package app

import (
	"bytes"
	"context"
	"database/sql"
	"net"
	"path/filepath"
	"text/template"

	"forge.cadoles.com/Cadoles/emissary/internal/agent/controller/app/spec"
	appSpec "forge.cadoles.com/Cadoles/emissary/internal/agent/controller/app/spec"
	"forge.cadoles.com/Cadoles/emissary/internal/jwk"
	"forge.cadoles.com/arcad/edge/pkg/app"
	"forge.cadoles.com/arcad/edge/pkg/bus"
	"forge.cadoles.com/arcad/edge/pkg/bus/memory"
	edgeHTTP "forge.cadoles.com/arcad/edge/pkg/http"
	"forge.cadoles.com/arcad/edge/pkg/module"
	appModule "forge.cadoles.com/arcad/edge/pkg/module/app"
	"forge.cadoles.com/arcad/edge/pkg/module/blob"
	"forge.cadoles.com/arcad/edge/pkg/module/cast"
	fetchModule "forge.cadoles.com/arcad/edge/pkg/module/fetch"
	netModule "forge.cadoles.com/arcad/edge/pkg/module/net"
	"forge.cadoles.com/arcad/edge/pkg/storage/sqlite"
	"github.com/Masterminds/sprig/v3"
	"github.com/lestrrat-go/jwx/v2/jwa"
	"github.com/pkg/errors"
	"gitlab.com/wpetit/goweb/logger"
)

const defaultSQLiteParams = "?_pragma=foreign_keys(1)&_pragma=busy_timeout=60000"

func (c *Controller) getHandlerOptions(ctx context.Context, appKey string, specs *spec.Spec) ([]edgeHTTP.HandlerOptionFunc, error) {
	dataDir, err := c.ensureAppDataDir(ctx, appKey)
	if err != nil {
		return nil, errors.Wrap(err, "could not retrieve app data dir")
	}

	dbFile := filepath.Join(dataDir, appKey+".sqlite")
	db, err := sqlite.Open(dbFile + defaultSQLiteParams)
	if err != nil {
		return nil, errors.Wrapf(err, "could not open database file '%s'", dbFile)
	}

	keySet, err := getAuthKeySet(specs.Config)
	if err != nil {
		return nil, errors.Wrap(err, "could not retrieve auth key set")
	}

	bus := memory.NewBus()
	modules := c.getAppModules(bus, db, specs, keySet)

	options := []edgeHTTP.HandlerOptionFunc{
		edgeHTTP.WithBus(bus),
		edgeHTTP.WithServerModules(modules...),
	}

	return options, nil
}

func getAuthKeySet(config *spec.Config) (jwk.Set, error) {
	keySet := jwk.NewSet()
	if config == nil {
		return nil, nil
	}

	auth := config.Auth

	if auth == nil {
		return nil, nil
	}

	switch {
	case auth.Local != nil:
		var (
			key jwk.Key
			err error
		)

		switch typedKey := auth.Local.Key.(type) {
		case string:
			key, err = jwk.FromRaw([]byte(typedKey))
			if err != nil {
				return nil, errors.Wrap(err, "could not parse local auth key")
			}

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

		default:
			return nil, errors.Errorf("unexpected key type '%T'", auth.Local.Key)
		}

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

	return keySet, nil
}

func createResolveAppURL(specs *spec.Spec) (ResolveAppURLFunc, error) {
	rawIfaceMappings := make(map[string]string, 0)
	if specs.Config != nil && specs.Config.AppURLResolving != nil && specs.Config.AppURLResolving.IfaceMappings != nil {
		rawIfaceMappings = specs.Config.AppURLResolving.IfaceMappings
	}

	ifaceMappings := make(map[string]*template.Template, len(rawIfaceMappings))
	for iface, rawTemplate := range rawIfaceMappings {
		tmpl, err := template.New("").Funcs(sprig.TxtFuncMap()).Parse(rawTemplate)
		if err != nil {
			return nil, errors.Wrapf(err, "could not parse iface '%s' template", iface)
		}

		ifaceMappings[iface] = tmpl
	}

	defaultRawTemplate := `http://{{ .DeviceIP }}:{{ .AppPort }}`
	if specs.Config != nil && specs.Config.AppURLResolving != nil && specs.Config.AppURLResolving.DefaultURLTemplate != "" {
		defaultRawTemplate = specs.Config.AppURLResolving.DefaultURLTemplate
	}

	defaultTemplate, err := template.New("").Funcs(sprig.TxtFuncMap()).Parse(defaultRawTemplate)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return func(ctx context.Context, manifest *app.Manifest, from string) (string, error) {
		var (
			urlTemplate *template.Template
			deviceIP    net.IP
		)

		fromIP := net.ParseIP(from)

		if fromIP != nil {
		LOOP:
			for ifaceName, ifaceTmpl := range ifaceMappings {
				iface, err := net.InterfaceByName(ifaceName)
				if err != nil {
					logger.Error(
						ctx, "could not find interface",
						logger.E(errors.WithStack(err)), logger.F("iface", ifaceName),
					)

					continue
				}

				addresses, err := iface.Addrs()
				if err != nil {
					logger.Error(
						ctx, "could not list interface addresses",
						logger.E(errors.WithStack(err)),
						logger.F("iface", iface.Name),
					)

					continue
				}

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

						continue
					}

					if !network.Contains(fromIP) {
						continue
					}

					deviceIP = ifaIP
					urlTemplate = ifaceTmpl

					break LOOP
				}
			}
		}

		if urlTemplate == nil {
			urlTemplate = defaultTemplate
		}

		if deviceIP == nil {
			deviceIP = net.ParseIP("127.0.0.1")
		}

		var appEntry *spec.AppEntry
		for appID, entry := range specs.Apps {
			if manifest.ID != app.ID(appID) {
				continue
			}

			appEntry = &entry
			break
		}

		if appEntry == nil {
			return "", errors.Errorf("could not find app '%s' in specs", manifest.ID)
		}

		_, port, err := net.SplitHostPort(appEntry.Address)
		if err != nil {
			return "", errors.WithStack(err)
		}

		data := struct {
			Manifest *app.Manifest
			Specs    *spec.Spec
			DeviceIP string
			AppPort  string
		}{
			Manifest: manifest,
			Specs:    specs,
			DeviceIP: deviceIP.String(),
			AppPort:  port,
		}

		var buf bytes.Buffer

		if err := urlTemplate.Execute(&buf, data); err != nil {
			return "", errors.WithStack(err)
		}

		return buf.String(), nil
	}, nil
}

func (c *Controller) getAppModules(bus bus.Bus, db *sql.DB, spec *appSpec.Spec, keySet jwk.Set) []app.ServerModuleFactory {
	ds := sqlite.NewDocumentStoreWithDB(db)
	bs := sqlite.NewBlobStoreWithDB(db)

	return []app.ServerModuleFactory{
		module.ContextModuleFactory(),
		module.ConsoleModuleFactory(),
		cast.CastModuleFactory(),
		module.LifecycleModuleFactory(),
		netModule.ModuleFactory(bus),
		module.RPCModuleFactory(bus),
		module.StoreModuleFactory(ds),
		blob.ModuleFactory(bus, bs),
		authModule(keySet),
		appModule.ModuleFactory(c.appRepository),
		fetchModule.ModuleFactory(bus),
	}
}