#!/usr/bin/env python3
"""Web remote control for the UV-K5 emulator.

Serves the LCD as a live stream and maps on-screen buttons to the keypad model,
so the emulated radio can be driven from a browser.

Start the emulator first (tools/run.sh), then:

    python3 tools/webui.py --frame-addr 0x200013DC --status-addr 0x2000175C

Then open http://127.0.0.1:8080/

Two things worth knowing:

  * The QMP socket takes a single client, so tools/key.py cannot talk to the same
    emulator while this server is running.
  * There is no authentication. It binds loopback and anyone who reaches the port
    has full control of the emulated radio. Do not expose it.
"""
import argparse
import json
import time

from flask import Flask, Response, jsonify, request

from uvk5_keys import KEYS, is_valid, normalise
from uvk5_lcd import FrameGrabber, encode_png, unpack

KEYPAD_PATH = "/machine/keypad"

# Firmware thresholds, from App/misc.c:
#   key_debounce_10ms     = 2  -> 20 ms to register a press
#   key_repeat_delay_10ms = 40 -> 400 ms counts as HELD, a different event
#
# The browser sends the duration it measured and the server holds the key for
# exactly that long. It must not be reproduced by sending `down` and `up` as two
# requests: over a slow link the round trip between them *becomes* the press
# duration. Measured against this server at 400 ms RTT, an intended tap arrived as
# a 407 ms hold, so every short press was dispatched as a held key and handlers
# like MAIN_Key_MENU did nothing. Jitter either side of the threshold is what made
# it look intermittent rather than simply broken.
TAP_MS = 200

# Below the 20 ms debounce nothing registers at all, so even a very fast click has
# to ask for at least this long.
MIN_HOLD_MS = 60

# A hold longer than this is a stuck key or a typo, not intent.
MAX_HOLD_MS = 5000

BOUNDARY = "uvk5frame"
TARGET_FPS = 15

# Physical layout of the UV-K5 keypad, for the on-screen grid.
KEY_GRID = [
    ["MENU", "UP",   "DOWN", "EXIT"],
    ["1",    "2",    "3",    "STAR"],
    ["4",    "5",    "6",    "0"],
    ["7",    "8",    "9",    "F"],
]
SIDE_KEYS = ["SIDE1", "SIDE2"]

# Keyboard shortcuts -> radio keys.
KEY_BINDINGS = {
    "ArrowUp": "UP", "ArrowDown": "DOWN",
    "Enter": "MENU", "Escape": "EXIT",
    "KeyF": "F", "KeyM": "MENU",
    "BracketLeft": "SIDE1", "BracketRight": "SIDE2",
    "Digit0": "0", "Digit1": "1", "Digit2": "2", "Digit3": "3", "Digit4": "4",
    "Digit5": "5", "Digit6": "6", "Digit7": "7", "Digit8": "8", "Digit9": "9",
}


def create_app(client, frame_addr: int, status_addr: int, scale: int = 4):
    app = Flask(__name__)
    grabber = FrameGrabber(client, frame_addr, status_addr)

    def set_press(value: str):
        client.command("qom-set", path=KEYPAD_PATH, property="press", value=value)

    @app.get("/")
    def index():
        return Response(render_index(scale), mimetype="text/html")

    @app.get("/api/status")
    def api_status():
        return jsonify(client.command("query-status"))

    @app.post("/api/key")
    def api_key():
        body = request.get_json(silent=True) or {}
        key = normalise(body.get("key", ""))
        action = (body.get("action") or "tap").strip().lower()

        if not is_valid(key):
            return jsonify(error=f"unknown key {body.get('key')!r}",
                           valid=list(KEYS)), 400
        if action not in ("down", "up", "tap"):
            return jsonify(error=f"unknown action {action!r}",
                           valid=["down", "up", "tap"]), 400

        hold_raw = body.get("hold_ms")
        if hold_raw is None:
            hold_ms = TAP_MS
        else:
            try:
                hold_ms = int(hold_raw)
            except (TypeError, ValueError):
                return jsonify(
                    error=f"hold_ms must be a number, got {hold_raw!r}"), 400
            if hold_ms < 0:
                return jsonify(error="hold_ms must not be negative"), 400
            hold_ms = min(hold_ms, MAX_HOLD_MS)

        if action == "down":
            set_press(key)
        elif action == "up":
            set_press("")
        else:
            # Hold here, locally. See the note on TAP_MS: doing this as two
            # requests puts the network round trip inside the press duration.
            set_press(key)
            time.sleep(hold_ms / 1000)
            set_press("")
        return jsonify(ok=True, key=key, action=action, hold_ms=hold_ms)

