package com.bfkj.unidia.DataBaseUtils;

import com.bfkj.unidia.Result;
import com.github.benmanes.caffeine.cache.Cache;
import com.github.benmanes.caffeine.cache.Caffeine;
import com.zaxxer.hikari.HikariDataSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

import java.math.BigDecimal;
import java.sql.*;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.locks.ReentrantLock;

import static com.bfkj.unidia.cacheUtils.CacheUtil.buildCaffeineCache;

/**
 * 表结构管理器，用于获取和缓存数据库表结构信息（多数据库兼容版）
 */
@Service
public class TableStructureManager {
    private static final Logger logger = LoggerFactory.getLogger(TableStructureManager.class);
    // 表结构缓存：数据源标识 -> 表名 -> 表结构信息
    private final Cache<String, ConcurrentMap<String, TableSchema>> schemaCache = buildCaffeineCache();
    // 数据库连接池管理器
    private final ConnectionPoolManager poolManager;
    // 数据库工具类
    private final DbUtils dbUtils;
    //数据命令执行工具（在此主要用于创建表和更新表结构）
    private final JdbcExecutor jdbcExecutor;
    @Autowired
    public TableStructureManager(ConnectionPoolManager poolManager,DbUtils dbUtils,
                                 JdbcExecutor jdbcExecutor){
        this.poolManager = poolManager;
        this.dbUtils = dbUtils;
        this.jdbcExecutor = jdbcExecutor;
    }
    // 表级锁管理器：保证同一时间只能有一个线程操作一张表
    private final ConcurrentMap<String, ReentrantLock> tableLocks = new ConcurrentHashMap<>();
    /**
     * 获取指定表的锁对象（如果不存在则创建）
     */
    public ReentrantLock getTableLock(String tableName) {
        return tableLocks.computeIfAbsent(tableName, k -> new ReentrantLock());
    }
    // 定义 ResultSet 列名常量
    private static final String COLUMN_NAME = "COLUMN_NAME";
    private static final String TYPE_NAME = "TYPE_NAME";
    private static final String DATA_TYPE = "DATA_TYPE";
    private static final String COLUMN_SIZE = "COLUMN_SIZE";
    private static final String NULLABLE = "NULLABLE";
    private static final String REMARKS = "REMARKS";
    private static final Set<String> ORACLE_TYPES = Set.of("oracle", "dm", "kingbase", "oceanbase");
    private static final Set<String> POSTGRESQL_TYPES = Set.of("postgresql", "gaussdb", "opengauss");
    private static final Set<String> SQLSERVER_TYPES = Set.of("sqlserver");
    private static final Set<String> SQLITE_TYPES = Set.of("sqlite");
    private static final Set<String> GOLDEN_DB_TYPES = Set.of("goldendb");
    /**
     * 获取表结构信息（线程安全、高性能）
     * @param dbConfig 数据库配置
     * @param tableName 表名
     * @return 表结构结果
     */
    public Result<TableSchema> getTableStructure(Map<String, String> dbConfig, String tableName) {
        Result<Map<String, String>> validation = dbUtils.validateConnection(dbConfig);
        if (!validation.isSuccess()) {
            return Result.fail(validation.getError());
        }
        Map<String, String> validationData = validation.getData();
        String dbKey = validationData.get("dbKey");
        String dbType = validationData.get("dbType");
        return getTableStructure(dbKey,dbType, dbConfig,tableName);
    }
    /**
     * 获取表结构信息（线程安全、高性能）
     *
     * @param dbConfig 数据库配置
     * @param tableName 表名
     * @return 表结构结果
     */
    public Result<TableSchema> getTableStructure(String dbKey,String dbType, Map<String, String> dbConfig, String tableName) {
        try {
            // 第一次尝试从缓存中获取
            ConcurrentMap<String, TableSchema> tableSchemas = schemaCache.getIfPresent(dbKey);
            if (tableSchemas != null) {
                TableSchema schema = tableSchemas.get(tableName);
                if (schema != null) {
                    return Result.success(schema);
                }
            }
            // 缓存未命中，同步加载并更新缓存
            synchronized (this) {
                // 再次检查缓存（双重检查锁）
                tableSchemas = schemaCache.getIfPresent(dbKey);
                if (tableSchemas == null) {
                    tableSchemas = new ConcurrentHashMap<>();
                    schemaCache.put(dbKey, tableSchemas);
                }

