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package com.oracle.graal.python.pegparser;

import java.util.ArrayList;
import java.util.EnumSet;

import com.oracle.graal.python.pegparser.tokenizer.SourceRange;
import com.oracle.graal.python.pegparser.tokenizer.Token;
import com.oracle.graal.python.pegparser.tokenizer.Tokenizer;

public class ParserTokenizer {
    private int pos; // position of the mark
    private final ArrayList<Token> tokens;

    private final Tokenizer tokenizer;

    public ParserTokenizer(ErrorCallback errorCallback, String code, InputType type, boolean interactiveTerminal) {
        this.pos = 0;
        this.tokens = new ArrayList<>();
        this.tokenizer = Tokenizer.fromString(errorCallback, code, getTokenizerFlags(type, interactiveTerminal));
    }

    public ParserTokenizer(ErrorCallback errorCallback, byte[] code, InputType type, boolean interactiveTerminal) {
        this.pos = 0;
        this.tokens = new ArrayList<>();
        this.tokenizer = Tokenizer.fromBytes(errorCallback, code, getTokenizerFlags(type, interactiveTerminal));
    }

    private static EnumSet<Tokenizer.Flag> getTokenizerFlags(InputType type, boolean interactiveTerminal) {
        EnumSet<Tokenizer.Flag> flags = EnumSet.noneOf(Tokenizer.Flag.class);
        if (type == InputType.FILE) {
            flags.add(Tokenizer.Flag.EXEC_INPUT);
        } else if (type == InputType.SINGLE && interactiveTerminal) {
            flags.add(Tokenizer.Flag.INTERACTIVE);
        }
        return flags;
    }

    public int mark() {
        return pos;
    }

    /**
     * Called by the parser when the first attempt to parse the source failed before starting the
     * second pass which uses the invalid_xxx grammar rules. The position in the token stream is
     * reset to the start and the tokenizer stops calling
     * {@link ErrorCallback#reportIncompleteSource(int)} in interactive mode, since the second pass
     * is run only to report errors (it is not expected to succeed).
     */
    public void prepareForSecondPass() {
        pos = 0;
        tokenizer.reportIncompleteSourceIfInteractive = false;
    }

    /**
     * Called by the parser whenever it needs to backtrack to reset the current position in the
     * token stream.
     */
    public void reset(int position) {
        pos = position;
    }

    public Token getToken() {
        Token token = peekToken();
        pos++;
        return token;
    }

    protected Token peekToken() {
        if (pos == tokens.size()) {
            tokens.add(tokenizer.next());
        }
        return tokens.get(pos);
    }

    protected Token peekToken(int position) {
        assert position < tokens.size();
        return tokens.get(position);
    }

    protected int getFill() {
        return tokens.size();
    }

    public String getText(Token token) {
        return tokenizer.getTokenString(token);
    }

    SourceRange extendRangeToCurrentPosition(SourceRange rangeStart) {
        return tokenizer.extendRangeToCurrentPosition(rangeStart);
    }

    public Tokenizer getTokenizer() {
        return tokenizer;
    }
}
