package transaction

import (
	"sync"
	"time"

	"github.com/bits-and-blooms/bloom/v3"
	"github.com/cosmos/iavl"
	"github.com/gbl08ma/stacktrace"
)

type readTx struct {
	ts     time.Time
	height int64

	mutableTree *iavl.MutableTree // only present if upgradable
	tree        ReadTree
	db          ExtendedDB

	bloomMu     *sync.RWMutex
	bloomFilter *bloom.BloomFilter
	bloomSeq    *uint64

	operationCounter func(tx Read) (uint64, error)
}

// Height implements [Read].
func (t *readTx) Height() int64 {
	return t.height
}

// Timestamp implements [Read].
func (t *readTx) Timestamp() time.Time {
	return t.ts
}

// CountOperations implements [Read].
func (t *readTx) CountOperations() (uint64, error) {
	count, err := t.operationCounter(t)
	return count, stacktrace.Propagate(err)
}

// Tree implements [Read].
func (t *readTx) Tree() ReadTree {
	if t.mutableTree != nil {
		return t.mutableTree
	}
	return t.tree
}

// IndexDB implements [Read].
func (t *readTx) IndexDB() IndexReader {
	return t.db
}

// TestDIDBloomFilter implements [Read].
func (t *readTx) TestDIDBloomFilter(did []byte) bool {
	t.bloomMu.RLock()
	defer t.bloomMu.RUnlock()
	return t.bloomFilter.Test(did)
}

// Upgrade implements [Read].
func (t *readTx) Upgrade() (Write, error) {
	if t.mutableTree == nil {
		return nil, stacktrace.NewError("historical transaction is not upgradable to a write transaction")
	}
	return &writeTx{
		readTx:                t,
		unsavedBloomAdditions: map[string]struct{}{},
	}, nil
}

// UpgradeForIndexOnly implements [Read].
func (t *readTx) UpgradeForIndexOnly() (WriteIndex, error) {
	return &writeIndexTx{
		db: t.db,
	}, nil
}