package app

import (
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"sort"
	"strings"

	"github.com/cosmos/cosmos-sdk/codec"
	"github.com/cosmos/cosmos-sdk/server"
	sdk "github.com/cosmos/cosmos-sdk/types"
	"github.com/cosmos/cosmos-sdk/x/auth"
	distr "github.com/cosmos/cosmos-sdk/x/distribution"
	"github.com/cosmos/cosmos-sdk/x/gov"
	"github.com/cosmos/cosmos-sdk/x/mint"
	"github.com/cosmos/cosmos-sdk/x/slashing"
	"github.com/cosmos/cosmos-sdk/x/stake"
	tmtypes "github.com/tendermint/tendermint/types"
)

var (
	// bonded tokens given to genesis validators/accounts
	freeFermionVal  = int64(100)
	freeFermionsAcc = sdk.NewInt(150)
)

// State to Unmarshal
type GenesisState struct {
	Accounts     []GenesisAccount      `json:"accounts"`
	StakeData    stake.GenesisState    `json:"stake"`
	MintData     mint.GenesisState     `json:"mint"`
	DistrData    distr.GenesisState    `json:"distr"`
	GovData      gov.GenesisState      `json:"gov"`
	SlashingData slashing.GenesisState `json:"slashing"`
	GenTxs       []json.RawMessage     `json:"gentxs"`
}

func NewGenesisState(accounts []GenesisAccount, stakeData stake.GenesisState, mintData mint.GenesisState,
	distrData distr.GenesisState, govData gov.GenesisState, slashingData slashing.GenesisState) GenesisState {

	return GenesisState{
		Accounts:     accounts,
		StakeData:    stakeData,
		MintData:     mintData,
		DistrData:    distrData,
		GovData:      govData,
		SlashingData: slashingData,
	}
}

// GenesisAccount doesn't need pubkey or sequence
type GenesisAccount struct {
	Address sdk.AccAddress `json:"address"`
	Coins   sdk.Coins      `json:"coins"`
}

func NewGenesisAccount(acc *auth.BaseAccount) GenesisAccount {
	return GenesisAccount{
		Address: acc.Address,
		Coins:   acc.Coins,
	}
}

func NewGenesisAccountI(acc auth.Account) GenesisAccount {
	return GenesisAccount{
		Address: acc.GetAddress(),
		Coins:   acc.GetCoins(),
	}
}

// convert GenesisAccount to auth.BaseAccount
func (ga *GenesisAccount) ToAccount() (acc *auth.BaseAccount) {
	return &auth.BaseAccount{
		Address: ga.Address,
		Coins:   ga.Coins.Sort(),
	}
}

// get app init parameters for server init command
func GaiaAppInit() server.AppInit {

	return server.AppInit{
		AppGenState: GaiaAppGenStateJSON,
	}
}

// Create the core parameters for genesis initialization for gaia
// note that the pubkey input is this machines pubkey
func GaiaAppGenState(cdc *codec.Codec, appGenTxs []json.RawMessage) (genesisState GenesisState, err error) {
	if len(appGenTxs) == 0 {
		err = errors.New("must provide at least genesis transaction")
		return
	}

	// start with the default staking genesis state
	stakeData := stake.DefaultGenesisState()
	slashingData := slashing.DefaultGenesisState()

	// get genesis flag account information
	genaccs := make([]GenesisAccount, len(appGenTxs))

	for i, genTx := range appGenTxs {
		var tx auth.StdTx
		err = cdc.UnmarshalJSON(genTx, &tx)
		if err != nil {
			return
		}
		msgs := tx.GetMsgs()
		if len(msgs) != 1 {
			err = errors.New("must provide genesis StdTx with exactly 1 CreateValidator message")
			return
		}
		msg := msgs[0].(stake.MsgCreateValidator)

		// create the genesis account, give'm few steaks and a buncha token with there name
		genaccs[i] = genesisAccountFromMsgCreateValidator(msg, freeFermionsAcc)
		stakeData.Pool.LooseTokens = stakeData.Pool.LooseTokens.Add(sdk.NewDecFromInt(freeFermionsAcc)) // increase the supply
	}

