package jnpf.elnFormula;

import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public final class FormulaAst {

    private FormulaAst() {
    }

    public interface Node {
        int getStartOffset();

        int getEndOffset();
    }

    public enum LiteralKind {
        DECIMAL,
        TEXT,
        BOOLEAN,
        NULL
    }

    private abstract static class BaseNode implements Node {
        private final int startOffset;
        private final int endOffset;

        private BaseNode(int startOffset, int endOffset) {
            this.startOffset = startOffset;
            this.endOffset = endOffset;
        }

        @Override
        public final int getStartOffset() {
            return startOffset;
        }

        @Override
        public final int getEndOffset() {
            return endOffset;
        }
    }

    public static final class Literal extends BaseNode {
        private final LiteralKind kind;
        private final Object value;

        public Literal(int startOffset, int endOffset, LiteralKind kind, Object value) {
            super(startOffset, endOffset);
            this.kind = kind;
            this.value = value;
        }

        public LiteralKind getKind() {
            return kind;
        }

        public Object getValue() {
            return value;
        }

        public BigDecimal getDecimalValue() {
            return (BigDecimal) value;
        }
    }

    public static final class Parameter extends BaseNode {
        private final String code;

        public Parameter(int startOffset, int endOffset, String code) {
            super(startOffset, endOffset);
            this.code = code;
        }

        public String getCode() {
            return code;
        }
    }

    public static final class Unary extends BaseNode {
        private final String operator;
        private final Node operand;

        public Unary(int startOffset, int endOffset, String operator, Node operand) {
            super(startOffset, endOffset);
            this.operator = operator;
            this.operand = operand;
        }

        public String getOperator() {
            return operator;
        }

        public Node getOperand() {
            return operand;
        }
    }

    public static final class Binary extends BaseNode {
        private final String operator;
        private final Node left;
        private final Node right;

        public Binary(int startOffset, int endOffset, String operator, Node left, Node right) {
            super(startOffset, endOffset);
            this.operator = operator;
            this.left = left;
            this.right = right;
        }

        public String getOperator() {
            return operator;
        }

        public Node getLeft() {
            return left;
        }

        public Node getRight() {
            return right;
        }
    }

    public static final class FunctionCall extends BaseNode {
        private final String name;
        private final List<Node> arguments;

        public FunctionCall(int startOffset, int endOffset, String name, List<Node> arguments) {
            super(startOffset, endOffset);
            this.name = name;
            this.arguments = Collections.unmodifiableList(new ArrayList<>(arguments));
        }

        public String getName() {
            return name;
        }

        public List<Node> getArguments() {
            return arguments;
        }
    }
}