LUA_VERSION.lua.in"

echo
BLUE "Done configuring."
echo
echo
echo "LuaRocks will be installed at......: $(GREEN "$PREFIX")"
echo "LuaRocks will install rocks at.....: $(GREEN "$ROCKS_TREE")"
echo "LuaRocks configuration directory...: $(GREEN "$SYSCONFDIR")"
echo "Using Lua from.....................: $(GREEN "$LUA_DIR")"
echo
echo "* Type $(BOLD make build) and $(BOLD make install):"
echo "  to install to $PREFIX as usual."
echo "* Type $(BOLD make bootstrap):"
echo "  to install LuaRocks into $ROCKS_TREE as a rock."
echo