package imapx

import (
	"context"
	"fmt"
	"testing"
)

// seedInbox logs in as login/pass and APPENDs n minimal messages with unique
// Message-IDs into INBOX via a dedicated connection.
func seedInbox(t *testing.T, ep Endpoint, login, pass string, n int) {
	t.Helper()
	ctx := context.Background()

	c, err := Connect(ctx, ep)
	if err != nil {
		t.Fatalf("seedInbox connect: %v", err)
	}
	defer func() { _ = c.Logout().Wait() }()

	if err := c.Login(login, pass).Wait(); err != nil {
		t.Fatalf("seedInbox login: %v", err)
	}

	for i := 0; i < n; i++ {
		msg := fmt.Sprintf(
			"From: sender@localhost\r\nTo: %s\r\nSubject: seed %d\r\nMessage-Id: <seed-%d-%p@localhost>\r\n\r\nBody %d\r\n",
			login, i, i, &i, i,
		)
		buf := []byte(msg)
		appendCmd := c.Append("INBOX", int64(len(buf)), nil)
		if _, err := appendCmd.Write(buf); err != nil {
			t.Fatalf("seedInbox write %d: %v", i, err)
		}
		if err := appendCmd.Close(); err != nil {
			t.Fatalf("seedInbox close %d: %v", i, err)
		}
		if _, err := appendCmd.Wait(); err != nil {
			t.Fatalf("seedInbox append %d: %v", i, err)
		}
	}
}

// Требует два ящика на greenmail. Первый запуск копирует N, второй — 0 (все skipped).
func TestCopyFolderIdempotent(t *testing.T) {
	ep := testEP(t) // plain greenmail
	ctx := context.Background()

	// подготовка: APPEND 2 письма в INBOX источника через отдельное соединение
	seedInbox(t, ep, "src@localhost", "p", 2)

	src, err := Connect(ctx, ep)
	if err != nil {
		t.Fatal(err)
	}
	defer func() { _ = src.Logout().Wait() }()
	if err := src.Login("src@localhost", "p").Wait(); err != nil {
		t.Fatal(err)
	}

	dst, err := Connect(ctx, ep)
	if err != nil {
		t.Fatal(err)
	}
	defer func() { _ = dst.Logout().Wait() }()
	if err := dst.Login("dst@localhost", "p").Wait(); err != nil {
		t.Fatal(err)
	}

	seen := map[string]bool{}
	deps := CopyDeps{
		IsMigrated:   func(k string) (bool, error) { return seen[k], nil },
		MarkMigrated: func(_, k string) error { seen[k] = true; return nil },
		OnProgress:   func(_, _ int) {},
	}

	r1, err := CopyFolder(ctx, src, dst, "INBOX", "INBOX", deps)
	if err != nil {
		t.Fatalf("run1: %v", err)
	}
	if r1.Copied != 2 {
		t.Fatalf("run1 copied=%d want 2", r1.Copied)
	}

	r2, err := CopyFolder(ctx, src, dst, "INBOX", "INBOX", deps)
	if err != nil {
		t.Fatalf("run2: %v", err)
	}
	if r2.Copied != 0 || r2.Skipped != 2 {
		t.Fatalf("run2 copied=%d skipped=%d want 0/2", r2.Copied, r2.Skipped)
	}
}