package bus

import (
	"context"
	"errors"
	"fmt"
	"strings"

	"git.novox.be/novox/mesh-sdk/go/buscalls"
	"git.novox.be/novox/mesh-sdk/go/catalogue"
	"git.novox.be/novox/mesh-sdk/go/stateobjects"
	"github.com/nats-io/nats.go/jetstream"
)

// SentGet reads one object of a sender's store of sent objects by the reference that carried it (ADR 0666 §16): the
// store is the sender's `<module>_sent-objects`, and no other — a state's objects are reached through their owner's
// bindings alone. It reads as this connection's account, which the bus lets read a sender's sent store only where the
// grants part granted it (a bundle is held to what its runtime channel carries by the runtime call, not here), from the manifests' callers and consumers; a refusal says the store.
func (c *Conn) SentGet(r buscalls.ObjectsSentGetRequest) (*buscalls.ObjectData, error) {
	ref := stateobjects.Ref{Store: r.Store, Object: r.Object, Size: r.Size, Digest: r.Digest, Form: stateobjects.FormVersion}
	if _, ok := stateobjects.ReadRef(stateobjects.Wrap(ref)); !ok {
		return nil, errors.New("a sent object is named by the reference's store, object, size and sha256, as the reply or event carried them")
	}
	if !strings.HasSuffix(r.Store, catalogue.BusNameSeparator+catalogue.SentObjectsLocal) {
		return nil, fmt.Errorf("%s is no sent store (a module's is `<module>%s%s`): only a sent object is read by its reference",
			r.Store, catalogue.BusNameSeparator, catalogue.SentObjectsLocal)
	}
	js, err := c.jetStream()
	if err != nil {
		return nil, err
	}
	ctx, cancel := context.WithTimeout(context.Background(), StateTimeout)
	defer cancel()
	obs, err := js.ObjectStore(ctx, r.Store)
	if err != nil {
		return nil, fmt.Errorf("the sent store %s cannot be read as %s: it is not on the bus, or the bus grants this account no "+
			"read of it (the manifests' callers and consumers are granted): %w", r.Store, c.cred.Module, err)
	}
	info, err := obs.GetInfo(ctx, r.Object)
	if errors.Is(err, jetstream.ErrObjectNotFound) {
		return nil, fmt.Errorf("the sent object %s is not in %s: it is kept 7 days, then expires", r.Object, r.Store)
	}
	if err != nil {
		return nil, fmt.Errorf("the sent object %s of %s: %w", r.Object, r.Store, err)
	}
	data, err := obs.GetBytes(ctx, r.Object)
	if err != nil {
		return nil, fmt.Errorf("the sent object %s of %s: %w", r.Object, r.Store, err)
	}
	return &buscalls.ObjectData{Info: objectInfoOf(info), Data: data}, nil
}