package service

import (
	"context"

	"github.com/cortezaproject/corteza/server/pkg/actionlog"
	"github.com/cortezaproject/corteza/server/pkg/apigw"
	a "github.com/cortezaproject/corteza/server/pkg/auth"
	"github.com/cortezaproject/corteza/server/pkg/errors"

	"github.com/cortezaproject/corteza/server/store"
	"github.com/cortezaproject/corteza/server/system/types"
)

type (
	apigwRoute struct {
		actionlog actionlog.Recorder
		store     store.Storer
		ac        routeAccessController
	}

	routeAccessController interface {
		CanGrant(context.Context) bool
		CanSearchApigwRoutes(ctx context.Context) bool

		CanCreateApigwRoute(context.Context) bool
		CanReadApigwRoute(context.Context, *types.ApigwRoute) bool
		CanUpdateApigwRoute(context.Context, *types.ApigwRoute) bool
		CanDeleteApigwRoute(context.Context, *types.ApigwRoute) bool
	}
)

func Route() *apigwRoute {
	return &apigwRoute{
		ac:        DefaultAccessControl,
		actionlog: DefaultActionlog,
		store:     DefaultStore,
	}
}

func (svc *apigwRoute) FindByID(ctx context.Context, ID uint64) (q *types.ApigwRoute, err error) {
	var (
		rProps = &apigwRouteActionProps{}
	)

	err = func() error {
		if q, err = loadApigwRoute(ctx, svc.store, ID); err != nil {
			return ApigwRouteErrInvalidID().Wrap(err)
		}

		rProps.setRoute(q)

		if !svc.ac.CanReadApigwRoute(ctx, q) {
			return ApigwRouteErrNotAllowedToRead(rProps)
		}

		return nil
	}()

	return q, svc.recordAction(ctx, rProps, ApigwRouteActionLookup, err)
}

func (svc *apigwRoute) Create(ctx context.Context, new *types.ApigwRoute) (q *types.ApigwRoute, err error) {
	var (
		qProps = &apigwRouteActionProps{route: new}
	)

	err = func() (err error) {
		if !svc.ac.CanCreateApigwRoute(ctx) {
			return ApigwRouteErrNotAllowedToCreate(qProps)
		}

		new.ID = nextID()
		new.CreatedAt = *now()
		new.CreatedBy = a.GetIdentityFromContext(ctx).Identity()

		// todo
		new.Group = 0

		qProps.setNew(new)

		if err = store.CreateApigwRoute(ctx, svc.store, new); err != nil {
			return err
		}

		q = new

		// send the signal to reload new route
		if new.Enabled {
			if err = apigw.Service().ReloadEndpoint(ctx, new.Method, new.Endpoint); err != nil {
				return err
			}
		}

		return nil
	}()

	return q, svc.recordAction(ctx, qProps, ApigwRouteActionCreate, err)
}

func (svc *apigwRoute) Update(ctx context.Context, upd *types.ApigwRoute) (res *types.ApigwRoute, err error) {
	var (
		qProps = &apigwRouteActionProps{update: upd}
		e      error
	)

	err = func() (err error) {
		if res, e = loadApigwRoute(ctx, svc.store, upd.ID); e != nil {
			return ApigwRouteErrNotFound(qProps)
		}

		var (
			// check if old endpoint moved and attach the 404 handler
			endpointMoved = res.Enabled != upd.Enabled || res.Method != upd.Method || res.Endpoint != upd.Endpoint
		)

		if !svc.ac.CanUpdateApigwRoute(ctx, res) {
			return ApigwRouteErrNotAllowedToUpdate(qProps)
		}

		// Test if stale (update has an older version of data)
		if isStale(upd.UpdatedAt, res.UpdatedAt, res.CreatedAt) {
			return ApigwRouteErrStaleData()
		}

		// copy (potentially) updated files from the payload
		res.Meta = upd.Meta
		res.Method = upd.Method
		res.Endpoint = upd.Endpoint
		res.Enabled = upd.Enabled
		res.Group = upd.Group

