from datetime import datetime
from os.path import isfile

from git_flow.git import Commit


class Changelog:
    FILENAME = "CHANGELOG.md"
    COMMIT_MESSAGE = "chore: bump version and update CHANGELOG.md [skip ci]"

    def update(self, title: str, commits: list[Commit]):
        self._prepend(self.generate_entry(title, commits))

    def generate_header(self, title):
        now = datetime.now()

        return f"""## {title} - {now.strftime("%F")}

"""

    def generate_content(self, commits: list[Commit]):
        content = ""

        for commit in commits:
            message = commit.subject
            email = commit.email
            username = email[: email.index("@")] if "@" in email else email
            description = message

            if ":" in message:
                index = message.index(":")
                commit_type = message[:index]
                commit_message = message[index + 1 :]
                description = f"**{commit_type}**: {commit_message}"

            content += f"- {description} [[{username}](mailto:{email})] ({commit.sha})\n"

        return content

    def generate_footer(self):
        return """
---


"""

    def generate_entry(self, title: str, commits: list[Commit]):
        return (
            self.generate_header(title)
            + self.generate_content(commits)
            + self.generate_footer()
        )

    def _prepend(self, content: str):
        if isfile(self.FILENAME):
            with open(self.FILENAME, "r") as f:
                content += f.read()

        with open(self.FILENAME, "w") as f:
            f.write(content)