module Nydp
  LOADFILES = []

  def self.rake_tasks
    load relative_path 'tasks/tests.rake'
  end

  def self.relative_path name
    File.join File.expand_path(File.dirname(__FILE__)), name
  end

  LOADFILES << relative_path('lisp/boot.nydp')
  LOADFILES << relative_path('lisp/test-runner.nydp')
  Dir.glob(relative_path 'lisp/tests/**/*.nydp').each { |f| LOADFILES << f }

  def self.compile_and_eval vm, expr
    vm.thread Pair.new(Compiler.compile(expr, Nydp.NIL), Nydp.NIL)
  end

  def self.setup ns
    Symbol.mk(:cons,  ns).assign(Nydp::Builtin::Cons.new)
    Symbol.mk(:car,   ns).assign(Nydp::Builtin::Car.new)
    Symbol.mk(:cdr,   ns).assign(Nydp::Builtin::Cdr.new)
    Symbol.mk(:+,     ns).assign(Nydp::Builtin::Plus.new)
    Symbol.mk(:-,     ns).assign(Nydp::Builtin::Minus.new)
    Symbol.mk(:*,     ns).assign(Nydp::Builtin::Times.new)
    Symbol.mk(:/,     ns).assign(Nydp::Builtin::Divide.new)
    Symbol.mk(:>,     ns).assign(Nydp::Builtin::GreaterThan.new)
    Symbol.mk(:<,     ns).assign(Nydp::Builtin::LessThan.new)
    Symbol.mk(:eval,  ns).assign(Nydp::Builtin::Eval.new(ns))
    Symbol.mk(:hash,  ns).assign(Nydp::Builtin::Hash.new)
    Symbol.mk(:apply, ns).assign(Nydp::Builtin::Apply.new)
    Symbol.mk(:error, ns).assign(Nydp::Builtin::Error.new)
    Symbol.mk(:quit,  ns).assign(Nydp::Builtin::Quit.new)
    Symbol.mk(:p,     ns).assign(Nydp::Builtin::Puts.new)
    Symbol.mk(:PI,    ns).assign Literal.new(3.1415)
    Symbol.mk(:nil,   ns).assign Nydp.NIL
    Symbol.mk(:t,     ns).assign Nydp.T
    Symbol.mk(:sym,   ns).assign Nydp::Builtin::ToSym.new(ns)
    Symbol.mk(:inspect,       ns).assign(Nydp::Builtin::Inspect.new)
    Symbol.mk(:comment,       ns).assign(Nydp::Builtin::Comment.new)
    Symbol.mk(:millisecs,     ns).assign(Nydp::Builtin::Millisecs.new)
    Symbol.mk("random-string",ns).assign(Nydp::Builtin::RandomString.new)
    Symbol.mk("to-string",    ns).assign(Nydp::Builtin::ToString.new)
    Symbol.mk(:"eq?",         ns).assign(Nydp::Builtin::IsEqual.new)
    Symbol.mk(:"pair?",       ns).assign(Nydp::Builtin::IsPair.new)
    Symbol.mk(:"cdr-set",     ns).assign(Nydp::Builtin::CdrSet.new)
    Symbol.mk(:"hash-get",    ns).assign(Nydp::Builtin::HashGet.new)
    Symbol.mk(:"hash-set",    ns).assign(Nydp::Builtin::HashSet.new)
    Symbol.mk(:"hash-keys",   ns).assign(Nydp::Builtin::HashKeys.new)
    Symbol.mk(:"vm-info",     ns).assign Nydp::Builtin::VmInfo.new
    Symbol.mk(:"pre-compile", ns).assign Nydp::Builtin::PreCompile.new
  end

  class Runner
    attr_accessor :vm, :ns

    def initialize vm, ns
      @vm = vm
      @ns = ns
      @precompile = Symbol.mk(:"pre-compile", ns)
      @quote      = Symbol.mk(:quote, ns)
    end

    def quote expr
      Pair.from_list [@quote, expr]
    end

    def precompile expr
      Pair.from_list [@precompile, quote(expr)]
    end

    def pre_compile expr
      Nydp.compile_and_eval(vm, precompile(expr))
    end

    def evaluate expr
      Nydp.compile_and_eval(vm, pre_compile(expr))
    end
  end

  class StreamRunner < Runner
    attr_accessor :stream, :parser

    def initialize vm, ns, stream
      super vm, ns
      @stream = stream
      @parser = Nydp::Parser.new(ns)
      @tokens = Nydp::Tokeniser.new stream
    end

    def prompt *_
    end

    def run
      res = Nydp.NIL
      prompt
      while !@tokens.finished
        expr = parser.expression(@tokens)
        unless expr.nil?
          res = evaluate expr
          prompt res
        end
      end
      res
    end
  end

  class Repl < StreamRunner
    def prompt val=nil
      puts val if val
      print "nydp > "
    end
  end

  def self.repl
    puts "welcome to nydp"
    root_ns = { }
    setup(root_ns)
    vm = VM.new
    LOADFILES.each { |f| StreamRunner.new(vm, root_ns, File.new(f)).run }
    Repl.new(vm, root_ns, $stdin).run
  end

  def self.tests
    puts "welcome to nydp : running tests"
    root_ns = { }
    setup(root_ns)
    vm = VM.new
    LOADFILES.each { |f| StreamRunner.new(vm, root_ns, File.new(f)).run }
    StreamRunner.new(vm, root_ns, "(run-all-tests)").run
  end
end

require "nydp/error"
require "nydp/truth"
require "nydp/version"
require "nydp/helper"
require "nydp/symbol"
require "nydp/symbol_lookup"
require "nydp/pair"
require "nydp/assignment"
require "nydp/builtin"
require "nydp/string_atom"
require "nydp/string_token"
require "nydp/tokeniser"
require "nydp/parser"
require "nydp/compiler"
require "nydp/vm"