#!/bin/sh

current_file=""
root="/kitchen/overlay"

while IFS= read -r line; do
    case "$line" in
        \#\ /*)
            current_file="${line#\# }"
            ;;
        \#\:*)
            continue
            ;;
        *=*)
            if [ -z "$current_file" ]; then
                echo "warning: value without file: $line" >&2
                continue
            fi
            key="${line%%=*}"
            value="${line#*=}"
            key_esc=$(printf '%s' "$key" | sed 's/[]\/$*.^[]/\\&/g')
            value_esc=$(printf '%s' "$value" | sed 's/[\/&]/\\&/g')
            sed -i "s/_${key_esc}_/${value_esc}/g" "$root$current_file"
            ;;
        "")
            continue
            ;;
        *)
            echo "unknown line: $line" >&2
            ;;
    esac
done