package main

import (
	"math"
	"testing"
	"time"

	"github.com/prometheus/common/model"
	"github.com/prometheus/prometheus/model/labels"
	"github.com/stretchr/testify/require"

	openapiserver "github.com/pyrra-dev/pyrra/openapi/server/go"
	"github.com/pyrra-dev/pyrra/slo"
)

func TestMatrixToValues(t *testing.T) {
	// v0 is from t 0-500 counting all up from 0 to 500
	v0 := make([]model.SamplePair, 500)
	e0 := [][]float64{
		make([]float64, 500),
		make([]float64, 500),
	}
	for i := 0; i < cap(v0); i++ {
		v0[i] = model.SamplePair{
			Timestamp: model.Time(i * 1000),
			Value:     model.SampleValue(i),
		}
		e0[0][i] = float64(i)
		e0[1][i] = float64(i)
	}

	v10 := make([]model.SamplePair, 100)
	for i := 0; i < cap(v10); i++ {
		v10[i] = model.SamplePair{
			Timestamp: model.Time(i * 1000),
			Value:     model.SampleValue(i),
		}
	}
	// offset by first 50 samples
	v11 := make([]model.SamplePair, 250)
	for i := 0; i < cap(v11); i++ {
		v11[i] = model.SamplePair{
			Timestamp: model.Time((i + 50) * 1000),
			Value:     model.SampleValue(i),
		}
	}

	e1 := [][]float64{
		make([]float64, 300), // [0-100] + [50-300]
		make([]float64, 300),
		make([]float64, 300),
	}
	for i := 0; i < 300; i++ {
		e1[0][i] = float64(i)
	}
	for i := 0; i < 100; i++ {
		e1[1][i] = float64(i)
	}
	for i := 0; i < 250; i++ {
		e1[2][50+i] = float64(i)
	}

	// Check if NaNs are returned as 0 (it's fine for errors for example to convert these).
	// Additionally, NaNs aren't possible to be marshalled to JSON. Not sure if there's a better way.
	v2 := make([]model.SamplePair, 100)
	for i := 0; i < cap(v2); i++ {
		v2[i] = model.SamplePair{
			Timestamp: model.Time(i * 1000),
			Value:     model.SampleValue(math.NaN()),
		}
	}
	e2 := [][]float64{
		make([]float64, 100),
		make([]float64, 100),
	}
	for i := 0; i < len(e2[0]); i++ {
		e2[0][i] = float64(i)
	}

	// Check NaN in multiple series
	v3 := make([]model.SamplePair, 100)
	for i := 0; i < len(v3); i++ {
		value := float64(i)
		if i%11 == 0 {
			value = math.NaN()
		}
		v3[i] = model.SamplePair{
			Timestamp: model.Time(i * 1000),
			Value:     model.SampleValue(value),
		}
	}
	e3 := [][]float64{
		make([]float64, 100), // x
		make([]float64, 100), // y[0]
		make([]float64, 100), // y[1]
	}
	for i := 0; i < len(e3[0]); i++ {
		e32value := float64(i)
		if i%11 == 0 {
			e32value = 0
		}
		e3[0][i] = float64(i)
		e3[1][i] = 0
		e3[2][i] = e32value
	}

	for _, tc := range []struct {
		name     string
		m        []*model.SampleStream
		expected [][]float64
	}{{
		name: "empty",
	}, {
		name:     "simple",
		m:        []*model.SampleStream{{Values: v0}},
		expected: e0,
	}, {
		name:     "overlapping",
		m:        []*model.SampleStream{{Values: v10}, {Values: v11}},
		expected: e1,
	}, {
		name:     "NaN",
		m:        []*model.SampleStream{{Values: v2}},
		expected: e2,
	}, {
		name:     "NaNMultiple",
		m:        []*model.SampleStream{{Values: v2}, {Values: v3}},
		expected: e3,
	}} {
		t.Run(tc.name, func(t *testing.T) {
			require.Equal(t, tc.expected, matrixToValues(tc.m))
		})
	}
}

func BenchmarkMatrixToValues(b *testing.B) {
	b.Run("one", func(b *testing.B) {
		v := make([]model.SamplePair, b.N)
		for i := 0; i < b.N; i++ {
			v[i] = model.SamplePair{
				Timestamp: model.Time(i * 1000),
				Value:     model.SampleValue(i),
			}
		}

