package hostexec

import (
	"context"
	"errors"
	"os"

	"github.com/carlosframework/platform/internal/rootparticipation"
)

func (b *RootBroker) servingView(ctx context.Context, peer ControllerProcess, q ExecutionRequest, authority ExecutionAuthority) (ExecutionResponse, error) {
	if authority.Kind != "serving" || (authority.Installation == "" && !authority.ParticipationOnly) {
		return ExecutionResponse{}, ErrInactive
	}
	unlock, err := b.cfg.State.Lock(ctx, "transaction.lock")
	if err != nil {
		return ExecutionResponse{}, err
	}
	defer unlock()
	if _, err := b.cfg.State.Read("update.json"); !errors.Is(err, os.ErrNotExist) {
		return ExecutionResponse{}, ErrInactive
	}
	census, err := (rootparticipation.Ledger{State: b.cfg.State, Box: authority.Box, Enrollment: authority.Enrollment}).Census()
	if err != nil || census.Migration != authority.Migration {
		return ExecutionResponse{}, errors.Join(err, ErrState)
	}
	if _, err := ReadRoot(ctx, b.cfg.State, b.cfg.Clock, q, true); err != nil {
		return ExecutionResponse{}, err
	}
	fresh, err := b.cfg.Authority(ctx, q, peer)
	if err != nil || fresh != authority {
		return ExecutionResponse{}, errors.Join(err, ErrLost)
	}
	if err := b.cfg.Alive(ctx, peer); err != nil {
		return ExecutionResponse{}, err
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	if b.closed || ctx.Err() != nil {
		return ExecutionResponse{}, ErrLost
	}
	return ExecutionResponse{Schema: 1, Host: q.Host, Incarnation: q.Incarnation, Stamp: q.Stamp, Session: q.Session, Op: q.Op, BootID: peer.KernelBootID, Status: "serving"}, nil
}