package com.puppetlabs;

import java.util.HashMap;
import java.util.TreeSet;

/**
 * The Java shim for libfacter.
 */
public class Facter {
    static {
        // Look for libfacter in the same place as facter.rb does
        String facterDir = System.getenv("FACTERDIR");
        if (facterDir == null) {
            facterDir = "${CMAKE_INSTALL_PREFIX}/${LIBFACTER_INSTALL_DESTINATION}";
        }

        // Load the library
        System.load(facterDir.replaceAll("/$", "") + "/libfacter.so");
    }

    /**
     * Lookup a fact value by name.
     * @param name The fact name.
     * @return Returns the fact's value or null if not found.
     */
    public static native Object lookup(String name);

    /**
     * Entry point for testing.
     * Expects one argument which is the fact to lookup.
     * @param args The program arguments.
     */
    public static void main(String[] args) {
        if (args.length != 1) {
            System.out.println("usage: Facter <fact>");
            return;
        }
        print(lookup(args[0]), 1);
        System.out.println();
    }

    private static void indent(int level) {
        if (level < 1) {
            return;
        }
        for (int i = 0; i < (level * 2); ++i) {
            System.out.print(" ");
        }
    }

    @SuppressWarnings("unchecked")
    private static void print(Object value, int level) {
        if (value == null) {
            return;
        }

        // Check for arrays
        if (value instanceof Object[]) {
            Object[] array = (Object[])value;
            System.out.print("[\n");
            boolean first = true;
            for (Object element : array) {
                if (first) {
                    first = false;
                } else {
                    System.out.print(",\n");
                }
                indent(level);
                print(element, 0);
            }
            System.out.print("\n");
            indent(level - 1);
            System.out.print("]");
            return;
        }

        // Check for maps
        if (value instanceof HashMap) {
            HashMap map = (HashMap)value;
            System.out.print("{\n");

            // Print out the keys in lexicographical order (like a std::map)
            TreeSet<String> keys = new TreeSet<String>(map.keySet());
            boolean first = true;
            for (String key : keys) {
                if (first) {
                    first = false;
                } else {
                    System.out.print(",\n");
                }
                indent(level);
                System.out.format("%s => ", key);
                print(map.get(key), level + 1);
            }
            System.out.print("\n");
            indent(level - 1);
            System.out.print("}");
            return;
        }

        // Check for strings (print with quotes)
        if (value instanceof String) {
            System.out.format("\"%s\"", value);
            return;
        }

        // Output the value
        System.out.print(value);
    }
}