#import os
import os.path
import re
import urllib
import xml.dom.minidom

from systemtest.util import printAndFlush

class ArtifactRepository():
    """
    Abstract artifact repository which keeps artifacts in a local repository folder.
    The main method is getPathToArtifact() which returns the path to the requested artifact in the repository.
    Concrete subclasses have to implement downloadArtifact().
    """
    def __init__(self, localRepositoryFolder):
        """
        Creates a new instance for the specified folder. The folder will be created if it does not exist. 
        """
        self.localRepositoryFolder = localRepositoryFolder
        if not os.path.exists(localRepositoryFolder):
            os.makedirs(localRepositoryFolder)
        printAndFlush("Artifact repository: %s" % localRepositoryFolder)
            
    def clear(self):
        """
        Removes all artifacts in the local repository folder.
        """
        for f in os.listdir(self.localRepositoryFolder):
            path = "%s/%s" % (self.localRepositoryFolder, f)
            if os.path.isfile(path):
                os.remove(path)
        printAndFlush("Artifact repository cleared.")
        
    def getPathToArtifact(self, project, pattern='.*'):
        """
        Returns the path to artifact requested by the specified pattern and project.
        The pattern is a regular expression which has to match the beginning of the artifact file name.
        The project specifies the project on CI server to download the artifact.
        
        An Exception is raised if non or more than one artifact matches the pattern.  
        """
        files = [f for f in os.listdir(self.localRepositoryFolder) if re.match(pattern, f)]
        if len(files) > 1:
            raise Exception("More than one artifact in '%s' matches the pattern '%s': %s" 
                            % (self.localRepositoryFolder, pattern, files))
        if len(files) == 0:
            f = self.downloadArtifact(project, pattern)
        else:
            f = files[0]
        return "%s/%s" % (self.localRepositoryFolder, f)
    
    def downloadArtifact(self, project, pattern):
        """
        Abstract method which needs to be implemented by subclasses.
        """
        pass
        
    def _download(self, readHandle, fileName):
        filePath = "%s/%s" % (self.localRepositoryFolder, fileName)
        writeHandle = open(filePath, 'wb')
        try:
            blockSize = 8192
            while True:
                dataBlock = readHandle.read(blockSize)
                if not dataBlock:
                    break
                writeHandle.write(dataBlock)
        finally:
            writeHandle.close()
    
class JenkinsArtifactRepository(ArtifactRepository):
    """
    Artifact repository for a CI server based on Jenkins.
    """
    def __init__(self, baseUrl, localRepositoryFolder):
        """
        Creates a new instance for the specified server URL and local repository.
        """
        ArtifactRepository.__init__(self, localRepositoryFolder)
        self.baseUrl = baseUrl
        
    def downloadArtifact(self, project, pattern):
        """
        Downloads the requested artifact from Jenkins. It uses the Jenkins API.
        """
        projectUrl = "%s/job/%s" % (self.baseUrl, project)
        handle = urllib.urlopen("%s/lastSuccessfulBuild/api/xml?xpath=//artifact&wrapper=bag" % projectUrl)
        url = None
        fileName = None
        dom = xml.dom.minidom.parseString(handle.read())
        for element in dom.getElementsByTagName('artifact'):
            elementFileName = element.getElementsByTagName('fileName')[0].firstChild.nodeValue
            if re.match(pattern, elementFileName):
                if fileName != None:
                    raise Exception("Pattern '%s' matches at least two artifacts in project '%s': %s and %s" 
                                    % (pattern, project, fileName, elementFileName))
                fileName = elementFileName
                relativePath = element.getElementsByTagName('relativePath')[0].firstChild.nodeValue
                url = "%s/lastSuccessfulBuild/artifact/%s" % (projectUrl, relativePath)
        if url == None:
            raise Exception("For pattern '%s' no artifact found in project '%s'." % (pattern, project))
        printAndFlush("Download %s to %s." % (url, self.localRepositoryFolder))
        self._download(urllib.urlopen(url), fileName)
        return fileName
    
class GitHubArtifactReporistory(ArtifactRepository):
    """
    Artifact repository for a GitHub project.
    """
    def __init__(self, localRepositoryFolder):
        ArtifactRepository.__init__(self, localRepositoryFolder)

    def downloadArtifact(self, project, pattern):
        url = "https://github.com/%s/archive/%s" % (project, pattern)
        printAndFlush("Download %s to %s." % (url, self.localRepositoryFolder))
        self._download(urllib.urlopen(url), pattern)
        return pattern