from urlparse import urljoin, urlparse
import urllib2
import re
import StringIO
import difflib

try:
    from BeautifulSoup import BeautifulSoup
except ImportError:
    from bs4 import BeautifulSoup

import portage

from euscan import CONFIG, SCANDIR_BLACKLIST_URLS, \
    BRUTEFORCE_BLACKLIST_PACKAGES, BRUTEFORCE_BLACKLIST_URLS, output, helpers

HANDLER_NAME = "generic"
CONFIDENCE = 45
PRIORITY = 0

BRUTEFORCE_HANDLER_NAME = "brute_force"
BRUTEFORCE_CONFIDENCE = 30


def confidence_score(found, original, minimum=CONFIDENCE):
    found_p = urlparse(found)
    original_p = urlparse(original)

    # check if the base url is the same
    if found_p.netloc != original_p.netloc:
        return minimum

    # check if the directory depth is the same
    if len(found_p.path.split("/")) != len(original_p.path.split("/")):
        return minimum

    # strip numbers
    found_path = re.sub(r"[\d+\.]?", "", found_p.path)
    original_path = re.sub(r"[\d+\.]?", "", original_p.path)

    # strip the first equal part of the path
    i = 0
    max_i = len(found_path)
    while i < max_i and found_path[i] == original_path[i]:
        i += 1
    found_path = found_path[i:]
    original_path = original_path[i:]

    # calculate difference ratio
    diff = difflib.SequenceMatcher(None, found_path, original_path).ratio()
    return int(minimum + minimum * diff)  # maximum score is minimum * 2


def scan_html(data, url, pattern):
    soup = BeautifulSoup(data)
    results = []

    for link in soup.findAll('a'):
        href = link.get("href")
        if not href:
            continue

        if href.startswith(url):
            href = href.replace(url, "", 1)

        match = re.match(pattern, href, re.I)
        if match:
            results.append(
                (".".join([x for x in match.groups() if x is not None]),
                 match.group(0))
            )
    return results


def scan_ftp(data, url, pattern):
    buf = StringIO.StringIO(data)
    results = []

    for line in buf.readlines():
        line = line.replace("\n", "").replace("\r", "")
        match = re.search(pattern, line, re.I)
        if match:
            results.append(
                (".".join([x for x in match.groups() if x is not None]),
                 match.group(0))
            )
    return results


def scan_directory_recursive(cp, ver, rev, url, steps, orig_url):
    if not steps:
        return []

    url += steps[0][0]
    pattern = steps[0][1]

    steps = steps[1:]

    output.einfo("Scanning: %s" % url)

    try:
        fp = helpers.urlopen(url)
    except urllib2.URLError:
        return []
    except IOError:
        return []

    if not fp:
        return []

    data = fp.read()

    results = []

    if re.search("<\s*a\s+[^>]*href", data, re.I):
        results.extend(scan_html(data, url, pattern))
    elif url.startswith('ftp://'):
        results.extend(scan_ftp(data, url, pattern))

    versions = []

    for up_pv, path in results:
        pv = helpers.gentoo_mangle_version(up_pv)
        if helpers.version_filtered(cp, ver, pv):
            continue
        if not url.endswith("/"):
            url = url + "/"
        path = urljoin(url, path)

        if not steps and path not in orig_url:
            confidence = confidence_score(path, orig_url)
            versions.append((path, pv, HANDLER_NAME, confidence))

        if steps:
            ret = scan_directory_recursive(cp, ver, rev, path, steps, orig_url)
            versions.extend(ret)

    return versions


def scan(pkg, url):
    if CONFIG["scan-dir"]:
        for bu in SCANDIR_BLACKLIST_URLS:
            if re.match(bu, url):
                output.einfo("%s is blacklisted by rule %s" % (url, bu))
                return []

        resolved_url = helpers.parse_mirror(url)
        if not resolved_url:
            return []

        cp, ver, rev = portage.pkgsplit(pkg.cpv)

        # 'Hack' for _beta/_rc versions where _ is used instead of -
        if ver not in resolved_url:
            newver = helpers.version_change_end_sep(ver)
            if newver and newver in resolved_url:
                output.einfo(
                    "Version: using %s instead of %s" % (newver, ver)
                )
                ver = newver

        template = helpers.template_from_url(resolved_url, ver)
        if '${' not in template:
            output.einfo(
                "Url doesn't seems to depend on version: %s not found in %s" %
                (ver, resolved_url)
            )
            return []
        else:
            output.einfo("Scanning: %s" % template)

        steps = helpers.generate_scan_paths(template)
        ret = scan_directory_recursive(cp, ver, rev, "", steps, url)

    if not ret:
        ret = brute_force(pkg, url)

    return ret


def brute_force(pkg, url):
    if CONFIG["brute-force"] == 0:
        return []

    cp, ver, rev = portage.pkgsplit(pkg.cpv)

    url = helpers.parse_mirror(url)
    if not url:
        return []

    for bp in BRUTEFORCE_BLACKLIST_PACKAGES:
        if re.match(bp, cp):
            output.einfo("%s is blacklisted by rule %s" % (cp, bp))
            return []

    for bp in BRUTEFORCE_BLACKLIST_URLS:
        if re.match(bp, url):
            output.einfo("%s is blacklisted by rule %s" % (cp, bp))
            return []

    output.einfo("Generating version from " + ver)

    components = helpers.split_version(ver)
    versions = helpers.gen_versions(components, CONFIG["brute-force"])

    # Remove unwanted versions
    for v in versions:
        if helpers.vercmp(cp, ver, helpers.join_version(v)) >= 0:
            versions.remove(v)

    if not versions:
        output.einfo("Can't generate new versions from " + ver)
        return []

    template = helpers.template_from_url(url, ver)

    if '${PV}' not in template:
        output.einfo(
            "Url doesn't seems to depend on full version: %s not found in %s" %
            (ver, url))
        return []
    else:
        output.einfo("Brute forcing: %s" % template)

    result = []

    i = 0
    done = []

    while i < len(versions):
        components = versions[i]
        i += 1
        if components in done:
            continue
        done.append(tuple(components))

        version = helpers.join_version(components)

        if helpers.version_filtered(cp, ver, version):
            continue

        try_url = helpers.url_from_template(template, version)
        infos = helpers.tryurl(try_url, template)

        if not infos:
            continue
        confidence = confidence_score(try_url, url,
                                      minimum=BRUTEFORCE_CONFIDENCE)
        result.append([try_url, version, BRUTEFORCE_HANDLER_NAME, confidence])

        if len(result) > CONFIG['brute-force-false-watermark']:
            output.einfo(
                "Broken server detected ! Skipping brute force."
            )
            return []

        if CONFIG["brute-force-recursive"]:
            for v in helpers.gen_versions(list(components),
                                          CONFIG["brute-force"]):
                if v not in versions and tuple(v) not in done:
                    versions.append(v)

        if CONFIG["oneshot"]:
            break

    return result


def can_handle(pkg, url):
    return True