package com.mini.capi.job;

import com.mini.capi.biz.domain.DbConfig;
import com.mini.capi.biz.domain.SyncTask;
import com.mini.capi.biz.service.DbConfigService;
import com.mini.capi.biz.service.SyncTaskService;
import com.mini.capi.config.DataSourceConfig;
import com.mini.capi.model.ApiResult;
import com.mini.capi.utils.vToken;
import jakarta.annotation.Resource;
import org.springframework.jdbc.core.BatchPreparedStatementSetter;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.sql.*;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Executor;

@RestController
@RequestMapping("/Sys/dbs")
public class taskDbSync {

    @Resource
    private SyncTaskService syncTaskService;

    @Resource
    private DbConfigService dbConfigService;

    @Resource
    private Executor hostExecutor;

    private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("yyyyMMdd");
    private static final String dsValue = LocalDate.now().format(DATE_FORMATTER);

    @GetMapping("/getTaskSyncDbInfo")
    public ApiResult<?> jobSyncTask(String token) {
        if (vToken.isValidToken(token)) {
            List<SyncTask> syncTasks = syncTaskService.list();
            // 记录是否有任务失败（仅用于后台日志，不影响接口返回）
            List<String> errorMessages = new ArrayList<>();
            for (SyncTask task : syncTasks) {
                // 提交任务到线程池（异步执行，接口不等待）
                hostExecutor.execute(() -> {
                    try {
                        // 1. 获取源/目标数据库配置
                        DbConfig sourceDbConfig = dbConfigService.getById(task.getSourceDbId());
                        DbConfig targetDbConfig = dbConfigService.getById(task.getTargetDbId());
                        // 2. 创建对应数据库的JdbcTemplate
                        JdbcTemplate sourceJdbc = DataSourceConfig.createJdbcTemplate(sourceDbConfig);
                        JdbcTemplate targetJdbc = DataSourceConfig.createJdbcTemplate(targetDbConfig);
                        // 3. 执行表同步逻辑（异步执行）
                        syncTableData(task, sourceJdbc, targetJdbc);
                        // 同步成功日志
                        System.out.println("任务 " + task.getTaskId() + "（" + task.getSourceTable() + "→" + task.getTargetTable() + "）已提交至后台执行");
                    } catch (Exception e) {
                        // 捕获任务执行异常，记录错误信息（仅后台打印，不阻塞接口）
                        String errorMsg = "任务 " + task.getTaskId() + " 同步失败: " + e.getMessage();
                        System.err.println(errorMsg);
                        // 加锁保证线程安全（多线程操作同一List）
                        synchronized (errorMessages) {
                            errorMessages.add(errorMsg);
                        }
                    }
                });
                System.out.println(errorMessages);
            }
            // 接口立即返回，不等待任务执行完成
            return ApiResult.success();
        }
        return ApiResult.error();
    }

    /**
     * 同步表数据
     */
    public void syncTableData(SyncTask task, JdbcTemplate sourceJdbc, JdbcTemplate targetJdbc) {
        try {
            // 确保源表和目标表名转为小写
            String sourceTable = task.getSourceTable().toLowerCase();
            String targetTable = task.getTargetTable().toLowerCase();

            // 1. 检查并创建目标表
            if (!tableExists(targetJdbc, targetTable)) {
                createTargetTable(sourceJdbc, targetJdbc, sourceTable, targetTable);
            }
            // 2. 清空目标表当前ds值的数据
            clearTargetTableData(targetJdbc, targetTable);
            // 3. 全量同步数据
            syncAllData(sourceJdbc, targetJdbc, sourceTable, targetTable);
            System.out.println("表 " + sourceTable + " 同步到 " + targetTable + " 成功");
        } catch (Exception e) {
            System.err.println("表同步失败: " + e.getMessage());
        }
    }

    /**
     * 检查目标表是否存在
     */
    private boolean tableExists(JdbcTemplate jdbcTemplate, String tableName) throws SQLException {
        // 表名已转为小写，直接使用
        try (Connection connection = jdbcTemplate.getDataSource().getConnection()) {
            DatabaseMetaData metaData = connection.getMetaData();
            try (ResultSet rs = metaData.getTables(
                    null, null, tableName, new String[]{"TABLE"})) {
                return rs.next();
            }
        }
    }

    /**
     * 创建目标表结构（复制源表结构并添加ds字段）
     */
    private void createTargetTable(JdbcTemplate sourceJdbc, JdbcTemplate targetJdbc,
                                   String sourceTable, String targetTable) throws SQLException {
        // 获取源表字段定义
        List<String> columnDefinitions = getColumnDefinitions(sourceJdbc, sourceTable);
        // 构建创建表SQL (PostgresSQL语法)
        StringBuilder createSql = new StringBuilder("CREATE TABLE ")
                .append(targetTable)
                .append(" (");
        // 添加原有字段
        for (int i = 0; i < columnDefinitions.size(); i++) {
            createSql.append(columnDefinitions.get(i));
            // 最后一个字段后不加逗号
            if (i < columnDefinitions.size() - 1) {
                createSql.append(", ");
            }
        }
        // 添加ds字段（如果有其他字段，需要加逗号分隔）
        if (!columnDefinitions.isEmpty()) {
            createSql.append(", ");
        }
        createSql.append("ds VARCHAR(20) NOT NULL)");
        // 执行创建表SQL
        targetJdbc.execute(createSql.toString());
        System.out.println("已创建目标表: " + targetTable);
    }

