package de.superx.bianalysis.sqlgeneration;

import java.sql.Types;
import java.util.ArrayList;
import java.util.List;
import java.util.StringJoiner;

import de.superx.bianalysis.FaultyMetadataException;
import de.superx.bianalysis.models.Condition;
import de.superx.bianalysis.models.CriteriaGroup;

public class AttributeGroupQueryBuilder {
    
    public final static String DEFAULT_LOGIC_CRITERIA_GROUP = "AND";

    public static StringJoiner buildConditionClause(List<String> caseParams, List<Integer> argTypes, CriteriaGroup group) {
        StringJoiner joinerConditions = null;
        if(group.logic != null) {
            joinerConditions = new StringJoiner(" " + group.logic   + " ");
        } else {
            joinerConditions = new StringJoiner(" " + DEFAULT_LOGIC_CRITERIA_GROUP + " ");
        }

        for (Object obj : group.conditions) {
        if (Condition.isCondition(obj)) {
            Condition condition = Condition.fromMap(obj);
            switch (condition.operator.toUpperCase()) {
            case "BETWEEN":
                if (condition.values == null || condition.values.size() != 2) {
                    throw new FaultyMetadataException("BETWEEN requires exactly two values: " + condition.column);
                }
                joinerConditions.add(condition.column + " BETWEEN ? AND ?");
                caseParams.add(condition.values.get(0));
                caseParams.add(condition.values.get(1));
                argTypes.add(Integer.valueOf(Types.VARCHAR));
                argTypes.add(Integer.valueOf(Types.VARCHAR));
                break;
            case "=", "!=": 
                    joinerConditions.add(condition.column + " " + condition.operator + " ?");
                    caseParams.add(condition.value);
                    argTypes.add(Integer.valueOf(Types.VARCHAR));
                    break;
            case "IN", "NOT IN":
                StringJoiner inJoiner = new StringJoiner(" ");
                inJoiner.add(condition.column);
                inJoiner.add(condition.operator + " (");
                StringJoiner joiner = new StringJoiner(", ");
                for (String value : condition.values) {
                    joiner.add("?");
                    caseParams.add(value);
                    argTypes.add(Integer.valueOf(Types.VARCHAR));
                }
                inJoiner.add(joiner.toString());
                joinerConditions.add(inJoiner.toString() + " )");
                break;

            case "<", ">", ">=", "<=":

                boolean isNumber = true;
                try {
                    Double.parseDouble(condition.value);
                } catch (NumberFormatException e) {
                    isNumber = false;
                }
                
                if(isNumber) {
                    String check = "%s ~ E'^-?\\\\d+$' AND %s::int %s ?";
                    joinerConditions.add(String.format(check, condition.column, condition.column, condition.operator));
                    caseParams.add(condition.value);
                    argTypes.add(Integer.valueOf(Types.INTEGER));
                } else {
                    joinerConditions.add(condition.column + " " + condition.operator + " ?");
                    caseParams.add(condition.value);
                    argTypes.add(Integer.valueOf(Types.VARCHAR));
                }

                break;
            default:
                throw new FaultyMetadataException("Unsupported operator: " + condition.operator);
            }
        } else if (CriteriaGroup.isGroup(obj)) {
            // Recursively handle nested groups
            CriteriaGroup subGroup = CriteriaGroup.fromMap(obj);
            StringJoiner subClause = buildConditionClause(caseParams, argTypes, subGroup);
            joinerConditions.add("(" + subClause + ")");
        }
        }
        return joinerConditions;
    }

    public static SqlQuery buildColumnQuery(List<CriteriaGroup> groups, String tableName, boolean isSortOrder, String columnname) {
        List<String> caseParams = new ArrayList<>();
        StringBuilder caseBuilder = new StringBuilder("CASE ");
        List<Integer> argTypes = new ArrayList<>();
        
        int sortOrderColumnNumber = 1;
        for (CriteriaGroup group : groups) {
            if(group.conditions == null) {
               continue; 
            }
            caseBuilder.append("WHEN ");
            
            StringJoiner joinerConditions = buildConditionClause(caseParams, argTypes, group);

            caseBuilder.append(joinerConditions.toString());
            caseBuilder.append(" THEN ? ");
            if(isSortOrder) {
                caseParams.add(String.valueOf(sortOrderColumnNumber++));
                argTypes.add(Integer.valueOf(Types.INTEGER));
            } else {
                caseParams.add(group.caption);
                argTypes.add(Integer.valueOf(Types.VARCHAR));
            }
        }

        caseBuilder.append("ELSE ? END");

        if(isSortOrder) {
            caseParams.add(String.valueOf(sortOrderColumnNumber++));
            argTypes.add(Integer.valueOf(Types.INTEGER));
        } else {
            String emptyLabel = groups.stream()
                .filter(p -> p.isElse)
                .findFirst()
                .map(p -> p.caption)
                .orElse("n.v.");
            caseParams.add(emptyLabel);
            argTypes.add(Integer.valueOf(Types.VARCHAR));
        }

        String updateSql = "UPDATE %s SET %s = %s"
                .formatted(tableName, columnname, caseBuilder);
        
        Object[] params = caseParams.toArray();
        int[] types = argTypes.stream().mapToInt(Integer::intValue).toArray();

        return new SqlQuery(updateSql, params, types);
    }

    public static SqlQuery buildValidationQuery(String tableName, String colList, List<CriteriaGroup> groups) {
        StringJoiner selectStatements = new StringJoiner(" INTERSECT ");
        List<String> caseParams = new ArrayList<>();
        List<Integer> argTypes = new ArrayList<>();
        
        for (CriteriaGroup group : groups) {
            if(group.isElse) {
               continue; 
            }
            StringBuilder criteraStmt = new StringBuilder("SELECT " + colList);
            StringJoiner selectParams = new StringJoiner(", ");

            criteraStmt.append(selectParams);
            criteraStmt.append(" FROM ");
            criteraStmt.append(tableName);
            criteraStmt.append(" WHERE ");

            StringJoiner joinerConditions = buildConditionClause(caseParams, argTypes, group);
            criteraStmt.append(joinerConditions.toString());
            selectStatements.add(criteraStmt);
        }
        
        Object[] params = caseParams.toArray();
        int[] types = argTypes.stream().mapToInt(Integer::intValue).toArray();

        return new SqlQuery(selectStatements.toString(), params, types);
    }

}