                TableSchema schema = tableSchemas.get(tableName);
                if (schema != null) {
                    return Result.success(schema);
                }

                // 获取数据源
                Result<HikariDataSource> dataSourceResult = poolManager.getDataSource(dbConfig);
                if (!dataSourceResult.isSuccess()) {
                    return Result.fail(dataSourceResult.getError());
                }
                HikariDataSource dataSource = dataSourceResult.getData();

                // 真正加载
                Result<TableSchema> result = loadTableStructure(dataSource, tableName, dbType);
                if (result.isSuccess()) {
                    tableSchemas.put(tableName, result.getData());
                }
                return result;
            }
        } catch (Exception e) {
            logger.error("获取表结构失败，dbKey: {}, tableName: {}", dbKey, tableName, e);
            return Result.fail("获取表结构失败: 系统错误");
        }
    }
    /**
     * 实际获取表结构的核心方法
     *
     * @param dataSource 数据库配置参数集合，包含连接池所需所有配置项
     * @param tableName 需要获取结构的数据库表名称
     * @return 包含表结构信息的Result对象，失败时返回错误信息
     */
    private Result<TableSchema> loadTableStructure(HikariDataSource dataSource, String tableName, String dbType) {
        try (Connection connection = dataSource.getConnection()) {
            DatabaseMetaData metaData = connection.getMetaData();
            String catalog = getCatalog(dbType, connection);
            String schema = getSchema(dbType, connection);

            try (ResultSet columns = metaData.getColumns(catalog, schema, tableName, "%")) {
                LinkedHashMap<String, ColumnInfo> columnMap = new LinkedHashMap<>();
                while (columns.next()) {
                    String columnName = columns.getString(COLUMN_NAME);
                    String columnType = columns.getString(TYPE_NAME);
                    int dataType = columns.getInt(DATA_TYPE);
                    int columnSize = columns.getInt(COLUMN_SIZE);
                    boolean nullable = columns.getBoolean(NULLABLE);
                    String remarks = columns.getString(REMARKS);

                    columnMap.put(columnName, createColumnInfo(columnName, columnType, dataType, columnSize, nullable, remarks));
                }
                return Result.success(new TableSchema(tableName, columnMap));
            } catch (SQLException e) {
                // 记录详细日志（示例）
                logger.error("获取表结构失败: {}", e.getMessage(), e);
                return Result.fail("获取表结构失败: ", e);
            }
        } catch (Exception e) {
            // 记录非 SQL 异常日志（示例）
            logger.error("非预期异常: {}", e.getMessage(), e);
            return Result.fail("获取表结构失败: ", e);
        }
    }
    public List<String> getColumns(Map<String, String> dbConfig,String tableName){
        Result<TableSchema> tableSchemaResult = getTableStructure(dbConfig, tableName);
        if(!tableSchemaResult.isSuccess()){
            return null;
        }
        return tableSchemaResult.getData().getColumns().keySet().stream().toList();
    }
    // 提取为独立方法
    private ColumnInfo createColumnInfo(String columnName, String columnType, int dataType, int columnSize, boolean nullable, String remarks) {
        return new ColumnInfo(columnName, columnType, dataType, columnSize, nullable, remarks);
    }
    private static final Set<String> SUPPORTED_DB_TYPES = Set.of(
            "mysql", "polardb", "tidb", "goldendb", "tdsql",
            "sqlserver", "kingbase", "gaussdb", "opengauss", "gbase"
    );