		b.ResetTimer()
		b.ReportAllocs()
		matrixToValues([]*model.SampleStream{{Values: v}})
	})

	b.Run("two", func(b *testing.B) {
		m := make([]*model.SampleStream, 2)
		for n := 0; n < 2; n++ {
			m[n] = &model.SampleStream{Values: make([]model.SamplePair, b.N)}
		}
		for i := 0; i < b.N; i++ {
			for n := 0; n < 2; n++ {
				m[n].Values[i] = model.SamplePair{
					Timestamp: model.Time(i * 1000),
					Value:     model.SampleValue(i),
				}
			}
		}

		b.ReportAllocs()
		b.ResetTimer()
		matrixToValues(m)
	})

	b.Run("five", func(b *testing.B) {
		m := make([]*model.SampleStream, 5)
		for n := 0; n < 5; n++ {
			m[n] = &model.SampleStream{Values: make([]model.SamplePair, b.N)}
		}
		for i := 0; i < b.N; i++ {
			for n := 0; n < 5; n++ {
				m[n].Values[i] = model.SamplePair{
					Timestamp: model.Time(i * 1000),
					Value:     model.SampleValue(i),
				}
			}
		}

		b.ReportAllocs()
		b.ResetTimer()
		matrixToValues(m)
	})
}

func TestAlertsMatchingObjectives(t *testing.T) {
	testcases := []struct {
		name       string
		metrics    []*model.Sample
		objectives []slo.Objective
		inactive   bool
		alerts     []openapiserver.MultiBurnrateAlert
	}{{
		name: "firing",
		metrics: []*model.Sample{{
			Metric: model.Metric{
				labels.MetricName: "ALERTS",
				"alertname":       "ErrorBudgetBurn",
				"alertstate":      "firing",
				"job":             "prometheus",
				"long":            "2d",
				"severity":        "warning",
				"short":           "3h",
				"slo":             "prometheus-rule-evaluation-failures",
			},
		}},
		objectives: []slo.Objective{{
			Labels: labels.Labels{
				{Name: labels.MetricName, Value: "prometheus-rule-evaluation-failures"},
				{Name: "namespace", Value: "monitoring"},
			},
			Window: model.Duration(14 * 24 * time.Hour),
		}},
		alerts: []openapiserver.MultiBurnrateAlert{{
			// In the UI we identify the SLO by these labels.
			Labels: map[string]string{
				labels.MetricName: "prometheus-rule-evaluation-failures",
				"namespace":       "monitoring",
				"job":             "prometheus",
			},
			Severity: "warning",
			State:    "firing",
			For:      5400000,
			Factor:   1,
			Short: openapiserver.Burnrate{
				Window:  10800000,
				Current: -1,
				Query:   "",
			},
			Long: openapiserver.Burnrate{
				Window:  172800000,
				Current: -1,
				Query:   "",
			},
		}},
	}, {
		name:    "inactive",
		metrics: []*model.Sample{},
		objectives: []slo.Objective{{
			Labels: labels.Labels{
				{Name: labels.MetricName, Value: "prometheus-rule-evaluation-failures"},
				{Name: "namespace", Value: "monitoring"},
			},
			Window: model.Duration(14 * 24 * time.Hour),
		}},
		inactive: true,
		alerts: []openapiserver.MultiBurnrateAlert{{
			Labels: map[string]string{
				labels.MetricName: "prometheus-rule-evaluation-failures",
				"namespace":       "monitoring",
				//"alertname":       "ErrorBudgetBurn",
				//"job":             "prometheus",
			},
			Severity: "critical",
			State:    "inactive",
			For:      60000,
			Factor:   14,
			Short: openapiserver.Burnrate{
				Window:  180000,
				Current: -1,
			},
			Long: openapiserver.Burnrate{
				Window:  1800000,
				Current: -1,
			},
		}, {
			Labels: map[string]string{
				labels.MetricName: "prometheus-rule-evaluation-failures",
				"namespace":       "monitoring",
				//"alertname":       "ErrorBudgetBurn",
				//"job":             "prometheus",
			},
			Severity: "critical",
			State:    "inactive",
			For:      480000,
			Factor:   7,
			Short: openapiserver.Burnrate{
