package memory

import (
	"context"
	"database/sql"
	"testing"
	"time"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/db"
)

// newTestDB opens an isolated in-memory SQLite DB for tests that must inspect
// the raw stored timestamp text.
func newTestDB(t *testing.T) *sql.DB {
	t.Helper()
	ctx := context.Background()
	d, err := db.Open(ctx, ":memory:", testLogger())
	if err != nil {
		t.Fatalf("open in-memory db: %v", err)
	}
	t.Cleanup(func() { _ = d.Close() })
	return d
}

// insertLegacyItemSQL writes a memory_items row with caller-supplied raw
// timestamps, standing in for a row persisted before the fixed-width layout.
const insertLegacyItemSQL = `INSERT INTO memory_items
	(id, persona_id, role_id, project_id, scope, kind, content, tags, confidence,
	 source_conversation, created_at, updated_at, decay_weight)
	VALUES (?, 'persona.a', '', '', 'persona', 'relationship', '旧数据', '[]', 1.0, '', ?, ?, 1.0)`

func TestFormatTime_定宽_正常(t *testing.T) {
	t.Parallel()
	tests := []struct {
		name string
		at   time.Time
		want string
	}{
		{"零小数秒", time.Date(2026, 9, 7, 3, 20, 5, 0, time.UTC), "2026-09-07T03:20:05.000000000Z"},
		{"一位小数秒", time.Date(2026, 9, 7, 3, 20, 5, 830000000, time.UTC), "2026-09-07T03:20:05.830000000Z"},
		{"纳秒", time.Date(2026, 9, 7, 3, 20, 5, 830978900, time.UTC), "2026-09-07T03:20:05.830978900Z"},
	}
	for _, tt := range tests {
		tt := tt
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()
			got := formatTime(tt.at)
			if got != tt.want {
				t.Errorf("formatTime = %q, want %q", got, tt.want)
			}
			if len(got) != storedTimeLen {
				t.Errorf("formatTime length = %d, want %d", len(got), storedTimeLen)
			}
		})
	}
}

func TestFormatTime_非UTC_正常(t *testing.T) {
	t.Parallel()
	zone := time.FixedZone("UTC+8", 8*60*60)
	// 11:20:05.830+08:00 is 03:20:05.830Z, so the stored text is UTC.
	at := time.Date(2026, 9, 7, 11, 20, 5, 830000000, zone)
	if got, want := formatTime(at), "2026-09-07T03:20:05.830000000Z"; got != want {
		t.Errorf("formatTime = %q, want %q", got, want)
	}
}

// TestNewStore_归一化历史时间戳_正常 writes a legacy variable-width row directly,
// re-opens the store to trigger normalization, and checks both the repaired text
// and its idempotence on a further open.
func TestNewStore_归一化历史时间戳_正常(t *testing.T) {
	t.Parallel()
	ctx := context.Background()
	d := newTestDB(t)
	s, err := NewStore(ctx, d, testLogger())
	if err != nil {
		t.Fatalf("NewStore: %v", err)
	}

	// RFC3339Nano drops the trailing fractional zeros, so this legacy value is
	// only 23 bytes wide and loses the text-ordering guarantee.
	const legacy = "2026-09-07T03:20:05.83Z"
	if _, err := d.ExecContext(ctx, insertLegacyItemSQL, "legacy", legacy, legacy); err != nil {
		t.Fatalf("insert legacy row: %v", err)
	}

	if _, err := NewStore(ctx, d, testLogger()); err != nil {
		t.Fatalf("NewStore (normalize): %v", err)
	}
	var raw string
	if err := d.QueryRowContext(ctx,
		`SELECT created_at FROM memory_items WHERE id = ?`, "legacy").Scan(&raw); err != nil {
		t.Fatalf("read normalized created_at: %v", err)
	}
	const want = "2026-09-07T03:20:05.830000000Z"
	if raw != want {
		t.Errorf("normalized created_at = %q, want %q", raw, want)
	}

	got, err := s.Get(ctx, "legacy")
	if err != nil {
		t.Fatalf("Get: %v", err)
	}
	wantTime := time.Date(2026, 9, 7, 3, 20, 5, 830000000, time.UTC)
	if !got.CreatedAt.Equal(wantTime) || !got.UpdatedAt.Equal(wantTime) {
		t.Errorf("timestamps = %v/%v, want %v", got.CreatedAt, got.UpdatedAt, wantTime)
	}

	// A further open must be a no-op: the length condition selects nothing once
	// the row is fixed width.
	if _, err := NewStore(ctx, d, testLogger()); err != nil {
		t.Fatalf("NewStore (second pass): %v", err)
	}
	var again string
	if err := d.QueryRowContext(ctx,
		`SELECT created_at FROM memory_items WHERE id = ?`, "legacy").Scan(&again); err != nil {
		t.Fatalf("read created_at after second open: %v", err)
	}
	if again != raw {
		t.Errorf("second open changed created_at: %q -> %q", raw, again)
	}
}

// TestNewStore_无法解析的时间戳_跳过 pins the "leave it alone" rule: one bad legacy
// value must not keep the store from opening, and must not be rewritten.
func TestNewStore_无法解析的时间戳_跳过(t *testing.T) {
	t.Parallel()
	ctx := context.Background()
	d := newTestDB(t)
	if _, err := NewStore(ctx, d, testLogger()); err != nil {
		t.Fatalf("NewStore: %v", err)
	}
	if _, err := d.ExecContext(ctx, insertLegacyItemSQL, "broken", "not-a-time", "not-a-time"); err != nil {
		t.Fatalf("insert unparseable row: %v", err)
	}

	if _, err := NewStore(ctx, d, testLogger()); err != nil {
		t.Fatalf("NewStore with unparseable timestamp: %v", err)
	}
	var raw string
	if err := d.QueryRowContext(ctx,
		`SELECT created_at FROM memory_items WHERE id = ?`, "broken").Scan(&raw); err != nil {
		t.Fatalf("read created_at: %v", err)
	}
	if raw != "not-a-time" {
		t.Errorf("created_at = %q, want the unparseable value left as is", raw)
	}
}