package io.gitlab.jfronny.muscript.compiler;

import java.io.Closeable;
import java.io.IOException;
import java.util.stream.Collectors;

public class ExprWriter implements Appendable, Closeable {
    private final Appendable target;
    private int indent = 0;

    public ExprWriter(Appendable target) {
        this.target = target;
    }

    @Override
    public ExprWriter append(CharSequence csq) throws IOException {
        target.append(csq.toString().lines().collect(Collectors.joining("\n" + indent())));
        return this;
    }

    @Override
    public ExprWriter append(CharSequence csq, int start, int end) throws IOException {
        return append(csq.subSequence(start, end));
    }

    @Override
    public ExprWriter append(char c) throws IOException {
        if (c == '\n' || c == '\r') target.append("\n").append(indent());
        else target.append(c);
        return this;
    }

    private String indent() {
        return " ".repeat(indent);
    }

    public ExprWriter increaseIndent() {
        indent += 2;
        return this;
    }

    public ExprWriter decreaseIndent() {
        if (indent <= 1) throw new IllegalStateException("Attempted to decrease indent lower than 0");
        indent -= 2;
        return this;
    }

    @Override
    public void close() {
        if (indent != 0) throw new IllegalStateException("Attempted to close ExprWriter before end");
    }
}