# Helper script to set up Verificarlo CI on the current branch

import git

import sys
import os
from jinja2 import Environment, FileSystemLoader

##########################################################################

# Helper functions


def gen_readme(dev_branch, ci_branch):

    # Init template loader
    path = os.path.dirname(os.path.abspath(__file__))
    env = Environment(loader=FileSystemLoader(path))
    template = env.get_template("workflow_templates/ci_README.j2.md")

    # Render template
    render = template.render(dev_branch=dev_branch, ci_branch=ci_branch)

    # Write template
    with open("README.md", "w") as fh:
        fh.write(render)


def gen_workflow(git_host, dev_branch, ci_branch, repo):

    # Init template loader
    path = os.path.dirname(os.path.abspath(__file__))
    env = Environment(loader=FileSystemLoader(path))

    if git_host == "github":
        # Load template
        template = env.get_template(
            "workflow_templates/vfc_test_workflow.j2.yml")

        # Render it
        render = template.render(dev_branch=dev_branch, ci_branch=ci_branch)

        # Write the file
        filename = ".github/workflows/vfc_test_workflow.yml"
        os.makedirs(os.path.dirname(filename), exist_ok=True)
        with open(filename, "w") as fh:
            fh.write(render)

    if git_host == "gitlab":
        template = env.get_template("workflow_templates/gitlab-ci.j2.yml")

        # Ask for the user who will run the jobs (Gitlab specific)
        username = input(
            "[vfc_ci] Enter the name of the user who will run the CI jobs:")
        email = input(
            "[vfc_ci] Enter the e-mail of the user who will run the CI jobs:")

        remote_url = repo.remotes[0].config_reader.get("url")
        remote_url = remote_url.replace("http://", "")
        remote_url = remote_url.replace("https://", "")

        render = template.render(
            dev_branch=dev_branch,
            ci_branch=ci_branch,
            username=username,
            email=email,
            remote_url=remote_url
        )

        filename = ".gitlab-ci.yml"
        with open(filename, "w") as fh:
            fh.write(render)


##########################################################################

def setup(git_host):

    # Init repo and make sure that the workflow setup is possible

    repo = git.Repo(".")
    repo.remotes.origin.fetch()

    # Make sure that repository is clean
    assert(not repo.is_dirty()), "Error [vfc_ci]: Unstaged changes detected " \
        "in your work tree."

    dev_branch = repo.active_branch
    dev_branch_name = str(dev_branch)
    dev_remote = dev_branch.tracking_branch()

    # Make sure that the active branch (on which to setup the workflow) has a
    # remote
    assert(dev_remote is not None), "Error [vfc_ci]: The current branch doesn't " \
        "have a remote."

    # Make sure that we are not behind the remote (so we can push safely later)
    rev = "%s...%s" % (dev_branch_name, str(dev_remote))
    commits_behind = list(repo.iter_commits(rev))
    assert(commits_behind == []), "Error [vfc_ci]: The local branch seems " \
        "to be at least one commit behind remote."

    # Commit the workflow on the current (dev) branch

    ci_branch_name = "vfc_ci_%s" % dev_branch_name
    gen_workflow(git_host, dev_branch_name, ci_branch_name, repo)
    repo.git.add(".")
    repo.index.commit("[auto] Set up Verificarlo CI on this branch")
    repo.remote(name="origin").push()

    # Create the CI branch (orphan branch with a readme on it)
    # (see : https://github.com/gitpython-developers/GitPython/issues/615)

    repo.head.reference = git.Head(repo, "refs/heads/" + ci_branch_name)

    repo.index.remove(["*"])
    gen_readme(dev_branch_name, ci_branch_name)
    repo.index.add(["README.md"])

    repo.index.commit(
        "[auto] Create the Verificarlo CI branch for %s" % dev_branch_name,
        parent_commits=None
    )
    repo.remote(name="origin").push(
        refspec="%s:%s" % (ci_branch_name, ci_branch_name)
    )

    # Force checkout back to the original (dev) branch
    repo.git.checkout(dev_branch_name, force=True)

    # Print termination messages

    print(
        "Info [vfc_ci]: A Verificarlo CI workflow has been setup on "
        "%s." % dev_branch_name
    )
    print(
        "Info [vfc_ci]: Make sure that you have a \"vfc_tests_config.json\" on "
        "this branch. You can also perform a \"vfc_ci test\" dry run before "
        "pushing other commits.")

    if git_host == "gitlab":
        print(
            "Info [vfc_ci]: Since you are using GitLab, make sure that you "
            "have created an access token for the user you specified (registered "
            "as a variable called \"CI_PUSH_TOKEN\" in your repository).")