"""
FastAPI application for remote MRI sequence interpretation.

Endpoints:
  POST /interpret/  — upload a .seq file, run full pipeline, return task_id
  GET  /status/     — return status of all processed tasks
"""
import asyncio
import os
import shutil

from fastapi import FastAPI, File, UploadFile

from src.config import config
from src.hardware.constraints import HardwareConstraints
from src.interfaces.pulseq_adapter import PulseqLoader
from src.core.synchronizer import Synchronizer
from src.interfaces.xml_generator import XMLGenerator
from src.interfaces.rf_exporter import RFExporter
from src.interfaces.gradient_exporter import GradientExporter
from src.interfaces.picoscope_exporter import PicoScopeExporter
from src.interfaces.post_request_generator import PostRequestGenerator

app = FastAPI(title="LF-MRI Sequence Interpreter API")

UPLOAD_DIR = config.get("upload_dir", "uploads")
OUTPUT_DIR = config.get("output_dir", "output")
os.makedirs(UPLOAD_DIR, exist_ok=True)
os.makedirs(OUTPUT_DIR, exist_ok=True)

_tasks: dict[str, str] = {}


async def _run_pipeline(seq_path: str, task_id: str) -> None:
    try:
        hw = HardwareConstraints()
        loader = PulseqLoader(hw)
        seq_data = await asyncio.to_thread(loader.load, seq_path)

        synchronizer = Synchronizer(hw)
        sync_data = await asyncio.to_thread(synchronizer.process, seq_data["sequence"])

        out_dir = os.path.join(OUTPUT_DIR, task_id)
        os.makedirs(out_dir, exist_ok=True)

        hw_cfg = config.hw_config

        xml_gen = XMLGenerator()
        adc_values, adc_starts = await asyncio.to_thread(
            xml_gen.generate, sync_data, os.path.join(out_dir, "sync_v2.xml"), hw
        )

        tasks = [asyncio.to_thread(RFExporter().export, seq_data, seq_data.get("params", {}), out_dir)]
        if all(k in seq_data for k in ["gx", "gy", "gz"]):
            tasks.append(asyncio.to_thread(
                GradientExporter().export, seq_data, seq_data.get("params", {}), out_dir
            ))
        iadc = hw_cfg.get("iadc", {})
        tasks.append(asyncio.to_thread(
            PicoScopeExporter().generate,
            adc_values, adc_starts, out_dir, hw,
            sampling_freq=iadc.get("srate", 8e6),
            num_channels=iadc.get("n_channels", 3),
        ))
        await asyncio.gather(*tasks)

        post_gen = PostRequestGenerator()
        post_payload = post_gen.build(
            seq_data=seq_data,
            adc_values=adc_values,
            sequence_path=seq_path,
            output_dir=out_dir,
            hw_cfg=hw_cfg,
            rf_raster_time=seq_data.get("params", {}).get("rf_raster_time", 1e-6),
        )
        post_gen.write(post_payload, out_dir)

        _tasks[task_id] = f"Completed → {out_dir}"
    except Exception as exc:
        _tasks[task_id] = f"Failed: {exc}"


@app.post("/interpret/")
async def interpret_endpoint(file: UploadFile = File(...)):
    """Upload a .seq file and run the full interpretation pipeline."""
    file_path = os.path.join(UPLOAD_DIR, file.filename)
    with open(file_path, "wb") as buf:
        shutil.copyfileobj(file.file, buf)

    task_id = os.path.splitext(file.filename)[0]
    _tasks[task_id] = "Processing"
    asyncio.create_task(_run_pipeline(file_path, task_id))
    return {"status": "accepted", "task_id": task_id,
            "message": f"Processing {file.filename}"}


@app.get("/status/")
async def status_endpoint():
    """Return the status of all submitted tasks."""
    return {"tasks": _tasks}