package index

import (
	"database/sql"
	"os"
	"path/filepath"
	"testing"
)

// newV1Store 手工构建一个 v1 schema 的老库（模拟迁移前状态）
func newV1Store(t *testing.T) (*Store, string) {
	t.Helper()
	dbPath := filepath.Join(t.TempDir(), "kb-v1.db")
	db, err := sql.Open("sqlite3", dbPath+"?_journal_mode=WAL")
	if err != nil {
		t.Fatal(err)
	}
	schema := `
	CREATE TABLE meta (key TEXT PRIMARY KEY, value TEXT NOT NULL);
	CREATE TABLE nodes (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		path TEXT NOT NULL UNIQUE,
		title TEXT, section TEXT, tags TEXT, entities TEXT, wikilinks TEXT,
		content_fts TEXT,
		created_at TEXT DEFAULT (datetime('now')),
		updated_at TEXT DEFAULT (datetime('now')));
	CREATE TABLE edges (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		from_node INTEGER NOT NULL, to_node INTEGER NOT NULL,
		relation TEXT NOT NULL, label TEXT,
		UNIQUE(from_node, to_node, relation, label));
	`
	if _, err := db.Exec(schema); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`INSERT INTO nodes (path, title, tags, entities, wikilinks, content_fts)
		VALUES ('FAQ/001-测试.md', '测试', '["a"]', '[]', '[]', '内容')`); err != nil {
		t.Fatal(err)
	}
	return &Store{db: db, dbPath: dbPath}, dbPath
}

func TestMigrateV1ToV2(t *testing.T) {
	store, dbPath := newV1Store(t)
	defer store.Close()

	// 迁移前备份文件必须存在
	if err := store.migrate(); err != nil {
		t.Fatalf("migrate: %v", err)
	}
	if _, err := os.Stat(dbPath + ".bak"); err != nil {
		t.Fatalf("备份文件不存在: %v", err)
	}

	// v2 列必须存在
	cols := store.nodeColumns(t)
	for _, want := range []string{"aliases", "status", "size", "mtime", "content_hash"} {
		if !cols[want] {
			t.Errorf("nodes 缺列 %s", want)
		}
	}
	if !store.edgeHasProvenance(t) {
		t.Error("edges 缺 provenance 列")
	}
	if !store.tableExists(t, "unresolved_links") {
		t.Error("缺 unresolved_links 表")
	}

	// 数据保留
	var title string
	if err := store.db.QueryRow(`SELECT title FROM nodes WHERE path='FAQ/001-测试.md'`).Scan(&title); err != nil {
		t.Fatal(err)
	}
	if title != "测试" {
		t.Errorf("迁移丢数据: %s", title)
	}
}

func TestMigrateIdempotent(t *testing.T) {
	store, _ := newV1Store(t)
	defer store.Close()
	if err := store.migrate(); err != nil {
		t.Fatalf("第一次: %v", err)
	}
	if err := store.migrate(); err != nil {
		t.Fatalf("第二次(幂等): %v", err)
	}
}

func TestNewDBIsV2(t *testing.T) {
	dbPath := filepath.Join(t.TempDir(), "kb-v2.db")
	store, err := Open(dbPath)
	if err != nil {
		t.Fatal(err)
	}
	defer store.Close()
	if !store.edgeHasProvenance(t) {
		t.Error("新建库应为 v2 schema")
	}
}

// 测试辅助：列检查
func (s *Store) nodeColumns(t *testing.T) map[string]bool {
	t.Helper()
	rows, err := s.db.Query(`SELECT name FROM pragma_table_info('nodes')`)
	if err != nil {
		t.Fatal(err)
	}
	defer rows.Close()
	m := map[string]bool{}
	for rows.Next() {
		var name string
		rows.Scan(&name)
		m[name] = true
	}
	return m
}

func (s *Store) edgeHasProvenance(t *testing.T) bool {
	t.Helper()
	var n int
	s.db.QueryRow(`SELECT COUNT(*) FROM pragma_table_info('edges') WHERE name='provenance'`).Scan(&n)
	return n > 0
}

func (s *Store) tableExists(t *testing.T, name string) bool {
	t.Helper()
	var n int
	s.db.QueryRow(`SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name=?`, name).Scan(&n)
	return n > 0
}