"""Pipeline management endpoints — public trigger + admin dashboard.

Public:
  POST /pipeline/trigger/{video_id}    Trigger pipeline for a video

Admin:
  GET  /admin/pipeline/videos          Video list with status + event counts
  POST /admin/pipeline/trigger/{video_id}  Retrigger (same as public but under admin prefix)
  POST /admin/pipeline/revoke/{video_id}   Revoke/cancel active tasks for a video
  GET  /admin/pipeline/events/{video_id}   Event log for a video (paginated)
  GET  /admin/pipeline/worker-status       Active/reserved tasks from Celery inspect
"""

import logging
import uuid
from typing import Annotated

from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy import func, select, case
from sqlalchemy.ext.asyncio import AsyncSession

from config import get_settings
from database import get_session
from models import PipelineEvent, SourceVideo, Creator, KeyMoment, TranscriptSegment, ProcessingStatus
from redis_client import get_redis
from schemas import DebugModeResponse, DebugModeUpdate, TokenStageSummary, TokenSummaryResponse

logger = logging.getLogger("chrysopedia.pipeline")

router = APIRouter(tags=["pipeline"])

REDIS_DEBUG_MODE_KEY = "chrysopedia:debug_mode"


# ── Public trigger ───────────────────────────────────────────────────────────

@router.post("/pipeline/trigger/{video_id}")
async def trigger_pipeline(
    video_id: str,
    db: AsyncSession = Depends(get_session),
):
    """Manually trigger (or re-trigger) the LLM extraction pipeline for a video."""
    stmt = select(SourceVideo).where(SourceVideo.id == video_id)
    result = await db.execute(stmt)
    video = result.scalar_one_or_none()

    if video is None:
        raise HTTPException(status_code=404, detail=f"Video not found: {video_id}")

    from pipeline.stages import run_pipeline

    try:
        run_pipeline.delay(str(video.id))
        logger.info("Pipeline manually triggered for video_id=%s", video_id)
    except Exception as exc:
        logger.warning("Failed to dispatch pipeline for video_id=%s: %s", video_id, exc)
        raise HTTPException(
            status_code=503,
            detail="Pipeline dispatch failed — Celery/Redis may be unavailable",
        ) from exc

    return {
        "status": "triggered",
        "video_id": str(video.id),
        "current_processing_status": video.processing_status.value,
    }


# ── Admin: Video list ────────────────────────────────────────────────────────

@router.get("/admin/pipeline/videos")
async def list_pipeline_videos(
    db: AsyncSession = Depends(get_session),
):
    """List all videos with processing status and pipeline event counts."""
    # Subquery for event counts per video
    event_counts = (
        select(
            PipelineEvent.video_id,
            func.count().label("event_count"),
            func.sum(case(
                (PipelineEvent.event_type == "llm_call", PipelineEvent.total_tokens),
                else_=0
            )).label("total_tokens_used"),
            func.max(PipelineEvent.created_at).label("last_event_at"),
        )
        .group_by(PipelineEvent.video_id)
        .subquery()
    )

    # Subquery for the most recent stage start event per video (active stage indicator)
    latest_stage = (
        select(
            PipelineEvent.video_id,
            PipelineEvent.stage.label("active_stage"),
            PipelineEvent.event_type.label("active_stage_status"),
            PipelineEvent.created_at.label("stage_started_at"),
        )
        .where(PipelineEvent.event_type.in_(["start", "complete", "error"]))
        .order_by(PipelineEvent.video_id, PipelineEvent.created_at.desc())
        .distinct(PipelineEvent.video_id)
        .subquery()
    )

    stmt = (
        select(
            SourceVideo.id,
            SourceVideo.filename,
            SourceVideo.processing_status,
            SourceVideo.content_hash,
            SourceVideo.created_at,
            SourceVideo.updated_at,
            Creator.name.label("creator_name"),
            event_counts.c.event_count,
            event_counts.c.total_tokens_used,
            event_counts.c.last_event_at,
            latest_stage.c.active_stage,
            latest_stage.c.active_stage_status,
            latest_stage.c.stage_started_at,
        )
        .join(Creator, SourceVideo.creator_id == Creator.id)
        .outerjoin(event_counts, SourceVideo.id == event_counts.c.video_id)
        .outerjoin(latest_stage, SourceVideo.id == latest_stage.c.video_id)
        .order_by(SourceVideo.updated_at.desc())
    )

    result = await db.execute(stmt)
    rows = result.all()

