"""FastAPI server for the sprite generation review GUI.

Serves the REST API for browsing sprites, reviewing variants, and approving/rejecting.
Also serves raw/variant images and the static GUI build.

Usage:
    uvicorn server:app --port 5801 --reload
    # or via CLI:
    python3 cli.py review --port 5801
"""
from __future__ import annotations

import asyncio
import json
import subprocess
import sys
from pathlib import Path
from typing import Annotated

from fastapi import FastAPI, HTTPException, Query
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse, JSONResponse, StreamingResponse
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel

from engine.registry import SpriteRegistry

TOOL_DIR = Path(__file__).resolve().parent
PROJECT = TOOL_DIR.parent.parent
DB_PATH = TOOL_DIR / "spritegen.db"
RAW_DIR = TOOL_DIR / "raw"
VARIANTS_DIR = TOOL_DIR / "variants"
GUI_DIST = TOOL_DIR / "gui" / "dist"
ASSETS_DIR = PROJECT / "public" / "games" / "age-of-dwarves" / "assets"
LOCAL_DATA = PROJECT / "public" / "games" / "age-of-dwarves" / "data"


class ApproveRequest(BaseModel):
    variant_id: int
    dimension_id: int | None = None


class RejectRequest(BaseModel):
    dimension_id: int | None = None


class RejectVariantRequest(BaseModel):
    reason: str | None = None


class RegenerateRequest(BaseModel):
    prompt: str | None = None
    dimension_id: int | None = None
    variants: int = 8


class PromptUpdate(BaseModel):
    prompt: str


class PipelineRunRequest(BaseModel):
    scorers: list[str] | None = None
    skip_process: bool = False
    score_only: bool = False
    rescore: bool = False


class PinSeedRequest(BaseModel):
    seed: int
    category: str
    entity_id: str = ""
    variant_id: int | None = None


class GenerateRequest(BaseModel):
    category: str | None = None
    sprite_id: str | None = None
    variants: int = 8
    priority: str = "normal"
    max_sprites: int | None = None
    backend: str | None = None  # "model-boss" | "grok"; defaults to sprite-config.json
    include_review: bool = False  # batch mode: also queue review sprites with deficit


class WorkerStartRequest(BaseModel):
    backend: str | None = None
    variants: int = 3
    category: str | None = None
    starter_only: bool = False
    max_attempts: int = 15
    batch_size: int = 4


class InstallRequest(BaseModel):
    category: str | None = None
    dry_run: bool = False


class ShipVariantRequest(BaseModel):
    alt_name: str | None = None


class CollectRequest(BaseModel):
    backend: str | None = None


class StarterRegisterRequest(BaseModel):
    reset_status: bool = True


def create_app(
    registry: SpriteRegistry | None = None,
    raw_dir: Path = RAW_DIR,
    variants_dir: Path = VARIANTS_DIR,
) -> FastAPI:
    if registry is None:
        registry = SpriteRegistry(DB_PATH)

    app = FastAPI(title="Magic Civilization Sprite Generator", version="1.0.0")

    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_methods=["*"],
        allow_headers=["*"],
    )

    # ── Sprites ───────────────────────────────────────────────────────────

    @app.get("/api/sprites")
    def list_sprites(
        category: Annotated[str | None, Query()] = None,
        status: Annotated[str | None, Query()] = None,
        search: Annotated[str | None, Query()] = None,
        limit: Annotated[int, Query(ge=1, le=10000)] = 200,
        offset: Annotated[int, Query(ge=0)] = 0,
    ) -> list[dict]:
        return registry.get_sprites(
            category=category, status=status, search=search,
            limit=limit, offset=offset,
        )

    @app.get("/api/sprites/{sprite_id:path}/variants")
    def get_variants(
        sprite_id: str,
        dimension_id: Annotated[int | None, Query()] = None,
    ) -> list[dict]:
        sprite = registry.get_sprite(sprite_id)
        if not sprite:
            raise HTTPException(404, f"Sprite not found: {sprite_id}")
        return registry.get_variants(sprite_id, dimension_id=dimension_id)

