/* eslint-disable no-console */
/* eslint-disable quote-props */
/* Command-line interface */

import { RuntimeState } from './runtime';
import { Runner } from './runner';
import { readJboardFromFile, writeJboardToFile } from './board_formats';

import fs from 'fs';
import { GbsInterpreterException } from '@gobstones/gobstones-parser';

const startsWith = (string: string, prefix: string): boolean =>
    string.substring(0, prefix.length) === prefix;

export interface Options {
    arguments: string[];
    'initial-board'?: string;
    'output-board'?: string;
    'print-ast': boolean;
    'print-code': boolean;
    help: boolean;
}

function readOptions(argv: string[]): Options {
    const options = {
        arguments: [],
        'initial-board': undefined,
        'output-board': undefined,
        'print-ast': false,
        'print-code': false,
        help: false
    };
    let i = 2;
    while (i < argv.length) {
        if (argv[i] === '-h' || argv[i] === '--help') {
            options['help'] = true;
        } else if (argv[i] === '-a' || argv[i] === '--ast') {
            options['print-ast'] = true;
        } else if (argv[i] === '-c' || argv[i] === '--code') {
            options['print-code'] = true;
        } else if (argv[i] === '-i' && i + 1 < argv.length) {
            options['initial-board'] = argv[i + 1];
            i++;
        } else if (startsWith(argv[i], '--initial-board=')) {
            options['initial-board'] = argv[i].substring('--initial-board='.length);
        } else if (argv[i] === '-o' && i + 1 < argv.length) {
            options['output-board'] = argv[i + 1];
            i++;
        } else if (startsWith(argv[i], '--output-board=')) {
            options['output-board'] = argv[i].substring('--output-board='.length);
        } else {
            options['arguments'].push(argv[i]);
        }
        i++;
    }
    return options;
}

function help(): void {
    const helpMessage = [
        'Usage:',
        'gobstones-lang input.gbs',
        '',
        ' -a, --ast                   Print AST (do not run).',
        ' -c, --code                  Print virtual machine code (do not run).',
        ' -i, --initial-board=<file>  Load initial board. Default: empty 9x9.',
        ' -o, --output-board=<file>   Save final board.',
        ' -h, --help                  Display this help message.'
    ];
    console.log(helpMessage.join('\n'));
}

function printGbsException(exception: GbsInterpreterException): void {
    console.log(exception.message);
    const startPos = [
        exception.startPos.filename,
        exception.startPos.line,
        exception.startPos.column
    ].join(':');
    const endPos = [exception.endPos.line, exception.endPos.column].join(':');
    console.log('At: ' + startPos + '--' + endPos);
}

function runProgram(options: Options, filename: string): void {
    const contents = fs.readFileSync(filename, 'utf8');
    try {
        const inputs = {};
        inputs[filename] = contents;
        const runner = new Runner();

        if (options['print-ast']) {
            runner.parse(inputs);
            runner.lint();
            console.log(runner.abstractSyntaxTree.toString());
            return;
        }

        if (options['print-code']) {
            runner.parse(inputs);
            runner.lint();
            runner.compile();
            console.log(runner.virtualMachineCode.toString());
            return;
        }

        const initialState = new RuntimeState();
        if (options['initial-board'] !== undefined) {
            initialState.load(readJboardFromFile(options['initial-board']));
        }

        const output = runner.runState(inputs, initialState);
        const finalState = output.state.dump();
        console.log(JSON.stringify(finalState));
        if (options['output-board'] !== undefined) {
            writeJboardToFile(options['output-board'], finalState);
        }
        if (output.result !== undefined) {
            /* The program has a return value */
            console.log(output.result.toString());
        }
    } catch (exception) {
        if (exception.isGobstonesException === undefined) {
            throw exception;
        }
        printGbsException(exception);
    }
}

function main(): void {
    const options = readOptions(process.argv);

    if (options['help']) {
        help();
        return;
    }

    if (options['arguments'].length === 1) {
        runProgram(options, options['arguments'][0]);
    } else {
        help();
    }
}

main();