package keeper

import (
	"time"

	sdk "github.com/cosmos/cosmos-sdk/types"
	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
	vestingtypes "github.com/cosmos/cosmos-sdk/x/auth/vesting/types"

	"github.com/kava-labs/kava/x/incentive/types"
	// validatorvesting "github.com/kava-labs/kava/x/validator-vesting"
)

const (
	// BeginningOfMonth harvest rewards that are claimed after the 15th at 14:00UTC of the month always vest on the first of the month
	BeginningOfMonth = 1
	// MidMonth harvest rewards that are claimed before the 15th at 14:00UTC of the month always vest on the 15 of the month
	MidMonth = 15
	// PaymentHour harvest rewards always vest at 14:00UTC
	PaymentHour = 14
)

// SendTimeLockedCoinsToAccount sends time-locked coins from the input module account to the recipient. If the recipients account is not a vesting account and the input length is greater than zero, the recipient account is converted to a periodic vesting account and the coins are added to the vesting balance as a vesting period with the input length.
func (k Keeper) SendTimeLockedCoinsToAccount(ctx sdk.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins, length int64) error {
	macc := k.accountKeeper.GetModuleAccount(ctx, senderModule)
	maccCoins := k.bankKeeper.GetAllBalances(ctx, macc.GetAddress())
	if !maccCoins.IsAllGTE(amt) {
		return sdkerrors.Wrapf(types.ErrInsufficientModAccountBalance, "%s", senderModule)
	}

	// 0. Get the account from the account keeper and do a type switch, error if it's a validator vesting account or module account (can make this work for validator vesting later if necessary)
	acc := k.accountKeeper.GetAccount(ctx, recipientAddr)
	if acc == nil {
		return sdkerrors.Wrapf(types.ErrAccountNotFound, recipientAddr.String())
	}
	if length == 0 {
		return k.bankKeeper.SendCoinsFromModuleToAccount(ctx, senderModule, recipientAddr, amt)
	}

	switch acc.(type) {
	case *vestingtypes.ContinuousVestingAccount, authtypes.ModuleAccountI:
		return sdkerrors.Wrapf(types.ErrInvalidAccountType, "%T", acc)
	case *vestingtypes.PeriodicVestingAccount:
		return k.SendTimeLockedCoinsToPeriodicVestingAccount(ctx, senderModule, recipientAddr, amt, length)
	case *authtypes.BaseAccount:
		return k.SendTimeLockedCoinsToBaseAccount(ctx, senderModule, recipientAddr, amt, length)
	default:
		return sdkerrors.Wrapf(types.ErrInvalidAccountType, "%T", acc)
	}
}

// SendTimeLockedCoinsToPeriodicVestingAccount sends time-locked coins from the input module account to the recipient
func (k Keeper) SendTimeLockedCoinsToPeriodicVestingAccount(ctx sdk.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins, length int64) error {
	err := k.bankKeeper.SendCoinsFromModuleToAccount(ctx, senderModule, recipientAddr, amt)
	if err != nil {
		return err
	}
	k.addCoinsToVestingSchedule(ctx, recipientAddr, amt, length)
	return nil
}

// SendTimeLockedCoinsToBaseAccount sends time-locked coins from the input module account to the recipient, converting the recipient account to a vesting account
func (k Keeper) SendTimeLockedCoinsToBaseAccount(ctx sdk.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins, length int64) error {
	err := k.bankKeeper.SendCoinsFromModuleToAccount(ctx, senderModule, recipientAddr, amt)
	if err != nil {
		return err
	}
	acc := k.accountKeeper.GetAccount(ctx, recipientAddr)
	// transition the account to a periodic vesting account:
	bacc := authtypes.NewBaseAccount(acc.GetAddress(), acc.GetPubKey(), acc.GetAccountNumber(), acc.GetSequence())

	newPeriods := vestingtypes.Periods{types.NewPeriod(amt, length)}
	bva := vestingtypes.NewBaseVestingAccount(bacc, amt, ctx.BlockTime().Unix()+length)
	pva := vestingtypes.NewPeriodicVestingAccountRaw(bva, ctx.BlockTime().Unix(), newPeriods)
	k.accountKeeper.SetAccount(ctx, pva)

	return nil
}

// GetPeriodLength returns the length of the lockup period based on the input blocktime and multiplier lockup.
// Note that pay dates are always the 1st or 15th of the month at 14:00UTC.
// Months lockup cannot be negative
func (k Keeper) GetPeriodLength(blockTime time.Time, monthsLockup int64) int64 {
	if monthsLockup < 0 {
		panic("months lockup must be non negative")
	}
	if monthsLockup == 0 {
		return 0
	}
	currentDay := blockTime.Day()
	payDay := BeginningOfMonth
	monthOffset := int64(1)
	if currentDay < MidMonth || (currentDay == MidMonth && blockTime.Hour() < PaymentHour) {
		payDay = MidMonth
		monthOffset = int64(0)
	}
	periodEndDate := time.Date(blockTime.Year(), blockTime.Month(), payDay, PaymentHour, 0, 0, 0, time.UTC).AddDate(0, int(monthsLockup+monthOffset), 0)
	return periodEndDate.Unix() - blockTime.Unix()
}

