from __future__ import annotations

from typing import Any

from jinja2 import Template

from .types import Prompt


class PromptRegistry:
    """Prompt 模板库：注册/取用/版本管理/渲染（集中管理待迁移 prompts/ 目录）。"""

    def __init__(self) -> None:
        self._templates: dict[tuple[str, str], str] = {}

    def register(self, name: str, version: str, template: str) -> None:
        """注册（或覆盖）一个版本的模板。"""
        self._templates[(name, version)] = template

    def get(
        self,
        name: str,
        version: str | None = None,
        variables: dict[str, Any] | None = None,
    ) -> str:
        """取模板；version=None 返回该 name 最新注册版本；variables 非空时渲染。"""
        if version is None:
            versions = self.list_versions(name)
            if not versions:
                raise KeyError(f"prompt not found: {name}")
            version = versions[-1]
        key = (name, version)
        if key not in self._templates:
            raise KeyError(f"prompt version not found: {name}@{version}")
        template = self._templates[key]
        if variables:
            return self.render(template, variables)
        return template

    def list_versions(self, name: str) -> list[str]:
        """返回某 name 的已注册版本（按注册顺序）。"""
        return [v for (n, v) in self._templates if n == name]

    def render(self, template: str, variables: dict[str, Any]) -> str:
        """用 jinja2 渲染模板。"""
        from jinja2 import Template

        return Template(template).render(**variables)