package com.trafficaudit.llmintegration.service;

import cn.hutool.json.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * AI 对话查询数据库的安全执行器：只允许查询白名单表与白名单列，
 * 过滤条件由列名+值组成，避免任意 SQL 注入。
 */
@Slf4j
@Component
public class DbQueryExecutor {

    @Resource
    private JdbcTemplate jdbcTemplate;

    public static final Set<String> ALLOWED_TABLES = new TreeSet<>();

    private static final Map<String, TableMeta> TABLES = new LinkedHashMap<>();

    private static final Pattern NUM_CMP = Pattern.compile("^(>=|<=|!=|>|<|=)(-?\\d+(\\.\\d+)?)$");

    static {
        register("h2032_enterprise_monthly", "企业月报H203-2表(道路货物运输月度生产情况)",
                new String[]{"id", "report_period", "region_code", "enterprise_code", "enterprise_name", "unified_credit_code",
                        "report_unit", "vehicle_total", "tons_total", "vehicle_tractor", "vehicle_trailer", "tons_trailer",
                        "vehicle_container", "tons_container", "vehicle_whole", "tons_whole", "freight_total", "turnover_total",
                        "freight_container", "freight_coal", "freight_oil_gas", "freight_crude_oil", "freight_metal_ore",
                        "freight_iron_ore", "freight_building", "freight_grain", "avg_tonnage", "avg_distance", "unit_leader",
                        "stats_leader", "contact_person", "contact_phone", "report_date", "verify_explanation", "report_notes"},
                new String[]{"主键", "报表期", "所属地区代码", "企业代码", "企业名称", "统一社会信用代码", "填报单位", "车辆数合计", "标记吨位数合计",
                        "牵引车数", "挂车数", "挂车吨位", "集装箱车数", "集装箱吨位", "整车数", "整车吨位", "货运量合计(吨)", "周转量合计(吨公里)",
                        "货运量-集装箱", "货运量-煤炭及制品", "货运量-石油天然气", "货运量-原油", "货运量-金属矿石", "货运量-铁矿石", "货运量-建材",
                        "货运量-粮食", "平均吨位", "平均运距(公里)", "单位负责人", "统计负责人", "填表人", "联系电话", "报出日期", "企业核实解释", "备注"},
                new String[]{"id", "report_period", "enterprise_name", "vehicle_total", "tons_total", "freight_total",
                        "turnover_total", "avg_distance", "verify_explanation"});
        register("transport_auth_vehicle", "运政车辆",
                new String[]{"id", "report_period", "enterprise_name", "tractor_count", "trailer_count", "other_count",
                        "trailer_tons", "other_tons"},
                new String[]{"主键", "报表期", "企业名称", "牵引车数", "挂车数", "其他车数", "挂车吨位", "其他吨位"},
                new String[]{"id", "report_period", "enterprise_name", "tractor_count", "trailer_count", "other_count",
                        "trailer_tons", "other_tons"});
        register("vehicle_track_mileage", "车辆轨迹里程",
                new String[]{"id", "report_period", "enterprise_name", "monthly_mileage", "tracked_vehicles"},
                new String[]{"主键", "报表期", "企业名称", "月度行驶里程(公里)", "有轨迹车辆数"},
                new String[]{"id", "report_period", "enterprise_name", "monthly_mileage", "tracked_vehicles"});
        register("scale_split_transport", "规上规下拆分运输量",
                new String[]{"id", "report_period", "period_type", "region_name", "above_scale_freight", "above_scale_turnover",
                        "above_scale_rank", "above_scale_yoy", "below_scale_freight", "below_scale_turnover", "below_scale_rank",
                        "below_scale_yoy", "total_freight", "total_turnover", "total_rank", "total_yoy"},
                new String[]{"主键", "报表期", "口径(MONTH当月/CUMULATIVE累计)", "市州名称(含全省)", "规上货运量", "规上周转量", "规上排名",
                        "规上同比", "规下货运量", "规下周转量", "规下排名", "规下同比", "合计货运量", "合计周转量", "合计排名", "合计同比"},
                new String[]{"report_period", "period_type", "region_name", "above_scale_freight", "above_scale_turnover",
                        "below_scale_freight", "below_scale_turnover", "total_freight", "total_turnover"});
        List<String> fcols = new ArrayList<>();
        List<String> flabels = new ArrayList<>();
        fcols.add("id");
        flabels.add("主键");
        fcols.add("report_period");
        flabels.add("报表期");
        fcols.add("region_name");
        flabels.add("市州名称");
        for (int m = 1; m <= 12; m++) {
