package main

import (
	"context"
	"fmt"
	"io"
	"log/slog"
	"os"
	"path/filepath"
	"syscall"
	"testing"
	"time"

	"github.com/monlet/agent/internal/config"
)

type reloadCall struct {
	cfg     *config.Config
	agentID string
}

type fakeReloadTarget struct {
	reloads  chan reloadCall
	failures chan struct{}
}

func (f *fakeReloadTarget) RecordReloadFailure() {
	f.failures <- struct{}{}
}

func (f *fakeReloadTarget) Reload(cfg *config.Config, agentID string) error {
	f.reloads <- reloadCall{cfg: cfg, agentID: agentID}
	return nil
}

func TestRunReloadLoopHandlesSIGHUP(t *testing.T) {
	cfgPath := writeTestConfig(t)
	target := &fakeReloadTarget{
		reloads:  make(chan reloadCall, 1),
		failures: make(chan struct{}, 1),
	}
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	hup := make(chan os.Signal, 1)
	go runReloadLoop(ctx, cfgPath, hup, target, discardLogger())

	hup <- syscall.SIGHUP
	select {
	case call := <-target.reloads:
		if call.agentID != "agent-test" || len(call.cfg.Checks) != 1 {
			t.Fatalf("unexpected reload call: agent_id=%q cfg=%+v", call.agentID, call.cfg)
		}
	case <-time.After(time.Second):
		t.Fatal("reload was not called")
	}
}

func TestRunReloadLoopRecordsLoadFailure(t *testing.T) {
	target := &fakeReloadTarget{
		reloads:  make(chan reloadCall, 1),
		failures: make(chan struct{}, 1),
	}
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	hup := make(chan os.Signal, 1)
	go runReloadLoop(ctx, filepath.Join(t.TempDir(), "missing.toml"), hup, target, discardLogger())

	hup <- syscall.SIGHUP
	select {
	case <-target.failures:
	case <-time.After(time.Second):
		t.Fatal("reload failure was not recorded")
	}
}

func TestShutdownWatchdogExitsAfterTimeout(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	exits := make(chan int, 1)
	startShutdownWatchdog(ctx, time.Millisecond, discardLogger(), func(code int) {
		exits <- code
	})
	cancel()
	select {
	case code := <-exits:
		if code != 1 {
			t.Fatalf("exit code: %d", code)
		}
	case <-time.After(time.Second):
		t.Fatal("watchdog did not exit")
	}
}

func writeTestConfig(t *testing.T) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), "agent.toml")
	body := fmt.Sprintf(`
agent_id = "agent-test"
state_dir = %q

[server]
enabled = true
url = "http://localhost"

[[checks]]
id = "c1"
command = "true"
interval = "10s"
timeout = "5s"
`, t.TempDir())
	if err := os.WriteFile(path, []byte(body), 0o600); err != nil {
		t.Fatal(err)
	}
	return path
}

func discardLogger() *slog.Logger {
	return slog.New(slog.NewTextHandler(io.Discard, nil))
}