import copy

import bs4
from bs4.element import NavigableString


class PreparedMessage:
    allowed_tags = (
        "b",
        "strong",
        "i",
        "em",
        "s",
        "strike",
        "del",
        "code",
        "pre",
        "a",
        "br",
        "p",
    )

    def __init__(self, html: str) -> None:
        self._soup = bs4.BeautifulSoup(html, "html.parser")
        self._clean()

    def _clean(self) -> None:
        # Remove disallowed tags
        for tag in self._soup.find_all(True):
            if isinstance(tag, bs4.Tag) and tag.name not in self.allowed_tags:
                tag.unwrap()

        # Replace <br> with line breaks
        for br in self._soup.find_all("br"):
            br.replace_with(NavigableString("\n"))

        # Replace <p> with its content + line break
        for p in self._soup.find_all("p"):
            content = p.get_text()
            p.replace_with(NavigableString(f"{content}\n"))

    def to_whatsapp(self) -> str:
        soup = copy.deepcopy(self._soup)
        formatting = {
            ("b", "strong"): "*",
            ("i", "em"): "_",
            ("s", "strike", "del"): "~",
            ("code",): "`",
            ("pre",): "```",
        }

        for tags, symbol in formatting.items():
            for tag in soup.find_all(tags):
                content = tag.get_text()
                if symbol == "```":
                    replacement = f"{symbol}\n{content}\n{symbol}"
                else:
                    replacement = f"{symbol}{content}{symbol}"
                tag.replace_with(NavigableString(replacement))

        # Convert <a> to "text (url)" only in WhatsApp
        for a in soup.find_all("a"):
            if not isinstance(a, bs4.Tag):
                continue
            text = a.get_text()
            href = a.get("href", "")
            if href and isinstance(href, str) and not href.startswith("javascript:"):
                replacement = href.strip()
            else:
                replacement = text
            a.replace_with(NavigableString(replacement))

        text = soup.get_text()
        lines = [line.strip() for line in text.splitlines()]
        return "\n".join(line for line in lines if line)

    def to_sms(self) -> str:
        soup = copy.deepcopy(self._soup)

        # Remove all tags
        for tag in soup.find_all(True):
            tag.replace_with(NavigableString(tag.get_text()))

        text = soup.get_text()
        lines = [line.strip() for line in text.splitlines() if line.strip()]
        return "\n".join(lines)