#!/bin/bash

pyenv_version=1.2.23
pyenv_virtualenv_version=1.1.5
pyenv_install_dir="/opt/pyenv"
python_version_path="$pyenv_install_dir/versions"
# PYENV_ROOT is the directory of pyenv, it needs to be loaded as a environment variable.
export PYENV_ROOT="$pyenv_install_dir"

# Required dependencies
pyenv_dependencies="build-essential libssl1.0-dev|libssl-dev zlib1g-dev libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm libncurses5-dev libncursesw5-dev xz-utils tk-dev libffi-dev liblzma-dev python-openssl git"

# Install Python Version Management
#
# [internal]
#
# usage: ynh_install_pyenv
#
# Requires YunoHost version 2.7.12 or higher.
ynh_install_pyenv () {
    ynh_print_info --message="Installation of pyenv - Python Version Management - pyenv-$pyenv_version/pyenv-virtualenv-$pyenv_virtualenv_version"

    # Build an app.src for pyenv
    mkdir -p "../conf"
    echo "SOURCE_URL=https://github.com/pyenv/pyenv/archive/v${pyenv_version}.tar.gz
SOURCE_SUM=805058aa5ce257157fb4769543e6a43bac45a88c723ff3c4fcf5b4f759056bf5" > "../conf/pyenv.src"
    # Download and extract pyenv
    ynh_setup_source --dest_dir="$pyenv_install_dir" --source_id=pyenv

    # Build an app.src for pyenv-virtualenv
    mkdir -p "../conf"
    echo "SOURCE_URL=https://github.com/pyenv/pyenv-virtualenv/archive/v${pyenv_virtualenv_version}.tar.gz
SOURCE_SUM=27ae3de027a6f6dccdca4085225512e559c6b94b31625bd2b357a18890a1e618" > "../conf/pyenv-virtualenv.src"
    # Download and extract pyenv-virtualenv
    ynh_setup_source --dest_dir="$pyenv_install_dir/plugins/pyenv-virtualenv" --source_id=pyenv-virtualenv

    (cd $pyenv_install_dir
    ./src/configure && make -C src)

    # Create shims directory if needed
    if [ ! -d $pyenv_install_dir/shims ] ; then
        mkdir $pyenv_install_dir/shims
    fi
}

# Load the version of Python for an app, and set variables.
#
# ynh_use_python has to be used in any app scripts before using Python for the first time.
# This helper will provide alias and variables to use in your scripts.
#
# To use pip or Python, use the alias `ynh_pip` and `ynh_python`
# Those alias will use the correct version installed for the app
# For example: use `ynh_pip install` instead of `pip install`
#
# With `sudo` or `ynh_exec_as`, use instead the fallback variables `$ynh_pip` and `$ynh_python`
# And propagate $PATH to sudo with $ynh_python_load_path
# Exemple: `ynh_exec_as $app $ynh_python_load_path $ynh_pip install`
#
# $PATH contains the path of the requested version of Python.
# However, $PATH is duplicated into $python_path to outlast any manipulation of $PATH
# You can use the variable `$ynh_python_load_path` to quickly load your Python version
#  in $PATH for an usage into a separate script.
# Exemple: $ynh_python_load_path $final_path/script_that_use_pip.sh`
#
#
# Finally, to start a Python service with the correct version, 2 solutions
#  Either the app is dependent of python or pip, but does not called it directly.
#  In such situation, you need to load PATH
#    `Environment="__YNH_PYTHON_LOAD_ENV_PATH__"`
#    `ExecStart=__FINALPATH__/my_app`
#     You will replace __YNH_PYTHON_LOAD_ENV_PATH__ with $ynh_python_load_path
#
#  Or Python start the app directly, then you don't need to load the PATH variable
#    `ExecStart=__YNH_PYTHON__ my_app run`
#     You will replace __YNH_PYTHON__ with $ynh_python
#
#
# one other variable is also available
#   - $python_path: The absolute path to Python binaries for the chosen version.
#
# usage: ynh_use_python
#
# Requires YunoHost version 2.7.12 or higher.
ynh_use_python () {
    python_version=$(ynh_app_setting_get --app=$app --key=python_version)

    # Get the absolute path of this version of Python
    python_path="$python_version_path/$YNH_APP_INSTANCE_NAME/bin"

    # Allow alias to be used into bash script
    shopt -s expand_aliases

    # Create an alias for the specific version of Python and a variable as fallback
    ynh_python="$python_path/python"
    alias ynh_python="$ynh_python"
    # And pip
    ynh_pip="$python_path/pip"
    alias ynh_pip="$ynh_pip"

    # Load the path of this version of Python in $PATH
    if [[ :$PATH: != *":$python_path"* ]]; then
        PATH="$python_path:$PATH"
    fi
    # Create an alias to easily load the PATH
    ynh_python_load_path="PATH=$PATH"