// addCoinsToVestingSchedule adds coins to the input account's vesting schedule where length is the amount of time (from the current block time), in seconds, that the coins will be vesting for
// the input address must be a periodic vesting account
func (k Keeper) addCoinsToVestingSchedule(ctx sdk.Context, addr sdk.AccAddress, amt sdk.Coins, length int64) {
	acc := k.accountKeeper.GetAccount(ctx, addr)
	vacc := acc.(*vestingtypes.PeriodicVestingAccount)
	// Add the new vesting coins to OriginalVesting
	vacc.OriginalVesting = vacc.OriginalVesting.Add(amt...)
	// update vesting periods
	// EndTime = 100
	// BlockTime  = 110
	// length == 6
	if vacc.EndTime < ctx.BlockTime().Unix() {
		// edge case one - the vesting account's end time is in the past (ie, all previous vesting periods have completed)
		// append a new period to the vesting account, update the end time, update the account in the store and return
		newPeriodLength := (ctx.BlockTime().Unix() - vacc.EndTime) + length // 110 - 100 + 6 = 16
		newPeriod := types.NewPeriod(amt, newPeriodLength)
		vacc.VestingPeriods = append(vacc.VestingPeriods, newPeriod)
		vacc.EndTime = ctx.BlockTime().Unix() + length
		k.accountKeeper.SetAccount(ctx, vacc)
		return
	}
	// StartTime = 110
	// BlockTime = 100
	// length = 6
	if vacc.StartTime > ctx.BlockTime().Unix() {
		// edge case two - the vesting account's start time is in the future (all periods have not started)
		// update the start time to now and adjust the period lengths in place - a new period will be inserted in the next code block
		updatedPeriods := vestingtypes.Periods{}
		for i, period := range vacc.VestingPeriods {
			updatedPeriod := period
			if i == 0 {
				updatedPeriod = types.NewPeriod(period.Amount, (vacc.StartTime-ctx.BlockTime().Unix())+period.Length) // 110 - 100 + 6 = 16
			}
			updatedPeriods = append(updatedPeriods, updatedPeriod)
		}
		vacc.VestingPeriods = updatedPeriods
		vacc.StartTime = ctx.BlockTime().Unix()
	}

	// logic for inserting a new vesting period into the existing vesting schedule
	remainingLength := vacc.EndTime - ctx.BlockTime().Unix()
	elapsedTime := ctx.BlockTime().Unix() - vacc.StartTime
	proposedEndTime := ctx.BlockTime().Unix() + length
	if remainingLength < length {
		// in the case that the proposed length is longer than the remaining length of all vesting periods, create a new period with length equal to the difference between the proposed length and the previous total length
		newPeriodLength := length - remainingLength
		newPeriod := types.NewPeriod(amt, newPeriodLength)
		vacc.VestingPeriods = append(vacc.VestingPeriods, newPeriod)
		// update the end time so that the sum of all period lengths equals endTime - startTime
		vacc.EndTime = proposedEndTime
	} else {
		// In the case that the proposed length is less than or equal to the sum of all previous period lengths, insert the period and update other periods as necessary.
		// EXAMPLE (l is length, a is amount)
		// Original Periods: {[l: 1 a: 1], [l: 2, a: 1], [l:8, a:3], [l: 5, a: 3]}
		// Period we want to insert [l: 5, a: x]
		// Expected result:
		// {[l: 1, a: 1], [l:2, a: 1], [l:2, a:x], [l:6, a:3], [l:5, a:3]}

		// StartTime = 100
		// Periods = [5,5,5,5]
		// EndTime = 120
		// BlockTime = 101
		// length = 2

		// for period in Periods:
		// iteration  1:
		// lengthCounter = 5
		// if 5 < 101 - 100 + 2 - no
		// if 5 = 3 - no
		// else
		// newperiod = 2 - 0
		newPeriods := vestingtypes.Periods{}
		lengthCounter := int64(0)
		appendRemaining := false
		for _, period := range vacc.VestingPeriods {
			if appendRemaining {
				newPeriods = append(newPeriods, period)
				continue
			}
			lengthCounter += period.Length
			if lengthCounter < elapsedTime+length { // 1
				newPeriods = append(newPeriods, period)
			} else if lengthCounter == elapsedTime+length {
				newPeriod := types.NewPeriod(period.Amount.Add(amt...), period.Length)
				newPeriods = append(newPeriods, newPeriod)
				appendRemaining = true
			} else {
				newPeriod := types.NewPeriod(amt, elapsedTime+length-types.GetTotalVestingPeriodLength(newPeriods))
				previousPeriod := types.NewPeriod(period.Amount, period.Length-newPeriod.Length)
				newPeriods = append(newPeriods, newPeriod, previousPeriod)
				appendRemaining = true
			}
		}
		vacc.VestingPeriods = newPeriods
	}
	k.accountKeeper.SetAccount(ctx, vacc)
}