#!/usr/bin/env python3
"""
REST API endpoints for GNSS Guard Server
Handles validation data submission and retrieval
"""

import json
import logging
from datetime import datetime, timedelta, timezone
from typing import List, Optional

from fastapi import APIRouter, Depends, HTTPException, Header, Query
from sqlalchemy.orm import Session
from sqlalchemy import desc

from database import get_db
from models import (
    Asset, ValidationHistory, AssetNotificationState,
    ValidationSubmission, ValidationBatchSubmission,
    ValidationResponse, AssetStatus, AssetResponse, AssetCreate, AssetWithToken,
    AssetImport, AssetBatchImport
)
from routes.auth import get_current_user
from services.telegram_service import get_telegram_service

logger = logging.getLogger("gnss_guard.server.api")

router = APIRouter(prefix="/api/v1", tags=["api"])


# =============================================================================
# Asset Token Authentication Dependency
# =============================================================================

async def get_current_asset(
    authorization: str = Header(..., description="Bearer token for asset authentication"),
    db: Session = Depends(get_db)
) -> Asset:
    """
    Dependency to authenticate asset using Bearer token.
    Returns the authenticated asset or raises 401.
    """
    if not authorization.startswith("Bearer "):
        raise HTTPException(status_code=401, detail="Invalid authorization header format")
    
    token = authorization[7:]  # Remove "Bearer " prefix
    token_hash = Asset.hash_token(token)
    
    asset = db.query(Asset).filter(
        Asset.token_hash == token_hash,
        Asset.is_active == True
    ).first()
    
    if not asset:
        raise HTTPException(status_code=401, detail="Invalid or inactive token")
    
    return asset


# =============================================================================
# Validation Endpoints (Asset Authentication Required)
# =============================================================================

@router.post("/validation", status_code=201)
async def submit_validation(
    data: ValidationSubmission,
    asset: Asset = Depends(get_current_asset),
    db: Session = Depends(get_db)
) -> dict:
    """
    Submit a single validation record from an asset.
    Also triggers Telegram notifications if state changed.
    """
    try:
        validation = ValidationHistory(
            asset_id=asset.id,
            validation_timestamp=data.validation_timestamp,
            validation_timestamp_unix=data.validation_timestamp_unix,
            is_valid=data.is_valid,
            sources_missing=json.dumps(data.sources_missing),
            sources_stale=json.dumps(data.sources_stale),
            coordinate_differences=json.dumps(data.coordinate_differences),
            source_coordinates=json.dumps(data.source_coordinates),
            validation_details=json.dumps(data.validation_details),
        )
        
        db.add(validation)
        db.commit()
        
        logger.info(f"Validation received from asset '{asset.name}' at {data.validation_timestamp}")
        
        # Process Telegram notification (will only send if state changed)
        try:
            telegram_service = get_telegram_service()
            validation_data = {
                "sources_missing": data.sources_missing,
                "sources_stale": data.sources_stale,
                "validation_details": data.validation_details,
                "source_coordinates": data.source_coordinates,
            }
            telegram_service.process_validation(db, asset, validation_data)
        except Exception as e:
            logger.warning(f"Telegram notification error for {asset.name}: {e}")
        
        return {
            "status": "success",
            "message": "Validation record saved",
            "id": validation.id
        }
        
    except Exception as e:
        logger.error(f"Error saving validation from {asset.name}: {e}")
        db.rollback()
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/validation/batch", status_code=201)
async def submit_validation_batch(
    data: ValidationBatchSubmission,
    asset: Asset = Depends(get_current_asset),
    db: Session = Depends(get_db)
) -> dict:
    """
    Submit multiple validation records (for catching up after offline period).
    Only sends Telegram notification for the most recent record to avoid spam.
    """
    try:
        saved_count = 0
        skipped_count = 0
        latest_record = None
        latest_timestamp = 0
        
        for record in data.records:
            # Check if this timestamp already exists for this asset
            existing = db.query(ValidationHistory).filter(
                ValidationHistory.asset_id == asset.id,
                ValidationHistory.validation_timestamp_unix == record.validation_timestamp_unix
            ).first()
            
            if existing:
                skipped_count += 1
                continue
            
            validation = ValidationHistory(
                asset_id=asset.id,
                validation_timestamp=record.validation_timestamp,
                validation_timestamp_unix=record.validation_timestamp_unix,
                is_valid=record.is_valid,
                sources_missing=json.dumps(record.sources_missing),
                sources_stale=json.dumps(record.sources_stale),
                coordinate_differences=json.dumps(record.coordinate_differences),
                source_coordinates=json.dumps(record.source_coordinates),
                validation_details=json.dumps(record.validation_details),
            )
            db.add(validation)
            saved_count += 1
            
            # Track the most recent record for notification
            if record.validation_timestamp_unix > latest_timestamp:
                latest_timestamp = record.validation_timestamp_unix
                latest_record = record
        
        db.commit()
        
        logger.info(f"Batch validation from '{asset.name}': {saved_count} saved, {skipped_count} skipped")
        
