// Copyright (c) Ultraviolet
// SPDX-License-Identifier: Apache-2.0
package main

import (
	"context"
	"encoding/hex"
	"encoding/pem"
	"flag"
	"fmt"
	"log"
	"log/slog"
	"os"
	"strconv"
	"strings"

	mglog "github.com/absmach/magistrala/logger"
	smqserver "github.com/absmach/magistrala/pkg/server"
	grpcserver "github.com/absmach/magistrala/pkg/server/grpc"
	"github.com/caarlos0/env/v11"
	"github.com/ultravioletrs/cocos/agent/cvms"
	cvmsgrpc "github.com/ultravioletrs/cocos/agent/cvms/api/grpc"
	"github.com/ultravioletrs/cocos/internal"
	"golang.org/x/sync/errgroup"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
	"google.golang.org/grpc/reflection"
)

var _ cvmsgrpc.Service = (*svc)(nil)

const (
	svcName     = "cvms_test_server"
	defaultPort = "7001"
)

var (
	algoPath          string
	dataPathString    string
	dataPaths         []string
	attestedTLSString string
	attestedTLS       bool
	pubKeyFile        string
	clientCAFile      string
	// Remote resource configuration.
	algoKBSURL          string
	algoSourceURL       string
	algoSourceType      string
	algoKBSResourcePath string
	datasetKBSURLs      string
	datasetSourceURLs   string
	datasetSourceType   string
	datasetKBSPaths     string
	algoType            string
	algoArgsString      string
	algoHash            string
	datasetTypeString   string
	datasetHash         string
	datasetDecompress   string
)

type svc struct {
	logger *slog.Logger
}

func (s *svc) Run(ctx context.Context, ipAddress string, sendMessage cvmsgrpc.SendFunc, authInfo credentials.AuthInfo) {
	s.logger.Debug(fmt.Sprintf("received who am on ip address %s", ipAddress))

	pubKey, err := os.ReadFile(pubKeyFile)
	if err != nil {
		s.logger.Error(fmt.Sprintf("failed to read public key file: %s", err))
		return
	}
	pubPem, _ := pem.Decode(pubKey)

	// Build datasets
	var datasets []*cvms.Dataset

	// Check if using remote datasets
	var datasetURLs []string
	var datasetKBSPathsList []string
	var datasetKBSURLsList []string
	if datasetSourceURLs != "" {
		datasetURLs = strings.Split(datasetSourceURLs, ",")
	}
	if datasetKBSPaths != "" {
		datasetKBSPathsList = strings.Split(datasetKBSPaths, ",")
	}
	if datasetKBSURLs != "" {
		datasetKBSURLsList = strings.Split(datasetKBSURLs, ",")
	}

	var datasetDecompressList []bool
	if datasetDecompress != "" {
		parts := strings.Split(datasetDecompress, ",")
		for _, p := range parts {
			val, _ := strconv.ParseBool(p)
			datasetDecompressList = append(datasetDecompressList, val)
		}
	}

	// Parse dataset hash if provided
	var dataHashBytes []byte
	if datasetHash != "" {
		var err error
		dataHashBytes, err = hex.DecodeString(datasetHash)
		if err != nil {
			s.logger.Error(fmt.Sprintf("failed to decode dataset hash: %s", err))
			return
		}
		if len(dataHashBytes) != 32 {
			s.logger.Error(fmt.Sprintf("dataset hash must be 32 bytes (SHA256), got %d", len(dataHashBytes)))
			return
		}
	} else {
		// Default to empty/zero hash
		dataHashBytes = make([]byte, 32)
	}

	if len(datasetURLs) > 0 && len(datasetKBSPathsList) > 0 {
		// Remote datasets mode
		if len(datasetURLs) != len(datasetKBSPathsList) {
			s.logger.Error("dataset source URLs and KBS paths must have the same count")
			return
		}

		for i := 0; i < len(datasetURLs); i++ {
			srcType := datasetSourceType
			if srcType == "" {
				srcType = "oci-image"
			}
			d := &cvms.Dataset{
				Hash:     dataHashBytes,
				UserKey:  pubPem.Bytes,
				Filename: fmt.Sprintf("dataset_%d.csv", i),
				Source: &cvms.Source{
					Type:            srcType,
					Url:             datasetURLs[i],
					KbsResourcePath: datasetKBSPathsList[i],
					Encrypted:       datasetKBSPathsList[i] != "",
				},
			}
			if len(datasetKBSURLsList) > i && datasetKBSURLsList[i] != "" {
				d.Kbs = &cvms.KBSConfig{
					Url:     datasetKBSURLsList[i],
					Enabled: true,
				}
			}
			datasets = append(datasets, d)
			if len(datasetDecompressList) > i {
				datasets[len(datasets)-1].Decompress = datasetDecompressList[i]
			}
		}
	} else {
		// Direct upload mode - use local files
		for _, dataPath := range dataPaths {
			if _, err := os.Stat(dataPath); os.IsNotExist(err) {
				s.logger.Error(fmt.Sprintf("data file does not exist: %s", dataPath))
				return
			}
			dataHash, err := internal.ChecksumHex(dataPath)
			if err != nil {
				s.logger.Error(fmt.Sprintf("failed to calculate checksum: %s", err))
				return
			}
			s.logger.Info("local dataset checksum", "path", dataPath, "hash", dataHash)

