package orderstate

import (
	"context"
	"errors"
	"fmt"
	"os"
	"sync"
	"testing"
	"time"

	"github.com/jackc/pgx/v5/pgxpool"
)

// 需要 PostgreSQL：TEST_DATABASE_URL=postgres://user:pass@localhost:5432/db?sslmode=disable go test ./...
func setup(t *testing.T) *pgxpool.Pool {
	t.Helper()
	url := os.Getenv("TEST_DATABASE_URL")
	if url == "" {
		t.Skip("未设置 TEST_DATABASE_URL，跳过集成测试")
	}
	ctx := context.Background()
	schema := fmt.Sprintf("t_order_%d", time.Now().UnixNano())
	admin, err := pgxpool.New(ctx, url)
	if err != nil {
		t.Fatal(err)
	}
	if _, err := admin.Exec(ctx, "CREATE SCHEMA "+schema); err != nil {
		t.Fatal(err)
	}
	cfg, _ := pgxpool.ParseConfig(url)
	cfg.ConnConfig.RuntimeParams["search_path"] = schema // 每次测试用独立的 schema
	db, err := pgxpool.NewWithConfig(ctx, cfg)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() {
		db.Close()
		_, _ = admin.Exec(ctx, "DROP SCHEMA "+schema+" CASCADE")
		admin.Close()
	})
	if _, err := db.Exec(ctx, Schema); err != nil {
		t.Fatal(err)
	}
	return db
}

func newOrder(t *testing.T, db *pgxpool.Pool) Order {
	t.Helper()
	var id int64
	if err := db.QueryRow(context.Background(), "INSERT INTO orders DEFAULT VALUES RETURNING id").Scan(&id); err != nil {
		t.Fatal(err)
	}
	o, err := Get(context.Background(), db, id)
	if err != nil {
		t.Fatal(err)
	}
	return o
}

func TestAllowed(t *testing.T) {
	if !allowed("pending", "paid") || allowed("pending", "shipped") || allowed("completed", "paid") {
		t.Fatal("状态流转表不对")
	}
}

func TestTransitionAndAudit(t *testing.T) {
	db := setup(t)
	ctx := context.Background()
	o := newOrder(t, db)
	o, err := Transition(ctx, db, o, "paid", "payment-callback", "")
	if err != nil {
		t.Fatal(err)
	}
	if _, err := Transition(ctx, db, o, "completed", "admin", ""); !errors.Is(err, ErrIllegal) {
		t.Fatalf("paid -> completed 应该不允许，得到 %v", err)
	}
	var n int
	_ = db.QueryRow(ctx, "SELECT count(*) FROM order_events WHERE order_id = $1", o.ID).Scan(&n)
	if n != 1 {
		t.Fatalf("审计日志条数 = %d", n)
	}
}

func TestConcurrentCancelAndPay(t *testing.T) {
	db := setup(t)
	ctx := context.Background()
	o := newOrder(t, db) // 两个操作读到的是同一个版本
	var wg sync.WaitGroup
	errs := make([]error, 2)
	for i, to := range []string{"paid", "cancelled"} {
		wg.Add(1)
		go func() {
			defer wg.Done()
			_, errs[i] = Transition(ctx, db, o, to, "test", "")
		}()
	}
	wg.Wait()
	ok, conflict := 0, 0
	for _, err := range errs {
		switch {
		case err == nil:
			ok++
		case errors.Is(err, ErrConflict):
			conflict++
		default:
			t.Fatal(err)
		}
	}
	if ok != 1 || conflict != 1 {
		t.Fatalf("应该一个成功一个冲突，得到 ok=%d conflict=%d", ok, conflict)
	}
	cur, _ := Get(ctx, db, o.ID)
	var n int
	_ = db.QueryRow(ctx, "SELECT count(*) FROM order_events WHERE order_id = $1", o.ID).Scan(&n)
	if cur.Version != 2 || n != 1 {
		t.Fatalf("版本 %d，审计 %d 条", cur.Version, n)
	}
}