import json
import os
from typing import Optional

from fastapi import APIRouter, Depends, HTTPException, Query
from fastapi.responses import FileResponse
from sqlalchemy.orm import Session
from sqlalchemy import func

from app.database import get_db
from app.models import Export, Image, Species
from app.schemas.export import (
    ExportCreate,
    ExportResponse,
    ExportListResponse,
    ExportPreview,
)
from app.workers.export_tasks import generate_export

router = APIRouter()


@router.get("", response_model=ExportListResponse)
def list_exports(
    limit: int = Query(50, ge=1, le=200),
    db: Session = Depends(get_db),
):
    """List all exports."""
    total = db.query(Export).count()
    exports = db.query(Export).order_by(Export.created_at.desc()).limit(limit).all()

    return ExportListResponse(
        items=[ExportResponse.model_validate(e) for e in exports],
        total=total,
    )


@router.post("/preview", response_model=ExportPreview)
def preview_export(export: ExportCreate, db: Session = Depends(get_db)):
    """Preview export without creating it."""
    criteria = export.filter_criteria
    min_images = criteria.min_images_per_species

    # Build query
    query = db.query(Image).filter(Image.status == "downloaded")

    if criteria.licenses:
        query = query.filter(Image.license.in_(criteria.licenses))

    if criteria.min_quality:
        query = query.filter(Image.quality_score >= criteria.min_quality)

    if criteria.species_ids:
        query = query.filter(Image.species_id.in_(criteria.species_ids))

    # Count images per species
    species_counts = db.query(
        Image.species_id,
        func.count(Image.id).label("count")
    ).filter(Image.status == "downloaded")

    if criteria.licenses:
        species_counts = species_counts.filter(Image.license.in_(criteria.licenses))
    if criteria.min_quality:
        species_counts = species_counts.filter(Image.quality_score >= criteria.min_quality)
    if criteria.species_ids:
        species_counts = species_counts.filter(Image.species_id.in_(criteria.species_ids))

    species_counts = species_counts.group_by(Image.species_id).all()

    valid_species = [s for s in species_counts if s.count >= min_images]
    total_images = sum(s.count for s in valid_species)

    # Estimate file size (rough: 50KB per image)
    estimated_size_mb = (total_images * 50) / 1024

    return ExportPreview(
        species_count=len(valid_species),
        image_count=total_images,
        estimated_size_mb=estimated_size_mb,
    )


@router.post("", response_model=ExportResponse)
def create_export(export: ExportCreate, db: Session = Depends(get_db)):
    """Create and start a new export job."""
    db_export = Export(
        name=export.name,
        filter_criteria=export.filter_criteria.model_dump_json(),
        train_split=export.train_split,
        status="pending",
    )
    db.add(db_export)
    db.commit()
    db.refresh(db_export)

    # Start Celery task
    task = generate_export.delay(db_export.id)
    db_export.celery_task_id = task.id
    db.commit()

    return ExportResponse.model_validate(db_export)


@router.get("/{export_id}", response_model=ExportResponse)
def get_export(export_id: int, db: Session = Depends(get_db)):
    """Get export status."""
    export = db.query(Export).filter(Export.id == export_id).first()
    if not export:
        raise HTTPException(status_code=404, detail="Export not found")

    return ExportResponse.model_validate(export)


@router.get("/{export_id}/progress")
def get_export_progress(export_id: int, db: Session = Depends(get_db)):
    """Get real-time export progress."""
    from app.workers.celery_app import celery_app

    export = db.query(Export).filter(Export.id == export_id).first()
    if not export:
        raise HTTPException(status_code=404, detail="Export not found")

    if not export.celery_task_id:
        return {"status": export.status}

    result = celery_app.AsyncResult(export.celery_task_id)

    if result.state == "PROGRESS":
        meta = result.info
        return {
            "status": "generating",
            "current": meta.get("current", 0),
            "total": meta.get("total", 0),
            "current_species": meta.get("species", ""),
        }

    return {"status": export.status}


@router.get("/{export_id}/download")
def download_export(export_id: int, db: Session = Depends(get_db)):
    """Download export zip file."""
    export = db.query(Export).filter(Export.id == export_id).first()
    if not export:
        raise HTTPException(status_code=404, detail="Export not found")

    if export.status != "completed":
        raise HTTPException(status_code=400, detail="Export not ready")

    if not export.file_path or not os.path.exists(export.file_path):
        raise HTTPException(status_code=404, detail="Export file not found")

    return FileResponse(
        export.file_path,
        media_type="application/zip",
        filename=f"{export.name}.zip",
    )


@router.delete("/{export_id}")
def delete_export(export_id: int, db: Session = Depends(get_db)):
    """Delete an export and its file."""
    export = db.query(Export).filter(Export.id == export_id).first()
    if not export:
        raise HTTPException(status_code=404, detail="Export not found")

    # Delete file if exists
    if export.file_path and os.path.exists(export.file_path):
        os.remove(export.file_path)

    db.delete(export)
    db.commit()

    return {"status": "deleted"}