package localapi

import (
	"bytes"
	"context"
	"encoding/json"
	"log/slog"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	"testing"

	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
)

// R-1008: after a power cut Proxmox keeps the dead vzdump task in `tasks?source=active` (measured on demo-hp
// 2026-10-14: still RUNNING after the boot, started 136 s before it). A task that started before this boot is
// dead, not in flight. These tests pin the helper (vzdumpInFlight), the production controller, and three of the
// four callers end to end; the fourth (the controller supervisor) by the structural pin at the bottom.

const testBoot = int64(1791967481) // the C3 boot (power-cut-fixes-2026-10-14)

func vz(vmid string, start int64) proxmox.TaskStatus {
	return proxmox.TaskStatus{UPID: "UPID:demo-hp:001E6EEC:00000001:6ACF4071:vzdump:" + vmid + ":felhom-agent@pve!agent:",
		Type: "vzdump", ID: vmid, Status: "RUNNING", StartTime: start}
}

// RED-PROOF: make vzdumpInFlight return true for every matching task (drop the `start >= boot` test) → this fails.
func TestVzdumpInFlight_PreBootTaskIsDead(t *testing.T) {
	running, dead := vzdumpInFlight([]proxmox.TaskStatus{vz("9201", testBoot-136)}, 9201, testBoot, true)
	if running || len(dead) != 1 {
		t.Fatalf("a task from before the boot must be dead: running=%v dead=%d", running, len(dead))
	}
}

func TestVzdumpInFlight_PostBootTaskRuns(t *testing.T) {
	for _, start := range []int64{testBoot, testBoot + 600} {
		if running, _ := vzdumpInFlight([]proxmox.TaskStatus{vz("9201", start)}, 9201, testBoot, true); !running {
			t.Fatalf("a task started at %d (boot %d) must be in flight", start, testBoot)
		}
	}
}

// RED-PROOF: drop the `!bootOK` early return → a pre-boot task with an unreadable boot is called dead → fails.
func TestVzdumpInFlight_UnreadableBootFailsSafe(t *testing.T) {
	// the boot value is a real one on purpose: only bootOK=false may make this „running"
	if running, _ := vzdumpInFlight([]proxmox.TaskStatus{vz("9201", testBoot-136)}, 9201, testBoot, false); !running {
		t.Fatal("an unreadable boot time must count as running (fail safe)")
	}
}

// RED-PROOF: make taskStart ignore the UPID → StartTime 0 counts as unknown → running; the first case fails.
func TestVzdumpInFlight_StartFromUPIDThenUnknownFailsSafe(t *testing.T) {
	tk := vz("9201", 0) // no starttime in the list: the UPID's 6ACF4071 = 1791967345 (before the boot)
	if running, dead := vzdumpInFlight([]proxmox.TaskStatus{tk}, 9201, testBoot, true); running || len(dead) != 1 {
		t.Fatalf("the UPID's start time must be used: running=%v", running)
	}
	tk.UPID = "garbage"
	if running, _ := vzdumpInFlight([]proxmox.TaskStatus{tk}, 9201, testBoot, true); !running {
		t.Fatal("an unknown start time must count as running (fail safe)")
	}
}

func TestVzdumpInFlight_OtherGuestOrTypeIgnored(t *testing.T) {
	tasks := []proxmox.TaskStatus{vz("9202", testBoot+5), {Type: "vzsnapshot", ID: "9201", StartTime: testBoot + 5}}
	if running, dead := vzdumpInFlight(tasks, 9201, testBoot, true); running || len(dead) != 0 {
		t.Fatalf("other guests' and other types' tasks are not 9201's backup: running=%v dead=%d", running, len(dead))
	}
}

func inflightCtrl(api *fakeStaleLockAPI, runner *recordingRunner, logger *slog.Logger) *staleLockController {
	c := NewStaleLockController(api, runner, "felhom", logger).(*staleLockController)
	c.bootTime = func() (int64, bool) { return testBoot, true }
	return c
}

// The production controller answers through the helper, and logs a dead task ONCE.
// RED-PROOF: make BackupRunning ignore bootTime (the pre-R-1008 body) → returns true → fails.
func TestStaleLockController_BackupRunningIgnoresDeadTask(t *testing.T) {
	var buf bytes.Buffer
	api := &fakeStaleLockAPI{tasks: []proxmox.TaskStatus{vz("9201", testBoot-136)}}
	c := inflightCtrl(api, &recordingRunner{}, slog.New(slog.NewTextHandler(&buf, nil)))
	for i := 0; i < 3; i++ {
		if running, err := c.BackupRunning(context.Background(), 9201); err != nil || running {
			t.Fatalf("dead pre-boot task reported running=%v err=%v", running, err)
		}
	}
	if n := strings.Count(buf.String(), "backup-in-flight: a vzdump task from before this boot"); n != 1 {
		t.Fatalf("the dead task must be logged exactly once, got %d", n)
	}
	api.tasks = []proxmox.TaskStatus{vz("9201", testBoot+30)}
	if running, _ := c.BackupRunning(context.Background(), 9201); !running {
		t.Fatal("a post-boot task must be running")
	}
}

func poolOf(vmids ...int) proxmox.PoolInfo {
	var p proxmox.PoolInfo
	raw := `{"members":[`
	for i, v := range vmids {
		if i > 0 {
			raw += ","
		}
		raw += `{"vmid":` + itoaT(v) + `,"type":"lxc"}`
	}
	raw += `]}`
	_ = json.Unmarshal([]byte(raw), &p)
	return p
}

