//go:build testing

package systems

import (
	"fmt"
	"testing"
	"time"

	"github.com/fxamacker/cbor/v2"
	"github.com/henrygd/beszel/internal/entities/monitor"
	"github.com/henrygd/beszel/internal/entities/system"
	"github.com/pocketbase/pocketbase/core"
	"github.com/pocketbase/pocketbase/tools/subscriptions"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestNetworkMonitorProbePruning(t *testing.T) {
	for _, tc := range []struct {
		name     string
		monitors map[string]monitor.Result
		fail     bool
		want     map[string]int64
	}{
		{"nil report", nil, false, map[string]int64{"monitor1": 1000, "monitor2": 1000}},
		{"empty report", map[string]monitor.Result{}, false, map[string]int64{}},
		{"removed monitor", map[string]monitor.Result{"monitor1": {LastProbeAt: 1000}}, false, map[string]int64{"monitor1": 1000}},
		{"rolled back report", map[string]monitor.Result{}, true, map[string]int64{"monitor1": 1000, "monitor2": 1000}},
	} {
		t.Run(tc.name, func(t *testing.T) {
			sys, app := newTestSystemWithHub(t)
			sys.lastSavedMonitorProbe = map[string]int64{"monitor1": 1000, "monitor2": 1000}
			// Preserve the distinction between nil and empty across the agent transport.
			encoded, err := cbor.Marshal(system.CombinedData{Monitors: tc.monitors})
			require.NoError(t, err)
			var data system.CombinedData
			require.NoError(t, cbor.Unmarshal(encoded, &data))
			if tc.fail {
				_, err = app.DB().NewQuery(`CREATE TRIGGER fail_system_update BEFORE UPDATE ON systems BEGIN SELECT RAISE(ABORT, 'test rollback'); END`).Execute()
				require.NoError(t, err)
			}
			_, err = sys.createRecords(&data)
			if tc.fail {
				require.Error(t, err)
			} else {
				require.NoError(t, err)
			}
			assert.Equal(t, tc.want, sys.lastSavedMonitorProbe)
		})
	}
}

func TestNetworkMonitorStatsFreshness(t *testing.T) {
	for _, realtime := range []bool{false, true} {
		name := "sql"
		if realtime {
			name = "realtime"
		}
		t.Run(name, func(t *testing.T) {
			sys, app := newTestSystemWithHub(t)
			if realtime {
				client := subscriptions.NewDefaultClient()
				client.Subscribe("network_monitors/*")
				app.SubscriptionsBroker().Register(client)
				t.Cleanup(func() { app.SubscriptionsBroker().Unregister(client.Id()) })
			}
			col, err := app.FindCachedCollectionByNameOrId("network_monitors")
			require.NoError(t, err)
			for _, id := range []string{"monitor1", "monitor2"} {
				record := core.NewRecord(col)
				record.Id = id
				record.Set("system", sys.Id)
				require.NoError(t, app.SaveNoValidate(record))
			}
			data := &system.CombinedData{Monitors: map[string]monitor.Result{
				"monitor1": {LastProbeAt: 1000, AvgResponse: 20, TotalCount: 6, SuccessCount: 6, ResponseSum: 123},
				"monitor2": {LastProbeAt: 1000, PacketLoss: 100, TotalCount: 1},
			}}
			count := func(want int64) {
				t.Helper()
				got, err := app.CountRecords("network_monitor_stats")
				require.NoError(t, err)
				assert.Equal(t, want, got)
			}
			save := func() {
				t.Helper()
				_, err := sys.createRecords(data)
				require.NoError(t, err)
			}
			save()
			count(2)
			stored, err := app.FindAllRecords("network_monitor_stats")
			require.NoError(t, err)
			for _, record := range stored {
				result := data.Monitors[record.GetString("monitor")]
				assert.EqualValues(t, result.TotalCount, record.GetInt("total_count"))
				assert.EqualValues(t, result.SuccessCount, record.GetInt("success_count"))
				assert.EqualValues(t, result.ResponseSum, record.GetInt("res_sum"))
			}
			// A resume can overlap the scheduled update with the same probe.
			errs := make(chan error, 4)
			for range 4 {
				go func() {
					_, err := sys.createRecords(data)
					errs <- err
				}()
			}
			for range 4 {
				require.NoError(t, <-errs)
			}
			count(2)

			// A rolling hourly value can change without a new probe.
			result := data.Monitors["monitor1"]
			result.AvgResponse1h = 42
			data.Monitors["monitor1"] = result
			save()
			count(2)
			record, err := app.FindRecordById("network_monitors", "monitor1")
			require.NoError(t, err)
			assert.Equal(t, 42, record.GetInt("resAvg1h"))

