package mediawire

import (
	"context"
	"fmt"
	"net"
	"strconv"
	"time"
)

// R-1060 (v0.314.0): every call the box makes to Plex goes to its ADDRESS, never to the name „plex".
//
// Plex refuses a request whose Host header is a name it does not know as non-local: „Request came in with unrecognized
// domain / IP 'plex' in header Host; treating as non-local" (its own log, demo-hp 9201, 2026-10-15). The claim answered
// 401 in 0 ms with two fresh codes; by address the same request is local (a fake code: 500 from plex.tv; measured,
// felhom.eu audits/media-build-2026-10-15/G7/G5e-host-measure.txt). The K6 spike on Tester 1 called by address and passed;
// the product called by name, and its tests replaced Plex with a seam, so nothing met the refusal before a household did.
// Used by all four calls: the claim and the identity (internal/web), the library wiring and the sessions (this package).
// Pinned by plexaddr_test.go and internal/web/r1060_plex_by_address_test.go.

// PlexLookup resolves the plex container on the docker network AT CALL TIME — never cached: a restarted container may
// get another address. A seam for tests.
var PlexLookup = func(ctx context.Context) ([]net.IPAddr, error) {
	return net.DefaultResolver.LookupIPAddr(ctx, "plex")
}

// PlexURL is Plex's base URL by address: http://<ip>:<port> (IPv4 first).
func PlexURL(port int) (string, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	addrs, err := PlexLookup(ctx)
	if err != nil {
		return "", fmt.Errorf("resolving the plex container: %w", err)
	}
	for _, a := range addrs {
		if ip4 := a.IP.To4(); ip4 != nil {
			return "http://" + net.JoinHostPort(ip4.String(), strconv.Itoa(port)), nil
		}
	}
	for _, a := range addrs {
		return "http://" + net.JoinHostPort(a.IP.String(), strconv.Itoa(port)), nil
	}
	return "", fmt.Errorf("the plex container resolves to no address")
}