lf_mri_platform/services/seq-interp/api.py

"""
seq_interp FastAPI service.

Endpoints:
  GET  /health              — liveness probe
  POST /interpret/          — upload .seq file, run full pipeline, return task_id
  GET  /status/             — status of all submitted tasks
  GET  /result/{task_id}    — full result: xml_text, post_json, metadata, waveforms
"""
from __future__ import annotations

import asyncio
import os
import shutil
from typing import Any

from fastapi import FastAPI, File, HTTPException, 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="seq-interp", version="1.0.0")

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

# task_id → {"status": str, "result": dict | None}
_tasks: dict[str, dict] = {}

_MAX_WAVEFORM_POINTS = 8000   # downsample for JSON transport


# ── helpers ────────────────────────────────────────────────────────────────

def _downsample(arr, max_pts: int) -> list:
    """Convert numpy array to list, downsampling if too long."""
    try:
        import numpy as np
        a = np.asarray(arr, dtype=float).flatten()
        if len(a) > max_pts:
            idx = np.linspace(0, len(a) - 1, max_pts, dtype=int)
            a = a[idx]
        return [float(x) for x in a]
    except Exception:
        return []


def _extract_waveforms(seq_data: dict, sync_data: dict) -> dict:
    """Extract waveform arrays from seq_data for GUI display."""
    waveforms: dict[str, list] = {}
    for key in ("gx", "gy", "gz", "t_gx", "t_gy", "t_gz"):
        if key in seq_data:
            waveforms[key] = _downsample(seq_data[key], _MAX_WAVEFORM_POINTS)
    # RF
    for key in ("rf_amp", "rf_phase", "t_rf"):
        if key in seq_data:
            waveforms[key] = _downsample(seq_data[key], _MAX_WAVEFORM_POINTS)
    # Sync gate arrays
    for key in ("gate_adc", "gate_rf", "gate_tr_switch", "blocks_duration"):
        if key in sync_data:
            waveforms[key] = _downsample(sync_data[key], _MAX_WAVEFORM_POINTS)
    return waveforms


async def _run_pipeline(file_path: str, task_id: str) -> None:
    """Run the full interpretation pipeline and store result in _tasks."""
    out_dir = os.path.join(OUTPUT_DIR, task_id)
    os.makedirs(out_dir, exist_ok=True)
    try:
        hw = HardwareConstraints(json_path=config.get("hw_config_path"))
        hw_cfg = config.hw_config

        loader = PulseqLoader(hw)
        seq_data = await asyncio.to_thread(loader.load, file_path)
        params = seq_data.get("params", {})

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

        xml_gen = XMLGenerator()
        xml_path = os.path.join(out_dir, "sync_v2.xml")
        adc_values, adc_starts = await asyncio.to_thread(
            xml_gen.generate, sync_data, xml_path, hw
        )
        with open(xml_path, encoding="utf-8") as fh:
            xml_text = fh.read()

        export_tasks = [
            asyncio.to_thread(RFExporter().export, seq_data, params, out_dir)
        ]
        if all(k in seq_data for k in ("gx", "gy", "gz")):
            export_tasks.append(
                asyncio.to_thread(GradientExporter().export, seq_data, params, out_dir)
            )
        iadc = hw_cfg.get("iadc", {})
        export_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(*export_tasks)

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

        blocks = seq_data.get("blocks", [])
        total_s = sum(sync_data.get("blocks_duration", []))
        adc_blocks = [b for b in blocks if b.get("has_adc")]

        result: dict[str, Any] = {
            "task_id": task_id,
            "status": "completed",
            "output_dir": out_dir,
            "xml_text": xml_text,
            "post_json": post_payload,
            "metadata": {
                "block_count": len(blocks),
                "sync_block_count": sync_data.get("number_of_blocks", 0),
                "adc_count": len(adc_blocks),
                "adc_windows": len(adc_values),
                "total_duration_ms": round(total_s * 1e3, 4),
                "rf_raster_us": params.get("rf_raster_time", 1e-6) * 1e6,
                "grad_raster_us": params.get("grad_raster_time", 1e-5) * 1e6,
            },
            "waveforms": _extract_waveforms(seq_data, sync_data),
        }
        _tasks[task_id] = {"status": "completed", "result": result}

    except Exception as exc:
        _tasks[task_id] = {"status": f"failed: {exc}", "result": None}


# ── endpoints ────────────────────────────────────────────────────────────────

@app.get("/health")
def health():
    return {"status": "ok"}


@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] = {"status": "processing", "result": None}
    asyncio.create_task(_run_pipeline(file_path, task_id))
    return {"status": "accepted", "task_id": task_id,
            "message": f"Processing {file.filename}"}


@app.get("/status/")
def status_endpoint():
    """Return the status of all submitted tasks."""
    return {"tasks": {tid: v["status"] for tid, v in _tasks.items()}}


@app.get("/result/{task_id}")
def result_endpoint(task_id: str):
    """Return full interpretation result (xml_text, post_json, metadata, waveforms)."""
    entry = _tasks.get(task_id)
    if entry is None:
        raise HTTPException(status_code=404, detail=f"Task '{task_id}' not found")
    if entry["status"] == "processing":
        raise HTTPException(status_code=202, detail="Still processing")
    if entry["result"] is None:
        raise HTTPException(status_code=500, detail=entry["status"])
    return entry["result"]