package com.jsaasta.froj;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.List;

public class Froj {

    private static final Interpreter interpreter = new Interpreter();

    static boolean hadError = false;
    static boolean hadRuntimeError = false;


    public static void main(String[] args) throws IOException {
        Froj froj = new Froj();
        if (args.length != 1) {
            System.out.println("Usage: froj [script]");
            System.exit(64);
        }
        froj.runFile(args[0]);

    }

    public void runFile(String path) throws IOException {
        try {
            byte[] bytes = Files.readAllBytes(Paths.get(path));
            run(new String(bytes, Charset.defaultCharset()));
            // Indicate an error in the exit code.
            if (hadError) System.exit(65);
            if (hadRuntimeError) System.exit(70);
        } catch (IOException exception) {
            System.err.println("File not found: " + path);
        }


    }

    /*
     * Old REPL implementation. Not tested functionality in a while.
     *
    private void runPrompt() throws IOException {
        InputStreamReader input = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(input);
        for (; ; ) {
            System.out.print("> ");
            String line = reader.readLine();
            if (line == null) break;
            run(line);
            hadError = false;
            hadRuntimeError = false;
        }
    }
     */

    private void run(String source) {
        Scanner scanner = new Scanner(source);
        List<Token> tokens = scanner.scanTokens();
        Parser parser = new Parser(tokens);
        List<Stmt> statements = parser.parse();

        if (hadError) return;

        Resolver resolver = new Resolver(interpreter);
        resolver.resolve(statements);

        if (hadError) return;

        interpreter.interpret(statements);

    }

    public static void error(int line, String message) {
        report(line, "", message);
    }

    private static void report(int line, String where, String message) {
        System.err.println(
                "[line " + line + "] Error" + where + ": " + message);
        hadError = true;
    }

    static void error(Token token, String message) {
        if (token.type == TokenType.EOF) {
            report(token.line, " at end", message);
        } else {
            report(token.line, " at '" + token.lexeme + "'", message);
        }
    }

    static void runtimeError(RuntimeError error) {
        System.err.println(error.getMessage() +
                "\n[line " + error.token.line + "]");
        hadRuntimeError = true;
    }

}