package app

import (
	"context"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"sync"

	"forge.cadoles.com/arcad/edge/pkg/app"
	"forge.cadoles.com/arcad/edge/pkg/bus"
	"forge.cadoles.com/arcad/edge/pkg/bus/memory"
	appHTTP "forge.cadoles.com/arcad/edge/pkg/http"
	"forge.cadoles.com/arcad/edge/pkg/module"
	appModule "forge.cadoles.com/arcad/edge/pkg/module/app"
	appModuleMemory "forge.cadoles.com/arcad/edge/pkg/module/app/memory"
	authModule "forge.cadoles.com/arcad/edge/pkg/module/auth"
	authHTTP "forge.cadoles.com/arcad/edge/pkg/module/auth/http"
	"forge.cadoles.com/arcad/edge/pkg/module/blob"
	"forge.cadoles.com/arcad/edge/pkg/module/cast"
	"forge.cadoles.com/arcad/edge/pkg/module/fetch"
	netModule "forge.cadoles.com/arcad/edge/pkg/module/net"
	shareModule "forge.cadoles.com/arcad/edge/pkg/module/share"
	shareSqlite "forge.cadoles.com/arcad/edge/pkg/module/share/sqlite"
	"forge.cadoles.com/arcad/edge/pkg/storage"
	storageSqlite "forge.cadoles.com/arcad/edge/pkg/storage/sqlite"
	"gitlab.com/wpetit/goweb/logger"

	"forge.cadoles.com/arcad/edge/pkg/bundle"
	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	"github.com/lestrrat-go/jwx/v2/jwa"
	"github.com/lestrrat-go/jwx/v2/jwk"
	"github.com/pkg/errors"
	"github.com/urfave/cli/v2"

	_ "embed"

	_ "forge.cadoles.com/arcad/edge/pkg/module/auth/http/passwd/argon2id"
	_ "forge.cadoles.com/arcad/edge/pkg/module/auth/http/passwd/plain"
)

func RunCommand() *cli.Command {
	return &cli.Command{
		Name:  "run",
		Usage: "Run the specified app bundle",
		Flags: []cli.Flag{
			&cli.StringSliceFlag{
				Name:    "path",
				Usage:   "use `PATH` as app bundle (zipped bundle or directory)",
				Aliases: []string{"p"},
				Value:   cli.NewStringSlice("."),
			},
			&cli.StringFlag{
				Name:    "address",
				Usage:   "use `ADDRESS` as http server base listening address",
				Aliases: []string{"a"},
				Value:   ":8080",
			},
			&cli.StringFlag{
				Name:  "log-format",
				Usage: "use `LOG-FORMAT` ('json' or 'human')",
				Value: "human",
			},
			&cli.IntFlag{
				Name:  "log-level",
				Usage: "use `LOG-LEVEL` (0: debug -> 5: fatal)",
				Value: 0,
			},
			&cli.StringFlag{
				Name:  "storage-file",
				Usage: "use `FILE` for SQLite storage database",
				Value: ".edge/%APPID%/data.sqlite?_pragma=foreign_keys(1)&_pragma=busy_timeout=60000",
			},
			&cli.StringFlag{
				Name:  "shared-resources-file",
				Usage: "use `FILE` for SQLite shared resources database",
				Value: ".edge/shared-resources.sqlite?_pragma=foreign_keys(1)&_pragma=busy_timeout=60000",
			},
			&cli.StringFlag{
				Name:  "accounts-file",
				Usage: "use `FILE` as local accounts",
				Value: ".edge/%APPID%/accounts.json",
			},
		},
		Action: func(ctx *cli.Context) error {
			address := ctx.String("address")
			paths := ctx.StringSlice("path")

			logFormat := ctx.String("log-format")
			logLevel := ctx.Int("log-level")
			storageFile := ctx.String("storage-file")
			accountsFile := ctx.String("accounts-file")
			sharedResourcesFile := ctx.String("shared-resources-file")

			logger.SetFormat(logger.Format(logFormat))
			logger.SetLevel(logger.Level(logLevel))

			cmdCtx := ctx.Context

			host, portStr, err := net.SplitHostPort(address)
			if err != nil {
				return errors.WithStack(err)
			}

			port, err := strconv.ParseUint(portStr, 10, 32)
			if err != nil {
				return errors.WithStack(err)
			}

			manifests := make([]*app.Manifest, len(paths))
			for idx, pth := range paths {
				bdl, err := bundle.FromPath(pth)
				if err != nil {
					return errors.WithStack(err)
				}

				manifest, err := app.LoadManifest(bdl)
				if err != nil {
					return errors.WithStack(err)
				}

				manifests[idx] = manifest
			}

			var wg sync.WaitGroup

			for idx, p := range paths {
				wg.Add(1)

				go func(path string, basePort uint64, appIndex int) {
					defer wg.Done()

					port := basePort + uint64(appIndex)
					address := fmt.Sprintf("%s:%d", host, port)
					appsRepository := newAppRepository(host, basePort, manifests...)

