# Common routines - do not execute directly.

# Sanitize environment
set -e
export LANG=C
export LC_ALL=C

_SHU_PROGDIR=$(dirname "$0")
_SHU_PROGNAME=$(basename "$0")

# Print an error message to stderr then exit the current process.
panic () {
    echo "ERROR: $@" >&2
    exit 1
}

# Internal verbosity level. Note that this value is inherited from
# the VERBOSE environment variable.
_SHU_VERBOSE=${VERBOSE:-1}

# Increment internal verbosity level.
increment_verbosity () {
    _SHU_VERBOSE=$(( $_SHU_VERBOSE + 1 ))
}

# Decrement internal verbosity level.
decrement_verbosity () {
    _SHU_VERBOSE=$(( $_SHU_VERBOSE - 1 ))
}

# Return internal verbosity level, clamped to 0 as a minimum bound.
get_verbosity () {
    local RET=$_SHU_VERBOSE
    if [ "$RET" -lt 0 ]; then
        RET=0
    fi
    echo "$RET"
}

# Used internally to conditionally print a message.
# $1: message's verbosity level. If greater or equal than $_SHU_VERBOSE then
#     the message will be ignored.
# $2+: message to print to stdout.
dump_n () {
    local LEVEL=$1
    shift
    if [ "$LEVEL" -lt "$_SHU_VERBOSE" ]; then
        printf "%s\n" "$@"
    fi
}

# Dump a message to standard output.
dump () {
    dump_n 0 "$@"
}

# Dump a message to standard output if --verbose was used.
log () {
    dump_n 1 "$@"
}

# Dump a message to standard output if --verbose --verbose is used.
log2 () {
    dump_n 2 "$@"
}

# Run a command, output depends on verbosity level
run () {
    local VERBOSE=$_SHU_VERBOSE
    if [ "$VERBOSE" -lt 0 ]; then
        VERBOSE=0
    fi
    if [ "$VERBOSE" -gt 1 ]; then
        echo "COMMAND: $@"
    fi
    case $VERBOSE in
        0|1)
             "$@" >/dev/null 2>&1
             ;;
        2)
            "$@" >/dev/null
            ;;
        *)
            "$@"
            ;;
    esac
}

# Return the current script's directory.
program_directory () {
    printf "%s" "$_SHU_PROGDIR"
}

# Return the current script's filename.
program_name () {
    printf "%s" "$_SHU_PROGNAME"
}

# Return the value of a given named variable.
# $1: variable name
#
# example:
#    FOO=BAR
#    BAR=ZOO
#    echo `var_value $FOO`
#    will print 'ZOO'
#
var_value () {
    eval printf %s \"\$$1\"
}

# Return success if variable $1 is set and non-empty, failure otherwise.
# $1: Variable name.
# Usage example:
#   if var_is_set FOO; then
#      .. Do something the handle FOO condition.
#   fi
var_is_set () {
    test -n "$(var_value $1)"
}

# Set the value of a given name variables.
# $1: Variable name.
# $2+: Variable value.
# example:
#    FOO=BAR
#    var_assign $FOO bar
# is equivalent to
#    BAR=bar
var_assign () {
    local _var_assign_varname
    _var_assign_varname=$1
    shift
    eval $_var_assign_varname=\'"$*"\'
}

# Append a space-separated list of items to a given variable.
# $1: Variable name.
# $2+: Variable value.
# Example:
#   FOO=
#   var_append FOO foo    (FOO is now 'foo')
#   var_append FOO bar    (FOO is now 'foo bar')
#   var_append FOO zoo    (FOO is now 'foo bar zoo')
var_append () {
    local _var_append_varname
    _var_append_varname=$1
    shift
    if test $(var_value $_var_append_varname); then
        eval $_var_append_varname=\$$_var_append_varname\'\ "$*"\'
    else
        eval $_var_append_varname=\'"$*"\'
    fi
}