    # Sets the local application-specific Python version
    (cd $final_path
    pyenv local $python_version)
}

# Install a specific version of Python
#
# ynh_install_python will install the version of Python provided as argument by using pyenv.
#
# This helper creates a /etc/profile.d/pyenv.sh that configures PATH environment for pyenv
# for every LOGIN user, hence your user must have a defined shell (as opposed to /usr/sbin/nologin)
#
# Don't forget to execute python-dependent command in a login environment
# (e.g. sudo --login option)
# When not possible (e.g. in systemd service definition), please use direct path
# to pyenv shims (e.g. $PYENV_ROOT/shims/bundle)
#
# usage: ynh_install_python --python_version=python_version
# | arg: -v, --python_version= - Version of Python to install.
#
# Requires YunoHost version 2.7.12 or higher.
ynh_install_python () {
    # Declare an array to define the options of this helper.
    local legacy_args=v
    local -A args_array=( [v]=python_version= )
    local python_version
    # Manage arguments with getopts
    ynh_handle_getopts_args "$@"

    # Store python_version into the config of this app
    ynh_app_setting_set --app=$YNH_APP_INSTANCE_NAME --key=python_version --value=$python_version

    # Create $pyenv_install_dir if doesn't exist already
    mkdir -p "$pyenv_install_dir/plugins/pyenv-virtualenv"

    # Install required dependencies
    ynh_add_app_dependencies --package="$pyenv_dependencies"

    # Load pyenv path in PATH
    local CLEAR_PATH="$pyenv_install_dir/bin:$PATH"

    # Remove /usr/local/bin in PATH in case of Python prior installation
    PATH=$(echo $CLEAR_PATH | sed 's@/usr/local/bin:@@')

    # Move an existing Python binary, to avoid to block pyenv
    #test -x /usr/bin/python && mv /usr/bin/python /usr/bin/python_pyenv

    # If pyenv is not previously setup, install it
    if ! type pyenv > /dev/null 2>&1
    then
        ynh_install_pyenv
    elif dpkg --compare-versions "$($pyenv_install_dir/bin/pyenv --version | cut -d" " -f2)" lt $pyenv_version
    then
        ynh_install_pyenv
    elif dpkg --compare-versions "$($pyenv_install_dir/bin/pyenv virtualenv --version | cut -d" " -f2)" lt $pyenv_virtualenv_version
    then
        ynh_install_pyenv
    fi

    # Restore /usr/local/bin in PATH
    PATH=$CLEAR_PATH

    # And replace the old Python binary
    # test -x /usr/bin/python_pyenv && mv /usr/bin/python_pyenv /usr/bin/python

    # Install the requested version of Python
    ynh_print_info --message="Installation of Python-"$python_version
    pyenv install --skip-existing $python_version &>/dev/null

    # Remove app virtualenv
    if `pyenv virtualenvs | grep --quiet "$YNH_APP_INSTANCE_NAME " 1>/dev/null 2>&1`
    then
        pyenv virtualenv-delete --force $YNH_APP_INSTANCE_NAME
    fi

    # Create app virtualenv
    pyenv virtualenv --force $python_version $YNH_APP_INSTANCE_NAME

    # Cleanup Python versions
    ynh_cleanup_python

    # Set environment for Python users
    echo  "#pyenv
export PYENV_ROOT=$pyenv_install_dir
export PATH=\"$pyenv_install_dir/bin:$PATH\"
eval \"\$(pyenv init -)\"
#pyenv" > /etc/profile.d/pyenv.sh

    # Load the environment
    eval "$(pyenv init -)"
}

# Remove the version of Python used by the app.
#
# This helper will also cleanup Python versions
#
# usage: ynh_remove_python
ynh_remove_python () {
    local python_version=$(ynh_app_setting_get --app=$YNH_APP_INSTANCE_NAME --key=python_version)

    # Load pyenv path in PATH
    local CLEAR_PATH="$pyenv_install_dir/bin:$PATH"

    # Remove /usr/local/bin in PATH in case of Python prior installation
    PATH=$(echo $CLEAR_PATH | sed 's@/usr/local/bin:@@')

    pyenv virtualenv-delete --force $YNH_APP_INSTANCE_NAME

    # Remove the line for this app
    ynh_app_setting_delete --app=$YNH_APP_INSTANCE_NAME --key=python_version

    # Cleanup Python versions
    ynh_cleanup_python
}

# Remove no more needed versions of Python used by the app.
#
# This helper will check what Python version are no more required,
# and uninstall them
# If no app uses Python, pyenv will be also removed.
#
# usage: ynh_cleanup_python
ynh_cleanup_python () {

    # List required Python version
    local installed_apps=$(yunohost app list | grep -oP 'id: \K.*$')
    local required_python_versions=""
    for installed_app in $installed_apps
    do
        local installed_app_python_version=$(yunohost app setting $installed_app python_version)
        if [[ $installed_app_python_version ]]
        then
            required_python_versions="${installed_app_python_version}\n${required_python_versions}"
        fi
    done
    
    # Remove no more needed Python version
    local installed_python_versions=$(pyenv versions --bare --skip-aliases | grep -Ev '/')
    for installed_python_version in $installed_python_versions
    do
        if ! `echo ${required_python_versions} | grep "${installed_python_version}" 1>/dev/null 2>&1`
        then
            ynh_print_info --message="Removing of Python-"$installed_python_version
            $pyenv_install_dir/bin/pyenv uninstall --force $installed_python_version
        fi
    done

    # If none Python version is required
    if [[ ! $required_python_versions ]]
    then
        # Remove pyenv environment configuration
        ynh_print_info --message="Removing of pyenv-"$pyenv_version
        ynh_secure_remove --file="$pyenv_install_dir"
        rm /etc/profile.d/pyenv.sh
    fi
}