					appCtx := logger.With(cmdCtx, logger.F("address", address))

					if err := runApp(appCtx, path, address, storageFile, accountsFile, appsRepository, sharedResourcesFile); err != nil {
						logger.Error(appCtx, "could not run app", logger.E(errors.WithStack(err)))
					}
				}(p, port, idx)
			}

			wg.Wait()

			return nil
		},
	}
}

func runApp(ctx context.Context, path string, address string, storageFile string, accountsFile string, appRepository appModule.Repository, sharedResourcesFile string) error {
	absPath, err := filepath.Abs(path)
	if err != nil {
		return errors.Wrapf(err, "could not resolve path '%s'", path)
	}

	logger.Info(ctx, "opening app bundle", logger.F("path", absPath))

	bundle, err := bundle.FromPath(path)
	if err != nil {
		return errors.Wrapf(err, "could not open path '%s' as an app bundle", path)
	}

	manifest, err := app.LoadManifest(bundle)
	if err != nil {
		return errors.Wrap(err, "could not load manifest from app bundle")
	}

	if valid, err := manifest.Validate(manifestMetadataValidators...); !valid {
		return errors.Wrap(err, "invalid app manifest")
	}

	ctx = logger.With(ctx, logger.F("appID", manifest.ID))

	// Add auth handler
	key, err := dummyKey()
	if err != nil {
		return errors.WithStack(err)
	}

	deps := &moduleDeps{}
	funcs := []ModuleDepFunc{
		initMemoryBus,
		initDatastores(storageFile, manifest.ID),
		initAccounts(accountsFile, manifest.ID),
		initShareRepository(sharedResourcesFile),
		initAppRepository(appRepository),
	}

	for _, fn := range funcs {
		if err := fn(deps); err != nil {
			return errors.WithStack(err)
		}
	}

	handler := appHTTP.NewHandler(
		appHTTP.WithBus(deps.Bus),
		appHTTP.WithServerModules(getServerModules(deps)...),
		appHTTP.WithHTTPMounts(
			appModule.Mount(appRepository),
			authModule.Mount(
				authHTTP.NewLocalHandler(
					jwa.HS256, key,
					authHTTP.WithRoutePrefix("/auth"),
					authHTTP.WithAccounts(deps.Accounts...),
				),
				authModule.WithJWT(dummyKeySet),
			),
		),
	)
	if err := handler.Load(bundle); err != nil {
		return errors.Wrap(err, "could not load app bundle")
	}

	router := chi.NewRouter()
	router.Use(middleware.Logger)
	router.Use(middleware.Compress(5))

	// Add app handler
	router.Handle("/*", handler)

	logger.Info(ctx, "listening", logger.F("address", address))

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

	return nil
}

type moduleDeps struct {
	AppID           app.ID
	Bus             bus.Bus
	DocumentStore   storage.DocumentStore
	BlobStore       storage.BlobStore
	AppRepository   appModule.Repository
	ShareRepository shareModule.Repository
	Accounts        []authHTTP.LocalAccount
}

type ModuleDepFunc func(*moduleDeps) error

func getServerModules(deps *moduleDeps) []app.ServerModuleFactory {
	return []app.ServerModuleFactory{
		module.ContextModuleFactory(),
		module.ConsoleModuleFactory(),
		cast.CastModuleFactory(),
		module.LifecycleModuleFactory(),
		netModule.ModuleFactory(deps.Bus),
		module.RPCModuleFactory(deps.Bus),
		module.StoreModuleFactory(deps.DocumentStore),
		blob.ModuleFactory(deps.Bus, deps.BlobStore),
		authModule.ModuleFactory(
			authModule.WithJWT(dummyKeySet),
		),
		appModule.ModuleFactory(deps.AppRepository),
		fetch.ModuleFactory(deps.Bus),
		shareModule.ModuleFactory(deps.AppID, deps.ShareRepository),
	}
}

var dummySecret = []byte("not_so_secret")

func dummyKey() (jwk.Key, error) {
	key, err := jwk.FromRaw(dummySecret)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return key, nil
}

func dummyKeySet() (jwk.Set, error) {
	key, err := dummyKey()
	if err != nil {
		return nil, errors.WithStack(err)
	}

	if err := key.Set(jwk.AlgorithmKey, jwa.HS256); err != nil {
		return nil, errors.WithStack(err)
	}

	set := jwk.NewSet()

	if err := set.AddKey(key); err != nil {
		return nil, errors.WithStack(err)
	}

	return set, nil
}

func ensureDir(path string) error {
	if err := os.MkdirAll(filepath.Dir(path), os.ModePerm); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

func injectAppID(str string, appID app.ID) string {
	return strings.ReplaceAll(str, "%APPID%", string(appID))
}