// Caller 1 — the startup stale-lock recovery clears the lock a power cut left (the night of 2026-10-14 it said
// „genuinely in-flight — leaving the lock").
func TestCaller_StartupStaleLockClearsAfterPowerCut(t *testing.T) {
	for _, tc := range []struct {
		start   int64
		cleared bool
	}{{testBoot - 136, true}, {testBoot + 30, false}} {
		api := &fakeStaleLockAPI{tasks: []proxmox.TaskStatus{vz("9201", tc.start)},
			cfg: map[int]proxmox.GuestConfig{9201: staleCfg("backup", true)}}
		runner := &recordingRunner{}
		s := &Server{staleLock: inflightCtrl(api, runner, nil), logger: slog.New(slog.NewTextHandler(discardW{}, nil))}
		s.recoverOneStaleLock(context.Background(), proxmox.Guest{VMID: 9201, Status: "running"})
		if runner.unlocked("9201") != tc.cleared {
			t.Fatalf("task start %d: unlocked=%v, want %v", tc.start, runner.unlocked("9201"), tc.cleared)
		}
	}
}

// Caller 2 — the guest-power watchdog starts a stopped guest despite a dead pre-boot vzdump task.
func TestCaller_GuestPowerStartsGuestAfterPowerCut(t *testing.T) {
	for _, tc := range []struct {
		start   int64
		started bool
	}{{testBoot - 136, true}, {testBoot + 30, false}} {
		api := &fakeStaleLockAPI{lxc: []proxmox.Guest{{VMID: 9201, Status: "stopped"}}, pool: poolOf(9201),
			tasks: []proxmox.TaskStatus{vz("9201", tc.start)}, cfg: map[int]proxmox.GuestConfig{9201: staleCfg("", true)}}
		s := gpServer(t, inflightCtrl(api, &recordingRunner{}, nil), nil)
		s.GuestPowerTick(context.Background())
		if (len(api.started) == 1) != tc.started {
			t.Fatalf("task start %d: started=%v, want %v", tc.start, api.started, tc.started)
		}
	}
}

// Caller 3 — the household power-off guard does not refuse „backup running" for a dead task.
func TestCaller_PowerOffJobBlockerIgnoresDeadTask(t *testing.T) {
	for _, tc := range []struct {
		start int64
		want  string
	}{{testBoot - 136, ""}, {testBoot + 30, PowerOffBackup}} {
		rig := newPowerRig(t, 0)
		rig.srv.staleLock = inflightCtrl(&fakeStaleLockAPI{tasks: []proxmox.TaskStatus{vz("9201", tc.start)}}, &recordingRunner{}, nil)
		if code, _ := rig.srv.jobBlocker(context.Background(), 9201); code != tc.want {
			t.Fatalf("task start %d: jobBlocker=%q, want %q", tc.start, code, tc.want)
		}
	}
}

// Caller 4 (the supervisor), the R-1006 cleanup (VzdumpInFlight) and the rest — structural pin: every non-test BackupRunning call in this package goes through
// s.staleLock (whose one production implementation is staleLockController, which uses vzdumpInFlight), and no
// other production type implements BackupRunning. If someone adds a second path, this fails.
func TestBackupRunning_AllCallersUseTheOneHelper(t *testing.T) {
	files, _ := filepath.Glob("*.go")
	call := regexp.MustCompile(`([A-Za-z_.]+)\.BackupRunning\(`)
	impl := regexp.MustCompile(`func \([a-z]+ \*?([A-Za-z]+)\) BackupRunning\(`)
	callers := 0
	for _, f := range files {
		if strings.HasSuffix(f, "_test.go") {
			continue
		}
		b, err := os.ReadFile(f)
		if err != nil {
			t.Fatal(err)
		}
		for _, m := range call.FindAllStringSubmatch(string(b), -1) {
			if m[1] != "s.staleLock" {
				t.Errorf("%s: BackupRunning called on %q, not s.staleLock", f, m[1])
			}
			callers++
		}
		for _, m := range impl.FindAllStringSubmatch(string(b), -1) {
			if m[1] != "staleLockController" {
				t.Errorf("%s: a second production BackupRunning on %s", f, m[1])
			}
		}
	}
	if callers != 5 {
		t.Errorf("expected the five known callers (stale-lock, guest-power, power-off, supervisor, the R-1006 cleanup), found %d", callers)
	}
	b, _ := os.ReadFile("stalelock.go")
	if !strings.Contains(string(b), "vzdumpInFlight(tasks, vmid, boot, ok)") {
		t.Error("staleLockController.BackupRunning no longer answers through vzdumpInFlight")
	}
}