    @app.get("/api/sprites/{sprite_id:path}")
    def get_sprite(sprite_id: str) -> dict:
        sprite = registry.get_sprite(sprite_id)
        if not sprite:
            raise HTTPException(404, f"Sprite not found: {sprite_id}")
        return sprite

    @app.post("/api/sprites/{sprite_id:path}/approve")
    def approve_sprite(sprite_id: str, body: ApproveRequest) -> dict:
        sprite = registry.get_sprite(sprite_id)
        if not sprite:
            raise HTTPException(404, f"Sprite not found: {sprite_id}")
        registry.approve_variant(body.variant_id)
        return {"status": "approved", "variant_id": body.variant_id}

    @app.post("/api/sprites/{sprite_id:path}/reject")
    def reject_sprite(sprite_id: str, body: RejectRequest) -> dict:
        sprite = registry.get_sprite(sprite_id)
        if not sprite:
            raise HTTPException(404, f"Sprite not found: {sprite_id}")
        registry.reject_sprite(sprite_id, dimension_id=body.dimension_id)
        return {"status": "rejected"}

    @app.post("/api/sprites/{sprite_id:path}/skip")
    def skip_sprite(sprite_id: str) -> dict:
        sprite = registry.get_sprite(sprite_id)
        if not sprite:
            raise HTTPException(404, f"Sprite not found: {sprite_id}")
        registry.update_sprite_status(sprite_id, "skip")
        return {"status": "skip"}

    @app.get("/api/variants/{variant_id:int}")
    def get_variant(variant_id: int) -> dict:
        variant = registry.get_variant(variant_id)
        if not variant:
            raise HTTPException(404, f"Variant not found: {variant_id}")
        sprite = registry.get_sprite(variant["sprite_id"])
        if sprite:
            variant["category"] = sprite["category"]
            variant["entity_id"] = sprite["entity_id"]
        return variant

    @app.get("/api/variants/{variant_id:int}/scores")
    def get_variant_scores(variant_id: int) -> list[dict]:
        """Get all per-scorer evaluations for a variant."""
        return registry.get_scores(variant_id)

    @app.post("/api/variants/{variant_id:int}/reject")
    def reject_variant(variant_id: int, body: RejectVariantRequest = RejectVariantRequest()) -> dict:
        registry.reject_variant(variant_id, body.reason)
        return {"status": "rejected", "variant_id": variant_id}

    @app.post("/api/sprites/{sprite_id:path}/regenerate")
    def regenerate_sprite(sprite_id: str, body: RegenerateRequest) -> dict:
        sprite = registry.get_sprite(sprite_id)
        if not sprite:
            raise HTTPException(404, f"Sprite not found: {sprite_id}")
        if body.prompt:
            registry.conn.execute(
                "UPDATE sprites SET prompt = ?, updated_at = datetime('now') WHERE id = ?",
                (body.prompt, sprite_id),
            )
            registry.conn.commit()
        registry.reject_sprite(sprite_id, dimension_id=body.dimension_id)
        return {"status": "needed", "message": "Ready for regeneration"}

    @app.put("/api/sprites/{sprite_id:path}/prompt")
    def update_prompt(sprite_id: str, body: PromptUpdate) -> dict:
        sprite = registry.get_sprite(sprite_id)
        if not sprite:
            raise HTTPException(404, f"Sprite not found: {sprite_id}")
        registry.conn.execute(
            "UPDATE sprites SET prompt = ?, updated_at = datetime('now') WHERE id = ?",
            (body.prompt, sprite_id),
        )
        registry.conn.commit()
        return {"status": "updated", "prompt": body.prompt}

    # ── Progress & Queue ─────────────────────────────────────────────────

    @app.get("/api/stats")
    def get_stats() -> dict:
        return registry.get_stats()

