package command

import (
	"context"
	"fmt"
	"net/http"
	"strings"
	"sync"
	"time"

	"github.com/hashicorp/golang-lru/v2/expirable"
	"github.com/keegancsmith/rpc"
	"github.com/lestrrat-go/jwx/v2/jwa"
	"github.com/lestrrat-go/jwx/v2/jwk"
	"gitlab.com/wpetit/goweb/logger"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	"github.com/pkg/errors"
	"github.com/urfave/cli/v2"

	// Register storage drivers
	"forge.cadoles.com/arcad/edge/cmd/storage-server/command/flag"
	"forge.cadoles.com/arcad/edge/pkg/jwtutil"
	"forge.cadoles.com/arcad/edge/pkg/storage"
	"forge.cadoles.com/arcad/edge/pkg/storage/driver"
	_ "forge.cadoles.com/arcad/edge/pkg/storage/driver/rpc"
	"forge.cadoles.com/arcad/edge/pkg/storage/driver/rpc/server"
	_ "forge.cadoles.com/arcad/edge/pkg/storage/driver/sqlite"
	"forge.cadoles.com/arcad/edge/pkg/storage/share"
)

func Run() *cli.Command {
	return &cli.Command{
		Name:  "run",
		Usage: "Run server",
		Flags: []cli.Flag{
			&cli.StringFlag{
				Name:    "address",
				Aliases: []string{"addr"},
				Value:   ":3001",
			},
			&cli.StringFlag{
				Name:    "blobstore-dsn-pattern",
				EnvVars: []string{"STORAGE_SERVER_BLOBSTORE_DSN_PATTERN"},
				Value:   fmt.Sprintf("sqlite://data/%%TENANT%%/%%APPID%%/blobstore.sqlite?_pragma=foreign_keys(1)&_pragma=busy_timeout=%d", (60 * time.Second).Milliseconds()),
			},
			&cli.StringFlag{
				Name:    "documentstore-dsn-pattern",
				EnvVars: []string{"STORAGE_SERVER_DOCUMENTSTORE_DSN_PATTERN"},
				Value:   fmt.Sprintf("sqlite://data/%%TENANT%%/%%APPID%%/documentstore.sqlite?_pragma=foreign_keys(1)&_pragma=busy_timeout=%d", (60 * time.Second).Milliseconds()),
			},
			&cli.StringFlag{
				Name:    "sharestore-dsn-pattern",
				EnvVars: []string{"STORAGE_SERVER_SHARESTORE_DSN_PATTERN"},
				Value:   fmt.Sprintf("sqlite://data/%%TENANT%%/sharestore.sqlite?_pragma=foreign_keys(1)&_pragma=busy_timeout=%d", (60 * time.Second).Milliseconds()),
			},
			flag.PrivateKey,
			flag.PrivateKeySigningAlgorithm,
			flag.PrivateKeyDefaultSize,
			&cli.DurationFlag{
				Name:    "cache-ttl",
				EnvVars: []string{"STORAGE_SERVER_CACHE_TTL"},
				Value:   time.Hour,
			},
			&cli.IntFlag{
				Name:    "cache-size",
				EnvVars: []string{"STORAGE_SERVER_CACHE_SIZE"},
				Value:   32,
			},
		},
		Action: func(ctx *cli.Context) error {
			addr := ctx.String("address")
			blobStoreDSNPattern := ctx.String("blobstore-dsn-pattern")
			documentStoreDSNPattern := ctx.String("documentstore-dsn-pattern")
			shareStoreDSNPattern := ctx.String("sharestore-dsn-pattern")
			cacheSize := ctx.Int("cache-size")
			cacheTTL := ctx.Duration("cache-ttl")
			privateKeyFile := flag.GetPrivateKey(ctx)
			signingAlgorithm := flag.GetSigningAlgorithm(ctx)
			privateKeyDefaultSize := flag.GetPrivateKeyDefaultSize(ctx)

			router := chi.NewRouter()

			privateKey, err := jwtutil.LoadOrGenerateKey(
				privateKeyFile,
				privateKeyDefaultSize,
			)
			if err != nil {
				return errors.WithStack(err)
			}

			publicKey, err := privateKey.PublicKey()
			if err != nil {
				return errors.WithStack(err)
			}

			getBlobStoreServer := createGetCachedStoreServer(
				func(dsn string) (storage.BlobStore, error) {
					return driver.NewBlobStore(dsn)
				},
				func(store storage.BlobStore) *rpc.Server {
					return server.NewBlobStoreServer(store)
				},
			)

			getShareStoreServer := createGetCachedStoreServer(
				func(dsn string) (share.Store, error) {
					return driver.NewShareStore(dsn)
				},
				func(store share.Store) *rpc.Server {
					return server.NewShareStoreServer(store)
				},
			)

