package commands

import (
	"bufio"
	"bytes"
	"context"
	"errors"
	"fmt"
	"os"
	"strings"
	"sync/atomic"
	"time"

	common2 "github.com/ledgerwatch/erigon-lib/common"
	"github.com/ledgerwatch/erigon-lib/kv"
	mdbx2 "github.com/ledgerwatch/erigon-lib/kv/mdbx"
	"github.com/ledgerwatch/erigon/common"
	"github.com/ledgerwatch/erigon/turbo/backup"
	"github.com/ledgerwatch/log/v3"
	"github.com/spf13/cobra"
	"golang.org/x/sync/errgroup"
	"golang.org/x/sync/semaphore"
)

var stateBuckets = []string{
	kv.HashedAccounts,
	kv.HashedStorage,
	kv.ContractCode,
	kv.PlainState,
	kv.AccountChangeSet,
	kv.StorageChangeSet,
	kv.PlainContractCode,
	kv.IncarnationMap,
	kv.Code,
	kv.TrieOfAccounts,
	kv.TrieOfStorage,
	kv.E2AccountsHistory,
	kv.E2StorageHistory,
	kv.TxLookup,
	kv.ContractTEVMCode,
}

var cmdWarmup = &cobra.Command{
	Use: "warmup",
	Run: func(cmd *cobra.Command, args []string) {
		ctx, _ := common2.RootContext()
		err := doWarmup(ctx, chaindata, bucket)
		if err != nil {
			if !errors.Is(err, context.Canceled) {
				log.Error(err.Error())
			}
			return
		}
	},
}

var cmdCompareBucket = &cobra.Command{
	Use:   "compare_bucket",
	Short: "compare bucket to the same bucket in '--chaindata.reference'",
	Run: func(cmd *cobra.Command, args []string) {
		ctx, _ := common2.RootContext()
		if referenceChaindata == "" {
			referenceChaindata = chaindata + "-copy"
		}
		err := compareBucketBetweenDatabases(ctx, chaindata, referenceChaindata, bucket)
		if err != nil {
			if !errors.Is(err, context.Canceled) {
				log.Error(err.Error())
			}
			return
		}
	},
}

var cmdCompareStates = &cobra.Command{
	Use:   "compare_states",
	Short: "compare state buckets to buckets in '--chaindata.reference'",
	Run: func(cmd *cobra.Command, args []string) {
		ctx, _ := common2.RootContext()
		if referenceChaindata == "" {
			referenceChaindata = chaindata + "-copy"
		}
		err := compareStates(ctx, chaindata, referenceChaindata)
		if err != nil {
			if !errors.Is(err, context.Canceled) {
				log.Error(err.Error())
			}
			return
		}
	},
}

var cmdMdbxToMdbx = &cobra.Command{
	Use:   "mdbx_to_mdbx",
	Short: "copy data from '--chaindata' to '--chaindata.to'",
	Run: func(cmd *cobra.Command, args []string) {
		ctx, _ := common2.RootContext()

		from, to := backup.OpenPair(chaindata, toChaindata, kv.ChainDB, 0)
		err := backup.Kv2kv(ctx, from, to, nil, backup.ReadAheadThreads)
		if err != nil && !errors.Is(err, context.Canceled) {
			if !errors.Is(err, context.Canceled) {
				log.Error(err.Error())
			}
			return
		}
	},
}

var cmdFToMdbx = &cobra.Command{
	Use:   "f_to_mdbx",
	Short: "copy data from '--chaindata' to '--chaindata.to'",
	Run: func(cmd *cobra.Command, args []string) {
		ctx, _ := common2.RootContext()
		logger := log.New()
		err := fToMdbx(ctx, logger, toChaindata)
		if err != nil && !errors.Is(err, context.Canceled) {
			if !errors.Is(err, context.Canceled) {
				log.Error(err.Error())
			}
			return
		}
	},
}

func init() {
	withDataDir(cmdCompareBucket)
	withReferenceChaindata(cmdCompareBucket)
	withBucket(cmdCompareBucket)

