package sqlite

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"time"

	"git.kingecg.top/kingecg/gomog/internal/database"
	"git.kingecg.top/kingecg/gomog/pkg/types"
	_ "github.com/mattn/go-sqlite3" // Import SQLite driver
)

// SQLiteAdapter SQLite适配器
type SQLiteAdapter struct {
	*database.BaseAdapter
}

// NewSQLiteAdapter 创建SQLite适配器
func NewSQLiteAdapter() *SQLiteAdapter {
	return &SQLiteAdapter{
		BaseAdapter: database.NewBaseAdapter("sqlite3"),
	}
}

// CollectionExists 检查集合是否存在
func (a *SQLiteAdapter) CollectionExists(ctx context.Context, name string) (bool, error) {
	query := "SELECT name FROM sqlite_master WHERE type='table' AND name=?"
	var exists bool
	err := a.GetDB().QueryRowContext(ctx, query, name).Scan(&exists)
	if err != nil {
		if err == sql.ErrNoRows {
			return false, nil
		}
		return false, err
	}
	return true, nil
}

// ListCollections 获取所有集合（表）列表
func (a *SQLiteAdapter) ListCollections(ctx context.Context) ([]string, error) {
	query := `SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%' ORDER BY name`
	rows, err := a.GetDB().QueryContext(ctx, query)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var tables []string
	for rows.Next() {
		var table string
		if err := rows.Scan(&table); err != nil {
			return nil, err
		}
		tables = append(tables, table)
	}

	return tables, rows.Err()
}

// FindPage 分页查询文档
func (a *SQLiteAdapter) FindPage(ctx context.Context, collection string, skip, limit int) (database.PageResult, error) {
	query := fmt.Sprintf("SELECT id, data, created_at, updated_at FROM %s LIMIT ? OFFSET ?", collection)
	rows, err := a.GetDB().QueryContext(ctx, query, limit, skip)
	if err != nil {
		return database.PageResult{}, err
	}
	defer rows.Close()

	var docs []types.Document
	for rows.Next() {
		var doc types.Document
		var jsonData []byte
		var createdAtStr, updatedAtStr string
		err := rows.Scan(&doc.ID, &jsonData, &createdAtStr, &updatedAtStr)
		if err != nil {
			return database.PageResult{}, err
		}

		if err := json.Unmarshal(jsonData, &doc.Data); err != nil {
			return database.PageResult{}, err
		}

		// 解析时间字符串
		if parsedTime, err := parseSQLiteTime(createdAtStr); err == nil {
			doc.CreatedAt = parsedTime
		}
		if parsedTime, err := parseSQLiteTime(updatedAtStr); err == nil {
			doc.UpdatedAt = parsedTime
		}

		docs = append(docs, doc)
	}

	// 检查是否还有更多数据
	checkQuery := fmt.Sprintf("SELECT 1 FROM %s LIMIT 1 OFFSET ?", collection)
	checkRows, err := a.GetDB().QueryContext(ctx, checkQuery, skip+limit)
	if err != nil {
		return database.PageResult{}, err
	}
	defer checkRows.Close()

	hasMore := checkRows.Next()

	return database.PageResult{
		Documents: docs,
		HasMore:   hasMore,
	}, rows.Err()
}

// parseSQLiteTime 解析SQLite时间字符串
func parseSQLiteTime(timeStr string) (time.Time, error) {
	layouts := []string{
		"2006-01-02 15:04:05",
		"2006-01-02T15:04:05Z",
		"2006-01-02T15:04:05.000Z",
		time.RFC3339,
		time.RFC3339Nano,
		"2006-01-02 15:04:05.000000",
		"2006-01-02 15:04:05.000",
	}

	for _, layout := range layouts {
		if t, err := time.Parse(layout, timeStr); err == nil {
			return t, nil
		}
	}

	// 如果标准布局失败，则尝试解析Unix时间戳
	if unixTime, err := time.Parse("2006-01-02 15:04:05.000000", timeStr); err == nil {
		return unixTime, nil
	}

	// 默认返回当前时间
	return time.Now(), fmt.Errorf("无法解析时间字符串: %s", timeStr)
}

// Connect 连接 SQLite 数据库
func (a *SQLiteAdapter) Connect(ctx context.Context, dsn string) error {
	// SQLite 需要启用 JSON1 扩展（大多数构建已默认包含）
	if err := a.BaseAdapter.Connect(ctx, dsn); err != nil {
		return err
	}

	// 设置 SQLite 特定的 PRAGMA
	_, err := a.GetDB().Exec("PRAGMA journal_mode = WAL")
	return err
}

// CreateCollection 创建集合（SQLite 表）
func (a *SQLiteAdapter) CreateCollection(ctx context.Context, name string) error {
	// SQLite 使用 CHECK 约束验证 JSON
	query := fmt.Sprintf(`
		CREATE TABLE IF NOT EXISTS %s (
			id TEXT PRIMARY KEY,
			data TEXT NOT NULL CHECK(json_valid(data)),
			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
			updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
		)`, name)

	_, err := a.GetDB().ExecContext(ctx, query)
	return err
}

// FindAll 查询所有文档（使用 SQLite JSON 函数）
func (a *SQLiteAdapter) FindAll(ctx context.Context, collection string) ([]types.Document, error) {
	query := fmt.Sprintf("SELECT id, data, created_at, updated_at FROM %s", collection)
	rows, err := a.GetDB().QueryContext(ctx, query)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var docs []types.Document
	for rows.Next() {
		var doc types.Document
		var jsonData []byte
		err := rows.Scan(&doc.ID, &jsonData, &doc.CreatedAt, &doc.UpdatedAt)
		if err != nil {
			return nil, err
		}

		if err := json.Unmarshal(jsonData, &doc.Data); err != nil {
			return nil, err
		}

		docs = append(docs, doc)
	}

	return docs, rows.Err()
}

// InsertMany 批量插入（SQLite 优化版本）
func (a *SQLiteAdapter) InsertMany(ctx context.Context, collection string, docs []types.Document) error {
	tx, err := a.GetDB().BeginTx(ctx, nil)
	if err != nil {
		return err
	}
	defer tx.Rollback()

	for _, doc := range docs {
		jsonData, err := json.Marshal(doc.Data)
		if err != nil {
			return err
		}

		query := fmt.Sprintf(
			"INSERT INTO %s (id, data, created_at, updated_at) VALUES (?, json(?), ?, ?)",
			collection,
		)

		now := doc.CreatedAt
		if now.IsZero() {
			now = doc.UpdatedAt
		}
		if now.IsZero() {
			now = doc.UpdatedAt
		}

		_, err = tx.ExecContext(ctx, query, doc.ID, string(jsonData), now, now)
		if err != nil {
			return err
		}
	}

	return tx.Commit()
}