package hostbox

import (
	"context"
	"time"

	"github.com/carlosframework/platform/internal/hostclaim"
	"github.com/carlosframework/platform/internal/park"
)

type Regional struct {
	Engine park.Engine
	// Owner checks complete deployment membership and this worker's assignment.
	Owner func(context.Context, hostclaim.Observed) error
}

func (r Regional) observe(ctx context.Context, host string) (hostclaim.Observed, error) {
	e := r.Engine
	if e.Claims == nil || e.Store == nil || e.Leases == nil || e.View == nil || e.Authorize == nil || e.Now == nil || e.NewID == nil || e.Bucket == "" || e.Region == "" || r.Owner == nil {
		return hostclaim.Observed{}, ErrUnsupported
	}
	obs, err := hostclaim.Read(ctx, e.Claims, host)
	if err != nil {
		return hostclaim.Observed{}, err
	}
	if obs.Absent || obs.Claim == nil {
		return hostclaim.Observed{}, ErrUnsupported
	}
	if err := r.Owner(ctx, obs); err != nil {
		return hostclaim.Observed{}, err
	}
	return obs, nil
}

func (r Regional) Run(ctx context.Context, work park.Work) error {
	obs, err := r.observe(ctx, work.Host)
	if err != nil {
		return err
	}
	for _, ob := range obs.Claim.Obligations {
		if ob.ID != work.ID || ob.Op != work.Op {
			continue
		}
		if !r.Engine.OwnsRegion(ob.Region) || ob.Owner != "region:"+ob.Region || (ob.Kind != "park-replica" && ob.Kind != "park-generation") {
			return ErrUnsupported
		}
		return r.Engine.Run(ctx, work)
	}
	return nil // Already acknowledged; no mutation.
}

func (r Regional) Sweep(ctx context.Context, host, legacyIncarnation string, evidenceAt time.Time, requestLimit time.Duration) (park.Decision, error) {
	if _, err := r.observe(ctx, host); err != nil {
		return park.Decision{}, err
	}
	if evidenceAt.IsZero() || requestLimit <= 0 {
		return park.Decision{}, ErrUnsupported
	}
	return r.Engine.Sweep(ctx, host, legacyIncarnation, evidenceAt, requestLimit)
}