#!/bin/bash
# create-patch.sh
# Creates a patch file from the current bssh-russh changes compared to upstream russh
#
# Usage: ./create-patch.sh

set -e

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
BSSH_ROOT="$SCRIPT_DIR/../.."
UPSTREAM_DIR="$BSSH_ROOT/references/russh/russh/src"
CURRENT_DIR="$SCRIPT_DIR/src"
PATCH_DIR="$SCRIPT_DIR/patches"
PATCH_FILE="$PATCH_DIR/handle-data-fix.patch"

# Colors for output
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

log_info() { echo -e "${GREEN}[INFO]${NC} $1"; }
log_warn() { echo -e "${YELLOW}[WARN]${NC} $1"; }

if [ ! -d "$UPSTREAM_DIR" ]; then
    echo "Error: Upstream russh not found at $UPSTREAM_DIR"
    echo "Please ensure references/russh exists with the upstream source."
    exit 1
fi

mkdir -p "$PATCH_DIR"

log_info "Creating patch from differences..."

# Create patch for server/session.rs (the main change)
diff -u "$UPSTREAM_DIR/server/session.rs" "$CURRENT_DIR/server/session.rs" \
    | sed 's|'"$UPSTREAM_DIR"'|a/src|g' \
    | sed 's|'"$CURRENT_DIR"'|b/src|g' \
    > "$PATCH_FILE" || true

if [ -s "$PATCH_FILE" ]; then
    LINES=$(wc -l < "$PATCH_FILE" | tr -d ' ')
    log_info "Patch created: $PATCH_FILE ($LINES lines)"

    echo ""
    echo "Patch summary:"
    echo "=============="
    grep -E "^@@|^\+\+\+|^---" "$PATCH_FILE" | head -20
else
    log_warn "No differences found - patch file is empty"
fi