// Package authctx carries the authenticated identity of a request.
//
// It is the successor to the development identity that used to be injected by
// httpserver.devOrgMiddleware. The difference is not the shape — both put a
// value on the request context — but the provenance: everything here was read
// out of a server-side session row, and nothing in it can be influenced by the
// request that carries it.
//
// That is the whole point of the package existing separately from the handlers.
// A handler that wants to know who is calling has exactly one place to ask, and
// that place cannot be reached from a request body, a query string or a header.
// There is deliberately no setter that takes a user id from a client.
package authctx

import (
	"context"
	"errors"
	"time"
)

type key struct{}

// ErrNoIdentity means a protected operation was reached without an
// authenticated identity. That is a routing or middleware bug rather than a
// client error: an unauthenticated request should have been refused before it
// got this far.
var ErrNoIdentity = errors.New("no authenticated identity in context")

// Identity is who the request is, as resolved from the session row.
//
// Role is carried because Phase 3D will need it, and because carrying it now
// means the middleware reads it once per request instead of every future
// authorization check re-querying the user. It is NOT consulted anywhere in
// Phase 3C: authentication only.
type Identity struct {
	UserID      string
	OrgID       string
	Email       string
	FullName    string
	Role        string
	AccountType string
	Status      string

	// SessionID is the row this identity came from, so logout and per-session
	// diagnostics do not have to re-hash the cookie.
	SessionID string
	// ExpiresAt is the session's sliding deadline as of this request.
	ExpiresAt time.Time
}

// With returns a context carrying the authenticated identity.
func With(ctx context.Context, id Identity) context.Context {
	return context.WithValue(ctx, key{}, id)
}

// From reads the identity, reporting whether one was present.
func From(ctx context.Context) (Identity, bool) {
	v, ok := ctx.Value(key{}).(Identity)
	return v, ok && v.UserID != ""
}

// MustFrom reads the identity or returns ErrNoIdentity.
func MustFrom(ctx context.Context) (Identity, error) {
	if v, ok := From(ctx); ok {
		return v, nil
	}
	return Identity{}, ErrNoIdentity
}