	rootCmd.AddCommand(cmdCompareBucket)

	withDataDir(cmdWarmup)
	withBucket(cmdWarmup)

	rootCmd.AddCommand(cmdWarmup)

	withDataDir(cmdCompareStates)
	withReferenceChaindata(cmdCompareStates)
	withBucket(cmdCompareStates)

	rootCmd.AddCommand(cmdCompareStates)

	withDataDir(cmdMdbxToMdbx)
	withToChaindata(cmdMdbxToMdbx)
	withBucket(cmdMdbxToMdbx)

	rootCmd.AddCommand(cmdMdbxToMdbx)

	withToChaindata(cmdFToMdbx)
	withFile(cmdFToMdbx)
	withBucket(cmdFToMdbx)

	rootCmd.AddCommand(cmdFToMdbx)
}

func doWarmup(ctx context.Context, chaindata string, bucket string) error {
	const ThreadsLimit = 5_000
	db := mdbx2.NewMDBX(log.New()).Path(chaindata).RoTxsLimiter(semaphore.NewWeighted(ThreadsLimit)).Readonly().MustOpen()
	defer db.Close()

	var total uint64
	db.View(ctx, func(tx kv.Tx) error {
		c, _ := tx.Cursor(bucket)
		total, _ = c.Count()
		return nil
	})
	progress := atomic.Int64{}

	logEvery := time.NewTicker(20 * time.Second)
	defer logEvery.Stop()

	g, ctx := errgroup.WithContext(ctx)
	g.SetLimit(ThreadsLimit)
	for i := 0; i < 256; i++ {
		for j := 0; j < 256; j++ {
			i := i
			j := j
			g.Go(func() error {
				return db.View(ctx, func(tx kv.Tx) error {
					it, err := tx.Prefix(bucket, []byte{byte(i), byte(j)})
					if err != nil {
						return err
					}
					for it.HasNext() {
						_, v, err := it.Next()
						if len(v) > 0 {
							_ = v[len(v)-1]
						}
						progress.Add(1)
						if err != nil {
							return err
						}

						select {
						case <-logEvery.C:
							log.Info(fmt.Sprintf("Progress: %.2f%%", 100*float64(progress.Load())/float64(total)))
						default:
						}
					}
					return nil
				})
			})
		}
	}
	g.Wait()
	return nil
}

func compareStates(ctx context.Context, chaindata string, referenceChaindata string) error {
	db := mdbx2.MustOpen(chaindata)
	defer db.Close()

	refDB := mdbx2.MustOpen(referenceChaindata)
	defer refDB.Close()

	if err := db.View(context.Background(), func(tx kv.Tx) error {
		if err := refDB.View(context.Background(), func(refTX kv.Tx) error {
			for _, bucket := range stateBuckets {
				fmt.Printf("\nBucket: %s\n", bucket)
				if err := compareBuckets(ctx, tx, bucket, refTX, bucket); err != nil {
					return err
				}
			}
			return nil
		}); err != nil {
			return err
		}
		return nil
	}); err != nil {
		return err
	}

	return nil
}
func compareBucketBetweenDatabases(ctx context.Context, chaindata string, referenceChaindata string, bucket string) error {
	db := mdbx2.MustOpen(chaindata)
	defer db.Close()

	refDB := mdbx2.MustOpen(referenceChaindata)
	defer refDB.Close()

	if err := db.View(context.Background(), func(tx kv.Tx) error {
		return refDB.View(context.Background(), func(refTX kv.Tx) error {
			return compareBuckets(ctx, tx, bucket, refTX, bucket)
		})
	}); err != nil {
		return err
	}