    private String getCatalog(String dbType, Connection connection) {
        if (dbType == null) {
            return null;
        }

        try {
            String catalog = SUPPORTED_DB_TYPES.contains(dbType) ? connection.getCatalog() : null;

            if ("oceanbase".equalsIgnoreCase(dbType)) {
                try (Statement stmt = connection.createStatement();
                     ResultSet rs = stmt.executeQuery("SELECT tenant_name FROM oceanbase.__all_virtual_tenant LIMIT 1")) {
                    if (rs.next()) {
                        catalog = rs.getString(1);
                    } else {
                        logger.warn("OceanBase查询成功但未找到租户信息，使用默认租户sys");
                        catalog = "sys";
                    }
                } catch (SQLException e) {
                    logger.warn("OceanBase查询异常，使用默认租户sys", e);
                    catalog = "sys";
                }
            }

            return catalog;
        } catch (SQLException e) {
            return null;
        }
    }
    private static final Set<String> PUBLIC_SCHEMA_TYPES = Set.of("kingbase", "gaussdb", "opengauss", "gbase");

    private String getSchema(String dbType, Connection connection) {
        if (dbType == null || connection == null) {
            // 可选：抛出IllegalArgumentException以强制约束输入
            return null;
        }

        try {
            if (dbType.equals("sqlserver")) {
                return "dbo";
            } else if ("oracle".equals(dbType) || "dm".equals(dbType)) {
                return connection.getMetaData().getUserName().toUpperCase();
            } else if (PUBLIC_SCHEMA_TYPES.contains(dbType)) {
                return "public";
            } else if (dbType.equals("oceanbase")) {
                return connection.getCatalog();
            } else {
                // 可选：记录未知dbType以辅助调试
                return null;
            }
        } catch (SQLException e) {
            // 建议记录日志，避免静默失败
            logger.info("Failed to get schema: " + e.getMessage());
            return null;
        }
    }
    /**
     * 创建表（如果不存在）并自动添加缺失字段
     */
    public Result<Integer> createTableIfNotExists(Map<String, String> dbConfig,
                                                  String tableName,
                                                  Map<String, Object> executeParam) {
        Result<TableSchema> schemaResult = getTableStructure(dbConfig, tableName);

        if (schemaResult.isSuccess() && !schemaResult.getData().getColumns().isEmpty()) {
            // 表已存在，尝试添加缺失字段
            return addMissingColumns(dbConfig, tableName, executeParam);
        }

        // 表不存在，创建新表
        Result<Integer> createResult = createTable(dbConfig, tableName, executeParam);
        if (createResult.isSuccess()) {
            return createResult;
        }

        // 创建失败可能是并发创建导致，检查是否存在后重试
        Result<TableSchema> retrySchema = getTableStructure(dbConfig, tableName);
        if (retrySchema.isSuccess() && !retrySchema.getData().getColumns().isEmpty()) {
            return addMissingColumns(dbConfig, tableName, executeParam);
        }

        return createResult;
    }
    public Result<Integer> createTable(Map<String, String> dbConfig,
                                       String tableName,
                                       Map<String, Object> executeParam) {
        ReentrantLock lock = getTableLock(tableName);
        lock.lock();
        try {
            Result<Map<String, String>> validateResult = dbUtils.validateConnection(dbConfig);
            if (!validateResult.isSuccess()) {
                return Result.fail(validateResult.getError());
            }
            String dbType = validateResult.getData().get("dbType");

            // 构建字段列表
            List<String> columns = buildColumnDefinitions(executeParam, dbType,tableName);

