"""Agent binary upload and retention routes.

Lets an operator drop in a new shopdbagent.exe or shopdb-endpoint-tray.exe from
the Endpoints page, keep the last few versions, and roll the current pointer
back to a retained build. The actual staging/retention logic lives in
agentstore.py; this module is only the HTTP surface and authorization.

Authorization boundary (deliberate):
  - Uploading, listing, and selecting the current staged version is
    endpoints.agentpackage - the same grant that already lets someone build and
    download the site-agent ZIP. Staging a binary only changes what a FUTURE
    download contains; it does not touch any running endpoint.
  - Pushing that binary to live endpoints (agent replacement) is a separate,
    heavier grant, endpoints.agentupdate, and is NOT wired here. It is a distinct
    command family from application deploys (endpoints.deploy) so app-push rights
    never imply SYSTEM-level agent replacement. That push pipe is a later slice.

Uploads are capped and PE-checked so a wrong or hostile file cannot be staged.
"""

from flask import request

from shopdb.api import (success_response, error_response, ErrorCodes,
                        require_permission)

from .routes import endpoints_bp
from . import agentstore

# Hard cap on an uploaded agent binary. The real agent is a few MB; this is a
# generous ceiling that still refuses an operator who points at a giant wrong
# file before it is buffered fully into memory-staged storage.
_MAX_UPLOAD_BYTES = 64 * 1024 * 1024


@endpoints_bp.route('/siteagent/binaries/<binkey>', methods=['GET'])
@require_permission('endpoints.agentpackage')
def list_agent_binaries(binkey):
    """List staged versions for a binary (agent or tray), newest first."""
    if not agentstore.is_valid_binary_key(binkey):
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'binkey must be one of: agent, tray',
            http_code=400)
    return success_response({
        'binary': binkey,
        'current': agentstore.current_version(binkey),
        'versions': agentstore.list_versions(binkey),
    })


@endpoints_bp.route('/siteagent/binaries/<binkey>', methods=['POST'])
@require_permission('endpoints.agentpackage')
def upload_agent_binary(binkey):
    """Stage an uploaded binary as a new version and make it current.

    Expects multipart/form-data with a 'file' upload and a 'version' field. The
    version must be a strict dotted-numeric string (for example 1.6.3) so it is
    safe as a directory name and orderable. The upload must be a Windows PE
    executable. Older versions past the retention window are pruned, but never
    the current one.
    """
    version = (request.form.get('version') or '').strip()
    if not agentstore.is_valid_binary_key(binkey):
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'binkey must be one of: agent, tray',
            http_code=400)
    if not agentstore.is_valid_version(version):
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'version must be a dotted-numeric string such as 1.6.3',
            http_code=400)

    upload = request.files.get('file')
    if upload is None or not upload.filename:
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'a file upload is required',
            http_code=400)

    data = upload.read(_MAX_UPLOAD_BYTES + 1)
    if len(data) > _MAX_UPLOAD_BYTES:
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'uploaded binary exceeds the size limit',
            http_code=400)
    if not agentstore.looks_like_pe(data):
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'uploaded file is not a Windows executable',
            http_code=400)

    result = agentstore.store_version(binkey, version, data)
    return success_response({
        'binary': binkey,
        'current': result['current'],
        'versions': result['versions'],
    })


@endpoints_bp.route('/siteagent/binaries/<binkey>/current', methods=['PUT'])
@require_permission('endpoints.agentpackage')
def set_current_agent_binary(binkey):
    """Point 'current' at an already-staged version (roll back or forward)."""
    if not agentstore.is_valid_binary_key(binkey):
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'binkey must be one of: agent, tray',
            http_code=400)
    source = request.get_json(silent=True) or {}
    version = (source.get('version') or '').strip()
    if not agentstore.is_valid_version(version):
        return error_response(
            ErrorCodes.VALIDATION_ERROR,
            'version must be a dotted-numeric string such as 1.6.3',
            http_code=400)
    if not agentstore.set_current(binkey, version):
        return error_response(
            ErrorCodes.NOT_FOUND,
            'that version is not staged',
            http_code=404)
    return success_response({
        'binary': binkey,
        'current': agentstore.current_version(binkey),
        'versions': agentstore.list_versions(binkey),
    })