#!/bin/bash

# This script does the following:
# 0. If indicated by environent variables, look for DBMS-supplied Python
#    installation. E.g., Greenplum supplies its own Python, and its currently
#    the first choice to use because it guarantees that python, pygresql
#    (currently needed to connect to a GP database), and libpg all have the same
#    architecture.
# 1. Of step 0 failed, find python interpreter by
#    - first looking for "python${VERSION}" in $PATH where
#      ${VERSION} in {2.7, 2.6}
#    - Only if that fails, look for "python" in $PATH
# 2. Pass all arguments to ../madpack/madpack.py

PYTHON_PREFIX="python"
PYTHON_VERSIONS="2.7 2.6"

# create absolute path to madpack.py
pushd `dirname $0` > /dev/null
MADPACK_PATH="$(pwd -P)/../madpack/madpack.py"
popd > /dev/null

# MADPACK_PATH="$(dirname 0)/../madpack/madpack.py"

# Initialization
DID_NOT_FIND_INTERPRETER=1

# Platform-specific overrides
if test "$GPHOME" && test "$PYTHONHOME" && \
    test "${PYTHONHOME:0:${#GPHOME}}" = "$GPHOME"; then

    DID_NOT_FIND_INTERPRETER=0
    PYTHON_EXE_NAME="${PYTHONHOME}/bin/python"
fi

errorNoPythonFound() {
    echo "No Python interpreter found. Please install Python 2.6 or higher to" \
        "run madpack."
    exit 1
}

setAndTestPythonVesion() {
    PYTHON_EXE_NAME="${PYTHON_PREFIX}$1"
    command -v "${PYTHON_EXE_NAME}" > /dev/null
    DID_NOT_FIND_INTERPRETER=$?
}


# function main()
if test $DID_NOT_FIND_INTERPRETER -ne 0; then
    for VERSION in $PYTHON_VERSIONS; do
        setAndTestPythonVesion "${VERSION}"
        if test $DID_NOT_FIND_INTERPRETER -eq 0; then
            break
        fi
    done
fi

if test $DID_NOT_FIND_INTERPRETER -ne 0; then
    setAndTestPythonVesion ""
fi

if test $DID_NOT_FIND_INTERPRETER -ne 0; then
    errorNoPythonFound
fi

"$PYTHON_EXE_NAME" "${MADPACK_PATH}" "$@"