#!/usr/bin/env python3
"""mesh-bot notify forwarder: POST /notify {text, from?} -> opencode session message (basic auth).

The opencode workspace UUID is regenerated on host restarts, so the target workspace + session are
resolved dynamically per request via the opencode API (no caching — messages are rare): list
workspaces, pick the mesh-bot one by path (fallback: name), then its most recently updated session.

Note on semantics: the opencode API accepts a session message immediately but holds the HTTP
response until the agent turn completes — so a read timeout here means DELIVERED, not failed.
"""
import json, base64, urllib.request
from http.server import BaseHTTPRequestHandler, HTTPServer
import os

API = os.environ.get("FORWARDER_API", "http://127.0.0.1:9898")
WORKSPACE_PATH = os.environ.get("FORWARDER_WORKSPACE_PATH", "/home/krzyw/projects/sandbox/mesh-bot")
SESSION_OVERRIDE = os.environ.get("FORWARDER_SESSION", "")  # when set, skips session discovery
USER = os.environ["FORWARDER_USER"]   # required; fail fast if missing
PASS = os.environ["FORWARDER_PASS"]   # required; fail fast if missing

def _auth_headers():
    return {"Authorization": "Basic " + base64.b64encode(f"{USER}:{PASS}".encode()).decode()}

def _get_json(url):
    req = urllib.request.Request(url, headers=_auth_headers())
    try:
        with urllib.request.urlopen(req, timeout=15) as r:
            return json.loads(r.read().decode())
    except Exception as e:
        raise RuntimeError(f"opencode API unreachable at {url}: {e!r}") from None

def resolve_target():
    """Resolve (base_url, session_id) fresh per request; raises RuntimeError with a clear reason."""
    workspaces = _get_json(API + "/api/workspaces")
    matches = [w for w in workspaces if w.get("path") == WORKSPACE_PATH] or \
        [w for w in workspaces if w.get("name") == "mesh-bot"]
    pool = [w for w in matches if w.get("status") == "ready"] or matches
    if not pool:
        raise RuntimeError(f"workspace not found: path={WORKSPACE_PATH} name=mesh-bot")
    base = API + pool[0]["proxyPath"]
    sid = SESSION_OVERRIDE
    if not sid:
        sessions = _get_json(base + "/session")
        if not sessions:
            raise RuntimeError(f"no sessions in workspace {pool[0]['id']} ({WORKSPACE_PATH})")

        def updated(s):
            return (s.get("time") or {}).get("updated") or 0
        sid = max(sessions, key=updated)["id"] if any(updated(s) for s in sessions) else sessions[0]["id"]
    return base, sid

class H(BaseHTTPRequestHandler):
    def do_POST(self):
        if self.path != "/notify":
            self.send_response(404); self.end_headers(); return
        n = int(self.headers.get("Content-Length", 0))
        try:
            body = json.loads(self.rfile.read(n) or b"{}")
            text, frm = body.get("text"), body.get("from")
            msg = 'New mesh message' + (f' from node {frm}' if frm is not None else '') + f': "{text}" — please react to it.'
            base, sid = resolve_target()  # fresh per request; RuntimeError on API/workspace/session failure
            req = urllib.request.Request(
                f"{base}/session/{sid}/message",
                data=json.dumps({"parts": [{"type": "text", "text": msg}]}).encode(),
                headers={"Content-Type": "application/json", **_auth_headers()},
                method="POST")
            try:
                r = urllib.request.urlopen(req, timeout=15)
                code = r.status  # headers received => opencode accepted the message
                try: out = r.read(200).decode(errors='replace')
                except Exception as e2: out = f'(body read failed after delivery: {e2!r})'
                print(f"forwarded to opencode session {sid}: HTTP {code} {out[:150]!r}", flush=True)
                self._reply(code if 200 <= code < 300 else 502, b'{"ok":true}' if 200 <= code < 300 else str(code).encode())
            except TimeoutError:
                # request was sent; opencode holds the response until the agent turn finishes => delivered
                print(f"forwarded to opencode session {sid}: accepted (response still pending after 15 s)", flush=True)
                self._reply(202, b'{"ok":true,"note":"accepted; opencode response pending"}')
        except RuntimeError as e:
            # resolve_target() failure modes: API unreachable / workspace not found / no sessions in workspace
            print(f"target resolution failed: {e!r}", flush=True)
            self._reply(502, repr(e).encode())
        except Exception as e:
            print(f"opencode call failed: {e!r}", flush=True)
            self._reply(502, repr(e).encode())

    def _reply(self, code, payload):
        try:
            self.send_response(code); self.end_headers(); self.wfile.write(payload)
        except (BrokenPipeError, ConnectionResetError):
            pass  # client went away; delivery state already logged above

    def log_message(self, fmt, *args):
        print("forwarder:", fmt % args, flush=True)

HTTPServer(("0.0.0.0", 4097), H).serve_forever()