#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Finding potential software vulnerabilities from git commit messages
#
# Software is free software released under the "GNU Affero General Public License v3.0"
#
# This software is part of cve-search.org
#
# Copyright (c) 2019-2020 Alexandre Dulaunoy - a@foo.be

import git
import re
import sys
import typing
from langdetect import detect as langdetect

from git_vuln_finder import get_patterns


def find(repo, tags_matching=False, commit_state="under-review", verbose=False, defaultpattern="all"):
    # Initialization of the variables for the results
    repo = git.Repo(repo)
    found = 0
    all_potential_vulnerabilities = {}
    all_cve_found = set()

    # Initialization of the patterns
    patterns = get_patterns()
    vulnpatterns = patterns["en"]["medium"]["vuln"]
    cryptopatterns = patterns["en"]["medium"]["crypto"]
    cpatterns = patterns["en"]["medium"]["c"]

    if defaultpattern == "vulnpatterns":
        defaultpattern = vulnpatterns
    elif defaultpattern == "cryptopatterns":
        defaultpattern = cryptopatterns
    elif defaultpattern == "cpatterns":
        defaultpattern = cpatterns
    elif defaultpattern == "all":
        defaultpattern = [vulnpatterns, cryptopatterns, cpatterns]

    repo_heads = repo.heads
    repo_heads_names = [h.name for h in repo_heads]
    print(repo_heads_names, file=sys.stderr)
    origin = repo.remotes.origin.url
    tagmap = {}
    if tags_matching:
        for t in repo.tags:
            tagmap.setdefault(repo.commit(t).hexsha, []).append(str(t))

    for branch in repo_heads_names:
        commits = list(repo.iter_commits(branch))
        defaultpattern
        for commit in commits:
            if isinstance(defaultpattern, typing.Pattern):
                ret = find_vuln(commit, pattern=defaultpattern, verbose=verbose)
                if ret:
                    rcommit = ret["commit"]
                    _, potential_vulnerabilities, cve_found = summary(
                        repo,
                        rcommit,
                        branch,
                        tagmap,
                        defaultpattern,
                        origin=origin,
                        vuln_match=ret["match"],
                        tags_matching=tags_matching,
                        commit_state=commit_state,
                    )
                    all_potential_vulnerabilities.update(potential_vulnerabilities)
                    all_cve_found.update(cve_found)
                    found += 1
            elif isinstance(defaultpattern, list):
                for p in defaultpattern:
                    ret = find_vuln(commit, pattern=p, verbose=verbose)
                    if ret:
                        rcommit = ret["commit"]
                        _, potential_vulnerabilities, cve_found = summary(
                            repo,
                            rcommit,
                            branch,
                            tagmap,
                            p,
                            origin=origin,
                            vuln_match=ret["match"],
                            tags_matching=tags_matching,
                            commit_state=commit_state,
                        )
                        all_potential_vulnerabilities.update(potential_vulnerabilities)
                        all_cve_found.update(cve_found)
                        found += 1

        return all_potential_vulnerabilities, all_cve_found, found


def find_vuln(commit, pattern, verbose=False):
    """Find a potential vulnerability from a commit message thanks to a regex
    pattern.
    """
    m = pattern.search(commit.message)
    if m:
        if verbose:
            print("Match found: {}".format(m.group(0)), file=sys.stderr)
            print(commit.message, file=sys.stderr)
            print("---", file=sys.stderr)
        ret = {}
        ret["commit"] = commit
        ret["match"] = m.groups()
        return ret
    else:
        return None


def summary(
    repo,
    commit,
    branch,
    tagmap,
    pattern,
    origin=None,
    vuln_match=None,
    tags_matching=False,
    commit_state="under-review",
):
    potential_vulnerabilities = {}
    rcommit = commit
    cve, cve_found = extract_cve(rcommit.message)
    if origin is not None:
        origin = origin
        if origin.find("github.com"):
            origin_github_api = origin.split(":")[1]
            (org_name, repo_name) = origin_github_api.split("/", 1)
            if repo_name.find(".git$"):
                repo_name = re.sub(r".git$", "", repo_name)
            origin_github_api = "https://api.github.com/repos/{}/{}/commits/{}".format(
                org_name, repo_name, rcommit.hexsha
            )

    else:
        origin = "git origin unknown"
    # deduplication if similar commits on different branches
    if rcommit.hexsha in potential_vulnerabilities:
        potential_vulnerabilities[rcommit.hexsha]["branches"].append(branch)
    else:
        potential_vulnerabilities[rcommit.hexsha] = {}
        potential_vulnerabilities[rcommit.hexsha]["message"] = rcommit.message
        potential_vulnerabilities[rcommit.hexsha]["language"] = langdetect(
            rcommit.message
        )
        potential_vulnerabilities[rcommit.hexsha]["commit-id"] = rcommit.hexsha
        potential_vulnerabilities[rcommit.hexsha]["summary"] = rcommit.summary
        potential_vulnerabilities[rcommit.hexsha]["stats"] = rcommit.stats.total
        potential_vulnerabilities[rcommit.hexsha]["author"] = rcommit.author.name
        potential_vulnerabilities[rcommit.hexsha]["author-email"] = rcommit.author.email
        potential_vulnerabilities[rcommit.hexsha][
            "authored_date"
        ] = rcommit.authored_date
        potential_vulnerabilities[rcommit.hexsha][
            "committed_date"
        ] = rcommit.committed_date
        potential_vulnerabilities[rcommit.hexsha]["branches"] = []
        potential_vulnerabilities[rcommit.hexsha]["branches"].append(branch)
        potential_vulnerabilities[rcommit.hexsha]["pattern-selected"] = pattern.pattern
        potential_vulnerabilities[rcommit.hexsha]["pattern-matches"] = vuln_match
        potential_vulnerabilities[rcommit.hexsha]["origin"] = origin
        if origin_github_api:
            potential_vulnerabilities[commit.hexsha][
                "origin-github-api"
            ] = origin_github_api
        potential_vulnerabilities[rcommit.hexsha]["tags"] = []
        if tags_matching:
            if repo.commit(rcommit).hexsha in tagmap:
                potential_vulnerabilities[rcommit.hexsha]["tags"] = tagmap[
                    repo.commit(rcommit).hexsha
                ]
        if cve:
            potential_vulnerabilities[rcommit.hexsha]["cve"] = cve
            potential_vulnerabilities[rcommit.hexsha]["state"] = "cve-assigned"
        else:
            potential_vulnerabilities[rcommit.hexsha]["state"] = commit_state

    return rcommit.hexsha, potential_vulnerabilities, cve_found


def extract_cve(commit):
    cve_found = set()
    cve_find = re.compile(r"CVE-[1-2]\d{1,4}-\d{1,7}", re.IGNORECASE)
    m = cve_find.findall(commit)
    if m:
        for v in m:
            cve_found.add(v)
        return m, cve_found
    else:
        return None, set()