import pycurl from cStringIO import StringIO import time from collecti

import pycurl
from cStringIO import StringIO
import time
from collections import deque
from itertools import islice
from urlparse import urlsplit
import select

# curl_multi_perform -> transfer data on ready sockets & get num of active handlers
# curl_multi_fdset -> extract handlers to use in select/poll
# curl_multi_info_read -> info about handlers completed their work

DEFAULT_POOL_SIZE = 200

class NoMoreTask(Exception):
    pass

class Crawler(object):
    def __init__(self, pool_size=DEFAULT_POOL_SIZE):
        self.pool_size = pool_size
        self._stat_timer = time.time()
        self.init_multi_interface()
        self.task_generator_object = self.task_generator()

    def init_multi_interface(self):
        self.handler_reg = {}
        self.free_handlers = deque()
        self.active_handlers = deque()
        self.multi = pycurl.CurlMulti()
        for x in xrange(self.pool_size):
            handler = pycurl.Curl()
            self.free_handlers.append(handler)
        self._next_timeout = None

    def process_handler_data(self, handler, task, body):
        try:
            result = body.splitlines()[0]
        except IndexError:
            result = 'NA'
        print task['url'], '-->', result

    def get_next_task(self):
        try:
            return self.task_generator_object.next()
        except StopIteration:
            raise NoMoreTask

    def add_task_to_work(self, task):
        handler = self.free_handlers.pop()
        handler.setopt(pycurl.URL, task['url'])
        handler.setopt(pycurl.FOLLOWLOCATION, True)
        handler.setopt(pycurl.MAXREDIRS, 5)
        handler.setopt(pycurl.TIMEOUT, 15)
        handler.setopt(pycurl.CONNECTTIMEOUT, 5)

        buf = StringIO()
        self.handler_reg[handler] = {
            'buffer': buf,
            'task': task,
            'start_time': time.time(),
        }
        handler.setopt(pycurl.WRITEFUNCTION, buf.write)
        self.multi.add_handle(handler)
        self.active_handlers.append(handler)

    def trigger_stat_logging(self):
        if time.time() - self._stat_timer > 2:
            self._stat_timer = time.time()
            print '===>>>'
            print 'Active handlers:'
            for handler in self.active_handlers:
                info = self.handler_reg[handler]
                age = time.time() - info['start_time'] 
                print '* %s --> %s [%.3f]' % (id(handler), info['task']['url'], age)
            print '<<<==='

    def trigger_data_io(self):
        rlist, wlist, xlist = self.multi.fdset()
        if rlist or wlist or xlist:
            timeout = self.multi.timeout()
            if timeout:
                select.select(rlist, wlist, xlist, timeout / 1000.0)
        else:
            time.sleep(0.1)

        # Trigger data transfers
        while True:
            opcode, active_num = self.multi.perform()
            if opcode != pycurl.E_CALL_MULTI_PERFORM:
                break

    def get_handler_results(self):
        more_count, ok_handlers, fails = self.multi.info_read()
        for ok_handler in ok_handlers: 
            yield ok_handler, None, None
        for fail_handler, err_no, err_msg in fails:
            yield fail_handler, err_no, err_msg

    def process_done_handler(self, handler, err_no, err_msg):
        info = self.handler_reg[handler]
        if err_no is None:
            info['task']['callback'](handler, info['task'], info['buffer'].getvalue())
        else:
            print u'ERROR [%s]: %s' % (info['task']['url'], err_msg)
        self.active_handlers.remove(handler)
        self.multi.remove_handle(handler)
        handler.reset()
        self.free_handlers.append(handler)

    def run(self):
        dump_time = time.time()

        while True:
            no_more_task = False
            if self.free_handlers:
                try:
                    task = self.get_next_task()
                except NoMoreTask:
                    no_more_task = True
                else:
                    self.add_task_to_work(task)
        
            self.trigger_stat_logging()

            self.trigger_data_io()

            for handler, err_no, err_msg in self.get_handler_results():
                self.process_done_handler(handler, err_no, err_msg)

            if not self.active_handlers and no_more_task:
                break


class TestCrawler(Crawler):
    def task_generator(self):
        #for line in islice(open('/web/gev/var/top-1m.csv'), 100):
            #url = 'http://%s/robots.txt' % line.strip()
            #yield {'url': url}
        for x in xrange(1000):
            yield {'url': 'http://localhost:9000/?delay=0', 'callback': self.task_page}

    def task_page(self, handler, task, body):
        try:
            result = body.decode('utf-8', 'ignore').splitlines()[0]
        except IndexError:
            result = 'NA'
        print u'%s --> %s' % (task['url'], result)




def main():
    crawler = TestCrawler()
    crawler.run()


if __name__ == '__main__':
    main()