package rules

import (
	"testing"
	"time"

	"github.com/SigNoz/signoz/pkg/instrumentation/instrumentationtest"
	v3 "github.com/SigNoz/signoz/pkg/query-service/model/v3"
	ruletypes "github.com/SigNoz/signoz/pkg/types/ruletypes"
	"github.com/SigNoz/signoz/pkg/valuer"
	pql "github.com/prometheus/prometheus/promql"
	"github.com/stretchr/testify/assert"
)

func getVectorValues(vectors []ruletypes.Sample) []float64 {
	if len(vectors) == 0 {
		return []float64{} // Return empty slice instead of nil
	}
	var values []float64
	for _, v := range vectors {
		values = append(values, v.V)
	}
	return values
}

func TestPromRuleShouldAlert(t *testing.T) {
	postableRule := ruletypes.PostableRule{
		AlertName: "Test Rule",
		AlertType: ruletypes.AlertTypeMetric,
		RuleType:  ruletypes.RuleTypeProm,
		Evaluation: &ruletypes.EvaluationEnvelope{Kind: ruletypes.RollingEvaluation, Spec: ruletypes.RollingWindow{
			EvalWindow: ruletypes.Duration(5 * time.Minute),
			Frequency:  ruletypes.Duration(1 * time.Minute),
		}},
		RuleCondition: &ruletypes.RuleCondition{
			CompositeQuery: &v3.CompositeQuery{
				QueryType: v3.QueryTypePromQL,
				PromQueries: map[string]*v3.PromQuery{
					"A": {
						Query: "dummy_query", // This is not used in the test
					},
				},
			},
		},
	}