            fcols.add(String.format("freight_m%02d", m));
            flabels.add("今年" + m + "月货运量");
        }
        for (int m = 1; m <= 12; m++) {
            fcols.add(String.format("last_freight_m%02d", m));
            flabels.add("去年" + m + "月货运量");
        }
        for (int m = 1; m <= 12; m++) {
            fcols.add(String.format("turnover_m%02d", m));
            flabels.add("今年" + m + "月周转量");
        }
        for (int m = 1; m <= 12; m++) {
            fcols.add(String.format("last_turnover_m%02d", m));
            flabels.add("去年" + m + "月周转量");
        }
        register("freight_turnover_import", "货运量周转量(月度导入)",
                fcols.toArray(new String[0]), flabels.toArray(new String[0]),
                new String[]{"report_period", "region_name", "freight_m01", "freight_m02", "freight_m03", "freight_m04",
                        "freight_m05", "freight_m06", "freight_m07", "freight_m08", "freight_m09", "freight_m10", "freight_m11",
                        "freight_m12", "turnover_m01", "turnover_m12"});
        register("h2031_enterprise_monthly", "公路旅客月报H203-1表(道路旅客运输月度生产情况)",
                new String[]{"id", "report_period", "region_code", "enterprise_code", "enterprise_name", "vehicle_total",
                        "seat_total", "passenger_total", "turnover_total", "avg_distance_total", "verify_explanation"},
                new String[]{"主键", "报表期", "所属地区代码", "企业代码", "企业名称", "车辆数", "载客位数",
                        "客运量(万人)", "旅客周转量(万人公里)", "平均运距(公里)", "企业核实解释"},
                new String[]{"id", "report_period", "enterprise_name", "vehicle_total", "seat_total",
                        "passenger_total", "turnover_total", "avg_distance_total", "verify_explanation"});
        register("city_bus_monthly", "城市公交月度运营情况(企业级，含轨道/轮渡字段)",
                new String[]{"id", "report_period", "region_code", "city", "enterprise_name", "op_vehicles",
                        "passenger_volume", "turnover", "avg_distance", "passenger_chengxiang", "turnover_chengxiang",
                        "verify_explanation"},
                new String[]{"主键", "报表期", "所属地区代码", "市州", "企业名称", "运营车数", "客运量(万人次)",
                        "旅客周转量(万人公里)", "平均运距(公里)", "城际城乡客运量", "城际城乡周转量", "企业核实解释"},
                new String[]{"id", "report_period", "enterprise_name", "op_vehicles", "passenger_volume",
                        "turnover", "avg_distance", "verify_explanation"});
        register("city_taxi_monthly", "巡游出租汽车运营服务情况月报(市州级)",
                new String[]{"id", "report_period", "region_code", "city", "trip_total", "passenger_volume",
                        "turnover", "op_vehicles", "avg_distance", "verify_explanation"},
                new String[]{"主键", "报表期", "所属地区代码", "市州", "载客车次总数", "客运量(万人次)",
                        "旅客周转量(万人公里)", "运营车辆数", "平均运距(公里)", "企业核实解释"},
                new String[]{"id", "report_period", "city", "trip_total", "passenger_volume",
                        "turnover", "op_vehicles", "avg_distance", "verify_explanation"});
        register("audit_result", "审核结果",
                new String[]{"id", "rule_id", "report_id", "enterprise_code", "report_period", "actual_value",
                        "threshold_value", "deviation", "status", "review_comment", "created_at"},
                new String[]{"主键", "规则ID", "上报记录ID", "企业代码", "报表期", "实际值", "阈值/对比值", "偏差说明", "状态(PENDING待处理/CONFIRMED确认/IGNORED忽略)", "审核意见", "创建时间"},
                new String[]{"id", "report_id", "enterprise_code", "report_period", "actual_value", "threshold_value",
                        "deviation", "status"});
        register("audit_rule", "审核规则",
                new String[]{"id", "rule_name", "rule_code", "description", "check_field", "compare_type", "threshold",
                        "alert_level", "report_type", "is_enabled"},
                new String[]{"主键", "规则名称", "规则编码", "规则描述", "检查字段", "比较方式", "阈值", "预警级别", "报表类型", "是否启用"},
                new String[]{"id", "rule_name", "rule_code", "description", "check_field", "compare_type", "threshold",
                        "alert_level"});
    }

