package transform

import (
	"context"
	"testing"
	"time"

	"codeberg.org/pata1704/guenther/internal/config"
	"codeberg.org/pata1704/guenther/pkg/types"
	"github.com/stretchr/testify/assert"
)

func TestTransformEngine_Fusion(t *testing.T) {
	logChan := make(chan types.LogEvent, 100)
	metricChan := make(chan types.MetricSnapshot, 100)
	serviceStatusChan := make(chan types.ServiceStatus, 100)
	featureChan := make(chan types.FeatureVector, 100)
	healthChan := make(chan types.StageHealth, 10)

	cfg := &config.Config{}
	cfg.Transformation.WindowSize = 1 * time.Second
	cfg.Transformation.DbPath = ":memory:"

	engine, err := NewTransformEngine(cfg, logChan, metricChan, serviceStatusChan, featureChan, healthChan)
	assert.NoError(t, err)

	baseTime := time.Date(2026, 1, 1, 12, 0, 0, 0, time.Local)

	// 1. Send data for first window
	metricChan <- types.MetricSnapshot{
		Timestamp:      baseTime,
		CPUPercent:     50.0,
		MemoryUsedMB:   1000,
		MemoryDirtyMB:  100,
		NetworkInMBps:  10.0,
		NetworkOutMBps: 20.0,
		TCPRetransPerS: 5,
		NetPacketsInPerS:  100,
		NetPacketsOutPerS: 200,
	}

	// 2. Start engine and wait for first window
	ctx, cancel := context.WithCancel(context.Background())
	engine.Start(ctx)
	defer func() {
		cancel()
		engine.Wait()
	}()

	select {
	case fv := <-featureChan:
		assert.Equal(t, 50.0, fv.AvgCPUPercent)
		// Deltas are absolute value on first window because tracker starts at 0
		assert.Equal(t, 10.0, fv.DeltaNetIn)
	case <-time.After(2 * time.Second):
		t.Fatal("Timeout waiting for first FeatureVector")
	}

	// 3. Send data for second window (triggers deltas)
	secondTime := baseTime.Add(cfg.Transformation.WindowSize)
	metricChan <- types.MetricSnapshot{
		Timestamp:      secondTime,
		CPUPercent:     60.0,
		MemoryUsedMB:   1000,
		MemoryDirtyMB:  200,
		NetworkInMBps:  15.0, // DeltaNetIn = 15.0 - 10.0 = 5.0
		NetworkOutMBps: 20.0,
		TCPRetransPerS: 10, // DeltaTCPRetrans = 10.0 - 5.0 = 5.0
		NetPacketsInPerS:  150,
		NetPacketsOutPerS: 200,
	}

	select {
	case fv := <-featureChan:
		// Check original logic
		assert.Equal(t, 60.0, fv.AvgCPUPercent)

		// Check new delta features
		assert.Equal(t, 5.0, fv.DeltaNetIn)
		assert.Equal(t, 5.0, fv.DeltaTCPRetrans)

		// Check ratio features
		// MemPressure = dirty / (used + 1) = 200/1001
		expectedPressure := 200.0 / 1001.0
		assert.InDelta(t, expectedPressure, fv.MemPressure, 1e-9)
		// NetAsymmetry = in / (out + 1e-3) = 15/20.001
		expectedAsym := 15.0 / 20.001
		assert.InDelta(t, expectedAsym, fv.NetAsymmetry, 1e-9)

		// Check NormalizedVector length (should be 45 base + params)
		assert.GreaterOrEqual(t, len(fv.NormalizedVector), 45)

		// Verify slots 39-44 (Engineered Features tail)
		nv := fv.NormalizedVector
		assert.Equal(t, 5.0, nv[39]) // DeltaNetIn
		assert.Equal(t, 5.0, nv[40]) // DeltaTCPRetrans
		// TcpRollStd and NetRollStd will have values (even if just 2 pts)
		assert.Greater(t, nv[41], 0.0)                    // TcpRollStd (10 and 5)
		assert.Equal(t, 0.0, nv[42])                      // NetRollStd (20 and 20 -> std=0)
		assert.InDelta(t, expectedPressure, nv[43], 1e-9) // MemPressure
		assert.InDelta(t, expectedAsym, nv[44], 1e-9)     // NetAsymmetry

	case <-time.After(2 * time.Second):
		t.Fatal("Timeout waiting for second FeatureVector")
	}
}