"""agent-browser ``credential.read`` plugin (agent-browser.plugin.v1).

agent-browser writes ONE JSON envelope on stdin::

    {"protocol": "agent-browser.plugin.v1",
     "type": "credential.resolve",
     "capability": "credential.read",
     "request": {"profileName": "...", "itemRef": "...", "url": "..."}}

and expects one JSON object on stdout::

    {"protocol": "agent-browser.plugin.v1", "success": true,
     "credential": {"username": ..., "password": ..., "url": ...,
                    "usernameSelector": ..., "passwordSelector": ...,
                    "submitSelector": ...}}

The plugin is a thin proxy: it forwards (itemRef, url) to the broker over
the unix socket and relays the credential. The broker enforces the
item's adapter policy and origin validation before releasing anything.
Secret values go agent-browser-stdin -> plugin -> agent-browser; the
agent model never sees them.
"""

from __future__ import annotations

import json
import sys

from .errors import BrokerError
from .server import call

PROTOCOL = "agent-browser.plugin.v1"


def _fail(message):
    sys.stdout.write(json.dumps({
        "protocol": PROTOCOL, "success": False, "error": str(message)[:300],
    }) + "\n")


def main():
    try:
        raw = sys.stdin.read(64 * 1024)
        envelope = json.loads(raw)
    except Exception:
        _fail("bad plugin envelope")
        return 1
    if (envelope.get("protocol") != PROTOCOL
            or envelope.get("type") != "credential.resolve"):
        _fail("unsupported plugin request")
        return 1
    req = envelope.get("request") or {}
    item_ref = req.get("itemRef")
    url = req.get("url")
    if not item_ref:
        _fail("missing itemRef")
        return 1
    try:
        cred = call("resolve", {"ref": item_ref, "url": url})
    except BrokerError as e:
        _fail(f"{e.code}: {e.message}")
        return 0  # a clean denial is still a protocol-level response
    sys.stdout.write(json.dumps({
        "protocol": PROTOCOL, "success": True, "credential": cred,
    }) + "\n")
    return 0


if __name__ == "__main__":
    sys.exit(main())