const _ = require('./underscore.js');

function TokenizationError(message, token) {
    if (Error.captureStackTrace) {
        Error.captureStackTrace(this, this.constructor);
    }
    this.name = this.constructor.name;

    this.input = token.input;
    this.line = token.line;

    var context = mkContext(token.input, token.line);
    this.message = message + '\n' + context;
}
TokenizationError.prototype = Object.create(Error.prototype);
TokenizationError.prototype.constructor = TokenizationError;

function ParseError(e, token) {
    this.name = this.constructor.name;
    this.stack = e.stack;

    this.input = token.input;
    this.line = token.line;

    var context = mkContext(token.input, token.line);
    this.message = e.message + '\n' + context;
}
ParseError.prototype = Object.create(Error.prototype);
ParseError.prototype.constructor = ParseError;

function RenderError(e, tpl) {
    this.name = this.constructor.name;
    this.stack = e.stack;

    this.input = tpl.token.input;
    this.line = tpl.token.line;

    var context = mkContext(tpl.token.input, tpl.token.line);
    this.message = e.message + '\n' + context;
}
RenderError.prototype = Object.create(Error.prototype);
RenderError.prototype.constructor = RenderError;

function RenderBreakError(message) {
    if (Error.captureStackTrace) {
        Error.captureStackTrace(this, this.constructor);
    }
    this.name = this.constructor.name;
    this.message = message || '';
}
RenderBreakError.prototype = Object.create(Error.prototype);
RenderBreakError.prototype.constructor = RenderBreakError;

function AssertionError(message) {
    if (Error.captureStackTrace) {
        Error.captureStackTrace(this, this.constructor);
    }
    this.name = this.constructor.name;
    this.message = message;
}
AssertionError.prototype = Object.create(Error.prototype);
AssertionError.prototype.constructor = AssertionError;

function mkContext(input, line) {
    var lines = input.split('\n');
    var begin = Math.max(line - 2, 1);
    var end = Math.min(line + 3, lines.length);

    var context = _
        .range(begin, end + 1)
        .map(l => [
            (l === line) ? '>> ' : '   ',
            align(l, end),
            '| ',
            lines[l - 1]
        ].join(''))
        .join('\n');

    return context;
}

function align(n, max) {
    var length = (max + '').length;
    var str = n + '';
    var blank = Array(length - str.length).join(' ');
    return blank + str;
}

module.exports = {
    TokenizationError,
    ParseError,
    RenderBreakError,
    AssertionError,
    RenderError
};