package main

import (
  "fmt"
  "bufio"
  "strings"
  "os"
  "errors"
  "encoding/hex"
  "github.com/ethereum/ethdb-go"
  "github.com/ethereum/ethutil-go"
)

type Console struct {
  db *ethdb.MemDatabase
  trie *ethutil.Trie
}

func NewConsole() *Console {
  db, _ := ethdb.NewMemDatabase()
  trie := ethutil.NewTrie(db, "")

  return &Console{db: db, trie: trie}
}

func (i *Console) ValidateInput(action string, argumentLength int) error {
  err := false
  var expArgCount int

  switch {
  case action == "update" && argumentLength != 2:
    err = true
    expArgCount = 2
  case action == "get" && argumentLength != 1:
    err = true
    expArgCount = 1
  case action == "dag" && argumentLength != 2:
    err = true
    expArgCount = 2
  }

  if err {
    return errors.New(fmt.Sprintf("'%s' requires %d args, got %d", action, expArgCount, argumentLength))
  } else {
    return nil
  }
}

func (i *Console) ParseInput(input string) bool {
  scanner := bufio.NewScanner(strings.NewReader(input))
  scanner.Split(bufio.ScanWords)

  count := 0
  var tokens []string
  for scanner.Scan() {
    count++
    tokens = append(tokens, scanner.Text())
  }
  if err := scanner.Err(); err != nil {
    fmt.Fprintln(os.Stderr, "reading input:", err)
  }

  if len(tokens) == 0 { return true }

  err := i.ValidateInput(tokens[0], count-1)
  if err != nil {
    fmt.Println(err)
  } else  {
    switch tokens[0] {
    case "update":
      i.trie.Update(tokens[1], tokens[2])

      fmt.Println(hex.EncodeToString([]byte(i.trie.Root)))
    case "get":
      fmt.Println(i.trie.Get(tokens[1]))
    case "root":
      fmt.Println(hex.EncodeToString([]byte(i.trie.Root)))
    case "rawroot":
      fmt.Println(i.trie.Root)
    case "print":
      i.db.Print()
    case "dag":
      fmt.Println(DaggerVerify( ethutil.Big(tokens[1]), // hash
                                ethutil.BigPow(2, 36),  // diff
                                ethutil.Big(tokens[2])))// nonce
    case "exit", "quit", "q":
      return false
    case "help":
      fmt.Printf( "COMMANDS:\n"+
                  "\033[1m= DB =\033[0m\n"+
                  "update KEY VALUE - Updates/Creates a new value for the given key\n"+
                  "get KEY - Retrieves the given key\n"+
                  "root - Prints the hex encoded merkle root\n"+
                  "rawroot - Prints the raw merkle root\n"+
                  "\033[1m= Dagger =\033[0m\n"+
                  "dag HASH NONCE - Verifies a nonce with the given hash with dagger\n")
    default:
      fmt.Println("Unknown command:", tokens[0])
    }
  }

  return true
}

func (i *Console) Start() {
  fmt.Printf("Eth Console. Type (help) for help\n")
  reader := bufio.NewReader(os.Stdin)
  for {
    fmt.Printf("eth >>> ")
    str, _, err := reader.ReadLine()
    if err != nil {
      fmt.Println("Error reading input", err)
    } else {
      if !i.ParseInput(string(str)) {
        return
      }
    }
  }
}