geo/backend/app/api/image.py

"""图片生成 API 路由"""

from typing import Optional

from fastapi import APIRouter, HTTPException, status
from pydantic import BaseModel, Field

from app.services.image_generator import (
    IMAGE_STYLES,
    LAYOUT_OPTIONS,
    ImageGenerator,
    ImageGenerationError,
    PLATFORM_IMAGE_SPECS,
)

router = APIRouter(prefix="/image", tags=["图片生成"])


class GenerateCoverRequest(BaseModel):
    """生成封面图请求"""
    title: str = Field(..., description="文章标题")
    platform: str = Field(..., description="目标平台")
    image_type: str = Field(default="cover", description="图片类型: cover/inline")
    style: str = Field(default="modern", description="风格选项")
    layout: str = Field(default="centered", description="排版选项")
    custom_prompt: Optional[str] = Field(default=None, description="自定义提示词")


class ImageResultResponse(BaseModel):
    """图片生成结果响应"""
    url: str
    width: int
    height: int
    prompt: str
    platform: str
    task_id: str


class ImageSpecsResponse(BaseModel):
    """平台图片规格响应"""
    platform: str
    specs: dict


class StyleOption(BaseModel):
    """风格选项"""
    value: str
    name: str


class LayoutOption(BaseModel):
    """排版选项"""
    value: str
    name: str


class ImageConfigResponse(BaseModel):
    """图片生成配置响应"""
    platforms: list[str]
    styles: list[StyleOption]
    layouts: list[LayoutOption]


@router.post("/generate-cover", response_model=ImageResultResponse)
async def generate_cover(request: GenerateCoverRequest):
    """生成封面图

    基于阿里云百炼（万相-文生图V1）生成封面图，自动适配目标平台的尺寸规格。

    Args:
        request: 生成请求参数

    Returns:
        ImageResultResponse: 包含图片URL和元数据

    Raises:
        HTTPException: 当平台不支持或API调用失败时
    """
    # 验证平台是否支持
    supported_platforms = ImageGenerator.get_supported_platforms()
    if request.platform not in supported_platforms:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"不支持的平台: {request.platform}，支持的平台: {', '.join(supported_platforms)}",
        )

    # 验证风格选项
    if request.style not in IMAGE_STYLES:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"不支持的风格: {request.style}，支持的风格: {', '.join(IMAGE_STYLES.keys())}",
        )

    # 验证排版选项
    if request.layout not in LAYOUT_OPTIONS:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"不支持的排版: {request.layout}，支持的排版: {', '.join(LAYOUT_OPTIONS.keys())}",
        )

    # 验证图片类型
    if request.image_type not in ("cover", "inline"):
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="图片类型只支持: cover, inline",
        )

    generator = ImageGenerator()

    try:
        result = await generator.generate_cover(
            title=request.title,
            platform=request.platform,
            image_type=request.image_type,
            style=request.style,
            layout=request.layout,
            custom_prompt=request.custom_prompt,
        )

        return ImageResultResponse(
            url=result.url,
            width=result.width,
            height=result.height,
            prompt=result.prompt,
            platform=result.platform,
            task_id=result.task_id,
        )

    except ImageGenerationError as e:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"图片生成失败: {str(e)}",
        )


@router.get("/platforms", response_model=list[str])
async def get_supported_platforms():
    """获取支持的平台列表"""
    return ImageGenerator.get_supported_platforms()


@router.get("/platforms/{platform}/specs", response_model=ImageSpecsResponse)
async def get_platform_specs(platform: str):
    """获取指定平台的图片规格

    Args:
        platform: 平台标识

    Returns:
        ImageSpecsResponse: 平台图片规格

    Raises:
        HTTPException: 当平台不支持时
    """
    specs = ImageGenerator.get_platform_specs(platform)
    if specs is None:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"不支持的平台: {platform}",
        )

    return ImageSpecsResponse(platform=platform, specs=specs)


@router.get("/config", response_model=ImageConfigResponse)
async def get_image_config():
    """获取图片生成配置（风格、排版选项等）"""
    styles = [
        StyleOption(value=key, name=value["name"])
        for key, value in IMAGE_STYLES.items()
    ]

    layouts = [
        LayoutOption(value=key, name=value["name"])
        for key, value in LAYOUT_OPTIONS.items()
    ]

    return ImageConfigResponse(
        platforms=ImageGenerator.get_supported_platforms(),
        styles=styles,
        layouts=layouts,
    )