from __future__ import annotations

from typing import Dict

import regex

from ..services.config_repo import ConfigRepository


class PatternService:
    """Builds regex patterns for the configured keywords."""

    def __init__(self, repo: ConfigRepository) -> None:
        self._repo = repo

    def load_patterns(self) -> Dict[str, regex.Pattern]:
        keywords = self._repo.read_keywords()
        word_patterns: Dict[str, regex.Pattern] = {}
        emoji_pattern = (
            r"[\U0001F600-\U0001F64F\U0001F300-\U0001F5FF"
            r"\U0001F680-\U0001F6FF\U0001F1E0-\U0001F1FF]"
        )

        for word in keywords:
            original_word = word
            if word.endswith("**"):
                word = word[:-2]
                pattern = rf"\b(?i)(?:{emoji_pattern})*{regex.escape(word)}\p{{L}}{{0,6}}\b"
            elif word.endswith("*"):
                word = word[:-1]
                pattern = rf"\b(?i)(?:{emoji_pattern})*{regex.escape(word)}\p{{L}}{{0,3}}\b"
            elif word.startswith("##"):
                word = word[2:]
                pattern = rf"(?i)(?:{emoji_pattern})*(?<=\b\d{{0,6}}){regex.escape(word)}\b"
            elif word.startswith("#"):
                word = word[1:]
                pattern = rf"(?i)(?:{emoji_pattern})*(?<=\b\d{{0,3}}){regex.escape(word)}\b"
            else:
                pattern = rf"\b(?i)(?:{emoji_pattern})*{regex.escape(word)}\b"
            try:
                compiled = regex.compile(pattern)
                word_patterns[original_word] = compiled
            except regex.error as exc:
                # Skip invalid patterns but continue building others.
                print(f"Invalid regex pattern for '{original_word}': {exc}")
        return word_patterns

    @staticmethod
    def escape_markdown(text: str) -> str:
        return regex.sub(r"(\*\*)", "* *", text)