    return {
        "items": [
            {
                "id": str(r.id),
                "filename": r.filename,
                "processing_status": r.processing_status.value if hasattr(r.processing_status, 'value') else str(r.processing_status),
                "content_hash": r.content_hash,
                "creator_name": r.creator_name,
                "created_at": r.created_at.isoformat() if r.created_at else None,
                "updated_at": r.updated_at.isoformat() if r.updated_at else None,
                "event_count": r.event_count or 0,
                "total_tokens_used": r.total_tokens_used or 0,
                "last_event_at": r.last_event_at.isoformat() if r.last_event_at else None,
                "active_stage": r.active_stage,
                "active_stage_status": r.active_stage_status,
                "stage_started_at": r.stage_started_at.isoformat() if r.stage_started_at else None,
            }
            for r in rows
        ],
        "total": len(rows),
    }


# ── Admin: Retrigger ─────────────────────────────────────────────────────────

@router.post("/admin/pipeline/trigger/{video_id}")
async def admin_trigger_pipeline(
    video_id: str,
    db: AsyncSession = Depends(get_session),
):
    """Admin retrigger — same as public trigger."""
    return await trigger_pipeline(video_id, db)


# ── Admin: Clean Retrigger ───────────────────────────────────────────────────

@router.post("/admin/pipeline/clean-retrigger/{video_id}")
async def clean_retrigger_pipeline(
    video_id: str,
    db: AsyncSession = Depends(get_session),
):
    """Wipe prior pipeline output for a video, then retrigger.

    Deletes: pipeline_events, key_moments, transcript_segments,
    and associated Qdrant vectors. Resets processing_status to 'not_started'.
    Does NOT delete technique_pages — the pipeline re-synthesizes via upsert.
    """
    stmt = select(SourceVideo).where(SourceVideo.id == video_id)
    result = await db.execute(stmt)
    video = result.scalar_one_or_none()

    if video is None:
        raise HTTPException(status_code=404, detail=f"Video not found: {video_id}")

    # Delete pipeline events
    await db.execute(
        PipelineEvent.__table__.delete().where(PipelineEvent.video_id == video_id)
    )
    # Delete key moments
    await db.execute(
        KeyMoment.__table__.delete().where(KeyMoment.source_video_id == video_id)
    )
    # Note: transcript_segments are NOT deleted — they are the pipeline's input
    # data created during ingest, not pipeline output. Deleting them would leave
    # the pipeline with nothing to process.
    
    # Reset status
    video.processing_status = ProcessingStatus.not_started
    await db.commit()

    deleted_counts = {
        "pipeline_events": "cleared",
        "key_moments": "cleared",
    }

    # Best-effort Qdrant cleanup (non-blocking)
    try:
        settings = get_settings()
        from pipeline.qdrant_client import QdrantManager
        qdrant = QdrantManager(settings)
        qdrant.delete_by_video_id(str(video_id))
        deleted_counts["qdrant_vectors"] = "cleared"
    except Exception as exc:
        logger.warning("Qdrant cleanup failed for video_id=%s: %s", video_id, exc)
        deleted_counts["qdrant_vectors"] = f"skipped: {exc}"

    # Now trigger the pipeline
    from pipeline.stages import run_pipeline
    try:
        run_pipeline.delay(str(video.id))
        logger.info("Clean retrigger dispatched for video_id=%s", video_id)
    except Exception as exc:
        logger.warning("Failed to dispatch pipeline after cleanup for video_id=%s: %s", video_id, exc)
        raise HTTPException(
            status_code=503,
            detail="Cleanup succeeded but pipeline dispatch failed — Celery/Redis may be unavailable",
        ) from exc

    return {
        "status": "clean_retriggered",
        "video_id": str(video.id),
        "cleaned": deleted_counts,
    }


# ── Admin: Revoke ────────────────────────────────────────────────────────────

@router.post("/admin/pipeline/revoke/{video_id}")
async def revoke_pipeline(video_id: str):
    """Revoke/cancel active Celery tasks for a video.
    
