import 'dart:io';

import 'printer.dart';
import 'reader.dart' as reader;
import 'types.dart';

Map<String, MalBuiltin> ns = <String, MalBuiltin>{
  '+': new MalBuiltin((List<MalType> args) {
    var a = args[0] as MalInt;
    var b = args[1] as MalInt;
    return new MalInt(a.value + b.value);
  }),
  '-': new MalBuiltin((List<MalType> args) {
    var a = args[0] as MalInt;
    var b = args[1] as MalInt;
    return new MalInt(a.value - b.value);
  }),
  '*': new MalBuiltin((List<MalType> args) {
    var a = args[0] as MalInt;
    var b = args[1] as MalInt;
    return new MalInt(a.value * b.value);
  }),
  '/': new MalBuiltin((List<MalType> args) {
    var a = args[0] as MalInt;
    var b = args[1] as MalInt;
    return new MalInt(a.value ~/ b.value);
  }),
  'list':
      new MalBuiltin((List<MalType> args) => new MalList(args.toList())),
  'list?': new MalBuiltin(
      (List<MalType> args) => new MalBool(args.single is MalList)),
  'empty?': new MalBuiltin((List<MalType> args) {
    var a = args.single as MalIterable;
    return new MalBool(a.elements.isEmpty);
  }),
  'count': new MalBuiltin((List<MalType> args) {
    var a = args.first as MalIterable;
    return new MalInt(a.elements.length);
  }),
  '=': new MalBuiltin((List<MalType> args) {
    var a = args[0];
    var b = args[1];
    return new MalBool(a == b);
  }),
  '<': new MalBuiltin((List<MalType> args) {
    var a = args[0] as MalInt;
    var b = args[1] as MalInt;
    return new MalBool(a.value < b.value);
  }),
  '<=': new MalBuiltin((List<MalType> args) {
    var a = args[0] as MalInt;
    var b = args[1] as MalInt;
    return new MalBool(a.value <= b.value);
  }),
  '>': new MalBuiltin((List<MalType> args) {
    var a = args[0] as MalInt;
    var b = args[1] as MalInt;
    return new MalBool(a.value > b.value);
  }),
  '>=': new MalBuiltin((List<MalType> args) {
    var a = args[0] as MalInt;
    var b = args[1] as MalInt;
    return new MalBool(a.value >= b.value);
  }),
  'pr-str': new MalBuiltin((List<MalType> args) {
    return new MalString(
        args.map((a) => pr_str(a, print_readably: true)).join(' '));
  }),
  'str': new MalBuiltin((List<MalType> args) {
    return new MalString(
        args.map((a) => pr_str(a, print_readably: false)).join());
  }),
  'prn': new MalBuiltin((List<MalType> args) {
    print(args.map((a) => pr_str(a, print_readably: true)).join(' '));
    return new MalNil();
  }),
  'println': new MalBuiltin((List<MalType> args) {
    print(args.map((a) => pr_str(a, print_readably: false)).join(' '));
    return new MalNil();
  }),
  'read-string': new MalBuiltin((List<MalType> args) {
    var code = args.single as MalString;
    return reader.read_str(code.value);
  }),
  'slurp': new MalBuiltin((List<MalType> args) {
    var fileName = args.single as MalString;
    var file = new File(fileName.value);
    return new MalString(file.readAsStringSync());
  }),
  'atom': new MalBuiltin((List<MalType> args) {
    var value = args.single;
    return new MalAtom(value);
  }),
  'atom?': new MalBuiltin((List<MalType> args) {
    var value = args.single;
    return new MalBool(value is MalAtom);
  }),
  'deref': new MalBuiltin((List<MalType> args) {
    var atom = args.single as MalAtom;
    return atom.value;
  }),
  'reset!': new MalBuiltin((List<MalType> args) {
    var atom = args[0] as MalAtom;
    var newValue = args[1];
    atom.value = newValue;
    return newValue;
  }),
  'swap!': new MalBuiltin((List<MalType> args) {
    var atom = args[0] as MalAtom;
    var func = args[1] as MalCallable;
    var fnArgs = [atom.value]..addAll(args.sublist(2));
    var result = func.call(fnArgs);
    atom.value = result;
    return result;
  }),
  'cons': new MalBuiltin((List<MalType> args) {
    var x = args[0];
    var xs = args[1] as MalIterable;
    return new MalList([x]..addAll(xs));
  }),
  'concat': new MalBuiltin((List<MalType> args) {
    var results = <MalType>[];
    for (MalIterable element in args) {
      results.addAll(element);
    }
    return new MalList(results);
  }),
  'vec': new MalBuiltin((List<MalType> args) {
    if (args.length == 1) {
      if (args[0] is MalVector) return args[0];
      if (args[0] is MalList) return new MalVector((args[0] as MalList).elements);
    }
    throw new MalException(new MalString("vec: wrong arguments"));
  }),
  'nth': new MalBuiltin((List<MalType> args) {
    var indexable = args[0] as MalIterable;
    var index = args[1] as MalInt;
    try {
      return indexable[index.value];
    } on RangeError catch (e) {
      throw new MalException(new MalString(e.toString()));
    }
  }),
  'first': new MalBuiltin((List<MalType> args) {
    var list = args.first as MalIterable;
    if (list.isEmpty) return new MalNil();
    return list.first;
  }),
  'rest': new MalBuiltin((List<MalType> args) {
    var list = args.first as MalIterable;
    if (list.isEmpty) return new MalList(<MalType>[]);
    return new MalList(list.sublist(1));
  }),
  'throw': new MalBuiltin((List<MalType> args) {
    throw new MalException(args.first);
  }),
  'nil?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalNil);
  }),
  'true?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalBool && (args.first as MalBool).value);
  }),
  'false?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalBool && !(args.first as MalBool).value);
  }),
  'symbol': new MalBuiltin((List<MalType> args) {
    return new MalSymbol((args.first as MalString).value);
  }),
  'symbol?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalSymbol);
  }),
  'keyword': new MalBuiltin((List<MalType> args) {
    if (args.first is MalKeyword) return args.first;
    return new MalKeyword((args.first as MalString).value);
  }),
  'keyword?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalKeyword);
  }),
  'number?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalInt);
  }),
  'fn?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalCallable && !(args.first.isMacro));
  }),
  'macro?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalCallable && args.first.isMacro);
  }),
  'vector': new MalBuiltin((List<MalType> args) {
    return new MalVector(args);
  }),
  'vector?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalVector);
  }),
  'hash-map': new MalBuiltin((List<MalType> args) {
    return new MalHashMap.fromSequence(args);
  }),
  'map?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalHashMap);
  }),
  'assoc': new MalBuiltin((List<MalType> args) {
    var map = args.first as MalHashMap;
    var assoc = new MalHashMap.fromSequence(args.skip(1).toList());
    var newMap = new Map<MalType, MalType>.from(map.value);
    newMap.addAll(assoc.value);
    return new MalHashMap(newMap);
  }),
  'dissoc': new MalBuiltin((List<MalType> args) {
    var map = args.first as MalHashMap;
    var newMap = new Map<MalType, MalType>.from(map.value);
    for (var key in args.skip(1)) {
      newMap.remove(key);
    }
    return new MalHashMap(newMap);
  }),
  'get': new MalBuiltin((List<MalType> args) {
    if (args[0] is MalNil) return new MalNil();
    var map = args[0] as MalHashMap;
    var key = args[1];
    return map.value[key] ?? new MalNil();
  }),
  'contains?': new MalBuiltin((List<MalType> args) {
    var map = args[0] as MalHashMap;
    var key = args[1];
    return new MalBool(map.value.containsKey(key));
  }),
  'keys': new MalBuiltin((List<MalType> args) {
    return new MalList((args.first as MalHashMap).value.keys.toList());
  }),
  'vals': new MalBuiltin((List<MalType> args) {
    return new MalList((args.first as MalHashMap).value.values.toList());
  }),
  'sequential?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalList || args.first is MalVector);
  }),
  'readline': new MalBuiltin((List<MalType> args) {
    var message = args.first as MalString;
    stdout.write(message.value);
    var input = stdin.readLineSync();
    if (input == null) return new MalNil();
    return new MalString(input);
  }),
  'time-ms': new MalBuiltin((List<MalType> args) {
    assert(args.isEmpty);
    return new MalInt(new DateTime.now().millisecondsSinceEpoch);
  }),
  'conj': new MalBuiltin((List<MalType> args) {
    var collection = args.first;
    var elements = args.sublist(1);
    if (collection is MalList) {
      return new MalList(
          elements.reversed.toList()..addAll(collection.elements));
    }
    if (collection is MalVector) {
      return new MalVector(collection.elements.toList()..addAll(elements));
    }
    throw new MalException(new MalString('"conj" takes a list or vector'));
  }),
  'string?': new MalBuiltin((List<MalType> args) {
    return new MalBool(args.first is MalString);
  }),
  'seq': new MalBuiltin((List<MalType> args) {
    var arg = args.first;
    if (arg is MalIterable && arg.isEmpty) return new MalNil();
    if (arg is MalString && arg.value.isEmpty) return new MalNil();