    @app.get("/api/progress")
    def get_progress() -> dict:
        return registry.get_progress()

    @app.get("/api/pipeline")
    def get_pipeline() -> dict:
        return registry.get_pipeline_dashboard()

    # Track the advance.py subprocess
    _pipeline_proc: dict[str, subprocess.Popen | None] = {"proc": None}

    _gen_worker: dict[str, object] = {"instance": None}

    def _get_worker():
        from engine.worker import GenerationWorker
        if _gen_worker["instance"] is None:
            _gen_worker["instance"] = GenerationWorker(
                registry=registry,
                raw_dir=raw_dir,
                log_path=TOOL_DIR / "worker.log",
            )
        return _gen_worker["instance"]

    @app.post("/api/pipeline/run")
    def run_pipeline(body: PipelineRunRequest) -> dict:
        """Spawn tools/advance.py as a background subprocess."""
        proc = _pipeline_proc["proc"]
        if proc is not None and proc.poll() is None:
            return {"status": "already_running", "pid": proc.pid}

        cmd = [sys.executable, "-u", str(TOOL_DIR / "tools" / "advance.py")]
        if body.scorers:
            cmd += ["--scorers"] + body.scorers
        if body.rescore:
            cmd.append("--rescore")
        if body.skip_process:
            cmd.append("--skip-process")
        if body.score_only:
            cmd.append("--score-only")

        log_path = TOOL_DIR / "advance.log"
        log_file = open(log_path, "w")
        proc = subprocess.Popen(
            cmd,
            stdout=log_file,
            stderr=subprocess.STDOUT,
            cwd=str(TOOL_DIR),
        )
        _pipeline_proc["proc"] = proc
        return {"status": "started", "pid": proc.pid}

    @app.get("/api/pipeline/status")
    def pipeline_run_status() -> dict:
        """Check if the advance.py process is still running."""
        proc = _pipeline_proc["proc"]
        if proc is None:
            return {"running": False, "pid": None, "returncode": None, "log_tail": ""}

        log_path = TOOL_DIR / "advance.log"
        log_tail = ""
        if log_path.exists():
            lines = log_path.read_text().splitlines()
            log_tail = "\n".join(lines[-20:])

        poll = proc.poll()
        return {
            "running": poll is None,
            "pid": proc.pid,
            "returncode": poll,
            "log_tail": log_tail,
        }

    @app.get("/api/queue")
    def get_review_queue(
        limit: Annotated[int, Query(ge=1, le=200)] = 50,
    ) -> list[dict]:
        return registry.get_review_queue(limit=limit)

    @app.post("/api/queue/{sprite_id:path}/approve")
    def approve_from_queue(sprite_id: str, body: ApproveRequest) -> dict:
        sprite = registry.get_sprite(sprite_id)
        if not sprite:
            raise HTTPException(404, f"Sprite not found: {sprite_id}")
        registry.approve_variant(body.variant_id)
        return {"status": "approved", "variant_id": body.variant_id}

    @app.get("/api/variants/recent")
    def get_recent_variants(
        limit: Annotated[int, Query(ge=1, le=5000)] = 30,
    ) -> list[dict]:
        return registry.get_recent_variants(limit=limit)

    @app.get("/api/variants/review")
    def get_review_variants(
        limit: Annotated[int, Query(ge=1, le=5000)] = 500,
    ) -> list[dict]:
        return registry.get_review_variants(limit=limit)

    @app.get("/api/terrain-grid")
    def terrain_grid(
        elevation: Annotated[str, Query(pattern=r"^(lowland|highland|alpine)$")] = "lowland",
    ) -> dict:
        """Biome grid cells for one elevation tier, with best variant per cell."""
        cells = registry.get_terrain_grid(elevation)
        return {"cells": cells}

