package gudusoft.gsqlparser.nodes;

import gudusoft.gsqlparser.ESqlClause;
import gudusoft.gsqlparser.TCustomSqlStatement;

/**
 * Represents a PostgreSQL INSERT ... ON CONFLICT clause (UPSERT).
 *
 * <p>PostgreSQL syntax:
 * <pre>
 * INSERT INTO table_name ...
 * ON CONFLICT [ conflict_target ] conflict_action
 *
 * conflict_target:
 *   ( { index_column_name | ( index_expression ) } [, ...] ) [ WHERE index_predicate ]
 *   | ON CONSTRAINT constraint_name
 *
 * conflict_action:
 *   DO NOTHING
 *   | DO UPDATE SET { column_name = expression } [, ...] [ WHERE condition ]
 * </pre>
 *
 * @see gudusoft.gsqlparser.stmt.TInsertSqlStatement#getOnConflictClause()
 */
public class TOnConflictClause extends TParseTreeNode {

    private EOnConflictActionType actionType;

    /**
     * Conflict target: index columns/expressions in parentheses.
     * Each item is a TOrderByItem representing an index element.
     * Null when ON CONSTRAINT is used or no conflict target is specified.
     */
    private TOrderByItemList indexColumns;

    /**
     * Conflict target: constraint name when ON CONSTRAINT syntax is used.
     * Null when column-based conflict target or no conflict target is specified.
     */
    private TObjectName constraintName;

    /**
     * WHERE clause on the conflict target (partial unique index predicate).
     * Only applicable when column-based conflict target is used.
     */
    private TWhereClause indexWhereClause;

    /**
     * SET clause assignments for DO UPDATE action.
     * Null when action is DO NOTHING.
     */
    private TResultColumnList updateSetClause;

    /**
     * WHERE clause for DO UPDATE action.
     * Null when action is DO NOTHING or no WHERE specified on the UPDATE.
     */
    private TWhereClause updateWhereClause;

    /**
     * Returns the conflict action type: DO NOTHING or DO UPDATE.
     * @return the action type
     */
    public EOnConflictActionType getActionType() {
        return actionType;
    }

    public void setActionType(EOnConflictActionType actionType) {
        this.actionType = actionType;
    }

    /**
     * Returns the list of index column names or expressions that form the conflict target.
     * @return the index column list, or null if ON CONSTRAINT or no target specified
     */
    public TOrderByItemList getIndexColumns() {
        return indexColumns;
    }

    public void setIndexColumns(TOrderByItemList indexColumns) {
        this.indexColumns = indexColumns;
    }

    /**
     * Returns the constraint name when ON CONSTRAINT syntax is used.
     * @return the constraint name, or null
     */
    public TObjectName getConstraintName() {
        return constraintName;
    }

    public void setConstraintName(TObjectName constraintName) {
        this.constraintName = constraintName;
    }

    /**
     * Returns the WHERE clause for the partial unique index predicate on the conflict target.
     * @return the index WHERE clause, or null
     */
    public TWhereClause getIndexWhereClause() {
        return indexWhereClause;
    }

    public void setIndexWhereClause(TWhereClause indexWhereClause) {
        this.indexWhereClause = indexWhereClause;
    }

    /**
     * Returns the SET clause assignments for the DO UPDATE action.
     * @return the SET clause result column list, or null if DO NOTHING
     */
    public TResultColumnList getUpdateSetClause() {
        return updateSetClause;
    }

    public void setUpdateSetClause(TResultColumnList updateSetClause) {
        this.updateSetClause = updateSetClause;
    }

    /**
     * Returns the WHERE clause for the DO UPDATE action.
     * @return the update WHERE clause, or null
     */
    public TWhereClause getUpdateWhereClause() {
        return updateWhereClause;
    }

    public void setUpdateWhereClause(TWhereClause updateWhereClause) {
        this.updateWhereClause = updateWhereClause;
    }

    /**
     * Sets the conflict target from a TDummy node produced by the grammar.
     * The TDummy carries: list1 = index columns (TOrderByItemList),
     * node1 = index WHERE clause (TWhereClause), node2 = constraint name (TObjectName).
     */
    public void setConflictTarget(TDummy dummy) {
        if (dummy == null) return;
        if (dummy.list1 != null) {
            this.indexColumns = (TOrderByItemList) dummy.list1;
        }
        if (dummy.node1 != null) {
            this.indexWhereClause = (TWhereClause) dummy.node1;
        }
        if (dummy.node2 != null) {
            this.constraintName = (TObjectName) dummy.node2;
        }
    }

    /**
     * Parses the ON CONFLICT clause within the context of the parent statement.
     */
    public void doParse(TCustomSqlStatement psql, ESqlClause clauseType) {
        if (indexColumns != null) {
            indexColumns.doParse(psql, clauseType);
        }
        if (constraintName != null) {
            constraintName.doParse(psql, clauseType);
        }
        if (indexWhereClause != null) {
            indexWhereClause.doParse(psql, clauseType);
        }
        if (updateSetClause != null) {
            updateSetClause.doParse(psql, clauseType);
        }
        if (updateWhereClause != null) {
            updateWhereClause.doParse(psql, clauseType);
        }
    }

    public void acceptChildren(TParseTreeVisitor v) {
        if (indexColumns != null) {
            indexColumns.acceptChildren(v);
        }
        if (indexWhereClause != null) {
            indexWhereClause.acceptChildren(v);
        }
        if (updateSetClause != null) {
            updateSetClause.acceptChildren(v);
        }
        if (updateWhereClause != null) {
            updateWhereClause.acceptChildren(v);
        }
    }
}