savepatch

#!/bin/bash

# Check if commit hash is provided
if [ $# -ne 1 ]; then
    echo "Usage: save-patch COMMIT_HASH"
    echo "Example: savepatch 43184d474a753ede9c2ccecb1396e24604bd613e"
    exit 1
fi

COMMIT="$1"

# Validate that we're in a git repository
if ! git rev-parse --git-dir > /dev/null 2>&1; then
    echo "Error: Not in a git repository"
    exit 1
fi

# Validate commit exists
if ! git rev-parse --verify "$COMMIT" > /dev/null 2>&1; then
    echo "Error: Commit '$COMMIT' not found"
    exit 1
fi

# Create patches directory if it doesn't exist
mkdir -p patches

# Find the highest numbered patch file
highest_num=0
if ls patches/*.patch > /dev/null 2>&1; then
    for patch_file in patches/*.patch; do
        # Extract number from filename (assuming format NNNN-*.patch)
        filename=$(basename "$patch_file")
        if [[ $filename =~ ^([0-9]{4})- ]]; then
            num=${BASH_REMATCH[1]}
            # Remove leading zeros for comparison
            num=$((10#$num))
            if [ $num -gt $highest_num ]; then
                highest_num=$num
            fi
        fi
    done
fi

# Next number is highest + 1
next_num=$((highest_num + 1))

# Get commit subject line and make it filename-safe
subject=$(git log -1 --pretty=format:%s "$COMMIT" | tr '[:upper:]' '[:lower:]' | tr -cs 'a-z0-9' '-')

# Remove trailing dashes
subject=$(echo "$subject" | sed 's/-*$//')

# Format number prefix (4 digits with leading zeros)
num_prefix=$(printf "%04d" "$next_num")

# Generate patch filename
patch_filename="patches/${num_prefix}-${subject}.patch"

# Create the patch file
git diff "${COMMIT}^!" > "$patch_filename"

echo "Saved $patch_filename"