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package com.megatim.fdxcommons.tools.database.queries;

import com.megatim.fdxcommons.model.pojo.JsonTableDefinition;
import com.megatim.fdxcommons.tools.database.contrat.DefaultPreparedStatementProcessor;
import com.megatim.fdxcommons.tools.database.contrat.QueryMetaData;
import com.megatim.fdxcommons.tools.database.queries.metadata.QueryCriterion;
import com.megatim.fdxcommons.tools.database.queries.metadata.WhereQueryParameters;
import com.megatim.fdxcommons.tools.database.tables.appcolumns.IndexColumnDefinition;
import com.megatim.fdxcommons.tools.database.tables.appcolumns.ParentIdColumnDefinition;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.naming.NamingException;

/**
 *
 * @author ASUS
 */
public class JsonSelectQuery implements QueryMetaData<Map<Long, Object>> {

    private final JsonTableDefinition tableDefinition;
    private final QueryCriterion queryCriterion;
    private final Connection connection;
    private final Map<String, String> tablesNameToAlias;
    private final int limit;
    private final int offset;

    public JsonSelectQuery(JsonTableDefinition tableDefinition, QueryCriterion queryCriterion, Connection connection, Map<String, String> tablesNameToAlias) {
        this(tableDefinition, queryCriterion, connection, tablesNameToAlias, -1, -1);
    }

    public JsonSelectQuery(JsonTableDefinition tableDefinition, QueryCriterion queryCriterion, Connection connection, Map<String, String> tablesNameToAlias, int limit, int offset) {
        this.tableDefinition = tableDefinition;
        this.queryCriterion = queryCriterion;
        this.connection = connection;
        this.tablesNameToAlias = tablesNameToAlias;
        this.limit = limit;
        this.offset = offset;
    }

    @Override
    public Map<Long, Object> execute() throws Exception {
        return result();
    }

    private Map<Long, Object> result() throws NamingException, SQLException {
        Map<Long, Object> finalData = new HashMap<>();
        String query = selectString() + fromString() + joinString() + whereString() + pagination();
        System.out.println("------------------------------------------------------------------------------------");
        System.out.println(query);
        System.out.println("------------------------------------------------------------------------------------");

        try ( PreparedStatement statement = connection.prepareStatement(query)) {
            new DefaultPreparedStatementProcessor().process(statement, new WhereQueryParameters(queryCriterion).parameters());
            ResultSet resultSet = statement.executeQuery();
            List<Long> indexes = new ArrayList<>();

            while (resultSet.next()) {
                indexes.add(resultSet.getLong(new IndexColumnDefinition().name()));
            }
            for (Long l : indexes) {
                Map<String, Object> data = selectData(l, tableDefinition.getTableName());

                for (JsonTableDefinition t : tableDefinition.getTablesDefinition()) {
                    data.put(t.getParentFieldName().toLowerCase(), selectChildren(l, t));
                }
                finalData.put(l, data);
            }
        }
        return finalData;
    }

    private Map<String, Object> selectData(Long index, String tableName) throws SQLException {
        Map<String, Object> data = new HashMap<>();
        String query = "SELECT * FROM " + tableName + " WHERE " + new IndexColumnDefinition().name() + " = ?";

        try ( PreparedStatement statement = connection.prepareStatement(query)) {
            statement.setLong(1, index);
            ResultSet resultSet = statement.executeQuery();

            ResultSetMetaData metaData = resultSet.getMetaData();
            int columnCount = metaData.getColumnCount();

            if (resultSet.next()) {
                for (int i = 1; i <= columnCount; i++) {
                    data.put(metaData.getColumnName(i).trim().toLowerCase(), resultSet.getObject(i));
                }
            }
        }
        return data;
    }

    private Map<Long, Object> selectChildren(Long index, JsonTableDefinition tableDef) throws SQLException {
        Map<Long, Object> finalData = new HashMap<>();
        String query = "SELECT * FROM " + tableDef.getTableName() + " WHERE " + new ParentIdColumnDefinition().name() + " = ?";

        try ( PreparedStatement statement = connection.prepareStatement(query)) {
            statement.setLong(1, index);
            ResultSet resultSet = statement.executeQuery();
            Map<Long, Object> data = retrieveData(resultSet);

            if (!tableDef.getTablesDefinition().isEmpty()) {

                for (Map.Entry<Long, Object> entry : data.entrySet()) {
                    Map<String, Object> map = new HashMap<>();
                    map.putAll((Map<String, Object>) entry.getValue());

                    for (JsonTableDefinition t : tableDef.getTablesDefinition()) {
                        map.put(t.getParentFieldName().toLowerCase(), selectChildren(entry.getKey(), t));
                    }
                    finalData.put(entry.getKey(), map);
                }
            } else {
                finalData.putAll(data);
            }
        }
        return finalData;
    }

    private Map<Long, Object> retrieveData(ResultSet resultSet) throws SQLException {
        Map<Long, Object> data = new HashMap<>();
        ResultSetMetaData metaData = resultSet.getMetaData();
        int columnCount = metaData.getColumnCount();

        while (resultSet.next()) {
            Map<String, Object> datum = new HashMap<>();
            for (int i = 1; i <= columnCount; i++) {
                datum.put(metaData.getColumnName(i).trim().toLowerCase(), resultSet.getObject(i));
            }
            data.put(resultSet.getLong(new IndexColumnDefinition().name()), datum);
        }
        return data;
    }

    private String whereString() {
        return "\n" + new WhereQueryString(queryCriterion).query();
    }

    private String pagination() {
        if (limit > 0 && offset >= 0) {
            return " LIMIT " + limit + " OFFSET " + offset;
        }
        return "";
    }

    private String fromString() {
        StringBuilder fromPart = new StringBuilder("\nFROM ");
        fromPart
                .append(tableDefinition.getTableName())
                .append(" ")
                .append(tablesNameToAlias.get(tableDefinition.getTableName()));

        return fromPart.toString();
    }

    private String joinString() {
        return joinString(tableDefinition.getTablesDefinition());
    }

    private String joinString(List<JsonTableDefinition> tablesDef) {
        StringBuilder joinPart = new StringBuilder("");

        if (tablesNameToAlias.size() > 1) {
            for (JsonTableDefinition t : tablesDef) {
                joinPart.append(joinString(t));
                joinPart.append(joinString(t.getTablesDefinition()));
            }
        }
        return joinPart.toString();
    }

    private String joinString(JsonTableDefinition tableDef) {
        StringBuilder joinPart = new StringBuilder("\nJOIN ");
        joinPart.append(tableDef.getTableName())
                .append(" ")
                .append(tablesNameToAlias.get(tableDef.getTableName()))
                .append(" ON ")
                .append(tablesNameToAlias.get(tableDef.getTableName()))
                .append(".")
                .append(new ParentIdColumnDefinition().name())
                .append(" = ")
                .append(tablesNameToAlias.get(tableDef.getParentTableName()))
                .append(".")
                .append(new IndexColumnDefinition().name());

        return joinPart.toString();
    }

    private String selectString() {
        return "SELECT " + columnsToSelect();
    }

    private String columnsToSelect() {
        StringBuilder columnsToSelect = new StringBuilder("");
        columnsToSelect
                .append("DISTINCT(")
                .append(tablesNameToAlias.get(tableDefinition.getTableName()))
                .append(".")
                .append(new IndexColumnDefinition().name())
                .append(")");
        return columnsToSelect.toString();
    }

}