			hashBytes, _ := hex.DecodeString(dataHash)
			datasets = append(datasets, &cvms.Dataset{Hash: hashBytes, UserKey: pubPem.Bytes})
		}
	}

	// Build algorithm
	var algorithm *cvms.Algorithm
	if algoSourceURL != "" && algoKBSResourcePath != "" {
		// Remote algorithm mode
		var algoHashBytes []byte
		if algoHash != "" {
			var err error
			algoHashBytes, err = hex.DecodeString(algoHash)
			if err != nil {
				s.logger.Error(fmt.Sprintf("failed to decode algo hash: %s", err))
				return
			}
			if len(algoHashBytes) != 32 {
				s.logger.Error(fmt.Sprintf("algo hash must be 32 bytes (SHA256), got %d", len(algoHashBytes)))
				return
			}
		} else {
			algoHashBytes = make([]byte, 32)
		}

		var algoArgs []string
		if algoArgsString != "" {
			algoArgs = strings.Split(algoArgsString, ",")
		}

		var algoSrcType string
		if algoSourceType != "" {
			algoSrcType = algoSourceType
		} else {
			algoSrcType = "oci-image"
		}

		algorithm = &cvms.Algorithm{
			Hash:     algoHashBytes,
			UserKey:  pubPem.Bytes,
			AlgoType: algoType,
			AlgoArgs: algoArgs,
			Source: &cvms.Source{
				Type:            algoSrcType,
				Url:             algoSourceURL,
				KbsResourcePath: algoKBSResourcePath,
				Encrypted:       algoKBSResourcePath != "",
			},
		}
		if algoKBSURL != "" {
			algorithm.Kbs = &cvms.KBSConfig{
				Url:     algoKBSURL,
				Enabled: true,
			}
		}
	} else {
		// Direct upload mode - use local file
		fileHash, err := internal.ChecksumHex(algoPath)
		if err != nil {
			s.logger.Error(fmt.Sprintf("failed to calculate checksum: %s", err))
			return
		}
		s.logger.Info("local algorithm checksum", "path", algoPath, "hash", fileHash)

		var algoArgs []string
		if algoArgsString != "" {
			algoArgs = strings.Split(algoArgsString, ",")
		}

		hashBytes, _ := hex.DecodeString(fileHash)
		algorithm = &cvms.Algorithm{
			Hash:     hashBytes,
			UserKey:  pubPem.Bytes,
			AlgoType: algoType,
			AlgoArgs: algoArgs,
		}
	}

	s.logger.Debug("sending computation run request")
	if err := sendMessage(&cvms.ServerStreamMessage{
		Message: &cvms.ServerStreamMessage_RunReq{
			RunReq: &cvms.ComputationRunReq{
				Id:              "1",
				Name:            "sample computation",
				Description:     "sample descrption",
				Datasets:        datasets,
				Algorithm:       algorithm,
				ResultConsumers: []*cvms.ResultConsumer{{UserKey: pubPem.Bytes}},
				AgentConfig: &cvms.AgentConfig{
					Port:         "7002",
					AttestedTls:  attestedTLS,
					ClientCaFile: clientCAFile,
				},
			},
		},
	}); err != nil {
		s.logger.Error(fmt.Sprintf("failed to send run request: %s", err))
		return
	}
	s.logger.Info("computation run request sent successfully")