    @app.post("/api/release-all")
    def api_release_all():
        """Safety valve: an empty press clears every key in the model."""
        set_press("")
        return jsonify(ok=True)

    @app.get("/frame.png")
    def frame_png():
        return Response(grabber.png(scale), mimetype="image/png",
                        headers={"Cache-Control": "no-store"})

    @app.get("/stream")
    def stream():
        # limit exists for tests; unset means stream until the client leaves.
        limit = request.args.get("limit", type=int)
        interval = 1.0 / TARGET_FPS

        def frames():
            sent, last = 0, None
            while limit is None or sent < limit:
                started = time.monotonic()
                status, frame = grabber.raw()
                current = (status, frame)
                # Only re-encode when the screen actually changed: the LCD is
                # static most of the time, so idle CPU stays near zero.
                if current != last or limit is not None:
                    last = current
                    png = encode_png(unpack(status, frame), scale)
                    yield (b"--" + BOUNDARY.encode() + b"\r\n"
                           b"Content-Type: image/png\r\n"
                           b"Content-Length: " + str(len(png)).encode()
                           + b"\r\n\r\n" + png + b"\r\n")
                    sent += 1
                slack = interval - (time.monotonic() - started)
                if slack > 0:
                    time.sleep(slack)

        return Response(frames(),
                        mimetype=f"multipart/x-mixed-replace; boundary={BOUNDARY}",
                        headers={"Cache-Control": "no-store",
                                 "X-Accel-Buffering": "no"})

    return app


def render_index(scale: int) -> str:
    grid = "\n".join(
        "<div class='row'>" + "".join(
            f'<button class="key" data-key="{k}">{"*" if k == "STAR" else k}</button>'
            for k in row) + "</div>"
        for row in KEY_GRID
    )
    sides = "".join(
        f'<button class="key side" data-key="{k}">{k}</button>' for k in SIDE_KEYS
    )
    return f"""<!doctype html>
<html lang="en"><head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>UV-K5 remote</title>
<style>
  :root {{ color-scheme: dark; }}
  body {{ margin:0; min-height:100vh; display:grid; place-items:center;
         background:#15171a; color:#c9d1d9;
         font:14px/1.4 ui-monospace,SFMono-Regular,Menlo,monospace; }}
  .radio {{ display:flex; flex-direction:column; align-items:center; gap:14px;
           padding:20px; background:#1e2126; border:1px solid #2d333b;
           border-radius:14px; }}
  /* pixelated keeps the 128x64 LCD crisp when scaled up */
  #screen {{ display:block; image-rendering:pixelated; background:#c8d6b9;
            border:3px solid #0d1117; border-radius:4px; }}
  .body {{ display:flex; gap:14px; align-items:flex-start; }}
  .sides {{ display:flex; flex-direction:column; gap:8px; }}
  .pad {{ display:flex; flex-direction:column; gap:8px; }}
  .row {{ display:flex; gap:8px; }}
  .key {{ width:62px; height:44px; font:inherit; font-weight:600; color:#c9d1d9;
         background:#2b3138; border:1px solid #3a424b; border-radius:8px;
         cursor:pointer; user-select:none; -webkit-user-select:none;
         touch-action:manipulation; }}
  .key:hover {{ background:#343b44; }}
  .key.active {{ background:#4b8bf5; border-color:#4b8bf5; color:#fff; }}
  .side {{ width:76px; }}
  .hint {{ color:#6e7681; font-size:12px; text-align:center; max-width:430px; }}
  #status {{ font-size:12px; color:#6e7681; }}
</style>
</head><body>
<div class="radio">
  <img id="screen" src="/stream" alt="radio LCD"
       width="{128 * scale}" height="{64 * scale}">
  <div class="body">
    <div class="sides">{sides}</div>
    <div class="pad">{grid}</div>
  </div>
  <div id="status">connecting...</div>
  <p class="hint">Hold a key to send a long press: over 400 ms the firmware
  treats it as held, which is a different event. Arrows move, Enter is MENU,
  Esc is EXIT, digits map straight through. No PTT button -- the keypad model
  has no PTT line.</p>
</div>
<script>
const BINDINGS = {json.dumps(KEY_BINDINGS)};
const held = new Set();

