from __future__ import annotations

import io
from pathlib import Path
import zipfile

ERP_LOCAL_AGENT_VERSION = "1.0.0"
ERP_LOCAL_AGENT_NAME = "ERP Local Agent"
RUNTIME_ROOT = Path(__file__).resolve().parent / "local_agent_runtime"


def build_agent_env(*, erp_base_url: str, node_code: str, node_secret: str, storage_root: str, tenant_id=None, branch_id=None, sync_interval_seconds: int = 30, request_timeout_seconds: int = 60, tunnel_enabled: bool = True, tunnel_reconnect_seconds: int = 10) -> str:
    erp_base_url = (erp_base_url or "").strip().rstrip("/")
    if erp_base_url.startswith("http://"):
        host = erp_base_url[7:].split("/", 1)[0].split(":", 1)[0].lower()
        if host not in {"localhost", "127.0.0.1", "::1"}:
            erp_base_url = "https://" + erp_base_url[7:]
    storage_root = (storage_root or r"D:\AuditFirmStorage").strip()
    return (
        f"ERP_BASE_URL={erp_base_url}\n"
        f"NODE_CODE={(node_code or '').strip()}\n"
        f"NODE_SECRET={(node_secret or '').strip()}\n"
        f"STORAGE_ROOT={storage_root}\n"
        f"TENANT_ID={'' if tenant_id is None else tenant_id}\n"
        f"AUDIT_FIRM_ID={'' if tenant_id is None else tenant_id}\n"
        f"BRANCH_ID={'' if branch_id is None else branch_id}\n"
        f"SYNC_INTERVAL_SECONDS={int(sync_interval_seconds or 30)}\n"
        f"POLL_INTERVAL_SECONDS={int(sync_interval_seconds or 30)}\n"
        f"REQUEST_TIMEOUT_SECONDS={int(request_timeout_seconds or 60)}\n"
        f"TUNNEL_ENABLED={str(bool(tunnel_enabled)).lower()}\n"
        f"TUNNEL_RECONNECT_SECONDS={int(tunnel_reconnect_seconds or 10)}\n"
        "AUTO_UPDATE=true\n"
        "UPDATE_CHECK_INTERVAL_SECONDS=300\n"
    )


def _build_zip(*, env_text: str | None, include_env: bool, include_admin_readme: bool) -> bytes:
    if not RUNTIME_ROOT.exists():
        raise RuntimeError(f"ERP Local Agent runtime is missing: {RUNTIME_ROOT}")
    buffer = io.BytesIO()
    with zipfile.ZipFile(buffer, "w", compression=zipfile.ZIP_DEFLATED) as dst:
        for path in sorted(RUNTIME_ROOT.rglob("*")):
            if not path.is_file() or "__pycache__" in path.parts:
                continue
            name = path.relative_to(RUNTIME_ROOT).as_posix()
            dst.writestr(name, path.read_bytes())
        if include_env and env_text is not None:
            dst.writestr(".env", env_text)
        if include_admin_readme:
            dst.writestr("README_ERP_LOCAL_AGENT.txt", f"ERP Local Agent {ERP_LOCAL_AGENT_VERSION}\nStorage behaviour and D:\\AuditFirmStorage are preserved. Future compatible releases self-update securely from ERP.\n")
    return buffer.getvalue()


def build_preconfigured_agent_zip(*, env_text: str, include_admin_readme: bool = False) -> bytes:
    return _build_zip(env_text=env_text, include_env=True, include_admin_readme=include_admin_readme)


def build_agent_update_zip() -> bytes:
    # Update package deliberately excludes .env, .venv, data, logs and client files.
    return _build_zip(env_text=None, include_env=False, include_admin_readme=False)
