memo

#!/usr/bin/env bash
# memo - Memoize command output with cache lifetime
# Usage: memo [OPTIONS] COMMAND [ARGS...]
# Example: memo curl example.com | jq '.data'

set -euo pipefail

# Default cache TTL in seconds (1 hour)
DEFAULT_TTL=3600
CACHE_DIR="${XDG_CACHE_HOME:-$HOME/.cache}/memo"

show_help() {
    cat <<EOF
memo - Memoize command output with cache lifetime

Usage: memo [OPTIONS] COMMAND [ARGS...]

Options:
  --ttl SECONDS   Cache lifetime in seconds (default: $DEFAULT_TTL)
  -f, --force     Force recreation of cache, ignoring existing cached value
  -h, --help      Show this help message

Examples:
  memo curl example.com              # Cache curl output for 1 hour
  memo --ttl 60 curl example.com     # Cache for 60 seconds
  memo -f curl example.com           # Force refresh, ignore cache
EOF
    exit 0
}

# Parse options
TTL="$DEFAULT_TTL"
FORCE=false
while [[ $# -gt 0 ]]; do
    case "$1" in
        -h|--help)
            show_help
            ;;
        --ttl)
            TTL="$2"
            shift 2
            ;;
        -f|--force)
            FORCE=true
            shift
            ;;
        *)
            break
            ;;
    esac
done

# Check if command provided
if [[ $# -eq 0 ]]; then
    echo "Usage: memo [OPTIONS] COMMAND [ARGS...]" >&2
    echo "Try 'memo --help' for more information." >&2
    exit 1
fi

# Create cache directory
mkdir -p "$CACHE_DIR"

# Clean up old cache files (older than DEFAULT_TTL)
find "$CACHE_DIR" -type f -mtime +$((DEFAULT_TTL / 86400)) -delete 2>/dev/null || true

# Generate cache key from command and arguments
CACHE_KEY=$(echo -n "$*" | shasum -a 256 | cut -d' ' -f1)
CACHE_FILE="$CACHE_DIR/$CACHE_KEY"

# Check if cache exists and is fresh (unless force is set)
if [[ "$FORCE" == false && -f "$CACHE_FILE" ]]; then
    # Get cache file age in seconds
    if [[ "$(uname)" == "Darwin" ]]; then
        # macOS
        CACHE_MTIME=$(stat -f %m "$CACHE_FILE")
    else
        # Linux
        CACHE_MTIME=$(stat -c %Y "$CACHE_FILE")
    fi
    
    CURRENT_TIME=$(date +%s)
    CACHE_AGE=$((CURRENT_TIME - CACHE_MTIME))
    
    if [[ $CACHE_AGE -lt $TTL ]]; then
        # Cache is fresh, return it
        cat "$CACHE_FILE"
        exit 0
    fi
fi

# Cache miss or expired - run command and cache output
"$@" | tee "$CACHE_FILE"