    @app.get("/api/theater")
    def theater_variants(
        mode: Annotated[str, Query(pattern=r"^(all|review)$")] = "all",
        limit: Annotated[int, Query(ge=1, le=200)] = 50,
        offset: Annotated[int, Query(ge=0)] = 0,
    ) -> dict:
        """Paginated, server-filtered variants for the Sprite Theater UI."""
        items, total = registry.query_variants(mode=mode, limit=limit, offset=offset)
        return {"items": items, "total": total}

    @app.get("/api/variants/browse")
    def browse_variants(
        stage: Annotated[str, Query(pattern=r"^(all|completed|review|processed|approved|installed|scored_[a-z0-9_]+)$")] = "completed",
        limit: Annotated[int, Query(ge=1, le=500)] = 120,
        offset: Annotated[int, Query(ge=0)] = 0,
    ) -> dict:
        """Paginated variant browse by funnel stage — used by the dashboard funnel click-throughs."""
        items, total = registry.query_variants(mode=stage, limit=limit, offset=offset)
        return {"items": items, "total": total}

    @app.get("/api/stream/variants")
    async def stream_variants() -> StreamingResponse:
        async def event_generator():
            # Own connection to avoid SQLite threading collisions with main registry
            sse_registry = SpriteRegistry(DB_PATH)
            current = sse_registry.get_recent_variants(limit=1)
            last_id = current[0]["variant_id"] if current else 0
            last_rating_snapshot = ""
            poll_count = 0
            while True:
                await asyncio.sleep(3)
                new_variants = sse_registry.get_recent_variants(limit=10, since_id=last_id)
                if new_variants:
                    last_id = max(v["variant_id"] for v in new_variants)
                    yield f"data: {json.dumps(new_variants)}\n\n"
                    continue

                # Check for rating updates every ~15s (5 cycles)
                poll_count += 1
                if poll_count % 5 == 0:
                    updated = sse_registry.get_recent_variants(limit=30)
                    snapshot = "|".join(
                        f"{v['variant_id']}:{v['rating']}" for v in updated
                    )
                    if snapshot != last_rating_snapshot:
                        last_rating_snapshot = snapshot
                        yield f"data: {json.dumps(updated)}\n\n"
                        continue

                yield ": keepalive\n\n"

        return StreamingResponse(
            event_generator(),
            media_type="text/event-stream",
            headers={"Cache-Control": "no-cache", "X-Accel-Buffering": "no"},
        )

    @app.get("/api/runs")
    def get_runs() -> list[dict]:
        return registry.get_runs()

    # ── Analytics + Seed pool ─────────────────────────────────────────────

    @app.get("/api/analytics/quality")
    def quality_analytics(
        category: Annotated[str | None, Query()] = None,
        scorer: Annotated[str | None, Query()] = None,
    ) -> dict:
        """Quality dimension averages and gate failure rates across scored variants."""
        return registry.get_quality_analytics(category=category, scorer=scorer)

    @app.get("/api/seeds")
    def list_seeds(
        category: Annotated[str | None, Query()] = None,
        limit: Annotated[int, Query(ge=1, le=200)] = 50,
    ) -> list[dict]:
        """Top seeds from the pool for a category."""
        return registry.get_seed_pool_report(category=category, limit=limit)

    @app.post("/api/seeds/pin")
    def pin_seed(body: PinSeedRequest) -> dict:
        """Manually pin a seed to the pool with max quality (user override)."""
        registry.pin_seed(
            seed=body.seed,
            category=body.category,
            entity_id=body.entity_id,
            variant_id=body.variant_id,
        )
        return {"status": "pinned", "seed": body.seed, "category": body.category}

    # ── Config ────────────────────────────────────────────────────────────

    @app.get("/api/config")
    def get_config() -> dict:
        from engine.factory import BACKENDS, backend_summary
        config = json.loads((TOOL_DIR / "sprite-config.json").read_text())
        return {
            "backends": list(BACKENDS),
            "default_backend": config.get("backend", "model-boss"),
            "backend_summary": backend_summary(config),
            "model": config.get("model"),
        }

