from __future__ import annotations

import json
from pathlib import Path
from typing import Any

from agente_contas_tim.workflows.contracts import WorkflowDef
from agente_contas_tim.workflows.exceptions import (
    WorkflowConfigurationError,
    WorkflowNotFoundError,
)


class FileWorkflowRepository:
    """Repositório de workflow baseado em arquivos no disco.

    Convenções suportadas:
    - Versão explícita: ``<name>.v<version>.json|yaml|yml``
    - Ativo por ponteiro: ``<name>.active.json|yaml|yml``
      - Pode conter um inteiro: ``{"version": 3}``
      - Ou conter o workflow completo.
    - Sem ponteiro ativo: usa maior versão disponível.
    """

    def __init__(self, base_dir: str | Path) -> None:
        self._base_dir = Path(base_dir)

    def get_active(self, name: str) -> WorkflowDef:
        self._ensure_base_dir()
        active = self._find_active_file(name)
        if active is not None:
            loaded = self._load_dict(active)
            if self._is_workflow_dict(loaded):
                return WorkflowDef.model_validate(loaded)
            version = loaded.get("version")
            if not isinstance(version, int):
                raise WorkflowConfigurationError(
                    f"Arquivo ativo inválido: {active}. "
                    "Esperado {'version': <int>} ou workflow completo."
                )
            return self.get_version(name, version)

        versions = self._list_versions(name)
        if not versions:
            raise WorkflowNotFoundError(f"Workflow {name!r} não encontrado")
        return self.get_version(name, max(versions))

    def get_version(self, name: str, version: int) -> WorkflowDef:
        self._ensure_base_dir()
        candidate = self._find_version_file(name, version)
        if candidate is not None:
            return WorkflowDef.model_validate(self._load_dict(candidate))

        raise WorkflowNotFoundError(
            f"Workflow {name!r} v{version} não encontrado em {self._base_dir}"
        )

    def _ensure_base_dir(self) -> None:
        if not self._base_dir.exists():
            raise WorkflowConfigurationError(
                f"Diretório de workflows não existe: {self._base_dir}"
            )

    def _find_active_file(self, name: str) -> Path | None:
        return self._find_unique_file(
            [f"{name}.active.json", f"{name}.active.yaml", f"{name}.active.yml"],
            not_found_message=None,
            ambiguous_message=(
                "Múltiplos ponteiros ativos encontrados para "
                f"{name!r} em {self._base_dir}. "
                "Mantenha apenas um arquivo <name>.active.<ext>."
            ),
        )

    def _list_versions(self, name: str) -> list[int]:
        versions: list[int] = []
        for file in self._base_dir.rglob(f"{name}.v*.*"):
            suffixes = file.suffixes
            if not suffixes:
                continue
            ext = suffixes[-1]
            if ext not in {".json", ".yaml", ".yml"}:
                continue
            stem = file.stem
            # stem ex.: vas_decision.v1
            if ".v" not in stem:
                continue
            version_str = stem.rsplit(".v", maxsplit=1)[-1]
            if version_str.isdigit():
                versions.append(int(version_str))
        return versions

    def _find_version_file(self, name: str, version: int) -> Path | None:
        return self._find_unique_file(
            [
                f"{name}.v{version}.json",
                f"{name}.v{version}.yaml",
                f"{name}.v{version}.yml",
            ],
            not_found_message=None,
            ambiguous_message=(
                f"Múltiplos workflows encontrados para {name!r} v{version} "
                f"em {self._base_dir}. Mantenha apenas um arquivo por versão."
            ),
        )

    def _find_unique_file(
        self,
        names: list[str],
        *,
        not_found_message: str | None,
        ambiguous_message: str,
    ) -> Path | None:
        matches: list[Path] = []
        for file_name in names:
            matches.extend(self._base_dir.rglob(file_name))

        if not matches:
            if not_found_message is None:
                return None
            raise WorkflowConfigurationError(not_found_message)

        unique_matches = sorted({path.resolve() for path in matches})
        if len(unique_matches) > 1:
            raise WorkflowConfigurationError(ambiguous_message)
        return unique_matches[0]

    def _load_dict(self, path: Path) -> dict[str, Any]:
        raw = path.read_text(encoding="utf-8")

        try:
            loaded = json.loads(raw)
            if not isinstance(loaded, dict):
                raise WorkflowConfigurationError(
                    f"Workflow em {path} deve ser um objeto/dict"
                )
            return loaded
        except json.JSONDecodeError:
            pass

        if path.suffix not in {".yaml", ".yml"}:
            raise WorkflowConfigurationError(f"Arquivo inválido: {path}")

        try:
            import yaml  # type: ignore
        except ModuleNotFoundError as exc:
            raise WorkflowConfigurationError(
                f"Arquivo YAML detectado em {path}, mas PyYAML não está instalado. "
                "Instale a dependência 'pyyaml' ou use JSON."
            ) from exc

        loaded_yaml = yaml.safe_load(raw)
        if not isinstance(loaded_yaml, dict):
            raise WorkflowConfigurationError(
                f"Workflow YAML em {path} deve ser um objeto/dict"
            )
        return loaded_yaml

    @staticmethod
    def _is_workflow_dict(data: dict[str, Any]) -> bool:
        return {"name", "version", "start", "nodes", "edges"} <= set(data.keys())