# Import shell script $1. Similar to sourcing the script except
# that each script will only be sourced once, even with multiple
# dependencies.
shell_import () {
    local SCRIPT="$_SHU_PROGDIR/$1"
    if [ ! -f "$SCRIPT" ]; then
        panic "Missing script: $SCRIPT"
    fi
    local SCRIPT_TAG=_SHU_SHELL_SCRIPT_TAG__${1%%.shi}
    SCRIPT_TAG=$(echo "$SCRIPT_TAG" | tr '-' '_')
	case $(var_value $SCRIPT_TAG) in
        imported)
            # Script is already imported.
            return 0
            ;;
        importing)
            # Script is already being imported, this is
            # a circular dependency.
            panic "Circular dependency when trying to import $1"
            ;;
        *)
            # Import the script.
            var_assign $SCRIPT_TAG importing
            . "$SCRIPT"
            var_assign $SCRIPT_TAG imported
            ;;
    esac
}

# Unpack a given archive into a given destination directory.
# $1: Archive path
# $2: Destination directory
unpack_archive () {
    local PKG_PATH="$1"
    local DEST_DIR="$2"
    case $PKG_PATH in
        *.tar.gz|*.tar.bz2|*.tar.xz)
            run tar xf "$PKG_PATH" -C "$DEST_DIR"
            ;;
        *.zip)
            run unzip -q -o -d "$DEST_DIR" "$PKG_PATH"
            ;;
        *)
            panic "Unsupported package format: $PKG_PATH"
            ;;
    esac
}

# Return the build machine's operating system tag.
# Valid return values are:
#    linux
#    darwin
#    freebsd
#    windows   (really MSys)
#    cygwin
get_build_os () {
    if [ -z "$_SHU_BUILD_OS" ]; then
        _SHU_BUILD_OS=$(uname -s)
        case $_SHU_BUILD_OS in
            Darwin)
                _SHU_BUILD_OS=darwin
                ;;
            FreeBsd)  # note: this is not tested
                _SHU_BUILD_OS=freebsd
                ;;
            Linux)
                # note that building  32-bit binaries on x86_64 is handled later
                _SHU_BUILD_OS=linux
                ;;
            CYGWIN*|*_NT-*)
                _SHU_BUILD_OS=windows
                if [ "x$OSTYPE" = xcygwin ] ; then
                    _SHU_BUILD_OS=cygwin
                fi
                ;;
        esac
    fi
    echo "$_SHU_BUILD_OS"
}

# Return the executable extension for a given operating system tag.
# $1: operating system tag.
_shu_get_exe_extension_for () {
    case $1 in
        windows|cygwin)
            echo ".exe"
            ;;
        *)
            echo ""
    esac
}

# Return the dynamic library extension for a given operating system tag.
# $1: operating system tag.
_shu_get_dll_extension_for () {
    case $1 in
        darwin)
            echo ".dylib"
            ;;
        windows|cygwin)
            echo ".dll"
            ;;
        *)
            echo ".so"
            ;;
    esac
}

# Return the extension of executables on the build machine.
get_build_exe_extension () {
    if [ -z "$_SHU_BUILD_EXE_EXTENSION_DEFINED" ]; then
        _SHU_BUILD_EXE_EXTENSION=$(_shu_get_exe_extension_for $(get_build_os))
        _SHU_BUILD_EXE_EXTENSION_DEFINED=true
    fi
    echo "$_SHU_BUILD_EXE_EXTENSION"
}

# Return the extension of dynamic libraries on the build machine.
get_build_dll_extension () {
    if [ -z "$_SHU_BUILD_DLL_EXTENSION_DEFINED" ]; then
        _SHU_BUILD_DLL_EXTENSION=$(_shu_get_dll_extension_for $(get_build_os))
        _SHU_BUILD_DLL_EXTENSION_DEFINED=true
    fi
    echo "$_SHU_BUILD_DLL_EXTENSION"
}

# Return the number of CPU cores on the build machine.
get_build_num_cores () {
    case $(get_build_os) in
        linux)
            grep -c -e processor /proc/cpuinfo
            ;;
        darwin|freebsd)
            sysctl -n hw.ncpu
            ;;
        windows|cygwin)
            echo "${NUMBER_OF_PROCESSORS:-1}"
            ;;
        *)
            echo "1"
            ;;
    esac
}