#!/usr/bin/env python2
from __future__ import unicode_literals

import datetime
import os
import subprocess
from contextlib import contextmanager

import frontmatter

PROJECT_DIR = os.path.abspath(os.path.dirname(__file__))
CHANGELOG_SITE_DIR = os.path.join(PROJECT_DIR, "site/changelog/")
CONTENT_DIR = os.path.join(CHANGELOG_SITE_DIR, "content/")
RELEASED_DIR = os.path.join(CONTENT_DIR, "released/")
EXPERIMENTAL_DIR = os.path.join(CONTENT_DIR, "experimental/")

INTRO_SAMPLE = "<!-- Available tags are: added, changed, deprecated, removed, fixed, performance, security -->"


@contextmanager
def project_dir():
    owd = os.getcwd()
    try:
        os.chdir(PROJECT_DIR)
        yield PROJECT_DIR
    finally:
        os.chdir(owd)


def main():
    changes = ""
    for item in os.listdir(EXPERIMENTAL_DIR):
        if item.endswith(".md"):
            changes = changes + process_change(os.path.join(EXPERIMENTAL_DIR, item))
        elif item == ".gitignore":
            pass
        else:
            print("Unexpected file: %s" % item)
    if changes:
        human_version = release(changes)
        commit_release(human_version)
    else:
        print("No changes")


def process_change(path):
    """
    Returns all changes from the file
    """
    print("Processing %s..." % path)
    with open(path, "rb") as md_file:
        data = frontmatter.load(md_file)
    os.remove(path)
    print("Removed: %s" % path)
    return data.content.replace(INTRO_SAMPLE, "")


def release(changes):
    """
    Release version - move from experimental/ to released/.
    Returns human version - the one suitable for tagging and displaying in changelog
    """
    print("Releasing changes...")
    current_internal_version = get_current_internal_version()
    human_version = increase_human_version(current_internal_version)
    data = frontmatter.loads(changes)
    data["weight"] = current_internal_version + 1
    data["subtitle"] = datetime.datetime.now().strftime("released on %Y-%m-%d")
    data["draft"] = False
    data["date"] = datetime.datetime.now()  # 2018-10-02T09:29:50Z
    data["version"] = human_version
    print("Assigning new version: %s / %s" % (data["weight"], data["version"]))
    released_file_path = os.path.join(RELEASED_DIR, "%s.md" % data["weight"])
    with open(released_file_path, "wb") as released_file:
        frontmatter.dump(data, released_file)
    print("Created: %s" % released_file_path)
    return human_version


def commit_release(human_version):
    """
    Autogenerates commit and tag
    """
    with project_dir():
        subprocess.call(["git", "add", CONTENT_DIR])
        subprocess.call(["git", "commit", "-m", "Generated by release script"])
        subprocess.call(["git", "fetch", "--tags"])
        subprocess.call(["git", "tag", "-d", "%s" % human_version])
        subprocess.call(["git", "tag", "%s" % human_version])


def get_current_internal_version():
    """
    Get current version from files in released/ folder (weight/filename)
    """
    version = 0
    files = os.listdir(RELEASED_DIR)
    files.sort(reverse=True, key=natural_sort)
    for item in files:
        if item.endswith(".md"):
            version = int(item[:-3])
            break
    return version


def increase_human_version(internal_version):
    """
    Increase human version from previous file
    """
    current_human_version = get_current_human_version(internal_version)
    ma, mi = current_human_version.split(".")
    return "%s.%s" % (ma, int(mi) + 1)


def get_current_human_version(internal_version):
    """
    Returns version from frontmatter (used for tagging and displaying)
    """
    md_path = os.path.join(RELEASED_DIR, "%s.md" % internal_version)
    with open(md_path, "rb") as md_file:
        data = frontmatter.load(md_file)
        return data["version"].strip()


def print_release_version():
    """
    Returns release version
    """
    version = get_current_human_version(get_current_internal_version())
    is_experimental = len([x for x in os.listdir(EXPERIMENTAL_DIR) if x.endswith(".md")]) > 0
    print("%s%s" % (version, "+" if is_experimental else ""))


def natural_sort(el):
    try:
        v = int(el[:-3])
    except ValueError:
        v = 0
    return v


if __name__ == "__main__":
    main()