	// Keep the connection alive
	<-ctx.Done()
	s.logger.Info("connection closed")
}

func main() {
	flagSet := flag.NewFlagSet("tests/cvms/main.go", flag.ContinueOnError)
	flagSet.StringVar(&algoPath, "algo-path", "", "Path to the algorithm (for direct upload mode)")
	flagSet.StringVar(&pubKeyFile, "public-key-path", "", "Path to the public key file")
	flagSet.StringVar(&attestedTLSString, "attested-tls-bool", "", "Should aTLS be used, must be 'true' or 'false'")
	flagSet.StringVar(&dataPathString, "data-paths", "", "Paths to data sources, list of string separated with commas (for direct upload mode)")
	flagSet.StringVar(&clientCAFile, "client-ca-file", "", "Client CA root certificate file path")
	// Remote resource flags
	flagSet.StringVar(&algoKBSURL, "algo-kbs-url", "", "Algorithm-specific KBS endpoint URL")
	flagSet.StringVar(&algoSourceURL, "algo-source-url", "", "Algorithm source URL (docker://..., s3://..., https://..., etc.)")
	flagSet.StringVar(&algoSourceType, "algo-source-type", "", "Algorithm source type (oci-image, s3, gcs, https, http). Auto-detected from URL if empty.")
	flagSet.StringVar(&algoKBSResourcePath, "algo-kbs-path", "", "Algorithm KBS resource path (e.g., 'default/key/algo-key')")
	flagSet.StringVar(&datasetKBSURLs, "dataset-kbs-urls", "", "Dataset-specific KBS endpoint URLs, comma-separated")
	flagSet.StringVar(&datasetSourceURLs, "dataset-source-urls", "", "Dataset source URLs, comma-separated")
	flagSet.StringVar(&datasetSourceType, "dataset-source-type", "", "Dataset source type (oci-image, s3, gcs, https, http). Auto-detected from URL if empty.")
	flagSet.StringVar(&datasetKBSPaths, "dataset-kbs-paths", "", "Dataset KBS resource paths, comma-separated")
	flagSet.StringVar(&algoType, "algo-type", "", "Algorithm execution type")
	flagSet.StringVar(&algoArgsString, "algo-args", "", "Algorithm arguments, comma-separated")
	flagSet.StringVar(&algoHash, "algo-hash", "", "Algorithm SHA256 hash (hex string)")
	flagSet.StringVar(&datasetTypeString, "dataset-type", "", "Dataset source type (deprecated, use --dataset-source-type)")
	flagSet.StringVar(&datasetHash, "dataset-hash", "", "Dataset SHA256 hash (hex string)")
	flagSet.StringVar(&datasetDecompress, "dataset-decompress", "", "Dataset decompression bools, comma-separated (e.g. true,false)")

	flagSetParseError := flagSet.Parse(os.Args[1:])
	if flagSetParseError != nil {
		log.Fatalf("Error parsing flags: %v", flagSetParseError)
	}

	parsingError := !flagSet.Parsed()
	var parsingErrorString strings.Builder

	parsingErrorString.WriteString("\n")

	// Validate that either algo-path OR (algo-source-url AND algo-kbs-path) is provided
	if algoPath == "" && (algoSourceURL == "" || algoKBSResourcePath == "") {
		parsingErrorString.WriteString("Either algo-path OR (algo-source-url AND algo-kbs-path) is required\n")
		parsingError = true
	}

	if pubKeyFile == "" {
		parsingErrorString.WriteString("Public key path is required\n")
		parsingError = true
	}

	attestedTLSBoolValue, err := strconv.ParseBool(attestedTLSString)
	if err != nil {
		parsingErrorString.WriteString("Attested TLS flag is required and it must be a boolean value\n")
		parsingError = true
		attestedTLS = false
	} else {
		attestedTLS = attestedTLSBoolValue
	}

	if dataPathString != "" {
		dataPaths = strings.Split(dataPathString, ",")
	}

	if parsingError {
		parsingErrorString.WriteString("Usage :\n")
		flagSet.SetOutput(&parsingErrorString)
		flagSet.PrintDefaults()
		log.Fatal(parsingErrorString.String())
	}

	ctx, cancel := context.WithCancel(context.Background())
	g, ctx := errgroup.WithContext(ctx)
	incomingChan := make(chan *cvms.ClientStreamMessage)

	logger, err := mglog.New(os.Stdout, "debug")
	if err != nil {
		log.Fatal(err.Error())
	}

	go func() {
		for incoming := range incomingChan {
			fmt.Println(incoming.Message)
		}
	}()

	registerAgentServiceServer := func(srv *grpc.Server) {
		reflection.Register(srv)
		cvms.RegisterServiceServer(srv, cvmsgrpc.NewServer(incomingChan, &svc{logger: logger}))
	}
	grpcServerConfig := smqserver.Config{
		Port: defaultPort,
	}
	if err := env.ParseWithOptions(&grpcServerConfig, env.Options{}); err != nil {
		logger.Error(fmt.Sprintf("failed to load %s gRPC client configuration : %s", svcName, err))
		return
	}

	gs := grpcserver.NewServer(ctx, cancel, svcName, grpcServerConfig, registerAgentServiceServer, logger)

	g.Go(func() error {
		return gs.Start()
	})

	g.Go(func() error {
		return smqserver.StopSignalHandler(ctx, cancel, logger, svcName, gs)
	})

	if err := g.Wait(); err != nil {
		logger.Error(fmt.Sprintf("%s service terminated: %s", svcName, err))
	}
}