#!/usr/bin/env bash
# Reverse sync: show diff between consumer-file and brain template, optionally apply
#
# Usage: extract.sh --source=<consumer-path> --file=<relative-path> [--dry-run]
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
source "$SCRIPT_DIR/lib/common.sh"

BRAIN_ROOT="${BRAIN_ROOT:-$(cd "$SCRIPT_DIR/.." && pwd)}"

source_dir=""
file=""
dry_run=0

while [ $# -gt 0 ]; do
    case "$1" in
        --source=*) source_dir="${1#--source=}" ;;
        --file=*) file="${1#--file=}" ;;
        --dry-run) dry_run=1 ;;
        *) log_error "Unknown: $1"; exit 1 ;;
    esac
    shift
done

[ -n "$source_dir" ] || { log_error "--source required"; exit 1; }
[ -n "$file" ] || { log_error "--file required"; exit 1; }

consumer_file="$source_dir/$file"
[ -f "$consumer_file" ] || { log_error "Not found: $consumer_file"; exit 1; }

# Find brain template (try with and without .template suffix)
brain_file=""
if [ -f "$BRAIN_ROOT/project-files/$file.template" ]; then
    brain_file="$BRAIN_ROOT/project-files/$file.template"
elif [ -f "$BRAIN_ROOT/project-files/$file" ]; then
    brain_file="$BRAIN_ROOT/project-files/$file"
else
    log_error "Brain template not found for: $file"
    exit 1
fi

log_info "Comparing $consumer_file <-> $brain_file"
if diff -q "$brain_file" "$consumer_file" >/dev/null; then
    log_info "Identical, no changes needed"
    exit 0
fi

log_warn "Files differ:"
diff -u "$brain_file" "$consumer_file" || true

if [ "$dry_run" -eq 1 ]; then
    exit 2
fi

# Interactive prompt
printf "Action [a]pply / [r]eject / [q]uit: " >&2
read -r action
case "$action" in
    a|apply)
        cp "$consumer_file" "$brain_file"
        log_info "Applied. Don't forget to commit brain repo + bump version."
        ;;
    r|reject)
        log_info "Rejected. Brain template unchanged."
        ;;
    *)
        log_info "Quit. No changes."
        ;;
esac