package system

import (
	"context"
	"errors"
	"strings"
	"testing"
	"time"
)

// pacman's own words from the control node on 2026-10-02 (novox/hq 04-ISSUES/205): every mirror
// 404s the versioned file a ten-week-old database names, and the one copy that arrives fails its
// signature. Errors are pacman's stderr, which the runner folds into the error, not the output.
const staleStderr = `error: failed retrieving file 'nodejs-26.5.0-1-x86_64.pkg.tar.zst' from mirror.hetzner.com : The requested URL returned error: 404
error: failed retrieving file 'nodejs-26.5.0-1-x86_64.pkg.tar.zst' from mirror.rackspace.com : The requested URL returned error: 404
error: failed retrieving file 'nodejs-26.5.0-1-x86_64.pkg.tar.zst' from arch.lucassymons.net : Could not resolve host: arch.lucassymons.net
warning: fatal error from arch.lucassymons.net, skipping for the remainder of this transaction
error: failed retrieving file 'nodejs-26.5.0-1-x86_64.pkg.tar.zst' from mirrors.cqu.edu.cn : Connection timed out after 10002 milliseconds
error: nodejs: signature from "Bert Peters (packager key) <bertptrs@archlinux.org>" is invalid
error: failed to commit transaction (invalid or corrupted package (PGP signature))`

const staleStdout = `resolving dependencies...
looking for conflicting packages...

Packages (4) ada-3.4.4-1  c-ares-1.34.8-1  simdjson-1:4.6.4-1  nodejs-26.5.0-1

:: Retrieving packages...
 nodejs-26.5.0-1-x86_64 downloading...
checking keyring...
checking package integrity...
:: File /var/cache/pacman/pkg/nodejs-26.5.0-1-x86_64.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)).
Errors occurred, no packages were upgraded.`

// A runner that behaves as ExecRunner does on failure: stdout as the output, stderr in the error.
func pacmanFailing(stdout, stderr string) Runner {
	return func(_ context.Context, name string, args ...string) (string, error) {
		return stdout, errors.New(name + " exited 1: " + stderr)
	}
}

func TestAStaleDatabaseIsSaidAsOneWithItsAgeAndTheRemedy(t *testing.T) {
	was := syncDatabaseAge
	defer func() { syncDatabaseAge = was }()
	syncDatabaseAge = func() string {
		return describeAge(time.Date(2026, 7, 24, 16, 56, 0, 0, time.UTC), time.Date(2026, 10, 3, 0, 0, 0, 0, time.UTC))
	}

	err := arch{}.InstallPackage(context.Background(), pacmanFailing(staleStdout, staleStderr), "nodejs")
	if err == nil {
		t.Fatal("a failed install must fail")
	}
	for _, want := range []string{
		"the package database on this machine is from 2026-07-24, 10 weeks old",
		"stale package index",
		"upgrading the machine — a full upgrade (`pacman -Syu`) by its operator — before the mesh can install nodejs",
		"partial upgrade",
		"returned error: 404", // pacman's own words follow
	} {
		if !strings.Contains(err.Error(), want) {
			t.Errorf("the error does not say %q:\n%s", want, err)
		}
	}
	if strings.Contains(err.Error(), "mirrors or the network") {
		t.Errorf("a stale database must not be read as a mirror outage:\n%s", err)
	}
}

// The same 404s read from stderr alone — the half this classifier used to be blind to.
func TestTheClassifierReadsWhatPacmanWroteToStderr(t *testing.T) {
	if classifyInstallFailure(staleStderr) != installStale {
		t.Fatal("every mirror 404ing the named file is a stale database")
	}
	if classifyInstallFailure(staleStdout) != installStale {
		t.Fatal("a corrupted-signature line alone is a stale keyring")
	}
	if classifyInstallFailure("") != installOther {
		t.Fatal("nothing said is nothing classified")
	}
}

func TestAnUnreachableMirrorWithAFreshDatabaseIsAMirrorProblem(t *testing.T) {
	was := syncDatabaseAge
	defer func() { syncDatabaseAge = was }()
	syncDatabaseAge = func() string { return "from 2026-10-02, less than a day old" }
	outage := `error: failed retrieving file 'core.db' from mirror.hetzner.com : Could not resolve host: mirror.hetzner.com
error: failed retrieving file 'core.db' from mirror.rackspace.com : Connection timed out after 10001 milliseconds
error: failed to synchronize all databases (failed to retrieve some files)`
	if classifyInstallFailure(outage) != installMirrors {
		t.Fatal("no mirror answering, no 404, no signature fault: the mirrors, not the machine")
	}
	err := arch{}.InstallPackage(context.Background(), pacmanFailing("", outage), "nodejs")
	if err == nil || !strings.Contains(err.Error(), "mirrors or the network") || !strings.Contains(err.Error(), "less than a day old") {
		t.Errorf("a mirror outage is said as one, with the database's age beside it:\n%v", err)
	}
}

func TestAFailureThatIsNeitherKeepsPacmansWords(t *testing.T) {
	err := arch{}.InstallPackage(context.Background(), pacmanFailing("", "error: target not found: nodejsx"), "nodejsx")
	if err == nil || !strings.Contains(err.Error(), "target not found") || strings.Contains(err.Error(), "package database on this machine") {
		t.Errorf("an unknown package is pacman's own error, not a stale database:\n%v", err)
	}
}

func TestDescribeAge(t *testing.T) {
	now := time.Date(2026, 10, 3, 0, 0, 0, 0, time.UTC)
	for when, want := range map[time.Time]string{
		now.Add(-2 * time.Hour):       "less than a day old",
		now.Add(-5 * 24 * time.Hour):  "5 days old",
		now.Add(-71 * 24 * time.Hour): "10 weeks old",
	} {
		if got := describeAge(when, now); !strings.HasSuffix(got, want) {
			t.Errorf("%s: got %q, want suffix %q", when, got, want)
		}
	}
}