			getDocumentStoreServer := createGetCachedStoreServer(
				func(dsn string) (storage.DocumentStore, error) {
					return driver.NewDocumentStore(dsn)
				},
				func(store storage.DocumentStore) *rpc.Server {
					return server.NewDocumentStoreServer(store)
				},
			)

			router.Use(middleware.RealIP)
			router.Use(middleware.Logger)
			router.Use(authenticate(publicKey, jwa.SignatureAlgorithm(signingAlgorithm)))

			router.Handle("/blobstore", createStoreHandler(getBlobStoreServer, blobStoreDSNPattern, true, cacheSize, cacheTTL))
			router.Handle("/documentstore", createStoreHandler(getDocumentStoreServer, documentStoreDSNPattern, true, cacheSize, cacheTTL))
			router.Handle("/sharestore", createStoreHandler(getShareStoreServer, shareStoreDSNPattern, false, cacheSize, cacheTTL))

			if err := http.ListenAndServe(addr, router); err != nil {
				return errors.WithStack(err)
			}

			return nil
		},
	}
}

type getRPCServerFunc func(cacheSize int, cacheTTL time.Duration, tenant, appID, dsnPattern string) (*rpc.Server, error)

func createGetCachedStoreServer[T any](storeFactory func(dsn string) (T, error), serverFactory func(store T) *rpc.Server) getRPCServerFunc {
	var (
		cache     *expirable.LRU[string, *rpc.Server]
		initCache sync.Once
	)

	return func(cacheSize int, cacheTTL time.Duration, tenant, appID, dsnPattern string) (*rpc.Server, error) {
		initCache.Do(func() {
			cache = expirable.NewLRU[string, *rpc.Server](cacheSize, nil, cacheTTL)
		})

		key := fmt.Sprintf("%s:%s", tenant, appID)

		storeServer, _ := cache.Get(key)
		if storeServer != nil {
			return storeServer, nil
		}

		dsn := strings.ReplaceAll(dsnPattern, "%TENANT%", tenant)
		dsn = strings.ReplaceAll(dsn, "%APPID%", appID)

		store, err := storeFactory(dsn)
		if err != nil {
			return nil, errors.WithStack(err)
		}

		storeServer = serverFactory(store)

		cache.Add(key, storeServer)

		return storeServer, nil
	}
}

func createStoreHandler(getStoreServer getRPCServerFunc, dsnPattern string, appIDRequired bool, cacheSize int, cacheTTL time.Duration) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		ctx := r.Context()

		tenant, ok := ctx.Value("tenant").(string)
		if !ok || tenant == "" {
			http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)

			return
		}

		appID := r.URL.Query().Get("appId")
		if appIDRequired && appID == "" {
			http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)

			return
		}

		server, err := getStoreServer(cacheSize, cacheTTL, tenant, appID, dsnPattern)
		if err != nil {
			logger.Error(r.Context(), "could not retrieve store server", logger.E(errors.WithStack(err)), logger.F("tenant", tenant))
			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)

			return
		}

		server.ServeHTTP(w, r)
	})
}

func authenticate(privateKey jwk.Key, signingAlgorithm jwa.SignatureAlgorithm) func(http.Handler) http.Handler {
	var (
		createKeySet sync.Once
		err          error
		getKeySet    jwtutil.GetKeySetFunc
	)

	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			ctx := r.Context()

			createKeySet.Do(func() {
				err = privateKey.Set(jwk.AlgorithmKey, signingAlgorithm)
				if err != nil {
					return
				}

				var keySet jwk.Set

				keySet, err = jwtutil.NewKeySet(privateKey)
				if err != nil {
					return
				}

				getKeySet = func() (jwk.Set, error) {
					return keySet, nil
				}
			})
			if err != nil {
				logger.Error(ctx, "could not create keyset accessor", logger.E(errors.WithStack(err)))
				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)

				return
			}

			token, err := jwtutil.FindToken(r, getKeySet, jwtutil.WithFinders(
				jwtutil.FindTokenFromQueryString("token"),
			))
			if err != nil {
				logger.Error(ctx, "could not find jwt token", logger.E(errors.WithStack(err)))
				http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)

				return
			}

			tokenMap, err := token.AsMap(ctx)
			if err != nil {
				logger.Error(ctx, "could not transform token to map", logger.E(errors.WithStack(err)))
				http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)

				return
			}

			rawTenant, exists := tokenMap["tenant"]
			if !exists {
				logger.Warn(ctx, "could not find tenant claim", logger.F("token", token))
				http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)

				return
			}

			tenant, ok := rawTenant.(string)
			if !ok {
				logger.Warn(ctx, "unexpected tenant claim value", logger.F("token", token))
				http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)

				return
			}

			r = r.WithContext(context.WithValue(ctx, "tenant", tenant))

			next.ServeHTTP(w, r)
		})
	}
}