		// ensure we have a valid endpoint
		res.UpdatedAt = now()
		res.UpdatedBy = a.GetIdentityFromContext(ctx).Identity()

		if err = store.UpdateApigwRoute(ctx, svc.store, res); err != nil {
			return
		}

		// @todo move this into struct of the service (svc),
		//       same as we do for services for other structs
		ags := apigw.Service()

		// old endpoint moved: attach 404 handler
		if endpointMoved {
			ags.NotFound(ctx, res.Method, res.Endpoint)
		}

		// send the signal to reload updated route
		if upd.Enabled {
			if err = ags.ReloadEndpoint(ctx, upd.Method, upd.Endpoint); err != nil {
				return err
			}
		}

		return nil
	}()

	return res, svc.recordAction(ctx, qProps, ApigwRouteActionUpdate, err)
}

func (svc *apigwRoute) DeleteByID(ctx context.Context, ID uint64) (err error) {
	var (
		qProps = &apigwRouteActionProps{}
		q      *types.ApigwRoute
	)

	err = func() (err error) {
		if q, err = loadApigwRoute(ctx, svc.store, ID); err != nil {
			return
		}

		if !svc.ac.CanDeleteApigwRoute(ctx, q) {
			return ApigwRouteErrNotAllowedToDelete(qProps)
		}

		qProps.setRoute(q)

		q.DeletedAt = now()
		q.DeletedBy = a.GetIdentityFromContext(ctx).Identity()

		if err = store.UpdateApigwRoute(ctx, svc.store, q); err != nil {
			return
		}

		// send the signal to reload deleted route
		if q.Enabled {
			apigw.Service().NotFound(ctx, q.Method, q.Endpoint)
		}

		return nil
	}()

	return svc.recordAction(ctx, qProps, ApigwRouteActionDelete, err)
}

func (svc *apigwRoute) UndeleteByID(ctx context.Context, ID uint64) (err error) {
	var (
		qProps = &apigwRouteActionProps{}
		q      *types.ApigwRoute
	)

	err = func() (err error) {
		if q, err = loadApigwRoute(ctx, svc.store, ID); err != nil {
			return
		}

		if !svc.ac.CanDeleteApigwRoute(ctx, q) {
			return ApigwRouteErrNotAllowedToUndelete(qProps)
		}

		qProps.setRoute(q)

		q.DeletedAt = nil
		q.UpdatedBy = a.GetIdentityFromContext(ctx).Identity()

		if err = store.UpdateApigwRoute(ctx, svc.store, q); err != nil {
			return
		}

		// send the signal to reload all queues
		if q.Enabled {
			if err = apigw.Service().ReloadEndpoint(ctx, q.Method, q.Endpoint); err != nil {
				return err
			}
		}

		return nil
	}()

	return svc.recordAction(ctx, qProps, ApigwRouteActionDelete, err)
}

func (svc *apigwRoute) Search(ctx context.Context, filter types.ApigwRouteFilter) (r types.ApigwRouteSet, f types.ApigwRouteFilter, err error) {
	var (
		aProps = &apigwRouteActionProps{search: &filter}
	)

	// For each fetched item, store backend will check if it is valid or not
	filter.Check = func(res *types.ApigwRoute) (bool, error) {
		if !svc.ac.CanReadApigwRoute(ctx, res) {
			return false, nil
		}

		return true, nil
	}

	err = func() error {
		if !svc.ac.CanSearchApigwRoutes(ctx) {
			return ApigwRouteErrNotAllowedToSearch()
		}

		if r, f, err = store.SearchApigwRoutes(ctx, svc.store, filter); err != nil {
			return err
		}

		return nil
	}()

	return r, f, svc.recordAction(ctx, aProps, ApigwRouteActionSearch, err)
}

func loadApigwRoute(ctx context.Context, s store.ApigwRoutes, ID uint64) (res *types.ApigwRoute, err error) {
	if ID == 0 {
		return nil, ApigwRouteErrInvalidID()
	}

	if res, err = store.LookupApigwRouteByID(ctx, s, ID); errors.IsNotFound(err) {
		return nil, ApigwRouteErrNotFound()
	}

	return
}