"""RuleSetRepository — loads SubtitleRuleSet from .alfred/ YAML files."""

import logging
from pathlib import Path
from typing import TYPE_CHECKING

import yaml

from alfred.domain.subtitles.aggregates import SubtitleRuleSet
from alfred.domain.subtitles.value_objects import RuleScope

if TYPE_CHECKING:
    from alfred.infrastructure.persistence.memory.ltm.components.subtitle_preferences import (
        SubtitlePreferences,
    )

logger = logging.getLogger(__name__)


def _load_yaml(path: Path) -> dict:
    if not path.exists():
        return {}
    try:
        with open(path, encoding="utf-8") as f:
            return yaml.safe_load(f) or {}
    except Exception as e:
        logger.warning(f"RuleSetRepository: could not read {path}: {e}")
        return {}


class RuleSetRepository:
    """
    Builds a fully chained SubtitleRuleSet by reading YAML from .alfred/.

    Inheritance chain:
        global (hardcoded defaults)
          └── release_group  (.alfred/release_groups/{GROUP}.yaml)
                └── local     (.alfred/rules.yaml)

    Rules are delta-only — None means "inherit from parent".
    The repository only creates intermediate nodes when the corresponding
    file exists and contains an override section.
    """

    def __init__(self, library_root: Path):
        self._alfred_dir = library_root / ".alfred"

    def load(
        self,
        release_group: str | None = None,
        subtitle_preferences: SubtitlePreferences | None = None,
    ) -> SubtitleRuleSet:
        """
        Build and return the resolved RuleSet chain.

        If subtitle_preferences is provided, it seeds the global base rule set
        from LTM (overriding the hardcoded DEFAULT_RULES).
        Returns global default if no overrides exist.
        """
        base = SubtitleRuleSet.global_default()
        if subtitle_preferences is not None:
            base.override(
                languages=subtitle_preferences.languages,
                formats=subtitle_preferences.formats,
                types=subtitle_preferences.types,
            )
        current = base

        # Release group level
        if release_group:
            rg_path = self._alfred_dir / "release_groups" / f"{release_group}.yaml"
            rg_data = _load_yaml(rg_path).get("override", {})
            if rg_data:
                rg_ruleset = SubtitleRuleSet(
                    scope=RuleScope(level="release_group", identifier=release_group),
                    parent=current,
                )
                rg_ruleset.override(**_filter_override(rg_data))
                current = rg_ruleset
                logger.debug(
                    f"RuleSetRepository: loaded release_group override for '{release_group}'"
                )

        # Local (show/movie) level
        local_data = _load_yaml(self._alfred_dir / "rules.yaml").get("override", {})
        if local_data:
            local_ruleset = SubtitleRuleSet(
                scope=RuleScope(level="show"),
                parent=current,
            )
            local_ruleset.override(**_filter_override(local_data))
            current = local_ruleset
            logger.debug("RuleSetRepository: loaded local rules.yaml override")

        return current

    def save_local(self, delta: dict) -> None:
        """Write or update .alfred/rules.yaml with override delta."""
        self._alfred_dir.mkdir(parents=True, exist_ok=True)
        path = self._alfred_dir / "rules.yaml"
        existing = _load_yaml(path)
        existing_override = existing.get("override", {})
        existing_override.update(delta)
        data = {"override": existing_override}
        tmp = path.with_suffix(".yaml.tmp")
        try:
            with open(tmp, "w", encoding="utf-8") as f:
                yaml.safe_dump(
                    data,
                    f,
                    allow_unicode=True,
                    default_flow_style=False,
                    sort_keys=False,
                )
            tmp.rename(path)
            logger.info(f"RuleSetRepository: saved local rules to {path}")
        except Exception as e:
            logger.error(f"RuleSetRepository: could not write {path}: {e}")
            tmp.unlink(missing_ok=True)
            raise


def _filter_override(data: dict) -> dict:
    """Keep only keys that SubtitleRuleSet.override() accepts."""
    valid = {"languages", "formats", "types", "format_priority", "min_confidence"}
    return {k: v for k, v in data.items() if k in valid}