"""清洗引擎：按规则顺序应用，输出清洗后文本 + 统计报告。"""

from __future__ import annotations

import difflib
from dataclasses import dataclass, field
from pathlib import Path
from typing import Dict, List, Optional

from cleaner.rules import REGISTRY, Rule, load_rules


@dataclass
class CleanResult:
    """一次清洗的结果：产物 + 可审计的统计。"""

    text: str
    stats: Dict[str, int] = field(default_factory=dict)
    rules_applied: List[str] = field(default_factory=list)

    @property
    def total_hits(self) -> int:
        return sum(v for k, v in self.stats.items() if k != "collapsed_blanks")


class MarkdownCleaner:
    def __init__(self, rules: Optional[List[Rule]] = None, rules_path: Optional[Path] = None):
        self.rules = rules if rules is not None else load_rules(rules_path)

    def clean_text(self, text: str) -> CleanResult:
        stats: Dict[str, int] = {}
        applied: List[str] = []
        for rule in self.rules:
            if not rule.enabled:
                continue
            func = REGISTRY[rule.name]
            text = func(text, rule.params, stats)
            applied.append(rule.name)
        return CleanResult(text=text, stats=stats, rules_applied=applied)

    def clean_file(self, src: Path, dst: Optional[Path] = None) -> CleanResult:
        raw = Path(src).read_text(encoding="utf-8")
        result = self.clean_text(raw)
        if dst is not None:
            Path(dst).parent.mkdir(parents=True, exist_ok=True)
            Path(dst).write_text(result.text, encoding="utf-8")
        return result

    @staticmethod
    def diff(before: str, after: str, context: int = 1) -> str:
        return "\n".join(
            difflib.unified_diff(
                before.splitlines(), after.splitlines(),
                fromfile="before", tofile="after", lineterm="", n=context,
            )
        )