from __future__ import annotations

from datetime import datetime
from typing import List, Optional
from uuid import uuid4

from pydantic import BaseModel, Field


def generate_id() -> str:
    """Generate deterministic-looking ids for templates and categories."""
    return uuid4().hex


class VariableDefinition(BaseModel):
    """Schema describing each dynamic input value for a template."""

    name: str = Field(..., description="变量唯一名称，用于在模板中引用")
    label: str = Field(..., description="变量可视化展示名称")
    description: Optional[str] = Field(None, description="变量说明提示")
    data_type: str = Field(
        "string",
        description="变量类型, 例如 string/number/boolean/options",
    )
    required: bool = Field(False, description="是否为必填字段")
    default: Optional[str] = Field(None, description="默认值")


class TemplateBase(BaseModel):
    name: str
    category: str
    description: Optional[str] = None
    output_description: Optional[str] = None
    call_method: Optional[str] = None
    input_variables: List[VariableDefinition] = Field(default_factory=list)
    template_body: str = Field(..., description="Jinja2 模板正文")


class TemplateCreate(TemplateBase):
    pass


class TemplateUpdate(BaseModel):
    name: Optional[str] = None
    category: Optional[str] = None
    description: Optional[str] = None
    output_description: Optional[str] = None
    call_method: Optional[str] = None
    input_variables: Optional[List[VariableDefinition]] = None
    template_body: Optional[str] = None


class TemplateRecord(TemplateBase):
    id: str = Field(default_factory=generate_id)
    created_at: datetime = Field(default_factory=datetime.utcnow)
    updated_at: datetime = Field(default_factory=datetime.utcnow)


class TemplateRenderRequest(BaseModel):
    template_id: str
    parameters: dict


class TemplatePreviewRequest(BaseModel):
    template_body: str
    parameters: dict = Field(default_factory=dict)


class TemplateRenderResponse(BaseModel):
    rendered_text: str