{-# LANGUAGE OverloadedStrings #-}

{- Copyright 2016 Joey Hess <id@joeyh.name>
 -
 - Licensed under the GNU AGPL version 3 or higher.
 -}

module Main where

import Types
import Tunables
import qualified CmdLine
import UI
import Encryption
import Cost
import Shard
import Storage
import Storage.LocalFiles

main :: IO ()
main = do
	cmdline <- CmdLine.get
	ui <- selectUI (CmdLine.gui cmdline)
	let name = CmdLine.name cmdline
	let keytype = CmdLine.keytype cmdline
	-- TODO determine gpg key id by examining secret key,
	-- or retrieving public key from keyserver and examining it.
	let keyid = KeyId keytype "dummy key id"
	case CmdLine.mode cmdline of
		CmdLine.Backup -> storedemo name keyid $
			if CmdLine.testMode cmdline
				then testModeTunables
				else defaultTunables
		CmdLine.Restore -> retrievedemo name keyid

storedemo :: Name -> KeyId -> Tunables -> IO ()
storedemo name keyid tunables = do
	kek <- genKeyEncryptionKey tunables name password
	putStrLn "Very rough estimate of cost to brute-force the password:"
	print $ estimateAttack spotAWS $ estimateBruteforceOf kek
		(passwordEntropy password)
	let esk = encrypt tunables kek secretkey
	let sis = shardIdents tunables name keyid
	shards <- genShards esk tunables
	print =<< mapM (uncurry (storeShard localFiles)) (zip (getIdents sis) shards)
	print =<< obscureShards localFiles
  where
	password = Password "correct horse battery staple"
	secretkey = SecretKey "this is a gpg private key"

retrievedemo :: Name -> KeyId -> IO ()
retrievedemo name keyid = do
	let sis = shardIdents tunables name keyid
	-- we drop 1 to simulate not getting all shards from the servers
	let l = drop 1 $ zip [1..] (getIdents sis)
	shards <- map (\(RetrieveSuccess s) -> s)
		<$> mapM (uncurry (retrieveShard localFiles)) l
	_ <- obscureShards localFiles
	let esk = combineShards tunables shards
	basekek <- genKeyEncryptionKey tunables name password
	go esk (candidateKeyEncryptionKeys tunables basekek)
  where
	go _ [] = error "decryption failed"
	go esk (kek:rest) = case decrypt kek esk of
		Just (SecretKey sk) -> print sk
		Nothing -> go esk rest

	password = Password "correct horse battery staple"
	-- TODO: derive by probing to find objects
	tunables = testModeTunables -- defaultTunables