package prom

import (
	"testing"
	"time"

	prommodel "github.com/prometheus/common/model"
	"github.com/stretchr/testify/require"
	"go.yaml.in/yaml/v3"

	"github.com/grafana/grafana/pkg/util"
)

func TestPrometheusRuleGroup_Validate(t *testing.T) {
	tests := []struct {
		name        string
		group       PrometheusRuleGroup
		expectError bool
		errorMsg    string
	}{
		{
			name: "valid group with no unsupported fields",
			group: PrometheusRuleGroup{
				Name:     "test_group",
				Interval: prommodel.Duration(60),
				Labels: map[string]string{
					"label-1": "value-1",
				},
				QueryOffset: util.Pointer(prommodel.Duration(time.Duration(1) * time.Second)),
				Rules: []PrometheusRule{
					{
						Alert:         "test_alert",
						Expr:          "up == 0",
						KeepFiringFor: util.Pointer(prommodel.Duration(10)),
					},
				},
			},
			expectError: false,
		},
		{
			name: "invalid group with negative query_offset",
			group: PrometheusRuleGroup{
				Name:        "test_group",
				Interval:    prommodel.Duration(60),
				QueryOffset: util.Pointer(prommodel.Duration(-1)),
			},
			expectError: true,
			errorMsg:    "query_offset must be >= 0",
		},
		{
			name: "invalid group with limit",
			group: PrometheusRuleGroup{
				Name:     "test_group",
				Interval: prommodel.Duration(60),
				Limit:    10,
			},
			expectError: true,
			errorMsg:    "limit is not supported",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := tt.group.Validate()
			if tt.expectError {
				require.Error(t, err)
				require.Contains(t, err.Error(), tt.errorMsg)
			} else {
				require.NoError(t, err)
			}
		})
	}
}

func TestPrometheusRulesFileYAML(t *testing.T) {
	interval := prommodel.Duration(5 * time.Minute)
	alertFor := prommodel.Duration(10 * time.Minute)
	keepFiring := prommodel.Duration(15 * time.Minute)

	tests := []struct {
		name         string
		input        PrometheusRulesFile
		expectedYAML string
	}{
		{
			name: "simple alert rule and a recording rule",
			input: PrometheusRulesFile{
				Groups: []PrometheusRuleGroup{
					{
						Name:     "test_group",
						Interval: interval,
						Rules: []PrometheusRule{
							{
								Alert:         "alert-1",
								Expr:          "vector(0) > 90",
								For:           &alertFor,
								KeepFiringFor: &keepFiring,
								Labels: map[string]string{
									"team": "alerting",
								},
								Annotations: map[string]string{
									"summary":     "some summary",
									"description": "some description",
								},
							},
							{
								Record: "vector(1)",
							},
						},
					},
				},
			},
			expectedYAML: `
groups:
    - name: test_group
      interval: 5m
      rules:
        - alert: alert-1
          expr: vector(0) > 90
          for: 10m
          keep_firing_for: 15m
          labels:
            team: alerting
          annotations:
            description: some description
            summary: some summary
        - record: vector(1)
`,
		},
		{
			name: "empty rules file",
			input: PrometheusRulesFile{
				Groups: []PrometheusRuleGroup{},
			},
			expectedYAML: `groups: []`,
		},
		{
			name: "empty group",
			input: PrometheusRulesFile{
				Groups: []PrometheusRuleGroup{
					{
						Name:     "empty_group",
						Interval: interval,
						Rules:    []PrometheusRule{},
					},
				},
			},
			expectedYAML: `
groups:
  - name: empty_group
    interval: 5m
    rules: []`,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			yamlData, err := yaml.Marshal(tt.input)
			require.NoError(t, err, "Failed to marshal to YAML")
			require.YAMLEq(t, tt.expectedYAML, string(yamlData))

			var parsed PrometheusRulesFile
			err = yaml.Unmarshal(yamlData, &parsed)
			require.NoError(t, err, "Failed to unmarshal from YAML")

			require.Equal(t, tt.input, parsed)
		})
	}
}