package io.gitlab.jfronny.muscript.ast.dynamic;

import io.gitlab.jfronny.muscript.ast.DynamicExpr;
import io.gitlab.jfronny.muscript.ast.Expr;
import io.gitlab.jfronny.muscript.annotations.CanThrow;
import io.gitlab.jfronny.muscript.annotations.UncheckedDynamic;
import io.gitlab.jfronny.muscript.ast.literal.StringLiteral;
import io.gitlab.jfronny.muscript.compiler.*;
import io.gitlab.jfronny.muscript.data.Scope;
import io.gitlab.jfronny.muscript.data.dynamic.*;
import io.gitlab.jfronny.muscript.error.LocationalException;
import io.gitlab.jfronny.muscript.error.TypeMismatchException;

import java.io.IOException;
import java.util.stream.Stream;

@CanThrow
@UncheckedDynamic
public class Get extends DynamicExpr {
    private final DynamicExpr left;
    private final Expr<?> name;

    public Get(CodeLocation location, DynamicExpr left, Expr<?> name) {
        super(Order.Call, location);
        this.left = left;
        this.name = name;
        if (name.getResultType() != Type.String && name.getResultType() != Type.Number && name.getResultType() != Type.Dynamic) {
            throw new TypeMismatchException(location, Type.String, name.getResultType(), "Name must be either a string or a number");
        }
    }

    @Override
    public Dynamic get(Scope dataRoot) {
        Dynamic left = this.left.get(dataRoot);
        if (Dynamic.isNull(left)) throw new LocationalException(location, "Could not get \"" + name.asStringExpr().get(dataRoot) + "\" because left is null");
        if (left.isObject()) {
            DObject o = left.asObject();
            var n = name.asStringExpr().get(dataRoot);
            if (!o.has(n)) throw new LocationalException(location, "Object does not contain \"" + n + "\"");
            return o.get(n);
        } else if (left.isList()) {
            DList l = left.asList();
            int idx = name.asNumberExpr().get(dataRoot).intValue();
            if (idx < 0 || idx >= l.size()) throw new LocationalException(location, "Index " + idx + " is out of range for list with size " + l.size());
            return l.get(idx);
        }
        throw new DynamicTypeConversionException("object or list", left).locational(location);
    }

    @Override
    public DynamicExpr optimize() {
        DynamicExpr left = this.left.optimize();
        Expr<?> name = this.name.optimize();
        return new Get(location, left, name);
    }

    @Override
    public Stream<Expr<?>> extractSideEffects() {
        return Stream.concat(left.extractSideEffects(), name.extractSideEffects());
    }

    @Override
    public void decompile(ExprWriter writer) throws IOException {
        parenthesize(left, writer, false);
        if (name instanceof StringLiteral lit && Lexer.isValidId(lit.value)) {
            writer.append('.').append(lit.value);
        } else {
            writer.append('[');
            name.decompile(writer);
            writer.append(']');
        }
    }

    @Override
    public boolean equals(Object obj) {
        return obj instanceof Get get && left.equals(get.left) && name.equals(get.name);
    }
}