package macode

import (
	"database/sql"
	"fmt"
	"os"
	"sync"
	"testing"

	_ "github.com/lib/pq"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// 集成测试：需本地 PostgreSQL。通过 TCS_TEST_PG_DSN 提供连接串；未提供则跳过。
func openTestDB(t *testing.T) *sql.DB {
	t.Helper()
	dsn := os.Getenv("TCS_TEST_PG_DSN")
	if dsn == "" {
		dsn = "postgres://postgres@localhost:5432/tcs_iptv?sslmode=disable"
	}
	db, err := sql.Open("postgres", dsn)
	if err != nil {
		t.Skipf("跳过 PG 集成测试：%v", err)
	}
	if err := db.Ping(); err != nil {
		t.Skipf("跳过 PG 集成测试（无法连接）：%v", err)
	}
	return db
}

func cleanupKey(t *testing.T, db *sql.DB, key string) {
	t.Helper()
	_, _ = db.Exec("DELETE FROM macode_cursor WHERE segment_key = $1", key)
}

func TestPostgresStore_Sequential(t *testing.T) {
	db := openTestDB(t)
	defer db.Close()
	store := NewPostgresStore(db)
	key := "test:seq:WD"
	cleanupKey(t, db, key)
	defer cleanupKey(t, db, key)

	for want := uint64(1); want <= 5; want++ {
		got, err := store.Next(key, 1, 100)
		require.NoError(t, err)
		assert.Equal(t, want, got)
	}
}

func TestPostgresStore_Exhausted(t *testing.T) {
	db := openTestDB(t)
	defer db.Close()
	store := NewPostgresStore(db)
	key := "test:exhaust:DY"
	cleanupKey(t, db, key)
	defer cleanupKey(t, db, key)

	_, err := store.Next(key, 1, 2)
	require.NoError(t, err)
	_, err = store.Next(key, 1, 2)
	require.NoError(t, err)
	_, err = store.Next(key, 1, 2)
	assert.ErrorIs(t, err, ErrSegmentExhausted)
}

func TestPostgresStore_ConcurrentNoDuplicate(t *testing.T) {
	db := openTestDB(t)
	defer db.Close()
	store := NewPostgresStore(db)
	key := "test:concurrent:WJ"
	cleanupKey(t, db, key)
	defer cleanupKey(t, db, key)

	const n = 200
	var wg sync.WaitGroup
	var mu sync.Mutex
	seen := make(map[uint64]bool)
	dup := 0
	errs := 0
	for i := 0; i < n; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			v, err := store.Next(key, 1, 1000)
			if err != nil {
				mu.Lock()
				errs++
				mu.Unlock()
				return
			}
			mu.Lock()
			if seen[v] {
				dup++
			}
			seen[v] = true
			mu.Unlock()
		}()
	}
	wg.Wait()
	assert.Equal(t, 0, errs, "并发分配不应报错")
	assert.Equal(t, 0, dup, "并发分配不得重号")
	assert.Len(t, seen, n)
}

// TestPostgresStore_WithGenerator 验证 PG 存储与生成器联动产出唯一 MA 码。
func TestPostgresStore_WithGenerator(t *testing.T) {
	db := openTestDB(t)
	defer db.Close()
	key := fmt.Sprintf("%s:%s:%s", "8531", "4401", CategoryAnimation)
	cleanupKey(t, db, key)
	defer cleanupKey(t, db, key)

	g := NewGenerator(NewPostgresStore(db))
	require.NoError(t, g.RegisterSegment(Segment{
		IndustryNode: "8531", OrgNode: "4401",
		Category: CategoryAnimation, Start: 1, End: 1000, SeqWidth: 7,
	}))

	seen := map[string]bool{}
	for i := 0; i < 10; i++ {
		issued, err := g.Allocate(CategoryAnimation)
		require.NoError(t, err)
		assert.False(t, seen[issued.MACode])
		assert.True(t, IsValid(issued.MACode))
		seen[issued.MACode] = true
	}
}