"""Fleet startup hook for the mcp-for-blender add-on (runs at every Blender launch, from the
user scripts/startup dir). Part of eshpfi-management stacks/blender; see its README.

The add-on (scripts/addons/blender_mcp.py, pinned upstream commit 41a18432) serves a socket that
runs arbitrary Python with NO authentication. The MCP server that talks to it runs INSIDE this
same container (/work/.mcp-venv), so the socket stays on the container's localhost and no port is
published. That same-container arrangement is also what makes viewport screenshots work: the MCP
server reads the image file Blender writes, which needs a shared filesystem.

This hook exists because the add-on is not listed in any saved user preferences. It enables the
add-on after the prefs have loaded, and makes sure its server is running.

Blender's stdout goes to /dev/null in this image, so every step is logged to
/config/.local/state/fleet_mcp.log.
"""
import os
import time
import traceback

import addon_utils
import bpy

MODULE, HOST, PORT = "blender_mcp", "localhost", 9876
LOG = "/config/.local/state/fleet_mcp.log"


def log(msg):
    os.makedirs(os.path.dirname(LOG), exist_ok=True)
    with open(LOG, "a") as f:
        f.write(f"{time.strftime('%Y-%m-%d %H:%M:%S')} {msg}\n")


def _ensure_serving():
    """Timer: once Blender is fully up, enable the add-on and make sure its server is running on
    HOST:PORT. Retries every second until it is.

    ⚠ The add-on is enabled HERE, not in register(). Startup scripts run before Blender loads
    the user preferences, and loading them disables any add-on the prefs do not list: an early
    enable was undone, taking the add-on's Scene properties with it, while the server object
    kept answering "'Scene' object has no attribute 'blendermcp_use_polyhaven'" (found
    2026-09-27)."""
    try:
        server = getattr(bpy.types, "blendermcp_server", None)
        if not addon_utils.check(MODULE)[1]:
            import blender_mcp                  # our object first, so the add-on's auto-start adopts it
            if server is None:
                bpy.types.blendermcp_server = blender_mcp.BlenderMCPServer(host=HOST, port=PORT)
            addon_utils.enable(MODULE, default_set=True)
            log(f"add-on enabled: {MODULE}")
            return 1.0
        import blender_mcp

        if server is not None and server.host != HOST:
            if server.running:
                server.stop()
            server = None
        if server is None:
            server = blender_mcp.BlenderMCPServer(host=HOST, port=PORT)
            bpy.types.blendermcp_server = server
        if not server.running:
            server.start()
        if server.running and hasattr(bpy.context.scene, "blendermcp_use_polyhaven"):
            log(f"serving on {server.host}:{server.port}")
            _gpu_by_default()
            return None
        log("not serving yet; retrying")
        return 1.0
    except Exception:
        log("ensure_serving failed:\n" + traceback.format_exc())
        return 2.0


def _gpu_by_default():
    """Point Cycles at GPU 3 through OptiX. Safe mode forbids agent code from touching
    bpy.context.preferences, so a model cannot select the GPU itself: "'preferences' reached
    through an unresolvable receiver" (found 2026-09-27). It CAN set scene.cycles.device, so the
    current scene is set to GPU here too, and agents set it on scenes they create."""
    try:
        prefs = bpy.context.preferences.addons["cycles"].preferences
        prefs.compute_device_type = "OPTIX"
        prefs.refresh_devices()
        for d in prefs.devices:
            d.use = d.type == "OPTIX"
        bpy.context.scene.cycles.device = "GPU"
        log("cycles: OPTIX on " + ", ".join(d.name for d in prefs.devices if d.use))
    except Exception:
        log("cycles GPU default failed:\n" + traceback.format_exc())


def register():
    if bpy.app.background:          # headless renders never need the socket
        return
    bpy.app.timers.register(_ensure_serving, first_interval=2.0, persistent=True)


def unregister():
    pass