#!/usr/bin/env bash
#
# Description:
#     Check to see if dependencies are installed.
#     If not, warn the user and tell them how to
#     install these dependencies.
#
# Usage:
#     check-deps <dep> ...
#
# Options:
#     One or more dependencies. Must use name of binary.

for dep in "$@"; do
    if ! which $dep &> /dev/null; then
        # Map binary name to package name
        case $dep in
            sphinx-apidoc|sphinx-build)
                spack_package=py-sphinx
                pip_package=sphinx
                ;;
            coverage)
                spack_package=py-coverage
                pip_package=coverage
                ;;
            flake8)
                spack_package=py-flake8
                pip_package=flake8
                ;;
            dot)
                spack_package=graphviz
                ;;
            git)
                spack_package=git
                ;;
            hg)
                spack_package=mercurial
                pip_package=mercurial
                ;;
            svn)
                spack_package=subversion
                ;;
            *)
                spack_package=$dep
                pip_package=$dep
                ;;
        esac

        echo "ERROR: $dep is required to run this script."
        echo

        if [[ $spack_package ]]; then
            echo "To install with Spack, run:"
            echo "    $ spack install $spack_package"
        fi

        if [[ $pip_package ]]; then
            echo "To install with pip, run:"
            echo "    $ pip install $pip_package"
        fi

        if [[ $spack_package || $pip_package ]]; then
            echo "Then add the bin directory to your PATH."
        fi

        exit 1
    fi

    # Flake8 and Sphinx require setuptools in order to run.
    # Otherwise, they print out this error message:
    #
    #   Traceback (most recent call last):
    #     File: "/usr/bin/flake8", line 5, in <module>
    #       from pkg_resources import load_entry_point
    #   ImportError: No module named pkg_resources
    #
    # Print a more useful error message if setuptools not found.
    if [[ $dep == flake8 || $dep == sphinx* ]]; then
        # Find which Python is being run
        # Spack-installed packages have a hard-coded shebang
        python_cmd=$(head -n 1 $(which $dep) | cut -c 3-)
        # May not have a shebang
        if [[ $python_cmd != *python* ]]; then
            python_cmd=python
        fi
        # Check if setuptools is in the PYTHONPATH
        if ! $python_cmd -c "import setuptools" 2> /dev/null; then
            echo "ERROR: setuptools is required to run $dep."
            echo "Please add it to your PYTHONPATH."

            exit 1
        fi
    fi
done

echo "Dependencies found."