            // 构建并执行建表语句
            String sqlTemplate = getCreateTableTemplate(dbType);
            String sql = String.format(sqlTemplate, tableName, String.join(", ", columns));
            Result<Integer> result = jdbcExecutor.executeDDL(dbConfig, sql);

            if (result.isSuccess()) {
                clearTableCache(dbConfig, tableName);
            }

            return result;
        } catch (Exception e) {
            logger.error("创建表失败", e);
            return Result.fail("创建表失败: " + e.getMessage());
        } finally {
            lock.unlock();
        }
    }
    /**
     * 添加缺失字段（适用于表已存在的情况）
     */
    public Result<Integer> addMissingColumns(Map<String, String> dbConfig,
                                             String tableName,
                                             Map<String, Object> executeParam) {
        Result<TableSchema> schemaResult = getTableStructure(dbConfig, tableName);
        if (!schemaResult.isSuccess()) {
            return Result.fail(schemaResult.getError());
        }

        // 筛选新字段
        Map<String, Object> newColumns = filterNewColumns(executeParam, schemaResult.getData());
        if (newColumns.isEmpty()) {
            return Result.fail("所有字段已存在");
        }

        // 添加字段
        return addColumns(dbConfig, tableName, newColumns);
    }
    /**
     * 构建字段定义列表
     */
    private List<String> buildColumnDefinitions(Map<String, Object> executeParam,
                                                String dbType,String tableName) {
        List<String> columns = new ArrayList<>();
        for (Map.Entry<String, Object> entry : executeParam.entrySet()) {
            String colName = entry.getKey();
            String colType = convertJavaTypeToSqlType(entry.getValue().getClass(), dbType);

            // 自动添加主键定义
            if (isPrimaryKey(colName, tableName)) {
                colType += " PRIMARY KEY ";
            }

            columns.add(colName + " " + colType);
        }
        return columns;
    }
    private String getCreateTableTemplate(String dbType) {
        return switch (dbType) {
            case "sqlserver" ->
                    "IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'%s') AND type in (N'U')) CREATE TABLE %s (%s)";
            case "oracle" ->
                    "BEGIN EXECUTE IMMEDIATE 'CREATE TABLE %s (%s)'; EXCEPTION WHEN OTHERS THEN IF SQLCODE != -955 THEN RAISE; END IF; END;";
            case "dm" ->
                    "DECLARE e_table_not_exist EXCEPTION; PRAGMA EXCEPTION_INIT(e_table_not_exist, -20071); BEGIN EXECUTE IMMEDIATE 'CREATE TABLE %s (%s)'; EXCEPTION WHEN e_table_not_exist THEN NULL; END;";
            default -> "CREATE TABLE IF NOT EXISTS %s (%s)";
        };
    }
    private boolean isPrimaryKey(String colName, String tableName) {
        return colName.equalsIgnoreCase(tableName + "_code") ||
                colName.equalsIgnoreCase("_id") ||
                colName.equalsIgnoreCase("id");
    }
    /**
     * 添加多个字段（支持批量执行以提升性能）
     */
    public Result<Integer> addColumns(Map<String, String> dbConfig, String tableName, Map<String, Object> columns) {
        ReentrantLock lock = getTableLock(tableName);
        lock.lock();
        try {
            // 2. 获取当前表结构
            Result<TableStructureManager.TableSchema> schemaResult = getTableStructure(dbConfig, tableName);
            if (!schemaResult.isSuccess()) {
                return Result.fail(schemaResult.getError());
            }
            // 3. 筛选新字段
            Map<String, Object> newColumns = filterNewColumns(columns, schemaResult.getData());

            if (newColumns.isEmpty()) {
                return Result.fail("所有字段已存在");
            }
            String dbType = dbUtils.getDatabaseType(dbConfig.get("url"));
            // 4. 构建ALTER语句
            List<String> alterStatements = buildAlterStatements(dbType, tableName, newColumns);

            // 5. 根据数据库类型选择执行方式
            int totalAffectedRows;
            if (Set.of("mysql","mariadb","polardb","tidb","gaussdb","sqlite").contains(dbType)) {
                String combinedSql = combineAlterStatements(tableName, alterStatements, dbType);
                Result<Integer> result = jdbcExecutor.executeDDL(dbConfig, combinedSql);

                if (!result.isSuccess()) {
                    return result;
                }
                totalAffectedRows = result.getData();
            } else {
                Result<Integer> singleResult = executeSingleAlters(dbConfig, alterStatements);
                if (singleResult.isSuccess()) {
                    totalAffectedRows = singleResult.getData();
                } else {
                    return Result.fail(singleResult.getError());
                }
            }

