"""Thumbnail rendering tasks.

Covers:
- render_step_thumbnail  — render thumbnail for a freshly-processed STEP file
- regenerate_thumbnail   — re-render thumbnail with updated per-part colours
"""
import logging
from pathlib import Path

from app.tasks.celery_app import celery_app
from app.core.task_logs import log_task_event
from app.core.pipeline_logger import PipelineLogger

logger = logging.getLogger(__name__)


@celery_app.task(bind=True, name="app.tasks.step_tasks.render_step_thumbnail", queue="asset_pipeline")
def render_step_thumbnail(self, cad_file_id: str):
    """Render the thumbnail for a freshly-processed STEP file.

    Runs on the dedicated asset_pipeline queue (concurrency=1) so the
    blender-renderer service is never overwhelmed by concurrent requests.
    On success, also auto-populates materials and marks the CadFile as completed.
    """
    pl = PipelineLogger(task_id=self.request.id)
    pl.step_start("render_step_thumbnail", {"cad_file_id": cad_file_id})
    logger.info(f"Rendering thumbnail for CAD file: {cad_file_id}")

    # Resolve and log tenant context at task start (required for RLS)
    from app.core.tenant_context import resolve_tenant_id_for_cad, set_tenant_context_sync
    _tenant_id = resolve_tenant_id_for_cad(cad_file_id)

    # Compute and persist STEP file hash for STL cache lookups
    try:
        from sqlalchemy import create_engine
        from sqlalchemy.orm import Session
        from app.config import settings as app_settings
        from app.models.cad_file import CadFile
        from app.domains.products.cache_service import compute_step_hash

        sync_url = app_settings.database_url.replace("+asyncpg", "")
        _eng = create_engine(sync_url)
        with Session(_eng) as _sess:
            set_tenant_context_sync(_sess, _tenant_id)
            _cad = _sess.get(CadFile, cad_file_id)
            if _cad and _cad.stored_path and not _cad.step_file_hash:
                _hash = compute_step_hash(_cad.stored_path)
                _cad.step_file_hash = _hash
                _sess.commit()
                logger.info(f"Saved step_file_hash for {cad_file_id}: {_hash[:12]}…")
        _eng.dispose()
    except Exception:
        logger.warning(f"step_file_hash computation failed for {cad_file_id} (non-fatal)")

    try:
        from app.services.step_processor import regenerate_cad_thumbnail
        pl.info("render_step_thumbnail", "Calling regenerate_cad_thumbnail")
        success = regenerate_cad_thumbnail(cad_file_id, part_colors={})
        if not success:
            raise RuntimeError("regenerate_cad_thumbnail returned False")
    except Exception as exc:
        pl.step_error("render_step_thumbnail", f"Thumbnail render failed: {exc}", exc)
        logger.error(f"Thumbnail render failed for {cad_file_id}: {exc}")
        raise self.retry(exc=exc, countdown=30, max_retries=2)

    # Extract bounding box from the thumbnail GLB generated by the renderer.
    # GLB bbox via trimesh is fast and avoids re-parsing the STEP file.
    # Falls back to cadquery STEP re-parse if GLB is not found.
    try:
        from sqlalchemy import create_engine
        from sqlalchemy.orm import Session
        from app.config import settings as _cfg2
        from app.models.cad_file import CadFile as _CadFile2
        from app.domains.pipeline.tasks.extract_metadata import _bbox_from_glb, _bbox_from_step_cadquery

        _sync_url2 = _cfg2.database_url.replace("+asyncpg", "")
        _eng2 = create_engine(_sync_url2)
        with Session(_eng2) as _sess2:
            set_tenant_context_sync(_sess2, _tenant_id)
            _cad2 = _sess2.get(_CadFile2, cad_file_id)
            _step_path = _cad2.stored_path if _cad2 else None
        _eng2.dispose()

        if _step_path and not (_cad2.mesh_attributes or {}).get("dimensions_mm"):
            _step = Path(_step_path)
            _glb = _step.parent / f"{_step.stem}_thumbnail.glb"
            bbox_data = _bbox_from_glb(str(_glb)) or _bbox_from_step_cadquery(_step_path)
            if bbox_data:
                _eng2 = create_engine(_sync_url2)
                with Session(_eng2) as _sess2:
                    set_tenant_context_sync(_sess2, _tenant_id)
                    _cad2 = _sess2.get(_CadFile2, cad_file_id)
                    if _cad2:
                        _cad2.mesh_attributes = {**(  _cad2.mesh_attributes or {}), **bbox_data}
                        _sess2.commit()
                        dims = bbox_data["dimensions_mm"]
                        logger.info(
                            f"bbox for {cad_file_id}: "
                            f"{dims['x']}×{dims['y']}×{dims['z']} mm"
                        )
                _eng2.dispose()
    except Exception:
        logger.exception(f"bbox extraction failed for {cad_file_id} (non-fatal)")