    private static void register(String table, String desc, String[] cols, String[] labels, String[] defaults) {
        Map<String, String> labelMap = new LinkedHashMap<>();
        for (int i = 0; i < cols.length && i < labels.length; i++) {
            labelMap.put(cols[i], labels[i]);
        }
        TABLES.put(table, new TableMeta(table, desc, cols, labelMap, defaults));
        ALLOWED_TABLES.add(table);
    }

    /** 供系统提示词使用的完整表结构说明 */
    public String schemaText() {
        StringBuilder sb = new StringBuilder();
        for (TableMeta meta : TABLES.values()) {
            sb.append(meta.table).append("【").append(meta.desc).append("】: ");
            List<String> parts = new ArrayList<>();
            for (String c : meta.cols) {
                parts.add(snakeToCamel(c) + "(" + meta.labels.getOrDefault(c, snakeToCamel(c)) + ")");
            }
            sb.append(String.join(", ", parts)).append("\n");
        }
        return sb.toString();
    }

    public String execute(String table, Object columnsParam, Object filtersParam, String orderBy, Integer limit,
                          String defaultPeriod) {
        JSONObject out = new JSONObject();
        try {
            TableMeta meta = TABLES.get(table);
            if (meta == null) {
                out.set("success", false);
                out.set("error", "表名不合法，可用表: " + ALLOWED_TABLES);
                return out.toString();
            }
            List<String> cols = resolveCols(meta, columnsParam);
            Map<String, Object> filters = filtersParam instanceof Map
                    ? (Map<String, Object>) filtersParam : new LinkedHashMap<>();
            WhereClause w = buildWhere(meta, filters, defaultPeriod);

            StringBuilder sql = new StringBuilder("SELECT ").append(String.join(", ", cols))
                    .append(" FROM ").append(meta.table);
            if (!w.sql.isEmpty()) {
                sql.append(" WHERE ").append(w.sql);
            }
            sql.append(" ORDER BY ").append(parseOrder(meta, orderBy));
            int lim = limit == null ? 20 : Math.min(Math.max(limit, 1), 100);
            sql.append(" LIMIT ").append(lim);

            List<Map<String, Object>> rows = jdbcTemplate.queryForList(sql.toString(), w.args.toArray());
            out.set("success", true);
            out.set("rows", rows);
            out.set("count", rows.size());
            out.set("total", countTotal(meta, filters, defaultPeriod));
            return out.toString();
        } catch (Exception ex) {
            log.warn("query_database tool error: {}", ex.getMessage());
            out.set("success", false);
            out.set("error", ex.getMessage() == null ? "查询失败" : ex.getMessage());
            return out.toString();
        }
    }

    private List<String> resolveCols(TableMeta meta, Object columnsParam) {
        if (columnsParam == null) {
            return aliased(meta.defaults);
        }
        if (columnsParam instanceof String && "*".equals(columnsParam)) {
            return aliased(meta.cols);
        }
        if (columnsParam instanceof List) {
            List<String> out = new ArrayList<>();
            for (Object o : (List<?>) columnsParam) {
                String c = normalizeCol(String.valueOf(o));
                if (!meta.cols.contains(c)) {
                    throw new IllegalArgumentException("列名不合法: " + o + "，该表可用列: " + camelList(meta.cols));
                }
                out.add(c);
            }
            return aliased(out.isEmpty() ? meta.defaults : out);
        }
        return aliased(meta.defaults);
    }

    private List<String> aliased(List<String> cols) {
        List<String> out = new ArrayList<>();
        for (String c : cols) {
            out.add(c + " AS " + snakeToCamel(c));
        }
        return out;
    }