async function send(key, action) {{
  try {{
    await fetch('/api/key', {{
      method: 'POST',
      headers: {{'Content-Type': 'application/json'}},
      body: JSON.stringify({{key: key, action: action}})
    }});
  }} catch (err) {{
    document.getElementById('status').textContent = 'send failed: ' + err;
  }}
}}

function mark(key, on) {{
  document.querySelectorAll('[data-key="' + key + '"]')
    .forEach(el => el.classList.toggle('active', on));
}}

// Press duration is decided by the browser, not the server.
function down(key) {{
  if (held.has(key)) return;
  held.add(key);
  mark(key, true);
  send(key, 'down');
}}
function up(key) {{
  if (!held.has(key)) return;
  held.delete(key);
  mark(key, false);
  send(key, 'up');
}}

document.querySelectorAll('.key').forEach(btn => {{
  const key = btn.dataset.key;
  btn.addEventListener('pointerdown', ev => {{ ev.preventDefault(); down(key); }});
  btn.addEventListener('pointerup', ev => {{ ev.preventDefault(); up(key); }});
  btn.addEventListener('pointerleave', () => up(key));
  btn.addEventListener('pointercancel', () => up(key));
  btn.addEventListener('contextmenu', ev => ev.preventDefault());
}});

addEventListener('keydown', ev => {{
  const key = BINDINGS[ev.code];
  if (!key || ev.repeat) return;
  ev.preventDefault();
  down(key);
}});
addEventListener('keyup', ev => {{
  const key = BINDINGS[ev.code];
  if (!key) return;
  ev.preventDefault();
  up(key);
}});
// Release on blur, so losing focus mid-press cannot leave a key stuck down.
addEventListener('blur', () => {{
  [...held].forEach(up);
  fetch('/api/release-all', {{method: 'POST'}}).catch(() => {{}});
}});

async function poll() {{
  try {{
    const r = await fetch('/api/status');
    const s = await r.json();
    document.getElementById('status').textContent =
      'guest: ' + (s.status || 'unknown');
  }} catch (err) {{
    document.getElementById('status').textContent = 'emulator unreachable';
  }}
}}
poll();
setInterval(poll, 3000);
</script>
</body></html>"""


def main() -> int:
    ap = argparse.ArgumentParser(description=__doc__.splitlines()[0])
    ap.add_argument("--qmp", default="/tmp/uvk5-qmp.sock")
    ap.add_argument("--frame-addr", type=lambda v: int(v, 0), required=True,
                    help="address of gFrameBuffer (moves between builds)")
    ap.add_argument("--status-addr", type=lambda v: int(v, 0), required=True,
                    help="address of gStatusLine")
    ap.add_argument("--host", default="127.0.0.1")
    ap.add_argument("--port", type=int, default=8080)
    ap.add_argument("--scale", type=int, default=4)
    args = ap.parse_args()

    from uvk5_qmp import QmpClient
    client = QmpClient(args.qmp)
    app = create_app(client, args.frame_addr, args.status_addr, args.scale)
    print(f"serving on http://{args.host}:{args.port}/  "
          f"(no authentication; loopback only unless you changed --host)")
    app.run(host=args.host, port=args.port, threaded=True)
    return 0


if __name__ == "__main__":
    raise SystemExit(main())