#! /usr/bin/env python
#
# Script name:   talos_from_code.py
# Purpose:       Read from a talos.json file the different files to download for a talos job
# Author(s):     Zambrano Gasparnian, Armen <armenzg@mozilla.com>
# Target:        Python 2.5
#
from optparse import OptionParser
try:
    import json
except:
    import simplejson as json
import re
import urllib2
import urlparse
import sys
import os

def main():
    '''
    This script downloads a talos.json file which indicates which files to download
    for a talos job.
    See a talos.json file for a better understand:
    http://hg.mozilla.org/mozilla-central/raw-file/default/testing/talos/talos.json
    '''
    parser = OptionParser()
    parser.add_option("--talos-json-url", dest="talos_json_url", type="string",
                      help="It indicates from where to download the talos.json file.")
    (options, args) = parser.parse_args()

    # 1) check that the url was passed
    if options.talos_json_url == None:
        print "You need to specify --talos-json-url."
        sys.exit(1)

    # 2) try to download the talos.json file
    try:
        jsonFilename = download_file(options.talos_json_url)
    except Exception, e:
        print "ERROR: We tried to download the talos.json file but something failed."
        print "ERROR: %s" % str(e)
        sys.exit(1)

    # 3) download the necessary files
    print "INFO: talos.json URL: %s" % options.talos_json_url
    try:
        for key in ('talos.zip', 'pageloader.xpi',):
            entity = get_value(jsonFilename, key)
            if passesRestrictions(options.talos_json_url, entity["url"]):
                # the key is at the same time the filename e.g. talos.zip
                download_file(entity["url"], entity["path"], key)
                print "INFO: %s -> %s" % (entity["url"], os.path.join(entity["path"], key))
            else:
                print "ERROR: You have tried to download a file " + \
                      "from: %s " % fileUrl + \
                      "which is a location different than http://build.mozilla.org/talos/"
                print "ERROR: This is only allowed for the certain branches."
                sys.exit(1)
    except Exception, e:
        print "ERROR: %s" % str(e)
        sys.exit(1)

def passesRestrictions(talosJsonUrl, fileUrl):
    '''
    Only certain branches are exempted from having to host their downloadable files
    in build.mozilla.org
    '''
    if talosJsonUrl.startswith("http://hg.mozilla.org/try/") == True or \
       talosJsonUrl.startswith("http://hg.mozilla.org/projects/pine/") == True:
        return True
    else:
        p = re.compile('^http://build.mozilla.org/talos/')
        m = p.match(fileUrl)
        if m == None:
            return False
        return True

def get_filename_from_url(url):
    '''
    This returns the filename of the file we're trying to download
    '''
    parsed = urlparse.urlsplit(url.rstrip('/'))
    if parsed.path != '':
        return parsed.path.rsplit('/', 1)[-1]
    else:
        print "ERROR: We were trying to download a file from %s " + \
              "but the URL seems to be incorrect."
        sys.exit(1)

def download_file(url, path="", saveAs=None):
    '''
    It downloads a file from URL to the indicated path
    '''
    req = urllib2.Request(url)
    f = urllib2.urlopen(req)
    if path != "" and not os.path.isdir(path):
        try:
            os.makedirs(path)
            print "INFO: directory %s created" % path
        except Exception, e:
            print "ERROR: %s" % str(e)
            sys.exit(1)
    filename = saveAs if saveAs else get_filename_from_url(url)
    local_file = open(os.path.join(path, filename), 'wb')
    local_file.write(f.read())
    local_file.close()
    return filename

def get_value(json_filename, key):
    '''
    It loads up a JSON file and returns the value for the given string
    '''
    f = open(json_filename, 'r')
    return json.load(f)[key]

if __name__ == '__main__':
    main()
