var defined = require('defined');
var EventEmitter = require('events').EventEmitter;
var inherits = require('inherits');
var through = require('through');
var resumer = require('resumer');
var inspect = require('object-inspect');
var bind = require('function-bind');
var has = require('has');
var regexpTest = bind.call(Function.call, RegExp.prototype.test);
var yamlIndicators = /\:|\-|\?/;
var nextTick = typeof setImmediate !== 'undefined'
    ? setImmediate
    : process.nextTick
;

module.exports = Results;
inherits(Results, EventEmitter);

function coalesceWhiteSpaces(str) {
    return String(str).replace(/\s+/g, ' ');
}

function Results() {
    if (!(this instanceof Results)) return new Results;
    this.count = 0;
    this.fail = 0;
    this.pass = 0;
    this.todo = 0;
    this._stream = through();
    this.tests = [];
    this._only = null;
    this._isRunning = false;
}

Results.prototype.createStream = function (opts) {
    if (!opts) opts = {};
    var self = this;
    var output, testId = 0;
    if (opts.objectMode) {
        output = through();
        self.on('_push', function ontest(t, extra) {
            if (!extra) extra = {};
            var id = testId++;
            t.once('prerun', function () {
                var row = {
                    type: 'test',
                    name: t.name,
                    id: id,
                    skip: t._skip,
                    todo: t._todo
                };
                if (has(extra, 'parent')) {
                    row.parent = extra.parent;
                }
                output.queue(row);
            });
            t.on('test', function (st) {
                ontest(st, { parent: id });
            });
            t.on('result', function (res) {
                res.test = id;
                res.type = 'assert';
                output.queue(res);
            });
            t.on('end', function () {
                output.queue({ type: 'end', test: id });
            });
        });
        self.on('done', function () { output.queue(null); });
    } else {
        output = resumer();
        output.queue('TAP version 13\n');
        self._stream.pipe(output);
    }

    if (!this._isRunning) {
        this._isRunning = true;
        nextTick(function next() {
            var t;
            while (t = getNextTest(self)) {
                t.run();
                if (!t.ended) return t.once('end', function () { nextTick(next); });
            }
            self.emit('done');
        });
    }

    return output;
};

Results.prototype.push = function (t) {
    var self = this;
    self.tests.push(t);
    self._watch(t);
    self.emit('_push', t);
};

Results.prototype.only = function (t) {
    this._only = t;
};

Results.prototype._watch = function (t) {
    var self = this;
    var write = function (s) { self._stream.queue(s); };
    t.once('prerun', function () {
        var premsg = '';
        if (t._skip) premsg = 'SKIP ';
        else if (t._todo) premsg = 'TODO ';
        write('# ' + premsg + coalesceWhiteSpaces(t.name) + '\n');
    });

    t.on('result', function (res) {
        if (typeof res === 'string') {
            write('# ' + res + '\n');
            return;
        }
        write(encodeResult(res, self.count + 1));
        self.count ++;

        if (res.ok || res.todo) self.pass ++;
        else {
            self.fail ++;
            self.emit('fail');
        }
    });

    t.on('test', function (st) { self._watch(st); });
};

Results.prototype.close = function () {
    var self = this;
    if (self.closed) self._stream.emit('error', new Error('ALREADY CLOSED'));
    self.closed = true;
    var write = function (s) { self._stream.queue(s); };

    write('\n1..' + self.count + '\n');
    write('# tests ' + self.count + '\n');
    write('# pass  ' + (self.pass + self.todo) + '\n');
    if (self.todo) write('# todo  ' + self.todo + '\n');
    if (self.fail) write('# fail  ' + self.fail + '\n');
    else write('\n# ok\n');

    self._stream.queue(null);
};

function encodeResult(res, count) {
    var output = '';
    output += (res.ok ? 'ok ' : 'not ok ') + count;
    output += res.name ? ' ' + coalesceWhiteSpaces(res.name) : '';

    if (res.skip) {
        output += ' # SKIP' + ((typeof res.skip === 'string') ? ' ' + coalesceWhiteSpaces(res.skip) : '');
    } else if (res.todo) {
        output += ' # TODO' + ((typeof res.todo === 'string') ? ' ' + coalesceWhiteSpaces(res.todo) : '');
    };

    output += '\n';
    if (res.ok) return output;

    var outer = '  ';
    var inner = outer + '  ';
    output += outer + '---\n';
    output += inner + 'operator: ' + res.operator + '\n';

    if (has(res, 'expected') || has(res, 'actual')) {
        var ex = inspect(res.expected, {depth: res.objectPrintDepth});
        var ac = inspect(res.actual, {depth: res.objectPrintDepth});

        if (Math.max(ex.length, ac.length) > 65 || invalidYaml(ex) || invalidYaml(ac)) {
            output += inner + 'expected: |-\n' + inner + '  ' + ex + '\n';
            output += inner + 'actual: |-\n' + inner + '  ' + ac + '\n';
        } else {
            output += inner + 'expected: ' + ex + '\n';
            output += inner + 'actual:   ' + ac + '\n';
        }
    }
    if (res.at) {
        output += inner + 'at: ' + res.at + '\n';
    }

    var actualStack = res.actual && (typeof res.actual === 'object' || typeof res.actual === 'function') ? res.actual.stack : undefined;
    var errorStack = res.error && res.error.stack;
    var stack = defined(actualStack, errorStack);
    if (stack) {
        var lines = String(stack).split('\n');
        output += inner + 'stack: |-\n';
        for (var i = 0; i < lines.length; i++) {
            output += inner + '  ' + lines[i] + '\n';
        }
    }

    output += outer + '...\n';
    return output;
}

function getNextTest(results) {
    if (!results._only) {
        return results.tests.shift();
    }

    do {
        var t = results.tests.shift();
        if (!t) continue;
        if (results._only === t) {
            return t;
        }
    } while (results.tests.length !== 0);
}

function invalidYaml(str) {
    return regexpTest(yamlIndicators, str);
}