    # ── Generation worker (submit → collect → score) ─────────────────────

    @app.post("/api/worker/start")
    def start_worker(body: WorkerStartRequest) -> dict:
        return _get_worker().start(
            backend=body.backend,
            variants=body.variants,
            category=body.category,
            starter_only=body.starter_only,
            max_attempts=body.max_attempts,
            batch_size=body.batch_size,
        )

    @app.post("/api/worker/stop")
    def stop_worker() -> dict:
        w = _gen_worker["instance"]
        if w is None:
            return {"status": "not_running"}
        return w.stop()

    def _read_log_tail(path: Path, lines: int = 30) -> str:
        if not path.exists():
            return ""
        all_lines = path.read_text(encoding="utf-8", errors="replace").splitlines()
        return "\n".join(all_lines[-lines:])

    def _generation_worker_status(log_lines: int = 30) -> dict:
        w = _gen_worker["instance"]
        log_path = TOOL_DIR / "worker.log"
        if w is None:
            queued = registry.conn.execute(
                "SELECT COUNT(*) FROM variants WHERE job_status = 'submitted'"
            ).fetchone()[0]
            total_row = registry.get_stats().get("total", {})
            return {
                "running": False,
                "queued_variants": queued,
                "needed": total_row.get("needed", 0),
                "review": total_row.get("review", 0),
                "approved": total_row.get("approved", 0),
                "installed": total_row.get("installed", 0),
                "log_tail": _read_log_tail(log_path, log_lines),
                "log_path": str(log_path.relative_to(TOOL_DIR)),
            }
        st = w.status()
        st["log_tail"] = _read_log_tail(log_path, log_lines)
        st["log_path"] = str(log_path.relative_to(TOOL_DIR))
        return st

    def _scoring_pipeline_status(log_lines: int = 30) -> dict:
        proc = _pipeline_proc["proc"]
        log_path = TOOL_DIR / "advance.log"
        if proc is None:
            return {
                "running": False,
                "pid": None,
                "returncode": None,
                "log_tail": _read_log_tail(log_path, log_lines),
                "log_path": str(log_path.relative_to(TOOL_DIR)),
            }
        poll = proc.poll()
        return {
            "running": poll is None,
            "pid": proc.pid,
            "returncode": poll,
            "log_tail": _read_log_tail(log_path, log_lines),
            "log_path": str(log_path.relative_to(TOOL_DIR)),
        }

    @app.get("/api/worker/status")
    def worker_status(
        log_lines: Annotated[int, Query(ge=10, le=500)] = 30,
    ) -> dict:
        return _generation_worker_status(log_lines)

    @app.get("/api/workers")
    def workers_overview(
        log_lines: Annotated[int, Query(ge=10, le=500)] = 80,
    ) -> dict:
        """Unified status for generation worker + scoring pipeline."""
        from engine.factory import BACKENDS, backend_summary
        config = json.loads((TOOL_DIR / "sprite-config.json").read_text())
        total_row = registry.get_stats().get("total", {})
        in_flight = registry.conn.execute(
            "SELECT COUNT(DISTINCT sprite_id) FROM variants WHERE job_status = 'submitted'"
        ).fetchone()[0]
        return {
            "generation": _generation_worker_status(log_lines),
            "scoring": _scoring_pipeline_status(log_lines),
            "sprites": {
                "needed": total_row.get("needed", 0),
                "generating": total_row.get("generating", 0),
                "review": total_row.get("review", 0),
                "approved": total_row.get("approved", 0),
                "installed": total_row.get("installed", 0),
            },
            "in_flight_sprites": in_flight,
            "config": {
                "backends": list(BACKENDS),
                "default_backend": config.get("backend", "model-boss"),
                "backend_summary": backend_summary(config),
            },
        }