    private String camelList(List<String> cols) {
        List<String> parts = new ArrayList<>();
        for (String c : cols) {
            parts.add(snakeToCamel(c));
        }
        return String.join(", ", parts);
    }

    private WhereClause buildWhere(TableMeta meta, Map<String, Object> filters, String defaultPeriod) {
        List<String> conds = new ArrayList<>();
        List<Object> args = new ArrayList<>();
        boolean hasPeriod = meta.cols.contains("report_period");
        if (defaultPeriod != null && !defaultPeriod.isEmpty() && hasPeriod && !filters.containsKey("report_period")) {
            conds.add("report_period = ?");
            args.add(defaultPeriod);
        }
        for (Map.Entry<String, Object> e : filters.entrySet()) {
            String col = normalizeCol(String.valueOf(e.getKey()));
            if (!meta.cols.contains(col)) {
                throw new IllegalArgumentException("列名不合法: " + e.getKey() + "，该表可用列: " + camelList(meta.cols));
            }
            Object v = e.getValue();
            if (v instanceof List) {
                List<?> list = (List<?>) v;
                if (list.isEmpty()) {
                    continue;
                }
                conds.add(col + " IN (" + String.join(",", Collections.nCopies(list.size(), "?")) + ")");
                args.addAll(list);
            } else if (v instanceof Number || v instanceof Boolean) {
                conds.add(col + " = ?");
                args.add(v);
            } else {
                String s = String.valueOf(v).trim();
                Matcher m = NUM_CMP.matcher(s);
                if (m.matches()) {
                    conds.add(col + " " + m.group(1) + " ?");
                    args.add(Double.parseDouble(m.group(2)));
                } else if (!s.isEmpty()) {
                    conds.add(col + " LIKE ?");
                    args.add("%" + s + "%");
                }
            }
        }
        return new WhereClause(String.join(" AND ", conds), args);
    }

    private String parseOrder(TableMeta meta, String orderBy) {
        if (orderBy == null || orderBy.trim().isEmpty()) {
            return "id DESC";
        }
        String s = orderBy.trim();
        boolean desc = false;
        if (s.toUpperCase().endsWith(" DESC")) {
            desc = true;
            s = s.substring(0, s.length() - 5).trim();
        } else if (s.toUpperCase().endsWith(" ASC")) {
            s = s.substring(0, s.length() - 4).trim();
        }
        String col = normalizeCol(s);
        if (!meta.cols.contains(col)) {
            throw new IllegalArgumentException("排序列不合法: " + orderBy);
        }
        return col + (desc ? " DESC" : " ASC");
    }

    private long countTotal(TableMeta meta, Map<String, Object> filters, String defaultPeriod) {
        WhereClause w = buildWhere(meta, filters, defaultPeriod);
        String sql = "SELECT COUNT(*) FROM " + meta.table;
        if (!w.sql.isEmpty()) {
            sql += " WHERE " + w.sql;
        }
        Long c = jdbcTemplate.queryForObject(sql, Long.class, w.args.toArray());
        return c == null ? 0 : c;
    }

    private static String normalizeCol(String name) {
        StringBuilder sb = new StringBuilder();
        for (char c : name.toCharArray()) {
            if (Character.isUpperCase(c)) {
                sb.append('_').append(Character.toLowerCase(c));
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }

    private static String snakeToCamel(String s) {
        StringBuilder sb = new StringBuilder();
        boolean up = false;
        for (char c : s.toCharArray()) {
            if (c == '_') {
                up = true;
                continue;
            }
            sb.append(up ? Character.toUpperCase(c) : c);
            up = false;
        }
        return sb.toString();
    }

    private static class TableMeta {
        final String table;
        final String desc;
        final List<String> cols;
        final Map<String, String> labels;
        final List<String> defaults;

        TableMeta(String table, String desc, String[] cols, Map<String, String> labels, String[] defaults) {
            this.table = table;
            this.desc = desc;
            this.cols = Arrays.asList(cols);
            this.labels = labels;
            this.defaults = Arrays.asList(defaults);
        }
    }

    private static class WhereClause {
        final String sql;
        final List<Object> args;

        WhereClause(String sql, List<Object> args) {
            this.sql = sql;
            this.args = args;
        }
    }
}