    /**
     * 获取表字段列表
     */
    private List<String> getTableColumns(JdbcTemplate jdbcTemplate, String tableName) throws SQLException {
        List<String> columns = new ArrayList<>();
        try (Connection connection = jdbcTemplate.getDataSource().getConnection()) {
            DatabaseMetaData metaData = connection.getMetaData();
            try (ResultSet rs = metaData.getColumns(null, null, tableName, null)) {
                while (rs.next()) {
                    // 字段名转为小写
                    columns.add(rs.getString("COLUMN_NAME").toLowerCase());
                }
            }
        }
        return columns;
    }

    /**
     * 获取PostgresSQL兼容的字段定义
     */
    private List<String> getColumnDefinitions(JdbcTemplate sourceJdbc, String tableName) throws SQLException {
        List<String> definitions = new ArrayList<>();
        try (Connection connection = sourceJdbc.getDataSource().getConnection()) {
            DatabaseMetaData metaData = connection.getMetaData();
            try (ResultSet rs = metaData.getColumns(null, null, tableName, null)) {
                while (rs.next()) {
                    // 字段名转为小写
                    String columnName = rs.getString("COLUMN_NAME").toLowerCase();
                    String typeName = rs.getString("TYPE_NAME").toUpperCase();
                    int columnSize = rs.getInt("COLUMN_SIZE");
                    int decimalDigits = rs.getInt("DECIMAL_DIGITS");
                    int nullable = rs.getInt("NULLABLE");
                    // MySQL到PostgresSQL类型映射
                    String pgType = mapMySqlTypeToPgType(typeName, columnSize, decimalDigits);
                    // 构建字段定义
                    StringBuilder colDef = new StringBuilder();
                    colDef.append(columnName).append(" ").append(pgType);
                    if (nullable == DatabaseMetaData.columnNoNulls) {
                        colDef.append(" NOT NULL");
                    }
                    definitions.add(colDef.toString());
                }
            }
        }
        return definitions;
    }

    /**
     * MySQL到PostgresSQL数据类型映射
     */
    private String mapMySqlTypeToPgType(String mySqlType, int columnSize, int decimalDigits) {
        return switch (mySqlType) {
            case "INT", "INTEGER" -> "INTEGER";
            case "BIGINT" -> "BIGINT";
            case "VARCHAR", "CHAR" -> "VARCHAR(" + columnSize + ")";
            case "TEXT" -> "TEXT";
            case "DATE" -> "DATE";
            case "DATETIME", "TIMESTAMP" -> "TIMESTAMP";
            case "FLOAT", "DOUBLE" -> "DOUBLE PRECISION";
            case "DECIMAL", "NUMERIC" -> "NUMERIC(" + columnSize + "," + decimalDigits + ")";
            case "BOOLEAN" -> "BOOLEAN";
            case "TINYINT" -> columnSize == 1 ? "BOOLEAN" : "SMALLINT";
            default -> "VARCHAR(" + (columnSize > 0 ? columnSize : 255) + ")";
        };
    }

    /**
     * 清空目标表中当前ds值的数据
     */
    private void clearTargetTableData(JdbcTemplate targetJdbc, String targetTable) {
        String sql = "DELETE FROM " + targetTable + " WHERE ds = ?";
        targetJdbc.update(sql, dsValue);
    }

    /**
     * 全量同步数据
     */
    private void syncAllData(JdbcTemplate sourceJdbc, JdbcTemplate targetJdbc,
                             String sourceTable, String targetTable) {
        // 1. 获取源表所有数据
        String selectSql = "SELECT * FROM " + sourceTable;
        List<Map<String, Object>> dataList = sourceJdbc.queryForList(selectSql);
        if (dataList.isEmpty()) {
            System.out.println("源表 " + sourceTable + " 没有数据需要同步");
            return;
        }
        // 2. 构建插入SQL
        List<String> columns = getTableColumnsWithoutException(sourceJdbc, sourceTable);
        String insertSql = buildInsertSql(targetTable, columns);
        // 3. 批量插入数据
        targetJdbc.batchUpdate(insertSql, new BatchPreparedStatementSetter() {
            @Override
            public void setValues(PreparedStatement ps, int i) throws SQLException {
                Map<String, Object> row = dataList.get(i);
                int paramIndex = 1;
                // 设置原有字段值
                for (String column : columns) {
                    ps.setObject(paramIndex++, row.get(column));
                }
                // 设置ds字段值
                ps.setString(paramIndex, dsValue);
            }
            @Override
            public int getBatchSize() {
                return dataList.size();
            }
        });
        System.out.println("成功同步 " + dataList.size() + " 条数据到表 " + targetTable);
    }

    /**
     * 构建插入SQL语句
     */
    private String buildInsertSql(String targetTable, List<String> columns) {
        StringBuilder sql = new StringBuilder();
        sql.append("INSERT INTO ").append(targetTable).append(" (");
        // 添加原有字段
        for (int i = 0; i < columns.size(); i++) {
            sql.append(columns.get(i));
            if (i < columns.size() - 1) {
                sql.append(", ");
            }
        }
        // 添加ds字段
        sql.append(", ds) VALUES (");
        // 添加参数占位符
        sql.append("?, ".repeat(columns.size()));
        sql.append("?)");
        return sql.toString();
    }

    /**
     * 无异常获取表字段（工具方法）
     */
    private List<String> getTableColumnsWithoutException(JdbcTemplate jdbcTemplate, String tableName) {
        try {
            return getTableColumns(jdbcTemplate, tableName);
        } catch (SQLException e) {
            throw new RuntimeException("获取表字段失败: " + e.getMessage(), e);
        }
    }
}