    @app.post("/api/collect")
    async def collect_pending(body: CollectRequest = CollectRequest()) -> dict:
        """One-shot: collect model-boss results and score affected sprites."""
        from engine.factory import create_generator, with_backend
        from engine.ranker import SpriteRanker

        config = json.loads((TOOL_DIR / "sprite-config.json").read_text())
        backend = body.backend
        if backend:
            config = with_backend(config, backend)
        if config["backend"] != "model-boss":
            return {"collected": 0, "message": f"{config['backend']} completes at generate time"}

        gen = create_generator(config=config, registry=registry, raw_dir=raw_dir)
        ranker = SpriteRanker(registry=registry, raw_dir=raw_dir)
        affected: set[str] = set()

        async def _on_complete(variant_id: int, sprite_id: str) -> None:
            affected.add(sprite_id)
            await ranker.advance_sprite(sprite_id)

        collected = await gen.collect_pending(on_complete=_on_complete)
        for sid in affected:
            await ranker.rank_and_filter(sid)
        return {"collected": collected, "sprites_scored": len(affected)}

    # ── Install / ship ────────────────────────────────────────────────────

    @app.post("/api/install")
    def install_approved(body: InstallRequest = InstallRequest()) -> dict:
        from engine.installer import SpriteInstaller
        installer = SpriteInstaller(assets_dir=ASSETS_DIR, registry=registry)
        count = installer.install_approved(category=body.category, dry_run=body.dry_run)
        return {"installed": count, "dry_run": body.dry_run}

    @app.post("/api/variants/{variant_id:int}/ship")
    def ship_variant(variant_id: int, body: ShipVariantRequest = ShipVariantRequest()) -> dict:
        """Approve → rembg → install → manifest (cli.py approve)."""
        from engine.pipeline import SpritePipeline
        variant = registry.get_variant(variant_id)
        if not variant:
            raise HTTPException(404, f"Variant not found: {variant_id}")
        pipeline = SpritePipeline(
            registry=registry,
            raw_dir=raw_dir,
            variants_dir=variants_dir,
            assets_dir=ASSETS_DIR,
            game_db_path=LOCAL_DATA / "sprites.db",
        )
        result = pipeline.approve_and_install(variant_id, alt_name=body.alt_name)
        if not result:
            raise HTTPException(500, "Install pipeline failed")
        return {"status": "shipped", "path": str(result)}

    # ── Starter set ───────────────────────────────────────────────────────

    @app.get("/api/starter/status")
    def starter_status() -> dict:
        from engine.starter import starter_sprite_ids
        ids = starter_sprite_ids()
        placeholders = ",".join("?" * len(ids))
        rows = registry.conn.execute(
            f"""
            SELECT s.id, s.status, s.category,
                   COUNT(v.id) AS variants,
                   SUM(CASE WHEN v.job_status='completed' THEN 1 ELSE 0 END) AS completed,
                   SUM(CASE WHEN COALESCE(v.rating, -1) > 0 AND v.rating != -1 THEN 1 ELSE 0 END) AS good
            FROM sprites s
            LEFT JOIN variants v ON v.sprite_id = s.id
            WHERE s.id IN ({placeholders})
            GROUP BY s.id, s.status, s.category
            ORDER BY s.id
            """,
            ids,
        ).fetchall()
        by_status: dict[str, int] = {}
        sprites = []
        for r in rows:
            by_status[r["status"]] = by_status.get(r["status"], 0) + 1
            sprites.append(dict(r))
        return {"total": len(ids), "by_status": by_status, "sprites": sprites}

    @app.post("/api/starter/register")
    def starter_register(body: StarterRegisterRequest = StarterRegisterRequest()) -> dict:
        from engine.starter import register_starter_set
        report = register_starter_set(registry, reset_status=body.reset_status)
        return {
            "registered": len(report.registered),
            "reset": report.reset,
            "missing_data": report.missing_data,
        }

