// Copyright 2025 PingCAP, Inc.
//
// 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 bindinfo

import (
	"testing"

	"github.com/stretchr/testify/require"
)

func TestRuleBasedPlanPerfPredictor(t *testing.T) {
	pointPlan := `       id  task    estRows operator info  actRows execution info  memory          disk
        Projection_4    root    1       plus(test.t.a, 1)->Column#3     0       time:173µs, open:24.9µs, close:8.92µs, loops:1, Concurrency:OFF                         380 Bytes       N/A
        └─Point_Get_5   root    1       table:t, handle:2               0       time:143.2µs, open:1.71µs, close:5.92µs, loops:1, Get:{num_rpc:1, total_time:40µs}      N/A             N/A`
	batchPointPlan := `id                      task    estRows operator info                                           actRows execution info                                                                                                                    memory          disk
        Projection_4            root    3.00    plus(test.t.a, 1)->Column#3                             0       time:218.3µs, open:14.5µs, close:9.79µs, loops:1, Concurrency:OFF                                                                 145 Bytes       N/A
        └─Batch_Point_Get_5     root    3.00    table:t, handle:[1 2 3], keep order:false, desc:false   0       time:201.1µs, open:3.83µs, close:6.46µs, loops:1, BatchGet:{num_rpc:2, total_time:65.7µs}, rpc_errors:{epoch_not_match:1} N/A             N/A   `
	nonPointPlan := `       id                      task            estRows operator info                           actRows execution info memory          disk
        TableReader_5           root            10000   data:TableFullScan_4                    0       time:456.3µs, open:141µs, close:6.79µs, loops:1, cop_task: {num: 1, max: 241.3µs, proc_keys: 0, copr_cache_hit_ratio: 0.00, build_task_duration: 91.5µs, max_distsql_concurrency: 1}, rpc_info:{Cop:{num_rpc:1, total_time:203.9µs}}      182 Bytes       N/A
        └─TableFullScan_4       cop[tikv]       10000   table:t, keep order:false, stats:pseudo 0       tikv_task:{time:155.2µs, loops:0}                                                                                                                                                                                                         N/A             N/A `

	// Test rule 1
	p1 := &BindingPlanInfo{
		Plan:                 nonPointPlan,
		AvgLatency:           100,
		ExecTimes:            100,
		AvgScanRows:          100,
		AvgReturnedRows:      100,
		LatencyPerReturnRow:  100,
		ScanRowsPerReturnRow: 100,
	}
	p2 := &BindingPlanInfo{
		Plan:                 pointPlan,
		AvgLatency:           100,
		ExecTimes:            100,
		AvgScanRows:          100,
		AvgReturnedRows:      100,
		LatencyPerReturnRow:  100,
		ScanRowsPerReturnRow: 100,
	}

	p := new(ruleBasedPlanPerfPredictor)

	scores, explanations, _ := p.PerfPredicate([]*BindingPlanInfo{p1, p2})
	require.Equal(t, scores, []float64{0, 1})
	require.Equal(t, explanations, []string{"", "Simple PointGet or BatchPointGet is the best plan"})

	p1.Plan, p2.Plan = batchPointPlan, nonPointPlan
	scores, explanations, _ = p.PerfPredicate([]*BindingPlanInfo{p1, p2})
	require.Equal(t, scores, []float64{1, 0})
	require.Equal(t, explanations, []string{"Simple PointGet or BatchPointGet is the best plan", ""})

	// Test rule 2
	p1.Plan, p2.Plan = nonPointPlan, nonPointPlan
	p2.ScanRowsPerReturnRow = 30
	scores, explanations, _ = p.PerfPredicate([]*BindingPlanInfo{p1, p2})
	require.Equal(t, scores, []float64{1, 0})
	require.Equal(t, explanations, []string{"Plan's scan_rows_per_returned_row is 50% better than others'", ""})
	p2.ScanRowsPerReturnRow = 100

	// Test rule 3
	p1.AvgLatency = 30
	p1.AvgScanRows = 30
	p1.LatencyPerReturnRow = 30
	scores, explanations, _ = p.PerfPredicate([]*BindingPlanInfo{p1, p2})
	require.Equal(t, scores, []float64{1, 0})
	require.Equal(t, explanations, []string{"Plan's latency, scan_rows and latency_per_returned_row are 50% better than others'", ""})
	p1.Reason, p1.Recommend = "", ""

	p1.AvgLatency = 60
	scores, _, _ = p.PerfPredicate([]*BindingPlanInfo{p1, p2})
	require.Equal(t, scores, []float64{0, 0}) // no recommendation
}