        # Process Telegram notification for the most recent record only
        if latest_record:
            try:
                telegram_service = get_telegram_service()
                validation_data = {
                    "sources_missing": latest_record.sources_missing,
                    "sources_stale": latest_record.sources_stale,
                    "validation_details": latest_record.validation_details,
                    "source_coordinates": latest_record.source_coordinates,
                }
                telegram_service.process_validation(db, asset, validation_data)
            except Exception as e:
                logger.warning(f"Telegram notification error for {asset.name}: {e}")
        
        return {
            "status": "success",
            "saved": saved_count,
            "skipped": skipped_count
        }
        
    except Exception as e:
        logger.error(f"Error saving batch validation from {asset.name}: {e}")
        db.rollback()
        raise HTTPException(status_code=500, detail=str(e))


# =============================================================================
# Read Endpoints (Session Authentication Required)
# =============================================================================

@router.get("/assets", response_model=List[AssetResponse])
async def list_assets(
    user: str = Depends(get_current_user),
    db: Session = Depends(get_db)
) -> List[AssetResponse]:
    """
    List all registered assets.
    Requires user session authentication.
    """
    assets = db.query(Asset).filter(Asset.is_active == True).all()
    return assets


@router.get("/assets/{asset_name}/status")
async def get_asset_status(
    asset_name: str,
    user: str = Depends(get_current_user),
    db: Session = Depends(get_db)
) -> AssetStatus:
    """
    Get current status of an asset (latest validation).
    Requires user session authentication.
    """
    asset = db.query(Asset).filter(
        Asset.name == asset_name,
        Asset.is_active == True
    ).first()
    
    if not asset:
        raise HTTPException(status_code=404, detail=f"Asset '{asset_name}' not found")
    
    # Get latest validation
    latest = db.query(ValidationHistory).filter(
        ValidationHistory.asset_id == asset.id
    ).order_by(desc(ValidationHistory.validation_timestamp_unix)).first()
    
    # Get online status from notification state (consistent with Telegram alerts)
    notification_state = db.query(AssetNotificationState).filter(
        AssetNotificationState.asset_id == asset.id
    ).first()
    
    is_online = notification_state.is_online if notification_state else False
    last_seen = notification_state.last_validation_at if notification_state else None
    
    # Fall back to validation timestamp if no notification state
    if not last_seen and latest and latest.received_at:
        last_seen = latest.received_at
    
    latest_validation = None
    if latest:
        latest_validation = ValidationResponse(
            id=latest.id,
            asset_name=asset.name,
            validation_timestamp=latest.validation_timestamp,
            validation_timestamp_unix=latest.validation_timestamp_unix,
            is_valid=latest.is_valid,
            sources_missing=json.loads(latest.sources_missing or "[]"),
            sources_stale=json.loads(latest.sources_stale or "[]"),
            coordinate_differences=json.loads(latest.coordinate_differences or "{}"),
            source_coordinates=json.loads(latest.source_coordinates or "{}"),
            validation_details=json.loads(latest.validation_details or "{}"),
            received_at=latest.received_at
        )
    
    return AssetStatus(
        asset_name=asset.name,
        is_online=is_online,
        last_seen=last_seen,
        latest_validation=latest_validation
    )


@router.get("/assets/{asset_name}/history")
async def get_asset_history(
    asset_name: str,
    hours: int = Query(default=72, ge=1, le=168, description="Hours of history (max 168 = 7 days)"),
    user: str = Depends(get_current_user),
    db: Session = Depends(get_db)
) -> List[ValidationResponse]:
    """
    Get validation history for an asset (default: 72 hours).
    Requires user session authentication.
    """
    asset = db.query(Asset).filter(
        Asset.name == asset_name,
        Asset.is_active == True
    ).first()
    
    if not asset:
        raise HTTPException(status_code=404, detail=f"Asset '{asset_name}' not found")
    
    # Calculate cutoff timestamp
    cutoff = datetime.utcnow() - timedelta(hours=hours)
    cutoff_unix = cutoff.timestamp()
    
    # Get validation history
    validations = db.query(ValidationHistory).filter(
        ValidationHistory.asset_id == asset.id,
        ValidationHistory.validation_timestamp_unix >= cutoff_unix
    ).order_by(desc(ValidationHistory.validation_timestamp_unix)).all()
    
    return [
        ValidationResponse(
            id=v.id,
            asset_name=asset.name,
            validation_timestamp=v.validation_timestamp,
            validation_timestamp_unix=v.validation_timestamp_unix,
            is_valid=v.is_valid,
            sources_missing=json.loads(v.sources_missing or "[]"),
            sources_stale=json.loads(v.sources_stale or "[]"),
            coordinate_differences=json.loads(v.coordinate_differences or "{}"),
            source_coordinates=json.loads(v.source_coordinates or "{}"),
            validation_details=json.loads(v.validation_details or "{}"),
            received_at=v.received_at
        )
        for v in validations
    ]