            // 6. 清除缓存以便下次重新加载表结构
            clearTableCache(dbConfig, tableName);

            return Result.success(totalAffectedRows);
        } catch (Exception e) {
            logger.error("添加字段失败", e);
            return Result.fail("添加字段失败: " + e.getMessage());
        }finally {
            lock.unlock();
        }
    }
    /**
     * 筛选出不存在的新字段
     */
    public Map<String, Object> filterNewColumns(
            Map<String, Object> columns,
            TableStructureManager.TableSchema schema) {

        Map<String, Object> newColumns = new HashMap<>();
        for (Map.Entry<String, Object> entry : columns.entrySet()) {
            String columnName = entry.getKey();
            if (!schema.getColumns().containsKey(columnName.toLowerCase())) {
                newColumns.put(columnName, entry.getValue());
            } else {
                logger.warn("字段 [{}] 已存在，跳过添加", columnName);
            }
        }
        return newColumns;
    }
    /**
     * 构建 ALTER TABLE ADD COLUMN 语句列表
     */
    private List<String> buildAlterStatements(String dbType, String tableName, Map<String, Object> columns) {
        List<String> statements = new ArrayList<>();
        for (Map.Entry<String, Object> entry : columns.entrySet()) {
            String quotedTableName = dbUtils.quoteIdentifier(tableName, dbType);
            String quotedColumnName = dbUtils.quoteIdentifier(entry.getKey(), dbType);
            String sql = "ALTER TABLE " + quotedTableName + " ADD COLUMN " + quotedColumnName + " " + entry.getValue();
            statements.add(sql);
        }
        return statements;
    }
    /**
     * 合并多条 ALTER TABLE 语句为一条 SQL
     */
    private String combineAlterStatements(String tableName, List<String> alterStatements, String dbType) {
        StringBuilder combined = new StringBuilder();
        String quotedTableName = dbUtils.quoteIdentifier(tableName, dbType);

        combined.append("ALTER TABLE ").append(quotedTableName).append(" ");

        // 提取每个语句中的 ADD COLUMN 子句
        List<String> addColumnClauses = new ArrayList<>();
        for (String stmt : alterStatements) {
            String clause = stmt.substring(stmt.indexOf("ADD COLUMN"));
            addColumnClauses.add(clause);
        }

        combined.append(String.join(", ", addColumnClauses));
        return combined.toString();
    }
    /**
     * 逐条执行 ADD COLUMN 操作
     */
    private Result<Integer> executeSingleAlters(Map<String, String> dbConfig, List<String> alterStatements) {
        int totalAffectedRows = 0;
        for (String sql : alterStatements) {
            Result<Integer> result = jdbcExecutor.executeDDL(dbConfig, sql);
            if (!result.isSuccess()) {
                logger.error("执行DDL失败: " + result.getError());
                //return Result.fail(result.getError()).getData(); // 返回错误结果
                continue;
            }
            totalAffectedRows += result.getData();
        }
        if(totalAffectedRows == 0){
            return Result.fail("所有字段已存在");
        }
        return Result.success(totalAffectedRows);
    }
    /**
     * 清除特定表的缓存
     */
    public void clearTableCache(Map<String, String> dbConfig, String tableName) {
        try {
            String cacheKey = dbUtils.generateCacheKey(dbConfig, null);
            // 第一次尝试从缓存中获取
            ConcurrentMap<String, TableSchema> tableSchemas = schemaCache.getIfPresent(cacheKey);
            if (tableSchemas != null) {
                tableSchemas.remove(tableName);
            }
            // 缓存未命中，同步加载并更新缓存
            synchronized (this) {
                // 再次检查缓存（双重检查锁）
                tableSchemas = schemaCache.getIfPresent(cacheKey);
                if (tableSchemas != null) {
                    tableSchemas.remove(tableName);
                }
            }
        } catch (Exception e) {
            logger.error("清除表结构失败", e);
        }
    }
    /**
     * 将Java类型转换为数据库支持的字段类型
     *
     * @param javaType Java类型（如String.class, Integer.class等）
     * @param dbType    数据库连接URL（用于识别数据库类型）
     * @return 数据库字段类型字符串（如VARCHAR, INTEGER等）
     * @throws UnsupportedOperationException 不支持的Java类型或数据库类型
     */
    public String convertJavaTypeToSqlType(Class<?> javaType, String dbType) {
        if (javaType == null || dbType == null) {
            throw new IllegalArgumentException("参数不能为空");
        }

