package services

import (
	"encoding/binary"
	"ripple/commands"
	"ripple/lockstep"
	"ripple/state"
	"ripple/types"
)

type Resilience struct {
	st       *state.State
	lockstep *lockstep.Lockstep
}

func NewResilience(
	st *state.State,
	lockstep *lockstep.Lockstep,
) *Resilience {
	return &Resilience{
		st:       st,
		lockstep: lockstep,
	}
}

func (r *Resilience) previewCreditline(id types.UserIdentifier) int64 {
	stateCopy := r.lockstep.PreviewAccount(id)
	acc := stateCopy.Storage.MustGetAccount(id)
	availableCreditline := acc.Creditline
	for paymentID := range acc.Pending {
		payment := stateCopy.Storage.MustGetPayment(paymentID)
		if payment.Outgoing == id {
			availableCreditline -= int64(payment.Amount+payment.Tax)
		}
	}
	for paymentID := range stateCopy.Memory.Commit[id] {
		pf, ok := stateCopy.Memory.GetPathfinding(paymentID)
		if !ok {
			continue
		}
		if pf.Commit && pf.Outgoing == id {
			amount := pf.Amount
			if amount < 0 {
				amount = -amount
			}
			availableCreditline -= amount+int64(pf.Tax)
		}
	}
	return availableCreditline
}

func (r *Resilience) Redistribute(from types.UserIdentifier, tax uint64, taxRate float32) {
	previewCreditlines := make(map[types.UserIdentifier]int64)
	var totalWidth float32

	for userID, acc := range r.st.Storage.Accounts {
		if userID == from {
			continue
		}
		preview := r.previewCreditline(userID)
		if preview > 0 {
			previewCreditlines[userID] = preview
			totalWidth += acc.Width
		}
	}

	if totalWidth == 0 {
		return
	}

	if totalWidth < taxRate {
		tax = uint64(float32(tax) * (totalWidth / taxRate))
	}

	for userID, previewCreditline := range previewCreditlines {
		acc := r.st.Storage.MustGetAccount(userID)
		proportion := acc.Width / totalWidth
		distributedTax := uint64(float32(tax) * proportion)
		if distributedTax == 0 {
			continue
		}
		r.st.Memory.TaxBuffer[userID] += distributedTax
		var taxBufferFull bool
		if r.st.Memory.TaxBuffer[userID] > uint64(previewCreditline) {
			r.st.Memory.TaxBuffer[userID] = uint64(previewCreditline)
			taxBufferFull = true
		}

		if !r.lockstep.CmdInQueue(userID, commands.LOCKSTEP_SWARM_REDISTRIBUTION) || taxBufferFull {
			buf := make([]byte, 8)
			binary.BigEndian.PutUint64(buf, r.st.Memory.TaxBuffer[userID])
			ok := r.lockstep.Enqueue(userID, types.Instruction{
				Command:   commands.LOCKSTEP_SWARM_REDISTRIBUTION,
				Arguments: buf,
			})
			if ok {
				r.st.Memory.TaxBuffer[userID] = 0
			}
		}
	}
}