#!/usr/bin/env python3
# SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
# SPDX-License-Identifier: GPL-3.0-only
"""A stand-in for a DECTRIS detector's SIMPLON control interface, for running jfjoch_broker without a
detector (demonstrations and tests). It answers the configuration and status requests the broker makes,
accepts every command, and always reads back as idle. The images come from tools/jfjoch_stream2_replay,
which plays the detector's stream2.

    fake_simplon.py --width 2068 --height 2164 --pixel-size 75e-6 [--port 80]

The broker reaches SIMPLON on port 80, so this has to be able to bind it (e.g. run it as root in a
container on the host network).
"""

import argparse
import base64
import json
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer


def main():
    p = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
    p.add_argument("--width", type=int, required=True)
    p.add_argument("--height", type=int, required=True)
    p.add_argument("--pixel-size", type=float, required=True, help="metres")
    p.add_argument("--sensor-thickness", type=float, default=320e-6, help="metres")
    p.add_argument("--sensor-material", default="Si")
    p.add_argument("--bit-depth", type=int, default=32)
    p.add_argument("--description", default="Replayed detector")
    p.add_argument("--port", type=int, default=80)
    a = p.parse_args()

    mask = base64.b64encode(bytes(4 * a.width * a.height)).decode()
    config = {
        "description": {"value": a.description},
        "detector_number": {"value": "replay-1"},
        "x_pixel_size": {"value": a.pixel_size},
        "y_pixel_size": {"value": a.pixel_size},
        "sensor_material": {"value": a.sensor_material},
        "sensor_thickness": {"value": a.sensor_thickness},
        "bit_depth_image": {"value": a.bit_depth},
        "x_pixels_in_detector": {"value": a.width},
        "y_pixels_in_detector": {"value": a.height},
        "frame_time": {"value": 0.01, "min": 0.0001},
        "count_time": {"value": 0.01, "min": 0.0001},
        "detector_readout_time": {"value": 0.0},
        "threshold_energy": {"value": 4000.0, "min": 1000.0},
        "photon_energy": {"value": 8000.0},
        "nimages": {"value": 1},
        "ntrigger": {"value": 1},
        "pixel_mask": {"value": {"shape": [a.height, a.width], "type": "uint32", "data": mask}},
    }
    status = {"state": {"value": "idle"}, "humidity": {"value": 0.0}, "temperature": {"value": 25.0}}

    class Handler(BaseHTTPRequestHandler):
        def reply(self, body):
            data = json.dumps(body).encode()
            self.send_response(200)
            self.send_header("Content-Type", "application/json")
            self.send_header("Content-Length", str(len(data)))
            self.end_headers()
            self.wfile.write(data)

        def do_GET(self):
            parts = self.path.strip("/").split("/")   # module/api/version/task/key
            key = parts[-1]
            if len(parts) >= 5 and parts[3] == "status":
                self.reply(status.get(key, {"value": 0}))
            else:
                self.reply(config.get(key, {"value": 0}))

        def do_POST(self):
            parts = self.path.strip("/").split("/")
            length = int(self.headers.get("Content-Length", 0))
            body = self.rfile.read(length) if length else b""
            if len(parts) >= 5 and parts[3] == "config" and body:
                config.setdefault(parts[-1], {})["value"] = json.loads(body)["value"]
            self.reply([])

        do_PUT = do_POST

        def log_message(self, fmt, *args):
            pass

    ThreadingHTTPServer(("0.0.0.0", a.port), Handler).serve_forever()


if __name__ == "__main__":
    main()