        if (javaType == String.class) {
            if (ORACLE_TYPES.contains(dbType)) return "VARCHAR2(255)";
            if (SQLITE_TYPES.contains(dbType)) return "TEXT";
            if (SQLSERVER_TYPES.contains(dbType)) return "NVARCHAR(MAX)";
            if (GOLDEN_DB_TYPES.contains(dbType)) return "VARCHAR(4096)";
            return "VARCHAR(255)";
        } else if (javaType == Integer.class || javaType == int.class) {
            if (ORACLE_TYPES.contains(dbType)) return "NUMBER(11)";
            if (POSTGRESQL_TYPES.contains(dbType) || SQLITE_TYPES.contains(dbType)) return "INTEGER";
            return "INT";
        } else if (javaType == Long.class || javaType == long.class) {
            if (ORACLE_TYPES.contains(dbType)) return "NUMBER(19)";
            return "BIGINT";
        } else if (javaType == Double.class || javaType == double.class) {
            if (ORACLE_TYPES.contains(dbType)) return "NUMBER(38,10)";
            if (SQLSERVER_TYPES.contains(dbType)) return "DECIMAL(38, 10)";
            if (SQLITE_TYPES.contains(dbType)) return "REAL";
            return "DECIMAL";
        } else if (javaType == LocalDate.class) {
            return "DATE";
        } else if (javaType == LocalDateTime.class) {
            if (Set.of("oracle", "dm", "kingbase", "oceanbase",
                    "postgresql", "gaussdb", "opengauss",
                    "polardb", "tidb").contains(dbType)) {
                return "TIMESTAMP";
            } else if (SQLSERVER_TYPES.contains(dbType)) {
                return "DATETIME2";
            }
            return "DATETIME";
        } else if (javaType == BigDecimal.class) {
            if (ORACLE_TYPES.contains(dbType)) return "NUMBER(38,10)";
            if (SQLSERVER_TYPES.contains(dbType)) return "DECIMAL(38, 10)";
            if (SQLITE_TYPES.contains(dbType)) return "REAL";
            return "DECIMAL";
        } else if (javaType == byte[].class) {
            if (ORACLE_TYPES.contains(dbType) || SQLITE_TYPES.contains(dbType)) {
                return "BLOB";
            } else if (POSTGRESQL_TYPES.contains(dbType)) {
                return "BYTEA";
            } else if (SQLSERVER_TYPES.contains(dbType)) {
                return "VARBINARY(MAX)";
            }
            return "LONGBLOB";
        }

        throw new UnsupportedOperationException("不支持的Java类型: " + javaType.getName());
    }
    /**
     * 表结构封装类
     */
    public record TableSchema(String name, Map<String, ColumnInfo> columns) {
        public Map<String, ColumnInfo> getColumns() {
            return Collections.unmodifiableMap(columns);
        }
    }
        /**
         * 列信息封装类
         */
        public record ColumnInfo(String name, String type,
                                 int dataType, int size,
                                 boolean nullable, String remarks) {
    }
}