	// create the final app state
	genesisState = GenesisState{
		Accounts:     genaccs,
		StakeData:    stakeData,
		MintData:     mint.DefaultGenesisState(),
		DistrData:    distr.DefaultGenesisState(),
		GovData:      gov.DefaultGenesisState(),
		SlashingData: slashingData,
		GenTxs:       appGenTxs,
	}

	return
}

func genesisAccountFromMsgCreateValidator(msg stake.MsgCreateValidator, amount sdk.Int) GenesisAccount {
	accAuth := auth.NewBaseAccountWithAddress(sdk.AccAddress(msg.ValidatorAddr))
	accAuth.Coins = []sdk.Coin{
		{msg.Description.Moniker + "Token", sdk.NewInt(1000)},
		{"steak", amount},
	}
	return NewGenesisAccount(&accAuth)
}

// GaiaValidateGenesisState ensures that the genesis state obeys the expected invariants
// TODO: No validators are both bonded and jailed (#2088)
// TODO: Error if there is a duplicate validator (#1708)
// TODO: Ensure all state machine parameters are in genesis (#1704)
func GaiaValidateGenesisState(genesisState GenesisState) (err error) {
	err = validateGenesisStateAccounts(genesisState.Accounts)
	if err != nil {
		return
	}
	// skip stakeData validation as genesis is created from txs
	if len(genesisState.GenTxs) > 0 {
		return nil
	}
	return stake.ValidateGenesis(genesisState.StakeData)
}

// Ensures that there are no duplicate accounts in the genesis state,
func validateGenesisStateAccounts(accs []GenesisAccount) (err error) {
	addrMap := make(map[string]bool, len(accs))
	for i := 0; i < len(accs); i++ {
		acc := accs[i]
		strAddr := string(acc.Address)
		if _, ok := addrMap[strAddr]; ok {
			return fmt.Errorf("Duplicate account in genesis state: Address %v", acc.Address)
		}
		addrMap[strAddr] = true
	}
	return
}

// GaiaAppGenState but with JSON
func GaiaAppGenStateJSON(cdc *codec.Codec, appGenTxs []json.RawMessage) (appState json.RawMessage, err error) {
	// create the final app state
	genesisState, err := GaiaAppGenState(cdc, appGenTxs)
	if err != nil {
		return nil, err
	}
	appState, err = codec.MarshalJSONIndent(cdc, genesisState)
	return
}

// CollectStdTxs processes and validates application's genesis StdTxs and returns the list of validators,
// appGenTxs, and persistent peers required to generate genesis.json.
func CollectStdTxs(moniker string, genTxsDir string, cdc *codec.Codec) (
	validators []tmtypes.GenesisValidator, appGenTxs []auth.StdTx, persistentPeers string, err error) {
	var fos []os.FileInfo
	fos, err = ioutil.ReadDir(genTxsDir)
	if err != nil {
		return
	}

	var addresses []string
	for _, fo := range fos {
		filename := filepath.Join(genTxsDir, fo.Name())
		if !fo.IsDir() && (filepath.Ext(filename) != ".json") {
			continue
		}

		// get the genStdTx
		var jsonRawTx []byte
		jsonRawTx, err = ioutil.ReadFile(filename)
		if err != nil {
			return
		}
		var genStdTx auth.StdTx
		err = cdc.UnmarshalJSON(jsonRawTx, &genStdTx)
		if err != nil {
			return
		}
		appGenTxs = append(appGenTxs, genStdTx)

		nodeAddr := genStdTx.GetMemo()
		if len(nodeAddr) == 0 {
			err = fmt.Errorf("couldn't find node's address in %s", fo.Name())
			return
		}

		msgs := genStdTx.GetMsgs()
		if len(msgs) != 1 {
			err = errors.New("each genesis transaction must provide a single genesis message")
			return
		}

		// TODO: this could be decoupled from stake.MsgCreateValidator
		// TODO: and we likely want to do it for real world Gaia
		msg := msgs[0].(stake.MsgCreateValidator)
		validators = append(validators, tmtypes.GenesisValidator{
			PubKey: msg.PubKey,
			Power:  freeFermionVal,
			Name:   msg.Description.Moniker,
		})

		// exclude itself from persistent peers
		if msg.Description.Moniker != moniker {
			addresses = append(addresses, nodeAddr)
		}
	}

	sort.Strings(addresses)
	persistentPeers = strings.Join(addresses, ",")

	return
}

func NewDefaultGenesisAccount(addr sdk.AccAddress) GenesisAccount {
	accAuth := auth.NewBaseAccountWithAddress(addr)
	accAuth.Coins = []sdk.Coin{
		{"fooToken", sdk.NewInt(1000)},
		{"steak", freeFermionsAcc},
	}
	return NewGenesisAccount(&accAuth)
}