	cases := []struct {
		values               pql.Series
		expectAlert          bool
		compareOp            string
		matchType            string
		target               float64
		expectedAlertSample  v3.Point
		expectedVectorValues []float64 // Expected values in result vector
	}{
		// Test cases for Equals Always
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
				},
			},
			expectAlert:          true,
			compareOp:            "3", // Equals
			matchType:            "2", // Always
			target:               0.0,
			expectedAlertSample:  v3.Point{Value: 0.0},
			expectedVectorValues: []float64{0.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 1.0},
				},
			},
			expectAlert:          false,
			compareOp:            "3", // Equals
			matchType:            "2", // Always
			target:               0.0,
			expectedVectorValues: []float64{},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 1.0},
					{F: 0.0},
					{F: 1.0},
					{F: 1.0},
				},
			},
			expectAlert:          false,
			compareOp:            "3", // Equals
			matchType:            "2", // Always
			target:               0.0,
			expectedVectorValues: []float64{},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
				},
			},
			expectAlert: false,
			compareOp:   "3", // Equals
			matchType:   "2", // Always
			target:      0.0,
		},
		// Test cases for Equals Once
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
				},
			},
			expectAlert:          true,
			compareOp:            "3", // Equals
			matchType:            "1", // Once
			target:               0.0,
			expectedAlertSample:  v3.Point{Value: 0.0},
			expectedVectorValues: []float64{0.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 1.0},
				},
			},
			expectAlert:         true,
			compareOp:           "3", // Equals
			matchType:           "1", // Once
			target:              0.0,
			expectedAlertSample: v3.Point{Value: 0.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 1.0},
					{F: 0.0},
					{F: 1.0},
					{F: 1.0},
				},
			},
			expectAlert:         true,
			compareOp:           "3", // Equals
			matchType:           "1", // Once
			target:              0.0,
			expectedAlertSample: v3.Point{Value: 0.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
				},
			},
			expectAlert:          false,
			compareOp:            "3", // Equals
			matchType:            "1", // Once
			target:               0.0,
			expectedVectorValues: []float64{},
		},
		// Test cases for Greater Than Always
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert:          true,
			compareOp:            "1", // Greater Than
			matchType:            "2", // Always
			target:               1.5,
			expectedAlertSample:  v3.Point{Value: 2.0},
			expectedVectorValues: []float64{2.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 11.0},
					{F: 4.0},
					{F: 3.0},
					{F: 7.0},
					{F: 12.0},
				},
			},
			expectAlert:         true,
			compareOp:           "1", // Above
			matchType:           "2", // Always
			target:              2.0,
			expectedAlertSample: v3.Point{Value: 3.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 11.0},
					{F: 4.0},
					{F: 3.0},
					{F: 7.0},
					{F: 12.0},
				},
			},
			expectAlert:         true,
			compareOp:           "2", // Below
			matchType:           "2", // Always
			target:              13.0,
			expectedAlertSample: v3.Point{Value: 12.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert: false,
			compareOp:   "1", // Greater Than
			matchType:   "2", // Always
			target:      4.5,
		},
		// Test cases for Greater Than Once
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert:          true,
			compareOp:            "1", // Greater Than
			matchType:            "1", // Once
			target:               4.5,
			expectedAlertSample:  v3.Point{Value: 10.0},
			expectedVectorValues: []float64{10.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 4.0},
					{F: 4.0},
					{F: 4.0},
					{F: 4.0},
					{F: 4.0},
				},
			},
			expectAlert: false,
			compareOp:   "1", // Greater Than
			matchType:   "1", // Once
			target:      4.5,
		},
		// Test cases for Not Equals Always
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 1.0},
					{F: 0.0},
					{F: 1.0},
					{F: 0.0},
				},
			},
			expectAlert: false,
			compareOp:   "4", // Not Equals
			matchType:   "2", // Always
			target:      0.0,
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 0.0},
				},
			},
			expectAlert: false,
			compareOp:   "4", // Not Equals
			matchType:   "2", // Always
			target:      0.0,
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
				},
			},
			expectAlert:         true,
			compareOp:           "4", // Not Equals
			matchType:           "2", // Always
			target:              0.0,
			expectedAlertSample: v3.Point{Value: 1.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 1.0},
					{F: 0.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
				},
			},
			expectAlert: false,
			compareOp:   "4", // Not Equals
			matchType:   "2", // Always
			target:      0.0,
		},
		// Test cases for Not Equals Once
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 1.0},
					{F: 0.0},
					{F: 1.0},
					{F: 0.0},
				},
			},
			expectAlert:         true,
			compareOp:           "4", // Not Equals
			matchType:           "1", // Once
			target:              0.0,
			expectedAlertSample: v3.Point{Value: 1.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
					{F: 0.0},
				},
			},
			expectAlert: false,
			compareOp:   "4", // Not Equals
			matchType:   "1", // Once
			target:      0.0,
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 0.0},
					{F: 0.0},
					{F: 1.0},
					{F: 0.0},
					{F: 1.0},
				},
			},
			expectAlert:         true,
			compareOp:           "4", // Not Equals
			matchType:           "1", // Once
			target:              0.0,
			expectedAlertSample: v3.Point{Value: 1.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
					{F: 1.0},
				},
			},
			expectAlert:         true,
			compareOp:           "4", // Not Equals
			matchType:           "1", // Once
			target:              0.0,
			expectedAlertSample: v3.Point{Value: 1.0},
		},
		// Test cases for Less Than Always
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 1.5},
					{F: 1.5},
					{F: 1.5},
					{F: 1.5},
					{F: 1.5},
				},
			},
			expectAlert:         true,
			compareOp:           "2", // Less Than
			matchType:           "2", // Always
			target:              4,
			expectedAlertSample: v3.Point{Value: 1.5},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 4.5},
					{F: 4.5},
					{F: 4.5},
					{F: 4.5},
					{F: 4.5},
				},
			},
			expectAlert: false,
			compareOp:   "2", // Less Than
			matchType:   "2", // Always
			target:      4,
		},
		// Test cases for Less Than Once
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 4.5},
					{F: 4.5},
					{F: 4.5},
					{F: 4.5},
					{F: 2.5},
				},
			},
			expectAlert:         true,
			compareOp:           "2", // Less Than
			matchType:           "1", // Once
			target:              4,
			expectedAlertSample: v3.Point{Value: 2.5},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 4.5},
					{F: 4.5},
					{F: 4.5},
					{F: 4.5},
					{F: 4.5},
				},
			},
			expectAlert: false,
			compareOp:   "2", // Less Than
			matchType:   "1", // Once
			target:      4,
		},
		// Test cases for OnAverage
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert:         true,
			compareOp:           "3", // Equals
			matchType:           "3", // OnAverage
			target:              6.0,
			expectedAlertSample: v3.Point{Value: 6.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert: false,
			compareOp:   "3", // Equals
			matchType:   "3", // OnAverage
			target:      4.5,
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert:         true,
			compareOp:           "4", // Not Equals
			matchType:           "3", // OnAverage
			target:              4.5,
			expectedAlertSample: v3.Point{Value: 6.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert: false,
			compareOp:   "4", // Not Equals
			matchType:   "3", // OnAverage
			target:      6.0,
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert:         true,
			compareOp:           "1", // Greater Than
			matchType:           "3", // OnAverage
			target:              4.5,
			expectedAlertSample: v3.Point{Value: 6.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert:         true,
			compareOp:           "2", // Less Than
			matchType:           "3", // OnAverage
			target:              12.0,
			expectedAlertSample: v3.Point{Value: 6.0},
		},
		// Test cases for InTotal
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert:         true,
			compareOp:           "3", // Equals
			matchType:           "4", // InTotal
			target:              30.0,
			expectedAlertSample: v3.Point{Value: 30.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 4.0},
					{F: 6.0},
					{F: 8.0},
					{F: 2.0},
				},
			},
			expectAlert: false,
			compareOp:   "3", // Equals
			matchType:   "4", // InTotal
			target:      20.0,
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
				},
			},
			expectAlert:         true,
			compareOp:           "4", // Not Equals
			matchType:           "4", // InTotal
			target:              9.0,
			expectedAlertSample: v3.Point{Value: 10.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
				},
			},
			expectAlert: false,
			compareOp:   "4", // Not Equals
			matchType:   "4", // InTotal
			target:      10.0,
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 10.0},
				},
			},
			expectAlert:         true,
			compareOp:           "1", // Greater Than
			matchType:           "4", // InTotal
			target:              10.0,
			expectedAlertSample: v3.Point{Value: 20.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 10.0},
				},
			},
			expectAlert: false,
			compareOp:   "1", // Greater Than
			matchType:   "4", // InTotal
			target:      20.0,
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 10.0},
				},
			},
			expectAlert:         true,
			compareOp:           "2", // Less Than
			matchType:           "4", // InTotal
			target:              30.0,
			expectedAlertSample: v3.Point{Value: 20.0},
		},
		{
			values: pql.Series{
				Floats: []pql.FPoint{
					{F: 10.0},
					{F: 10.0},
				},
			},
			expectAlert: false,
			compareOp:   "2", // Less Than
			matchType:   "4", // InTotal
			target:      20.0,
		},
	}