//go:embed default-accounts.json
var defaultAccounts []byte

func loadLocalAccounts(path string) ([]authHTTP.LocalAccount, error) {
	if err := ensureDir(path); err != nil {
		return nil, errors.WithStack(err)
	}

	data, err := ioutil.ReadFile(path)
	if err != nil {
		if errors.Is(err, os.ErrNotExist) {
			if err := ioutil.WriteFile(path, defaultAccounts, 0o640); err != nil {
				return nil, errors.WithStack(err)
			}

			data = defaultAccounts
		} else {
			return nil, errors.WithStack(err)
		}
	}

	var accounts []authHTTP.LocalAccount

	if err := json.Unmarshal(data, &accounts); err != nil {
		return nil, errors.WithStack(err)
	}

	return accounts, nil
}

func findMatchingDeviceAddress(ctx context.Context, from string, defaultAddr string) (string, error) {
	if from == "" {
		return defaultAddr, nil
	}

	fromIP := net.ParseIP(from)

	if fromIP == nil {
		return defaultAddr, nil
	}

	ifaces, err := net.Interfaces()
	if err != nil {
		return "", errors.WithStack(err)
	}

	for _, ifa := range ifaces {
		addrs, err := ifa.Addrs()
		if err != nil {
			logger.Error(
				ctx, "could not retrieve iface adresses",
				logger.E(errors.WithStack(err)), logger.F("iface", ifa.Name),
			)

			continue
		}

		for _, addr := range addrs {
			ip, network, err := net.ParseCIDR(addr.String())
			if err != nil {
				logger.Error(
					ctx, "could not parse address",
					logger.E(errors.WithStack(err)), logger.F("address", addr.String()),
				)

				continue
			}

			if !network.Contains(fromIP) {
				continue
			}

			if ip.To4() == nil {
				continue
			}

			return ip.To4().String(), nil
		}
	}

	return defaultAddr, nil
}

func newAppRepository(host string, basePort uint64, manifests ...*app.Manifest) *appModuleMemory.Repository {
	if host == "" {
		host = "127.0.0.1"
	}

	return appModuleMemory.NewRepository(
		func(ctx context.Context, id app.ID, from string) (string, error) {
			appIndex := 0
			for i := 0; i < len(manifests); i++ {
				if manifests[i].ID == id {
					appIndex = i
					break
				}
			}

			addr, err := findMatchingDeviceAddress(ctx, from, host)
			if err != nil {
				return "", errors.WithStack(err)
			}

			return fmt.Sprintf("http://%s:%d", addr, int(basePort)+appIndex), nil
		},
		manifests...,
	)
}

func initAppRepository(repo appModule.Repository) ModuleDepFunc {
	return func(deps *moduleDeps) error {
		deps.AppRepository = repo
		return nil
	}
}

func initMemoryBus(deps *moduleDeps) error {
	deps.Bus = memory.NewBus()

	return nil
}

func initDatastores(storageFile string, appID app.ID) ModuleDepFunc {
	return func(deps *moduleDeps) error {
		storageFile = injectAppID(storageFile, appID)

		if err := ensureDir(storageFile); err != nil {
			return errors.WithStack(err)
		}

		db, err := storageSqlite.Open(storageFile)
		if err != nil {
			return errors.WithStack(err)
		}

		deps.DocumentStore = storageSqlite.NewDocumentStoreWithDB(db)
		deps.BlobStore = storageSqlite.NewBlobStoreWithDB(db)

		return nil
	}
}

func initAccounts(accountsFile string, appID app.ID) ModuleDepFunc {
	return func(deps *moduleDeps) error {
		accountsFile = injectAppID(accountsFile, appID)

		accounts, err := loadLocalAccounts(accountsFile)
		if err != nil {
			return errors.Wrap(err, "could not load local accounts")
		}

		deps.Accounts = accounts

		return nil
	}
}

func initShareRepository(shareRepositoryFile string) ModuleDepFunc {
	return func(deps *moduleDeps) error {
		if err := ensureDir(shareRepositoryFile); err != nil {
			return errors.WithStack(err)
		}

		repo := shareSqlite.NewRepository(shareRepositoryFile)

		deps.ShareRepository = repo

		return nil
	}
}