// Package testutil provides isolated infrastructure for integration tests.
package testutil

import (
	"context"
	"net"
	"os"
	"os/exec"
	"testing"
	"time"

	_ "github.com/gogf/gf/contrib/nosql/redis/v2"
	"github.com/gogf/gf/v2/database/gredis"
)

// Redis starts a disposable loopback-only server with persistence disabled.
// Tests never use the application's Redis configuration or an existing server.
func Redis(t *testing.T) *gredis.Redis {
	t.Helper()
	binary := os.Getenv("REDIS_SERVER_BINARY")
	if binary == "" {
		var err error
		binary, err = exec.LookPath("redis-server")
		if err != nil {
			t.Skip("real Redis tests require redis-server on PATH or REDIS_SERVER_BINARY")
		}
	}
	listener, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	address := listener.Addr().String()
	_, port, err := net.SplitHostPort(address)
	if err != nil {
		t.Fatal(err)
	}
	_ = listener.Close()
	command := exec.Command(binary, "--bind", "127.0.0.1", "--port", port, "--save", "", "--appendonly", "no")
	command.Dir = t.TempDir()
	if err = command.Start(); err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() {
		_ = command.Process.Kill()
		_ = command.Wait()
	})
	client, err := gredis.New(&gredis.Config{Address: address, DialTimeout: 100 * time.Millisecond, ReadTimeout: time.Second, WriteTimeout: time.Second})
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = client.Close(context.Background()) })
	for deadline := time.Now().Add(5 * time.Second); time.Now().Before(deadline); {
		var connection net.Conn
		connection, err = net.DialTimeout("tcp", address, 50*time.Millisecond)
		if err == nil {
			_ = connection.Close()
			if _, err = client.Do(context.Background(), "PING"); err == nil {
				return client
			}
		}
		time.Sleep(20 * time.Millisecond)
	}
	t.Fatalf("isolated Redis did not start: %v", err)
	return nil
}