				Window:  900000,
				Current: -1,
			},
			Long: openapiserver.Burnrate{
				Window:  10800000,
				Current: -1,
			},
		}, {
			Labels: map[string]string{
				labels.MetricName: "prometheus-rule-evaluation-failures",
				"namespace":       "monitoring",
				//"alertname":       "ErrorBudgetBurn",
				//"job":             "prometheus",
			},
			Severity: "warning",
			State:    "inactive",
			For:      1800000,
			Factor:   2,
			Short: openapiserver.Burnrate{
				Window:  3600000,
				Current: -1,
			},
			Long: openapiserver.Burnrate{
				Window:  43200000,
				Current: -1,
			},
		}, {
			Labels: map[string]string{
				labels.MetricName: "prometheus-rule-evaluation-failures",
				"namespace":       "monitoring",
				//"alertname":       "ErrorBudgetBurn",
				//"job":             "prometheus",
			},
			Severity: "warning",
			State:    "inactive",
			For:      5400000,
			Factor:   1,
			Short: openapiserver.Burnrate{
				Window:  10800000,
				Current: -1,
			},
			Long: openapiserver.Burnrate{
				Window:  172800000,
				Current: -1,
			},
		}},
	}, {
		name: "mixed",
		metrics: []*model.Sample{{
			Metric: model.Metric{
				labels.MetricName: "ALERTS",
				"alertname":       "ErrorBudgetBurn",
				"alertstate":      "firing",
				"job":             "prometheus",
				"long":            "2d",
				"severity":        "warning",
				"short":           "3h",
				"slo":             "prometheus-rule-evaluation-failures",
			},
		}},
		objectives: []slo.Objective{{
			Labels: labels.Labels{
				{Name: labels.MetricName, Value: "prometheus-rule-evaluation-failures"},
				{Name: "namespace", Value: "monitoring"},
			},
			Window: model.Duration(14 * 24 * time.Hour),
		}},
		inactive: true,
		alerts: []openapiserver.MultiBurnrateAlert{{
			Labels: map[string]string{
				labels.MetricName: "prometheus-rule-evaluation-failures",
				"namespace":       "monitoring",
			},
			Severity: "critical",
			State:    "inactive",
			For:      60000,
			Factor:   14,
			Short: openapiserver.Burnrate{
				Window:  180000,
				Current: -1,
			},
			Long: openapiserver.Burnrate{
				Window:  1800000,
				Current: -1,
			},
		}, {
			Labels: map[string]string{
				labels.MetricName: "prometheus-rule-evaluation-failures",
				"namespace":       "monitoring",
			},
			Severity: "critical",
			State:    "inactive",
			For:      480000,
			Factor:   7,
			Short: openapiserver.Burnrate{
				Window:  900000,
				Current: -1,
			},
			Long: openapiserver.Burnrate{
				Window:  10800000,
				Current: -1,
			},
		}, {
			Labels: map[string]string{
				labels.MetricName: "prometheus-rule-evaluation-failures",
				"namespace":       "monitoring",
			},
			Severity: "warning",
			State:    "inactive",
			For:      1800000,
			Factor:   2,
			Short: openapiserver.Burnrate{
				Window:  3600000,
				Current: -1,
			},
			Long: openapiserver.Burnrate{
				Window:  43200000,
				Current: -1,
			},
		}, {
			Labels: map[string]string{
				labels.MetricName: "prometheus-rule-evaluation-failures",
				"namespace":       "monitoring",
			},
			Severity: "warning",
			State:    "firing", // THIS IS THE IMPORTANT UPDATE IN THIS TEST
			For:      5400000,
			Factor:   1,
			Short: openapiserver.Burnrate{
				Window:  10800000,
				Current: -1,
			},
			Long: openapiserver.Burnrate{
				Window:  172800000,
				Current: -1,
			},
		}},
	}}
	for _, tc := range testcases {
		t.Run(tc.name, func(t *testing.T) {
			require.Equal(t, tc.alerts, alertsMatchingObjectives(tc.metrics, tc.objectives, tc.inactive))
		})
	}
}