# =============================================================================
# Admin Endpoints (Session Authentication Required)
# =============================================================================

@router.post("/admin/assets", response_model=AssetWithToken, status_code=201)
async def create_asset(
    data: AssetCreate,
    user: str = Depends(get_current_user),
    db: Session = Depends(get_db)
) -> AssetWithToken:
    """
    Create a new asset and return its token.
    Requires user session authentication.
    """
    # Check if asset already exists
    existing = db.query(Asset).filter(Asset.name == data.name).first()
    if existing:
        raise HTTPException(status_code=400, detail=f"Asset '{data.name}' already exists")
    
    # Generate token
    token = Asset.generate_token()
    token_hash = Asset.hash_token(token)
    
    asset = Asset(
        name=data.name,
        token_hash=token_hash,
        description=data.description,
        telegram_chat_id=data.telegram_chat_id,
        telegram_enabled=data.telegram_enabled
    )
    
    db.add(asset)
    db.commit()
    db.refresh(asset)
    
    logger.info(f"Created new asset: {data.name}")
    
    # Return asset with the unhashed token (only shown once!)
    return AssetWithToken(
        id=asset.id,
        name=asset.name,
        is_active=asset.is_active,
        created_at=asset.created_at,
        description=asset.description,
        telegram_chat_id=asset.telegram_chat_id,
        telegram_enabled=asset.telegram_enabled,
        token=token
    )


@router.delete("/admin/assets/{asset_name}")
async def deactivate_asset(
    asset_name: str,
    user: str = Depends(get_current_user),
    db: Session = Depends(get_db)
) -> dict:
    """
    Deactivate an asset (soft delete).
    Requires user session authentication.
    """
    asset = db.query(Asset).filter(Asset.name == asset_name).first()
    
    if not asset:
        raise HTTPException(status_code=404, detail=f"Asset '{asset_name}' not found")
    
    asset.is_active = False
    db.commit()
    
    logger.info(f"Deactivated asset: {asset_name}")
    
    return {"status": "success", "message": f"Asset '{asset_name}' deactivated"}


@router.post("/admin/assets/import", response_model=AssetResponse, status_code=201)
async def import_asset(
    data: AssetImport,
    user: str = Depends(get_current_user),
    db: Session = Depends(get_db)
) -> AssetResponse:
    """
    Import an asset with a specific token.
    If asset exists, updates its token. If not, creates it.
    Requires user session authentication.
    """
    # Hash the provided token
    token_hash = Asset.hash_token(data.token)
    
    # Check if asset already exists
    existing = db.query(Asset).filter(Asset.name == data.name).first()
    
    if existing:
        # Update existing asset's token
        existing.token_hash = token_hash
        existing.is_active = True
        if data.description:
            existing.description = data.description
        if data.telegram_chat_id is not None:
            existing.telegram_chat_id = data.telegram_chat_id
        existing.telegram_enabled = data.telegram_enabled
        db.commit()
        db.refresh(existing)
        logger.info(f"Updated token for existing asset: {data.name}")
        return existing
    else:
        # Create new asset with provided token
        asset = Asset(
            name=data.name,
            token_hash=token_hash,
            description=data.description,
            telegram_chat_id=data.telegram_chat_id,
            telegram_enabled=data.telegram_enabled
        )
        db.add(asset)
        db.commit()
        db.refresh(asset)
        logger.info(f"Imported new asset: {data.name}")
        return asset


@router.post("/admin/assets/import/batch")
async def import_assets_batch(
    data: AssetBatchImport,
    user: str = Depends(get_current_user),
    db: Session = Depends(get_db)
) -> dict:
    """
    Batch import assets with specific tokens.
    Creates new assets or updates existing ones.
    Requires user session authentication.
    """
    created = 0
    updated = 0
    errors = []
    
    for asset_data in data.assets:
        try:
            token_hash = Asset.hash_token(asset_data.token)
            existing = db.query(Asset).filter(Asset.name == asset_data.name).first()
            
            if existing:
                existing.token_hash = token_hash
                existing.is_active = True
                if asset_data.description:
                    existing.description = asset_data.description
                if asset_data.telegram_chat_id is not None:
                    existing.telegram_chat_id = asset_data.telegram_chat_id
                existing.telegram_enabled = asset_data.telegram_enabled
                updated += 1
                logger.info(f"Updated token for asset: {asset_data.name}")
            else:
                asset = Asset(
                    name=asset_data.name,
                    token_hash=token_hash,
                    description=asset_data.description,
                    telegram_chat_id=asset_data.telegram_chat_id,
                    telegram_enabled=asset_data.telegram_enabled
                )
                db.add(asset)
                created += 1
                logger.info(f"Created asset: {asset_data.name}")
        except Exception as e:
            errors.append({"name": asset_data.name, "error": str(e)})
            logger.error(f"Failed to import asset {asset_data.name}: {e}")
    
    db.commit()
    
    return {
        "status": "success",
        "created": created,
        "updated": updated,
        "errors": errors
    }