			// Identical response values and failed probes still count as new measurements.
			for id, result := range data.Monitors {
				result.LastProbeAt = 301000
				data.Monitors[id] = result
			}
			save()
			count(4)

			// A failed individual insert must remain retryable, even if others commit.
			_, err = app.DB().NewQuery(`CREATE TRIGGER fail_monitor_insert BEFORE INSERT ON network_monitor_stats WHEN NEW.monitor = 'monitor1' BEGIN SELECT RAISE(ABORT, 'test insert failure'); END`).Execute()
			require.NoError(t, err)
			for id, result := range data.Monitors {
				result.LastProbeAt = 601000
				data.Monitors[id] = result
			}
			save()
			count(5)
			assert.Equal(t, int64(301000), sys.lastSavedMonitorProbe["monitor1"])
			assert.Equal(t, int64(601000), sys.lastSavedMonitorProbe["monitor2"])
			_, err = app.DB().NewQuery("DROP TRIGGER fail_monitor_insert").Execute()
			require.NoError(t, err)
			save()
			count(6)

			// Failure after inserting stats rolls back the whole transaction and its markers.
			_, err = app.DB().NewQuery(`CREATE TRIGGER fail_system_update BEFORE UPDATE ON systems BEGIN SELECT RAISE(ABORT, 'test rollback'); END`).Execute()
			require.NoError(t, err)
			result = data.Monitors["monitor1"]
			result.LastProbeAt = 901000
			data.Monitors["monitor1"] = result
			_, err = sys.createRecords(data)
			require.Error(t, err)
			count(6)
			assert.Equal(t, int64(601000), sys.lastSavedMonitorProbe["monitor1"])
			_, err = app.DB().NewQuery("DROP TRIGGER fail_system_update").Execute()
			require.NoError(t, err)
			save()
			count(7)

			// Clock rollback is a new probe identity, not a reason to stall writes.
			result.LastProbeAt = 500
			data.Monitors["monitor1"] = result
			save()
			count(8)

			// Recreated systems intentionally accept the first result without restoring state.
			sys = &System{Id: sys.Id, manager: sys.manager}
			save()
			count(10)
		})
	}
}

// Observes the committed DB through the hub, not the transaction's app.
type monitorAlertHub struct {
	stubHub
	handle func(*core.Record, map[string]monitor.Result) error
}

func (h monitorAlertHub) HandleNetworkMonitorAlerts(record *core.Record, results map[string]monitor.Result) error {
	return h.handle(record, results)
}

func TestNetworkMonitorAlertsAfterCommit(t *testing.T) {
	for _, realtime := range []bool{false, true} {
		t.Run(fmt.Sprint(realtime), func(t *testing.T) {
			sys, app := newTestSystemWithHub(t)
			if realtime {
				client := subscriptions.NewDefaultClient()
				client.Subscribe("network_monitors/*")
				app.SubscriptionsBroker().Register(client)
			}
			collection, err := app.FindCachedCollectionByNameOrId("network_monitors")
			require.NoError(t, err)
			record := core.NewRecord(collection)
			record.Set("system", sys.Id)
			require.NoError(t, app.SaveNoValidate(record))
			called := 0
			result := monitor.Result{LastProbeAt: time.Now().UnixMilli(), SampleCount: 3, PacketLoss1h: 10}
			sys.manager.hub = monitorAlertHub{stubHub: stubHub{app}, handle: func(systemRecord *core.Record, results map[string]monitor.Result) error {
				called++
				assert.Equal(t, sys.Id, systemRecord.Id)
				assert.Equal(t, result, results[record.Id])
				saved, err := app.FindRecordById("network_monitors", record.Id)
				require.NoError(t, err)
				assert.Equal(t, 10.0, saved.GetFloat("loss1h"))
				return nil
			}}
			data := &system.CombinedData{Monitors: map[string]monitor.Result{record.Id: result}}
			_, err = sys.createRecords(data)
			require.NoError(t, err)
			assert.Equal(t, 1, called)
			// A transaction that fails after writing monitor stats must not notify.
			_, err = app.DB().NewQuery(`CREATE TRIGGER fail_system BEFORE UPDATE ON systems BEGIN SELECT RAISE(ABORT, 'test rollback'); END`).Execute()
			require.NoError(t, err)
			_, err = sys.createRecords(data)
			require.Error(t, err)
			assert.Equal(t, 1, called)
		})
	}
}