	return nil
}

func compareBuckets(ctx context.Context, tx kv.Tx, b string, refTx kv.Tx, refB string) error {
	count := 0
	c, err := tx.Cursor(b)
	if err != nil {
		return err
	}
	k, v, e := c.First()
	if e != nil {
		return e
	}
	refC, err := refTx.Cursor(refB)
	if err != nil {
		return err
	}
	refK, refV, revErr := refC.First()
	if revErr != nil {
		return revErr
	}
	for k != nil || refK != nil {
		count++
		if count%10_000_000 == 0 {
			select {
			case <-ctx.Done():
				return ctx.Err()
			default:
			}
			fmt.Printf("Compared %d records\n", count)
		}
		if k == nil {
			fmt.Printf("Missing in db: %x [%x]\n", refK, refV)
			refK, refV, revErr = refC.Next()
			if revErr != nil {
				return revErr
			}
		} else if refK == nil {
			fmt.Printf("Missing refDB: %x [%x]\n", k, v)
			k, v, e = c.Next()
			if e != nil {
				return e
			}
		} else {
			switch bytes.Compare(k, refK) {
			case -1:
				fmt.Printf("Missing refDB: %x [%x]\n", k, v)
				k, v, e = c.Next()
				if e != nil {
					return e
				}
			case 1:
				fmt.Printf("Missing in db: %x [%x]\n", refK, refV)
				refK, refV, revErr = refC.Next()
				if revErr != nil {
					return revErr
				}
			case 0:
				if !bytes.Equal(v, refV) {
					fmt.Printf("Different values for %x. db: [%x], refDB: [%x]\n", k, v, refV)
				}
				k, v, e = c.Next()
				if e != nil {
					return e
				}
				refK, refV, revErr = refC.Next()
				if revErr != nil {
					return revErr
				}
			default:
				fmt.Printf("Unexpected result of bytes.Compare: %d\n", bytes.Compare(k, refK))
			}
		}
	}
	return nil
}

func fToMdbx(ctx context.Context, logger log.Logger, to string) error {
	file, err := os.Open(file)
	if err != nil {
		panic(err)
	}
	defer file.Close()

	dst := mdbx2.NewMDBX(logger).Path(to).MustOpen()
	dstTx, err1 := dst.BeginRw(ctx)
	if err1 != nil {
		return err1
	}
	defer dstTx.Rollback()

	commitEvery := time.NewTicker(5 * time.Second)
	defer commitEvery.Stop()
	fileScanner := bufio.NewScanner(file)
	endData := []byte("DATA=END")
	endHeader := []byte("HEADER=END")

MainLoop:
	for {
		bucket := ""
		for { // header
			if !fileScanner.Scan() {
				break
			}
			kk := fileScanner.Bytes()
			if bytes.Equal(kk, endHeader) {
				break
			}

			parts := strings.Split(string(kk), "=")
			k, v := parts[0], parts[1]
			if k == "database" {
				bucket = v
			}
		}
		err = fileScanner.Err()
		if err != nil {
			panic(err)
		}
		err = fileScanner.Err()
		if err != nil {
			panic(err)
		}
		if bucket == "" {
			panic("bucket not parse")
		}

		c, err := dstTx.RwCursor(bucket)
		if err != nil {
			return err
		}

		for {
			if !fileScanner.Scan() {
				break MainLoop
			}
			k := common.CopyBytes(fileScanner.Bytes())
			if bytes.Equal(k, endData) {
				break
			}
			k = common.FromHex(string(k[1:]))
			if !fileScanner.Scan() {
				break MainLoop
			}
			v := common.CopyBytes(fileScanner.Bytes())
			v = common.FromHex(string(v[1:]))

			if casted, ok := c.(kv.RwCursorDupSort); ok {
				if err = casted.AppendDup(k, v); err != nil {
					panic(err)
				}
			} else {
				if err = c.Append(k, v); err != nil {
					panic(err)
				}
			}
			select {
			default:
			case <-ctx.Done():
				return ctx.Err()
			case <-commitEvery.C:
				log.Info("Progress", "bucket", bucket, "key", fmt.Sprintf("%x", k))
			}
		}
		err = fileScanner.Err()
		if err != nil {
			panic(err)
		}
	}
	err = dstTx.Commit()
	if err != nil {
		return err
	}

	return nil
}