package main

import (
  "fmt"
  "io/ioutil"
  "log"
  "os"
  "strings"

  "github.com/chzyer/readline"

  "github.com/hellerve/argos/eval"
  "github.com/hellerve/argos/parser"
)

func runRepl() {
  rl, err := readline.New("argos> ")

  if err != nil {
    log.Fatal(err)
  }

  defer rl.Close()

  e := eval.ParentEnv()
  for {
    input, err := rl.Readline()

    if err != nil {
      return
    }

    parsed, err, unconsumed := parser.Parse(input)

    if err != nil {
      fmt.Println(err)
      continue
    }

    if len(unconsumed) != 0 {
      fmt.Println("Unconsumed input:", strings.Join(unconsumed, " "))
      continue
    }

    // TODO: how to avoid bindings on error?
    evald, err := eval.Eval(parsed, e)


    if err != nil {
      fmt.Println(err)
      continue
    }

    fmt.Println(evald.Pretty())
  }
}

func runFile(path string) {
  e := eval.ParentEnv()
  input, err := ioutil.ReadFile(path)

  if err != nil {
    fmt.Println(err)
    return
  }

  parsed, err, unconsumed := parser.Parse(string(input))

  if err != nil {
    fmt.Println(err)
    return
  }

  if len(unconsumed) != 0 {
    fmt.Println("Unconsumed input:", strings.Join(unconsumed, " "))
    return
  }

  evald, err := eval.Eval(parsed, e)

  if err != nil {
    fmt.Println(err)
    return
  }

  fmt.Println(evald.Pretty())
}

func main() {
  args := os.Args
  if len(args) == 1 {
    runRepl()
  } else {
    runFile(os.Args[1])
  }
}