// Copyright 2022 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package scrape

import (
	"testing"
	"time"

	"github.com/prometheus/prometheus/promql"

	"github.com/stretchr/testify/require"

	"github.com/prometheus/prometheus/config"
	"github.com/prometheus/prometheus/model/labels"
)

func TestRuleEngine(t *testing.T) {
	now := time.Now()
	samples := []Sample{
		{
			metric: labels.FromStrings("__name__", "http_requests_total", "code", "200", "handler", "/"),
			t:      now.UnixMilli(),
			f:      10,
		},
		{
			metric: labels.FromStrings("__name__", "http_requests_total", "code", "200", "handler", "/metrics"),
			t:      now.UnixMilli(),
			f:      6,
		},
	}
	rules := []*config.ScrapeRuleConfig{
		{
			Expr:   "sum by (code) (http_requests_total)",
			Record: "code:http_requests_total:sum",
		},
	}

	engine := promql.NewEngine(promql.EngineOpts{
		MaxSamples:    50000000,
		Timeout:       10 * time.Second,
		LookbackDelta: 5 * time.Minute,
	})
	re := newRuleEngine(rules, engine)
	b := re.NewScrapeBatch()
	for _, s := range samples {
		b.AddFloatSample(s.metric, s.t, s.f)
	}

	result, err := re.EvaluateRules(b, now, nopMutator)
	require.NoError(t, err)

	if len(result) != 1 {
		t.Fatalf("Invalid sample count, got %d, want %d", len(result), 3)
	}

	expectedSamples := []Sample{
		{
			metric: labels.FromStrings("__name__", "code:http_requests_total:sum", "code", "200"),
			t:      now.UnixMilli(),
			f:      16,
		},
	}
	require.ElementsMatch(t, expectedSamples, result)
}