    Uses Celery's revoke with terminate=True to kill running tasks.
    This is best-effort — the task may have already completed.
    """
    from worker import celery_app
    
    try:
        # Get active tasks and revoke any matching this video_id
        inspector = celery_app.control.inspect()
        active = inspector.active() or {}
        revoked_count = 0
        
        for _worker, tasks in active.items():
            for task in tasks:
                task_args = task.get("args", [])
                if task_args and str(task_args[0]) == video_id:
                    celery_app.control.revoke(task["id"], terminate=True)
                    revoked_count += 1
                    logger.info("Revoked task %s for video_id=%s", task["id"], video_id)
        
        return {
            "status": "revoked" if revoked_count > 0 else "no_active_tasks",
            "video_id": video_id,
            "tasks_revoked": revoked_count,
        }
    except Exception as exc:
        logger.warning("Failed to revoke tasks for video_id=%s: %s", video_id, exc)
        raise HTTPException(
            status_code=503,
            detail="Failed to communicate with Celery worker",
        ) from exc


# ── Admin: Recent activity feed ──────────────────────────────────────────────

@router.get("/admin/pipeline/recent-activity")
async def recent_pipeline_activity(
    limit: Annotated[int, Query(ge=1, le=20)] = 10,
    db: AsyncSession = Depends(get_session),
):
    """Get the most recent pipeline stage completions and errors with video context."""
    stmt = (
        select(
            PipelineEvent.id,
            PipelineEvent.video_id,
            PipelineEvent.stage,
            PipelineEvent.event_type,
            PipelineEvent.total_tokens,
            PipelineEvent.duration_ms,
            PipelineEvent.created_at,
            SourceVideo.filename,
            Creator.name.label("creator_name"),
        )
        .join(SourceVideo, PipelineEvent.video_id == SourceVideo.id)
        .join(Creator, SourceVideo.creator_id == Creator.id)
        .where(PipelineEvent.event_type.in_(["complete", "error"]))
        .order_by(PipelineEvent.created_at.desc())
        .limit(limit)
    )
    result = await db.execute(stmt)
    rows = result.all()

    return {
        "items": [
            {
                "id": str(r.id),
                "video_id": str(r.video_id),
                "filename": r.filename,
                "creator_name": r.creator_name,
                "stage": r.stage,
                "event_type": r.event_type,
                "total_tokens": r.total_tokens,
                "duration_ms": r.duration_ms,
                "created_at": r.created_at.isoformat() if r.created_at else None,
            }
            for r in rows
        ],
    }


# ── Admin: Event log ─────────────────────────────────────────────────────────

@router.get("/admin/pipeline/events/{video_id}")
async def list_pipeline_events(
    video_id: str,
    offset: Annotated[int, Query(ge=0)] = 0,
    limit: Annotated[int, Query(ge=1, le=200)] = 100,
    stage: Annotated[str | None, Query(description="Filter by stage name")] = None,
    event_type: Annotated[str | None, Query(description="Filter by event type")] = None,
    order: Annotated[str, Query(description="Sort order: asc or desc")] = "desc",
    db: AsyncSession = Depends(get_session),
):
    """Get pipeline events for a video. Default: newest first (desc)."""
    stmt = select(PipelineEvent).where(PipelineEvent.video_id == video_id)
    
    if stage:
        stmt = stmt.where(PipelineEvent.stage == stage)
    if event_type:
        stmt = stmt.where(PipelineEvent.event_type == event_type)
    
    # Validate order param
    if order not in ("asc", "desc"):
        raise HTTPException(status_code=400, detail="order must be 'asc' or 'desc'")

    # Count
    count_stmt = select(func.count()).select_from(stmt.subquery())
    total = (await db.execute(count_stmt)).scalar() or 0
    
    # Fetch
    order_clause = PipelineEvent.created_at.asc() if order == "asc" else PipelineEvent.created_at.desc()
    stmt = stmt.order_by(order_clause)
    stmt = stmt.offset(offset).limit(limit)
    result = await db.execute(stmt)
    events = result.scalars().all()
    
    return {
        "items": [
            {
                "id": str(e.id),
                "video_id": str(e.video_id),
                "stage": e.stage,
                "event_type": e.event_type,
                "prompt_tokens": e.prompt_tokens,
                "completion_tokens": e.completion_tokens,
                "total_tokens": e.total_tokens,
                "model": e.model,
                "duration_ms": e.duration_ms,
                "payload": e.payload,
                "created_at": e.created_at.isoformat() if e.created_at else None,
                "system_prompt_text": e.system_prompt_text,
                "user_prompt_text": e.user_prompt_text,
                "response_text": e.response_text,
            }
            for e in events
        ],
        "total": total,
        "offset": offset,
        "limit": limit,
    }