    # Extract sharp edge topology (PCurve-based) if not already present.
    # This runs on render-worker which has OCP (cadquery's OCC fork).
    try:
        from sqlalchemy import create_engine
        from sqlalchemy.orm import Session
        from app.config import settings as _cfg3
        from app.models.cad_file import CadFile as _CadFile3
        from app.services.step_processor import extract_mesh_edge_data

        _sync_url3 = _cfg3.database_url.replace("+asyncpg", "")
        _eng3 = create_engine(_sync_url3)
        with Session(_eng3) as _sess3:
            set_tenant_context_sync(_sess3, _tenant_id)
            _cad3 = _sess3.get(_CadFile3, cad_file_id)
            _attrs = _cad3.mesh_attributes or {} if _cad3 else {}
            _step_path3 = _cad3.stored_path if _cad3 else None
        _eng3.dispose()

        if _step_path3 and "sharp_edge_pairs" not in _attrs:
            edge_data = extract_mesh_edge_data(_step_path3)
            if edge_data:
                _eng3 = create_engine(_sync_url3)
                with Session(_eng3) as _sess3:
                    set_tenant_context_sync(_sess3, _tenant_id)
                    _cad3 = _sess3.get(_CadFile3, cad_file_id)
                    if _cad3:
                        _cad3.mesh_attributes = {**(_cad3.mesh_attributes or {}), **edge_data}
                        _sess3.commit()
                        n_pairs = len(edge_data.get("sharp_edge_pairs", []))
                        logger.info(f"Sharp edge data extracted for {cad_file_id}: {n_pairs} sharp edges")
                _eng3.dispose()
    except Exception:
        logger.exception(f"Sharp edge extraction failed for {cad_file_id} (non-fatal)")

    # Auto-populate materials now that parsed_objects are available
    try:
        from app.domains.pipeline.tasks.extract_metadata import _auto_populate_materials_for_cad
        _auto_populate_materials_for_cad(cad_file_id, tenant_id=_tenant_id)
    except Exception:
        logger.exception(
            f"Auto material population failed for cad_file {cad_file_id} (non-fatal)"
        )

    # Broadcast WebSocket event for live UI updates
    try:
        from sqlalchemy import create_engine, select as sql_select2
        from sqlalchemy.orm import Session as _Session
        from app.config import settings as _cfg
        from app.models.cad_file import CadFile as _CadFile
        _sync_url = _cfg.database_url.replace("+asyncpg", "")
        _eng = create_engine(_sync_url)
        with _Session(_eng) as _s:
            set_tenant_context_sync(_s, _tenant_id)
            _cad = _s.get(_CadFile, cad_file_id)
            _tid = str(_cad.tenant_id) if _cad and _cad.tenant_id else None
        _eng.dispose()
        if _tid:
            from app.core.websocket import publish_event_sync
            publish_event_sync(_tid, {
                "type": "cad_processing_complete",
                "cad_file_id": cad_file_id,
                "status": "completed",
            })
    except Exception:
        logger.debug("WebSocket publish for CAD complete skipped (non-fatal)")

    # Auto-generate geometry GLB so the 3D viewer is ready without manual trigger
    try:
        from app.domains.pipeline.tasks.export_glb import generate_gltf_geometry_task
        generate_gltf_geometry_task.delay(cad_file_id)
        pl.info("render_step_thumbnail", f"Queued generate_gltf_geometry_task for {cad_file_id}")
        logger.info("render_step_thumbnail: queued generate_gltf_geometry_task for %s", cad_file_id)
    except Exception:
        logger.debug("Could not queue generate_gltf_geometry_task (non-fatal)")

    pl.step_done("render_step_thumbnail")


@celery_app.task(bind=True, name="app.tasks.step_tasks.regenerate_thumbnail", queue="asset_pipeline")
def regenerate_thumbnail(self, cad_file_id: str, part_colors: dict):
    """Regenerate thumbnail with per-part colours."""
    pl = PipelineLogger(task_id=self.request.id)
    pl.step_start("regenerate_thumbnail", {"cad_file_id": cad_file_id})
    logger.info(f"Regenerating thumbnail for CAD file: {cad_file_id}")

    # Resolve and log tenant context at task start (required for RLS)
    from app.core.tenant_context import resolve_tenant_id_for_cad
    _tenant_id = resolve_tenant_id_for_cad(cad_file_id)

    try:
        from app.services.step_processor import regenerate_cad_thumbnail
        success = regenerate_cad_thumbnail(cad_file_id, part_colors)
        if not success:
            raise RuntimeError("regenerate_cad_thumbnail returned False")
    except Exception as exc:
        pl.step_error("regenerate_thumbnail", f"Thumbnail regeneration failed: {exc}", exc)
        logger.error(f"Thumbnail regeneration failed for {cad_file_id}: {exc}")
        raise self.retry(exc=exc, countdown=30, max_retries=2)
    pl.step_done("regenerate_thumbnail")