package builtin

import (
	"context"
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"testing"

	"git.flytoex.net/yuanwei/flyto-agent/pkg/tools"
)

// noProgress is a no-op ProgressFunc for benchmarks.
var noProgress tools.ProgressFunc

// BenchmarkFileRead_BulkVsScanner benchmarks the text file read path
// with fileCache enabled (collectFull=true, bulk io.ReadAll path)
// and without cache (scanner path with early break).
func BenchmarkFileRead_BulkVsScanner(b *testing.B) {
	// Generate a 10K-line temp file.
	dir := b.TempDir()
	filePath := filepath.Join(dir, "large.txt")
	f, err := os.Create(filePath)
	if err != nil {
		b.Fatal(err)
	}
	const totalLines = 10_000
	for i := 1; i <= totalLines; i++ {
		fmt.Fprintf(f, "line %d: some representative content that mimics real source code with variables and expressions\n", i)
	}
	f.Close()

	ctx := context.Background()

	b.Run("with_cache_bulk_read", func(b *testing.B) {
		cache := newMockFileCacheForRead()
		tool := &FileReadTool{fileCache: cache}
		input, _ := json.Marshal(fileReadInput{FilePath: filePath, Limit: 100})
		b.ResetTimer()
		for b.Loop() {
			res, err := tool.Execute(ctx, input, noProgress)
			if err != nil || res.IsError {
				b.Fatalf("Execute failed: err=%v isError=%v", err, res.IsError)
			}
		}
	})

	b.Run("no_cache_scanner", func(b *testing.B) {
		// No fileCache = scanner path, breaks at limit.
		tool := &FileReadTool{}
		input, _ := json.Marshal(fileReadInput{FilePath: filePath, Limit: 100})
		b.ResetTimer()
		for b.Loop() {
			res, err := tool.Execute(ctx, input, noProgress)
			if err != nil || res.IsError {
				b.Fatalf("Execute failed: err=%v isError=%v", err, res.IsError)
			}
		}
	})

	b.Run("with_cache_offset", func(b *testing.B) {
		// offset>0 + cache: collectFull=false, scanner path.
		cache := newMockFileCacheForRead()
		tool := &FileReadTool{fileCache: cache}
		input, _ := json.Marshal(fileReadInput{FilePath: filePath, Offset: 5000, Limit: 100})
		b.ResetTimer()
		for b.Loop() {
			res, err := tool.Execute(ctx, input, noProgress)
			if err != nil || res.IsError {
				b.Fatalf("Execute failed: err=%v isError=%v", err, res.IsError)
			}
		}
	})
}