	logger := instrumentationtest.New().Logger()

	for idx, c := range cases {
		postableRule.RuleCondition.CompareOp = ruletypes.CompareOp(c.compareOp)
		postableRule.RuleCondition.MatchType = ruletypes.MatchType(c.matchType)
		postableRule.RuleCondition.Target = &c.target
		postableRule.RuleCondition.Thresholds = &ruletypes.RuleThresholdData{
			Kind: ruletypes.BasicThresholdKind,
			Spec: ruletypes.BasicRuleThresholds{
				{
					TargetValue: &c.target,
					MatchType:   ruletypes.MatchType(c.matchType),
					CompareOp:   ruletypes.CompareOp(c.compareOp),
				},
			},
		}

		rule, err := NewPromRule("69", valuer.GenerateUUID(), &postableRule, logger, nil, nil)
		if err != nil {
			assert.NoError(t, err)
		}

		resultVectors, err := rule.Threshold.ShouldAlert(toCommonSeries(c.values), rule.Unit())
		assert.NoError(t, err)

		// Compare full result vector with expected vector
		actualValues := getVectorValues(resultVectors)
		if c.expectedVectorValues != nil {
			// If expected vector values are specified, compare them exactly
			assert.Equal(t, c.expectedVectorValues, actualValues, "Result vector values don't match expected for case %d", idx)
		} else {
			// Fallback to the old logic for cases without expectedVectorValues
			if c.expectAlert {
				assert.NotEmpty(t, resultVectors, "Expected alert but got no result vectors for case %d", idx)
				// Verify at least one of the result vectors matches the expected alert sample
				if len(resultVectors) > 0 {
					found := false
					for _, sample := range resultVectors {
						if sample.V == c.expectedAlertSample.Value {
							found = true
							break
						}
					}
					assert.True(t, found, "Expected alert sample value %.2f not found in result vectors for case %d. Got values: %v", c.expectedAlertSample.Value, idx, actualValues)
				}
			} else {
				assert.Empty(t, resultVectors, "Expected no alert but got result vectors for case %d", idx)
			}
		}

	}
}