    # ── Generation trigger ────────────────────────────────────────────────

    def _sprites_for_generate(body: GenerateRequest) -> tuple[list[dict], str | None]:
        """Resolve sprite list for generate. Returns (sprites, error_message)."""
        if body.sprite_id:
            sprite = registry.get_sprite(body.sprite_id)
            if not sprite:
                return [], f"Sprite not found: {body.sprite_id}"
            if sprite["status"] in ("skip", "rejected"):
                return [], f"Cannot generate for status '{sprite['status']}'"
            return [sprite], None

        statuses = ("needed", "review") if body.include_review else ("needed",)
        sprites: list[dict] = []
        for status in statuses:
            sprites.extend(registry.get_sprites(
                category=body.category,
                status=status,
                limit=body.max_sprites or 10000,
            ))
        if body.include_review:
            # Only sprites still missing gate-passing variants
            dashboard = registry.get_pipeline_dashboard()
            deficit_ids = {
                r["sprite_id"] for r in dashboard["sprite_coverage"] if r["deficit"] > 0
            }
            sprites = [s for s in sprites if s["id"] in deficit_ids]
        if body.max_sprites:
            sprites = sprites[: body.max_sprites]
        if not sprites:
            return [], "No eligible sprites to generate"
        return sprites, None

    @app.post("/api/generate")
    async def trigger_generate(body: GenerateRequest) -> dict:
        from engine.factory import create_generator, with_backend
        from engine.ranker import SpriteRanker

        config = json.loads((TOOL_DIR / "sprite-config.json").read_text())
        if body.backend:
            config = with_backend(config, body.backend)
        gen = create_generator(config=config, registry=registry, raw_dir=raw_dir)

        sprites, err = _sprites_for_generate(body)
        if not sprites:
            return {"submitted": 0, "sprites": 0, "message": err}

        sprite_ids = [s["id"] for s in sprites]
        ranker = SpriteRanker(registry=registry, raw_dir=raw_dir)

        async def _on_complete(variant_id: int, sprite_id: str) -> None:
            await ranker.advance_sprite(sprite_id)

        on_complete = _on_complete if config["backend"] == "model-boss" else None
        submitted = await gen.submit_batch(
            sprite_ids=sprite_ids,
            variants_per=body.variants,
            priority=body.priority,
            on_complete=on_complete,
        )

        if config["backend"] == "grok" and submitted:
            for sid in sprite_ids:
                await ranker.rank_and_filter(sid)

        return {
            "submitted": submitted,
            "sprites": len(sprite_ids),
            "backend": config["backend"],
            "message": None if submitted else "Submission failed — check server logs",
        }

    # ── Image serving ─────────────────────────────────────────────────────

    @app.get("/images/raw/{file_path:path}")
    def serve_raw(file_path: str) -> FileResponse:
        full = raw_dir / file_path
        if not full.exists():
            raise HTTPException(404, f"Image not found: {file_path}")
        return FileResponse(full, media_type="image/png")

    @app.get("/images/variants/{file_path:path}")
    def serve_variant(file_path: str) -> FileResponse:
        full = variants_dir / file_path
        if not full.exists():
            raise HTTPException(404, f"Image not found: {file_path}")
        return FileResponse(full, media_type="image/png")

    # ── Static GUI (SPA fallback) ────────────────────────────────────────

    if GUI_DIST.exists():
        index_html = GUI_DIST / "index.html"

        app.mount("/assets", StaticFiles(directory=str(GUI_DIST / "assets")), name="assets")

        @app.get("/{full_path:path}")
        def spa_fallback(full_path: str) -> FileResponse:
            if full_path.startswith("api/") or full_path.startswith("images/"):
                raise HTTPException(404)
            candidate = GUI_DIST / full_path
            if full_path and candidate.is_file():
                return FileResponse(candidate)
            return FileResponse(index_html)

    return app


# Direct run support
app = create_app()