package host

import (
	"bytes"
	"log"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

func TestSystemChannelDefaultsToStable(t *testing.T) {
	env := func(v string) func(string) string {
		return func(k string) string {
			if k == systemChannelEnv {
				return v
			}
			return ""
		}
	}
	for _, c := range []struct {
		name            string
		set             string
		want, wantBadCh string
	}{
		{"unset", "", "stable", ""},
		{"set", " canary ", "canary", ""},
		{"a branch canary", "canary/paul", "canary/paul", ""},
		// Not a channel: it would travel into a bucket key and an on-box
		// state file, so the box follows stable and says which value it
		// refused, rather than asking for a pointer nobody publishes.
		{"a path traversal", "../../etc", "stable", "../../etc"},
		{"a word with a space", "not a channel", "stable", "not a channel"},
	} {
		t.Run(c.name, func(t *testing.T) {
			got, bad := systemChannel(env(c.set))
			if got != c.want || bad != c.wantBadCh {
				t.Fatalf("systemChannel(%q) = %q, %q; want %q, %q", c.set, got, bad, c.want, c.wantBadCh)
			}
		})
	}
}

// The refused value is said ONCE, where the leg is armed — not on every one
// of the two-second ticks that read the channel.
func TestNewSystemLegSaysWhichChannelValueItRefused(t *testing.T) {
	var buf bytes.Buffer
	out, flags := log.Writer(), log.Flags()
	log.SetOutput(&buf)
	log.SetFlags(0)
	defer func() { log.SetOutput(out); log.SetFlags(flags) }()

	leg := newSystemLeg(nil, nil, func(k string) string {
		if k == systemChannelEnv {
			return "canary/too/deep"
		}
		return ""
	}, t.TempDir(), t.TempDir())
	if leg.channel != "stable" {
		t.Fatalf("channel = %q, want stable", leg.channel)
	}
	said := strings.Count(buf.String(), "canary/too/deep")
	lines := len(strings.Split(strings.TrimSpace(buf.String()), "\n"))
	if said != 1 || lines != 1 {
		t.Fatalf("arming said the refused value %d times over %d lines:\n%s", said, lines, buf.String())
	}
}

func TestSystemStateProbeReadsRootsResult(t *testing.T) {
	opt := t.TempDir()
	if got := systemStateProbe(opt); got != nil {
		t.Fatalf("no result.json → %+v, want nil", got)
	}
	root := systemRootDir(opt)
	os.MkdirAll(root, 0o755)
	at := time.Date(2026, 9, 6, 9, 0, 0, 0, time.UTC)
	writeJSONDurable(filepath.Join(root, "result.json"), systemResult{Channel: "stable", Version: "v3", PromotedAt: at, Outcome: "applied", At: at}, 0o644)
	got := systemStateProbe(opt)
	if got == nil || got.Version != "v3" || got.Outcome != "applied" || !got.PromotedAt.Equal(at) {
		t.Fatalf("probe = %+v", got)
	}
}