package hostguard

import (
	"context"
	"github.com/carlosframework/platform/internal/hostclaim"
)

// AdmissionFenced reports whether the host's admission is closed for the
// installation and session captured names on claim c. It is With's own
// reading of the record (record.admits), exposed for region HA §5.3's row
// decision ("the source in releasing until its admission fence closes"):
// closed whenever With would refuse on the record, so a stop root that
// began (ActiveFence) or completed (a FenceJournal receipt) for that
// session, and also an inactive or retired installation, a stamp that is
// not the active one, or another incarnation on the record. Absence is
// never evidence: a retired fenced installation still reads closed. With's
// other refusals (no record, a malformed record, a claim for another host
// or incarnation) are errors, never "open". It takes no lock: the record
// is replaced atomically, and callers already hold the host lock
// (Activate's reader, WithLocal) or need no lock for one consistent read.
// The claim is the caller's fresh read. It grants nothing.
func (g Guard) AdmissionFenced(host string, c *hostclaim.Claim, captured Captured) (bool, error) {
	if c == nil || c.Holder == nil {
		return false, ErrNoHolder
	}
	if c.Host != host || c.Holder.Incarnation == "" {
		return false, ErrMalformedClaim
	}
	if c.Holder.Incarnation != captured.Incarnation {
		return false, ErrClaimIncarnation
	}
	if g.Root != nil {
		r, err := g.Root.read(host)
		if err != nil {
			return false, err
		}
		return r.admits(c, captured) != nil, nil
	}
	if g.FenceView != nil {
		v, err := g.FenceView(context.Background(), host, captured)
		if err != nil {
			return false, err
		}
		if err := v.validate(host, captured); err != nil {
			return false, err
		}
		if v.admit(host, captured, c.Holder.Session) != nil {
			return true, nil
		}
	}
	r, err := readRecord(g.DataDir, host)
	if err != nil {
		return false, err
	}
	// Every refusal admits gives is a record state, never a read failure.
	return r.admits(c, captured) != nil, nil
}