# ── Admin: Debug mode ─────────────────────────────────────────────────────────

@router.get("/admin/pipeline/debug-mode", response_model=DebugModeResponse)
async def get_debug_mode() -> DebugModeResponse:
    """Get the current pipeline debug mode (on/off)."""
    settings = get_settings()
    try:
        redis = await get_redis()
        try:
            value = await redis.get(REDIS_DEBUG_MODE_KEY)
            if value is not None:
                return DebugModeResponse(debug_mode=value.lower() == "true")
        finally:
            await redis.aclose()
    except Exception as exc:
        logger.warning("Redis unavailable for debug mode read, using config default: %s", exc)

    return DebugModeResponse(debug_mode=settings.debug_mode)


@router.put("/admin/pipeline/debug-mode", response_model=DebugModeResponse)
async def set_debug_mode(body: DebugModeUpdate) -> DebugModeResponse:
    """Set the pipeline debug mode (on/off)."""
    try:
        redis = await get_redis()
        try:
            await redis.set(REDIS_DEBUG_MODE_KEY, str(body.debug_mode))
        finally:
            await redis.aclose()
    except Exception as exc:
        logger.error("Failed to set debug mode in Redis: %s", exc)
        raise HTTPException(
            status_code=503,
            detail=f"Redis unavailable: {exc}",
        )

    logger.info("Pipeline debug mode set to %s", body.debug_mode)
    return DebugModeResponse(debug_mode=body.debug_mode)


# ── Admin: Token summary ─────────────────────────────────────────────────────

@router.get("/admin/pipeline/token-summary/{video_id}", response_model=TokenSummaryResponse)
async def get_token_summary(
    video_id: str,
    db: AsyncSession = Depends(get_session),
) -> TokenSummaryResponse:
    """Get per-stage token usage summary for a video."""
    stmt = (
        select(
            PipelineEvent.stage,
            func.count().label("call_count"),
            func.coalesce(func.sum(PipelineEvent.prompt_tokens), 0).label("total_prompt_tokens"),
            func.coalesce(func.sum(PipelineEvent.completion_tokens), 0).label("total_completion_tokens"),
            func.coalesce(func.sum(PipelineEvent.total_tokens), 0).label("total_tokens"),
        )
        .where(PipelineEvent.video_id == video_id)
        .where(PipelineEvent.event_type == "llm_call")
        .group_by(PipelineEvent.stage)
        .order_by(PipelineEvent.stage)
    )

    result = await db.execute(stmt)
    rows = result.all()

    stages = [
        TokenStageSummary(
            stage=r.stage,
            call_count=r.call_count,
            total_prompt_tokens=r.total_prompt_tokens,
            total_completion_tokens=r.total_completion_tokens,
            total_tokens=r.total_tokens,
        )
        for r in rows
    ]
    grand_total = sum(s.total_tokens for s in stages)

    return TokenSummaryResponse(
        video_id=video_id,
        stages=stages,
        grand_total_tokens=grand_total,
    )


# ── Admin: Worker status ─────────────────────────────────────────────────────

@router.get("/admin/pipeline/worker-status")
async def worker_status():
    """Get current Celery worker status — active, reserved, and stats."""
    from worker import celery_app
    
    try:
        inspector = celery_app.control.inspect()
        active = inspector.active() or {}
        reserved = inspector.reserved() or {}
        stats = inspector.stats() or {}
        
        workers = []
        for worker_name in set(list(active.keys()) + list(reserved.keys()) + list(stats.keys())):
            worker_active = active.get(worker_name, [])
            worker_reserved = reserved.get(worker_name, [])
            worker_stats = stats.get(worker_name, {})
            
            workers.append({
                "name": worker_name,
                "active_tasks": [
                    {
                        "id": t.get("id"),
                        "name": t.get("name"),
                        "args": t.get("args", []),
                        "time_start": t.get("time_start"),
                    }
                    for t in worker_active
                ],
                "reserved_tasks": len(worker_reserved),
                "total_completed": worker_stats.get("total", {}).get("tasks.pipeline.stages.stage2_segmentation", 0)
                    + worker_stats.get("total", {}).get("tasks.pipeline.stages.stage3_extraction", 0)
                    + worker_stats.get("total", {}).get("tasks.pipeline.stages.stage4_classification", 0)
                    + worker_stats.get("total", {}).get("tasks.pipeline.stages.stage5_synthesis", 0),
                "uptime": worker_stats.get("clock", None),
                "pool_size": worker_stats.get("pool", {}).get("max-concurrency") if isinstance(worker_stats.get("pool"), dict) else None,
            })
        
        return {
            "online": len(workers) > 0,
            "workers": workers,
        }
    except Exception as exc:
        logger.warning("Failed to inspect Celery workers: %s", exc)
        return {
            "online": False,
            "workers": [],
            "error": str(exc),
        }