package threadsafeset

import (
	"bufio"
	"context"
	"math/rand/v2"
	"os"
	"runtime"
	"slices"
	"strings"
	"sync"
	"testing"
	"time"
)

var Words = func() []string {
	f, err := os.Open("../words")
	if err != nil {
		panic("error opening ../words: " + err.Error())
	}
	defer f.Close()
	scanner := bufio.NewScanner(f)
	results := make([]string, 0)
	for scanner.Scan() {
		if line := strings.TrimSpace(scanner.Text()); len(line) > 0 {
			results = append(results, line)
		}
	}
	if err := scanner.Err(); err != nil {
		panic("error from scanner.Err(): " + err.Error())
	}
	return results
}()

func CloneWords() []string {
	results := make([]string, 0, len(Words))
	for _, word := range Words {
		results = append(results, strings.Clone(word))
	}
	return results
}

func RandomWord() string {
	return Words[rand.IntN(len(Words))]
}

func ContextNotDone(ctx context.Context) bool {
	select {
	case <-ctx.Done():
		return false
	default:
		return true
	}
}

func TestAdd(t *testing.T) {
	set := New[string]()
	var wg sync.WaitGroup
	ctx, cancel := context.WithTimeout(t.Context(), time.Second*2)
	defer cancel()
	for range runtime.NumCPU() * 10 {
		wg.Go(func() {
			for i := 0; i < len(Words) && ContextNotDone(ctx); i++ {
				set.Add(Words[i])
			}
		})
	}
	wg.Wait()
}

func TestContains(t *testing.T) {
	set := New(Words...)
	var wg sync.WaitGroup
	ctx, cancel := context.WithTimeout(t.Context(), time.Second*2)
	defer cancel()
	for range runtime.NumCPU() * 10 {
		wg.Go(func() {
			for i := 0; i < len(Words) && ContextNotDone(ctx); i++ {
				if !set.Contains(Words[i]) {
					panic("error: " + Words[i] + " not found")
				}
			}
		})
	}
	wg.Wait()
}

func TestRemove(t *testing.T) {
	set := New(Words...)
	var wg sync.WaitGroup
	for range runtime.NumCPU() * 10 {
		wg.Go(func() {
			for _, word := range Words {
				set.Remove(word)
			}
		})
	}
	wg.Wait()
}

func TestSize(t *testing.T) {
	set := New[string]()
	for index, word := range Words {
		if want, got := index, set.Size(); want != got {
			t.Fatalf("error: wanted size %d; got %d\n", want, got)
		}
		set.Add(word)
		if want, got := index+1, set.Size(); want != got {
			t.Fatalf("error: wanted size %d; got %d\n", want, got)
		}
	}
}

func TestToSlice(t *testing.T) {
	want := CloneWords()
	slices.Sort(want)
	set := New(Words...)
	got := set.ToSlice()
	slices.Sort(got)
	if !slices.Equal(want, got) {
		t.Fatalf("error: mismatched ToSlice() output\n")
	}
}

func BenchmarkAdd(b *testing.B) {
	set := New[string]()
	for b.Loop() {
		set.Add(RandomWord())
	}
}

func BenchmarkContains(b *testing.B) {
	set := New(Words...)
	for b.Loop() {
		set.Contains(RandomWord())
	}
}