.bash_command_prompt

#!/bin/env bash
# PROMPT_COMMAND environment variable. 
# This variable allows you to execute a command before the display of each prompt. 


# Prevent sourcing more than once.
# New shell is required for changes to take effect.
[ "$BASH_COMMAND_PROMPT_SOURCED" = 1 ] && return 1
self="$HOME/.bash_utils"
echo Sourcing "$self"
export BASH_COMMAND_PROMPT_SOURCED=1

LAST_DIR=$(pwd)

# Function to trigger action on directory change.
function check_directory_change {
    if [[ "$PWD" != "$LAST_DIR" ]]; then
        on-directory-change "$PWD" # Directory has changed, trigger action.
        LAST_DIR="$PWD" # Update the last directory.
    fi
}

# Cache variables that might be slow to evaluate often where non-delay is expected (such as prompt).
function update-cached-vars {
    CACHED_PYTHON_VERSION=$(pyenv version-name); export CACHED_PYTHON_VERSION
    CACHED_PNPM_VERSION=$(pnpm -v); export CACHED_PNPM_VERSION
    CACHED_YARN_VERSION=$(yarn -v || echo); export CACHED_YARN_VERSION
}

# Actions to trigger when directory changes.
function on-directory-change {
    update-cached-vars # Will cause slight delay.
}


function prompt_command {
    echo
    # check_directory_change
}

# Add the check function to PROMPT_COMMAND.
# Not idempotent!
export PROMPT_COMMAND="$PROMPT_COMMAND"
# export PROMPT_COMMAND="prompt_command; $PROMPT_COMMAND"