#!/bin/sh
# Stand-in script for the 'freqcd' binary. Do not modify.
#
# This stub is required for compliance with pyproject.toml specification,
# when the 'freqcd' binary has not yet been compiled. For convenience,
# this script will automatically trigger the compilation and then proceed
# to run the desired binary :)
#
# Works only on Linux, with 'ps', 'awk' and 'python3' dependencies.

# Gets the full call to current script, then retrieves program path
# e.g. /bin/sh /home/justin/.pyenv/versions/3.10.6/bin/freqcd -x ...
PROGRAM=$(ps -q $$ -o args= | awk -F ' ' '{print $2}')

# Get root directory of installed library, where postinstall script is located
ENTRYPOINT=$(python3 -c "import importlib; print(importlib.util.find_spec('fpfind').origin)")
INSTALL_ROOT=$(dirname "$(readlink -f ${ENTRYPOINT})")

# Keep a record of program path, in case one desires a manual recompilation;
# will be created in-situ only in an editable installation.
rm -f ${INSTALL_ROOT}/freqcd_path \
    && echo "${PROGRAM}" > ${INSTALL_ROOT}/freqcd_path

# Trigger post-install compilation and write directly to target
cd ${INSTALL_ROOT} && ./_postinstall ${PROGRAM} \
    || { echo "'freqcd.c' failed to compile... not running."; exit 1; }

# Pass arguments and directly execute
exec "${PROGRAM}" "$@"



# Explanation of this script as follows.
#
# We go through this trouble of adding console scripts via the build backend
# is so that the backend can manage its installation/uninstallation, as
# opposed to manual aliases/symlinks.
#
# Some issues need to be addressed before this will work:
#   1. The use of 'pyenv' for Python management causes the binaries
#      to be called as a shim, i.e. the call occurs within a nested script
#      that first sources the Python environment dynamically. The actual
#      binary location needs to be identified.
#   2. The binaries, during the library installation process, are copied
#      over from the repo directly, and is not a soft link. The binary
#      itself will thus need to be replaced.
#
# Using the 'importlib' mechanism, i.e.
#
#    import importlib; print(importlib.util.find_spec('fpfind').origin)
#
# does not work when the library is installed as an editable package,
# although it does work otherwise. The same applies to the pip discovery
# method, with the additional 'pip' dependency, i.e.
#
#    python3 -m pip show ${LIBNAME} | grep 'Location' | awk -F ': ' '{print $2}'
#
# Instead, we rely on the fact that this script will be triggered by 'sh',
# with the desired path supplied as an argument. Extracting the path is thus
# a simple matter of a 'ps' + 'awk' hack.
#
# A small side-note, use of '$PPID' to extract the parent path will not work,
# which may end up deferring to the shell emulator's process instead.
#
# Soft links could have been used instead of directly copying the binary,
# so that editable installations can still freely recompile, independently
# of the Python library install flow. However, Git will continue to track
# this file (potentially leading to accidental binary commits), and requiring
# users to run 'git-skip-worktree' manually is not ideal. A security concern
# may also arise when the editable installation is publicly modifiable.
#
# We instead the binary directly. To accomodate the need for updates, the
# path to the binary is provided during the compilation process, at:
#
#    'src/fpfind/freqcd_path'
#
# To use the soft link behaviour (at your risk), replace the code with:
#
#    cd ${INSTALL_ROOT} && ./_postinstall ${INSTALL_ROOT}/freqcd \
#        || { echo "'freqcd.c' failed to compile... not running."; exit 1; }
#    rm -f ${PROGRAM} && ln -s ${INSTALL_ROOT}/freqcd ${PROGRAM}