//go:build dbtest

// PostgresRepository（agent）的真 DB 整合測試（WP-B B2）。
//
// build tag `dbtest`：只在帶 `-tags=dbtest` 時編譯/執行（需 Docker / testcontainers）。
//
// 執行：
//
//	go test -tags=dbtest ./internal/agent/...
//	# 無本機 Docker 時在 130 補跑：
//	DOCKER_HOST=tcp://192.168.0.130:2375 TESTCONTAINERS_RYUK_DISABLED=true \
//	  go test -tags=dbtest ./internal/agent/...
package agent

import (
	"context"
	"sync"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"visiona-backend/internal/db"
	"visiona-backend/internal/db/testsupport"
)

// newPGRepo 啟動測試 DB、truncate、確保 demo user，回傳 repo + owner。
func newPGRepo(t *testing.T) (*PostgresRepository, *testsupport.TestDB, string) {
	t.Helper()
	tdb := testsupport.SetupTestDB(t)
	tdb.Truncate(t, "devices", "agents", "users")
	owner := tdb.EnsureDemoUser(t)
	return NewPostgresRepository(tdb.Pool), tdb, owner
}

// GetOrCreate 新建：DB 中先無 agent → 建一筆、欄位正確。
func TestPG_GetOrCreate_CreatesWhenAbsent(t *testing.T) {
	ctx := context.Background()
	r, tdb, owner := newPGRepo(t)
	paired := time.Now().Add(-1 * time.Minute).UTC().Truncate(time.Microsecond)

	a, err := r.GetOrCreateAgentTx(ctx, tdb.Pool, owner, "", "darwin", "1.2.3", paired)
	require.NoError(t, err)
	require.NotNil(t, a)
	assert.NotEmpty(t, a.ID)
	assert.Equal(t, owner, a.OwnerUserID)
	assert.Equal(t, "local-agent", a.Name, "空 name 走 DEFAULT")
	assert.Equal(t, "darwin", a.Platform)
	assert.Equal(t, "1.2.3", a.AgentVersion)
	require.NotNil(t, a.LastPairedAt)
	assert.True(t, paired.Equal(*a.LastPairedAt))
	assert.Equal(t, 1, tdb.CountRows(t, "agents"))
}

// GetOrCreate 復用：同 owner 第二次呼叫復用同 agent、不新建。
func TestPG_GetOrCreate_ReusesExisting(t *testing.T) {
	ctx := context.Background()
	r, tdb, owner := newPGRepo(t)

	first, err := r.GetOrCreateAgentTx(ctx, tdb.Pool, owner, "local-agent", "darwin", "1.0", time.Now().UTC())
	require.NoError(t, err)

	later := time.Now().Add(1 * time.Minute).UTC().Truncate(time.Microsecond)
	second, err := r.GetOrCreateAgentTx(ctx, tdb.Pool, owner, "", "", "", later)
	require.NoError(t, err)

	assert.Equal(t, first.ID, second.ID, "同 owner 應復用")
	assert.Equal(t, 1, tdb.CountRows(t, "agents"), "復用不應多建 agent")
	// 空上報值不覆寫既有欄位（COALESCE NULLIF 保留）。
	assert.Equal(t, "darwin", second.Platform)
	assert.Equal(t, "1.0", second.AgentVersion)
	require.NotNil(t, second.LastPairedAt)
	assert.True(t, later.Equal(*second.LastPairedAt), "last_paired_at 應更新")
}

// GetOrCreate 復用時非空上報值更新既有欄位。
func TestPG_GetOrCreate_UpdatesNonEmptyOnReuse(t *testing.T) {
	ctx := context.Background()
	r, tdb, owner := newPGRepo(t)

	_, err := r.GetOrCreateAgentTx(ctx, tdb.Pool, owner, "local-agent", "darwin", "1.0", time.Now().UTC())
	require.NoError(t, err)

	upd, err := r.GetOrCreateAgentTx(ctx, tdb.Pool, owner, "renamed", "linux", "2.0", time.Now().UTC())
	require.NoError(t, err)
	assert.Equal(t, "renamed", upd.Name)
	assert.Equal(t, "linux", upd.Platform)
	assert.Equal(t, "2.0", upd.AgentVersion)
}

// GetOrCreate 在 WithTx 內：與其他寫入同一交易，成功 commit。
func TestPG_GetOrCreate_WithinTx(t *testing.T) {
	ctx := context.Background()
	r, tdb, owner := newPGRepo(t)

	var agentID string
	err := db.WithTx(ctx, tdb.Pool, func(q db.Querier) error {
		a, e := r.GetOrCreateAgentTx(ctx, q, owner, "", "", "", time.Now().UTC())
		if e != nil {
			return e
		}
		agentID = a.ID
		return nil
	})
	require.NoError(t, err)
	assert.NotEmpty(t, agentID)
	assert.Equal(t, 1, tdb.CountRows(t, "agents"))

	// commit 後 GetByOwner 讀得到。
	got, err := r.GetByOwnerTx(ctx, tdb.Pool, owner)
	require.NoError(t, err)
	assert.Equal(t, agentID, got.ID)
}

// GetOrCreate 在 WithTx rollback：交易失敗時 agent 不殘留。
func TestPG_GetOrCreate_RollbackOnTxError(t *testing.T) {
	ctx := context.Background()
	r, tdb, owner := newPGRepo(t)

	sentinel := assertErr("forced rollback")
	err := db.WithTx(ctx, tdb.Pool, func(q db.Querier) error {
		if _, e := r.GetOrCreateAgentTx(ctx, q, owner, "", "", "", time.Now().UTC()); e != nil {
			return e
		}
		return sentinel // 強制 rollback
	})
	require.ErrorIs(t, err, sentinel)
	assert.Equal(t, 0, tdb.CountRows(t, "agents"), "rollback 後 agent 不應殘留")
}

// GetByOwner 不存在回 ErrNotFound。
func TestPG_GetByOwner_NotFound(t *testing.T) {
	ctx := context.Background()
	r, tdb, owner := newPGRepo(t)
	_, err := r.GetByOwnerTx(ctx, tdb.Pool, owner)
	assert.ErrorIs(t, err, ErrNotFound)
}

// 併發 GetOrCreate 同 owner（各自 WithTx）：FOR UPDATE 序列化，最終恰一筆 agent。
func TestPG_GetOrCreate_ConcurrentSameOwner(t *testing.T) {
	ctx := context.Background()
	r, tdb, owner := newPGRepo(t)

	const n = 10
	var wg sync.WaitGroup
	ids := make([]string, n)
	errs := make([]error, n)
	for i := 0; i < n; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			errs[i] = db.WithTx(ctx, tdb.Pool, func(q db.Querier) error {
				a, e := r.GetOrCreateAgentTx(ctx, q, owner, "", "", "", time.Now().UTC())
				if e != nil {
					return e
				}
				ids[i] = a.ID
				return nil
			})
		}(i)
	}
	wg.Wait()

	for i, e := range errs {
		require.NoError(t, e, "併發 GetOrCreate #%d 不應報錯", i)
	}
	// 所有 goroutine 應拿到同一個 agent id。
	first := ids[0]
	for i, id := range ids {
		assert.Equal(t, first, id, "併發應復用同一 agent（#%d）", i)
	}
	assert.Equal(t, 1, tdb.CountRows(t, "agents"), "併發同 owner 最終恰一筆 agent")
}

// assertErr 是測試用 sentinel error。
type assertErr string

func (e assertErr) Error() string { return string(e) }