"""Creator Vision API.

Phase 1: POST /analyze (BackgroundTasks + in-memory job store) and
GET /status/{job_id}. The analysis is currently stubbed (see analysis.py);
Phase 2 wires real SAM 3. See DesignDoc.md for the result schema.
"""

import json
import os
import shutil
import uuid
from pathlib import Path

from dotenv import load_dotenv
from fastapi import BackgroundTasks, FastAPI, File, Form, HTTPException, UploadFile
from fastapi.middleware.cors import CORSMiddleware

from .analysis import (
    BuildOpts,
    ProductInput,
    owlv2_needs_images,
    requires_name,
    requires_reference,
    run_analysis,
)
from .jobs import store
from .schemas import DetectionMode, JobResponse, StatusResponse

# Load backend/.env (and fall back to repo-root .env).
load_dotenv()

UPLOAD_DIR = Path(__file__).resolve().parent.parent / "uploads"
UPLOAD_DIR.mkdir(exist_ok=True)

app = FastAPI(title="Creator Vision API", version="0.1.0")

# Allowed browser origins. Defaults to the local Next.js dev server; in prod set
# ALLOWED_ORIGINS to your deployed frontend URL(s), comma-separated.
_origins = os.getenv("ALLOWED_ORIGINS", "http://localhost:3000")
app.add_middleware(
    CORSMiddleware,
    allow_origins=[o.strip() for o in _origins.split(",") if o.strip()],
    allow_methods=["*"],
    allow_headers=["*"],
)


@app.get("/health")
def health() -> dict:
    """Liveness + config sanity check (does the SAM3 key exist?)."""
    return {
        "status": "ok",
        "fal_key_configured": bool(os.getenv("FAL_KEY")),
    }


def _save_upload(upload: UploadFile, dest_dir: Path) -> str:
    """Persist an UploadFile under dest_dir with a collision-proof name."""
    suffix = Path(upload.filename or "").suffix
    dest = dest_dir / f"{uuid.uuid4().hex}{suffix}"
    with dest.open("wb") as f:
        shutil.copyfileobj(upload.file, f)
    return str(dest)


@app.post("/analyze", response_model=JobResponse)
def analyze(
    background_tasks: BackgroundTasks,
    video: UploadFile = File(...),
    # `products` is JSON: [{"name": str, "image_count": int}, ...]. `exemplars` is a
    # flat file list in product order, sliced back per product by `image_count`.
    products: str = Form(...),
    exemplars: list[UploadFile] = File(default=[]),
    caption: str = Form(default=""),
    mention_keywords: str = Form(default=""),
    mode: DetectionMode = Form(default=DetectionMode.sam3_text),
    split_on_cut: bool = Form(default=False),
    dino_variant: str = Form(default="v2"),
    owl_ref_type: str = Form(default="text"),  # owlv2: text | image | both
    owl_dino: str = Form(default="none"),  # owlv2 DINO-on-top: none | v2 | v3
) -> JobResponse:
    """Accept the uploads, kick off background analysis, return a job id."""
    if not video.filename:
        raise HTTPException(status_code=400, detail="A video file is required.")

    try:
        product_meta = json.loads(products)
        assert isinstance(product_meta, list) and product_meta
    except (json.JSONDecodeError, AssertionError):
        raise HTTPException(status_code=400, detail="`products` must be a non-empty JSON list.")

    job = store.create()
    job_dir = UPLOAD_DIR / job.id
    job_dir.mkdir(parents=True, exist_ok=True)

    video_path = _save_upload(video, job_dir)
    exemplar_files = [ex for ex in exemplars if ex.filename]

    # Slice the flat exemplar list back into per-product groups by image_count.
    product_inputs: list[ProductInput] = []
    cursor = 0
    for p in product_meta:
        name = str(p.get("name", "")).strip()
        count = int(p.get("image_count", 0))
        group = exemplar_files[cursor : cursor + count]
        cursor += count
        paths = [_save_upload(ex, job_dir) for ex in group]
        product_inputs.append(ProductInput(name=name, exemplar_paths=paths))

    # Validation is driven by the mode registry (single source of truth).
    opts = BuildOpts(dino_variant=dino_variant, owl_ref_type=owl_ref_type, owl_dino=owl_dino)
    if requires_name(mode) and any(not p.name for p in product_inputs):
        raise HTTPException(status_code=400, detail="Every product needs a name in this mode.")
    if (requires_reference(mode) or owlv2_needs_images(mode, opts)) and any(
        not p.exemplar_paths for p in product_inputs
    ):
        raise HTTPException(
            status_code=400,
            detail=f"{mode.value} mode requires a reference image for every product.",
        )

    variant = dino_variant if dino_variant in ("v2", "v3") else "v2"
    owl_dino_v = owl_dino if owl_dino in ("none", "v2", "v3") else "none"
    owl_ref = owl_ref_type if owl_ref_type in ("text", "image", "both") else "text"
    background_tasks.add_task(
        run_analysis, job.id, video_path, product_inputs, caption,
        mention_keywords, mode, split_on_cut, variant, owl_ref, owl_dino_v,
    )
    return JobResponse(job_id=job.id)


@app.get("/status/{job_id}", response_model=StatusResponse)
def status(job_id: str) -> StatusResponse:
    job = store.get(job_id)
    if job is None:
        raise HTTPException(status_code=404, detail="Unknown job_id.")
    return StatusResponse(
        job_id=job.id, status=job.status, result=job.result, error=job.error
    )