from __future__ import annotations

import json
from io import BytesIO

from fastapi import FastAPI, File, Form, HTTPException, UploadFile
from fastapi.responses import JSONResponse, Response

from app.image_io import ImageLoadError, load_image_from_bytes, load_image_from_url
from app.models import CardRenderRequest
from app.render import render_nova_artwork_v1

app = FastAPI(title="card-renderer", version="1.0.0")

# Supported templates (extend here as new templates are added)
_TEMPLATES = [
    {
        "key": "nova-artwork-v1",
        "label": "Skinbase Nova Artwork Card v1",
        "supports": ["url", "file"],
        "recommended_sizes": [
            {"width": 1200, "height": 630},
            {"width": 1600, "height": 900},
            {"width": 1080, "height": 1080},
        ],
    }
]


@app.get("/health")
async def health():
    return {"ok": True, "service": "card-renderer"}


@app.get("/templates")
async def templates():
    return {"items": _TEMPLATES}


@app.post("/render")
async def render(payload: CardRenderRequest):
    """Render a card from a remote image URL. Returns binary image bytes."""
    try:
        image = await load_image_from_url(str(payload.image_url))
    except ImageLoadError as exc:
        raise HTTPException(status_code=400, detail=str(exc))
    except Exception as exc:
        raise HTTPException(status_code=502, detail=f"Failed to fetch image: {exc}")

    try:
        rendered, _ = render_nova_artwork_v1(
            source=image,
            width=payload.width,
            height=payload.height,
            title=payload.title,
            subtitle=payload.subtitle,
            username=payload.username,
            category=payload.category,
            show_logo=payload.show_logo,
        )
        return _image_response(rendered, payload.output, payload.quality)
    except Exception as exc:
        raise HTTPException(status_code=500, detail=f"Render failed: {exc}")


@app.post("/render/file")
async def render_file(
    file: UploadFile = File(...),
    template: str = Form("nova-artwork-v1"),
    width: int = Form(1200),
    height: int = Form(630),
    output: str = Form("webp"),
    quality: int = Form(90),
    title: str | None = Form(None),
    subtitle: str | None = Form(None),
    username: str | None = Form(None),
    category: str | None = Form(None),
    tags_json: str | None = Form(None),
    show_logo: bool = Form(True),
):
    """Render a card from an uploaded image file. Returns binary image bytes."""
    _ = json.loads(tags_json) if tags_json else []  # validate JSON early; unused in v1

    try:
        image = load_image_from_bytes(await file.read())
    except ImageLoadError as exc:
        raise HTTPException(status_code=400, detail=str(exc))

    try:
        rendered, _ = render_nova_artwork_v1(
            source=image,
            width=width,
            height=height,
            title=title,
            subtitle=subtitle,
            username=username,
            category=category,
            show_logo=show_logo,
        )
        return _image_response(rendered, output, quality)
    except Exception as exc:
        raise HTTPException(status_code=500, detail=f"Render failed: {exc}")


@app.post("/render/meta")
async def render_meta(payload: CardRenderRequest):
    """Return layout and crop metadata without producing an image (dry run)."""
    try:
        image = await load_image_from_url(str(payload.image_url))
    except ImageLoadError as exc:
        raise HTTPException(status_code=400, detail=str(exc))
    except Exception as exc:
        raise HTTPException(status_code=502, detail=f"Failed to fetch image: {exc}")

    try:
        _, crop_box = render_nova_artwork_v1(
            source=image,
            width=payload.width,
            height=payload.height,
            title=payload.title,
            subtitle=payload.subtitle,
            username=payload.username,
            category=payload.category,
            show_logo=payload.show_logo,
        )
    except Exception as exc:
        raise HTTPException(status_code=500, detail=f"Render failed: {exc}")

    return JSONResponse(
        {
            "template": payload.template,
            "width": payload.width,
            "height": payload.height,
            "crop_box": list(crop_box),
            "safe_area": {
                "left": 48,
                "right": payload.width - 48,
                "top": 36,
                "bottom": payload.height - 36,
            },
            "theme": payload.theme,
        }
    )


# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

def _image_response(img, output: str, quality: int) -> Response:
    """Encode a PIL image and return it as an HTTP Response."""
    fmt = "JPEG" if output.lower() in ("jpg", "jpeg") else output.upper()
    # JPEG does not support alpha
    save_img = img.convert("RGB") if fmt == "JPEG" else img

    buf = BytesIO()
    save_kwargs: dict = {}
    if fmt in ("WEBP", "JPEG"):
        save_kwargs["quality"] = quality

    save_img.save(buf, format=fmt, **save_kwargs)

    media_type = "image/jpeg" if fmt == "JPEG" else f"image/{output.lower()}"
    return Response(content=buf.getvalue(), media_type=media_type)