    if (arg is MalNil || arg is MalList) return arg;
    if (arg is MalVector) return new MalList(arg.elements.toList());
    if (arg is MalString) {
      var chars = <MalString>[];
      for (var i = 0; i < arg.value.length; i++) {
        chars.add(new MalString(arg.value[i]));
      }
      return new MalList(chars);
    }
    throw new MalException(new MalString('bad argument to "seq"'));
  }),
  'map': new MalBuiltin((List<MalType> args) {
    var fn = args[0] as MalCallable;
    var list = args[1] as MalIterable;
    var newList = <MalType>[];
    for (var element in list) {
      newList.add(fn.call([element]));
    }
    return new MalList(newList);
  }),
  'apply': new MalBuiltin((List<MalType> args) {
    var func = args.first as MalCallable;
    var argList = args.last as MalIterable;
    var newArgs = args.sublist(1, args.length - 1);
    newArgs.addAll(argList);
    return func.call(newArgs);
  }),
  'meta': new MalBuiltin((List<MalType> args) {
    var arg = args.first;
    return arg.meta ?? new MalNil();
  }),
  'with-meta': new MalBuiltin((List<MalType> args) {
    var evaled = args.first;
    var evaledWithMeta = evaled.clone();
    evaledWithMeta.meta = args[1];
    return evaledWithMeta;
  }),
};