from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session
from typing import List
from .. import models, schemas, auth
from ..database import get_db
from ..db_manager import DbManager
from ..scheduler import sync_scheduler_config
from fastapi.responses import FileResponse
from fastapi import UploadFile, File

router = APIRouter(
    prefix="/admin/db",
    tags=["Admin Database"]
)

@router.get("/backups", response_model=List[schemas.BackupInfo])
def get_backups(
    db: Session = Depends(get_db),
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """List available database backups."""
    return DbManager.get_backup_list()

@router.get("/stats", response_model=schemas.DatabaseStats)
def get_db_stats(
    db: Session = Depends(get_db),
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """Get database backup storage statistics."""
    return DbManager.get_stats()

@router.post("/backup", response_model=schemas.BackupInfo)
def trigger_manual_backup(
    db: Session = Depends(get_db),
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """Trigger a manual database backup."""
    filename = DbManager.create_backup(db, label="manual", user_id=current_admin.sub)
    # Re-fetch the newly created file info
    backups = DbManager.get_backup_list()
    for b in backups:
        if b.filename == filename:
            return b
    raise HTTPException(status_code=500, detail="Backup created but info not found")

@router.post("/restore")
def restore_database(
    payload: dict,
    db: Session = Depends(get_db),
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """Restore database from a specific file. DANGEROUS."""
    filename = payload.get("filename")
    confirm = payload.get("confirm", False)
    
    if not filename:
        raise HTTPException(status_code=400, detail="Filename required")
    if not confirm:
        raise HTTPException(status_code=400, detail="Confirmation required")
        
    try:
        success = DbManager.restore_backup(filename, db, user_id=current_admin.sub)
        return {"status": "success", "message": f"Database restored from {filename}"}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

@router.get("/settings", response_model=schemas.DbSettingsUpdate)
def get_db_settings(
    db: Session = Depends(get_db),
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """Get database retention and scheduling settings."""
    # Ensure default settings exist
    retention = db.query(models.SystemSetting).filter(models.SystemSetting.key == "backup_retention_count").first()
    hour = db.query(models.SystemSetting).filter(models.SystemSetting.key == "backup_schedule_hour").first()
    freq = db.query(models.SystemSetting).filter(models.SystemSetting.key == "backup_schedule_freq_days").first()
    
    return {
        "retention_count": int(retention.value) if retention else 10,
        "schedule_hour": int(hour.value) if hour else 3,
        "schedule_freq_days": int(freq.value) if freq else 1
    }

@router.patch("/settings", response_model=schemas.DbSettingsUpdate)
def update_db_settings(
    settings: schemas.DbSettingsUpdate,
    db: Session = Depends(get_db),
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """Update database settings and re-trigger scheduler sync."""
    pairs = {
        "backup_retention_count": str(settings.retention_count),
        "backup_schedule_hour": str(settings.schedule_hour),
        "backup_schedule_freq_days": str(settings.schedule_freq_days)
    }
    
    for key, val in pairs.items():
        existing = db.query(models.SystemSetting).filter(models.SystemSetting.key == key).first()
        if existing:
            existing.value = val
        else:
            db.add(models.SystemSetting(key=key, value=val))
    
    db.commit()
    # Re-trigger scheduler sync
    sync_scheduler_config()
    return settings

@router.get("/export")
def export_database(
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """Download the current database file."""
    try:
        path = DbManager.export_db()
        return FileResponse(
            path, 
            media_type="application/x-sqlite3", 
            filename="inventory_export.db"
        )
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

@router.post("/import")
async def import_database(
    file: UploadFile = File(...),
    db: Session = Depends(get_db),
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """Upload and replace the current database. DANGEROUS."""
    contents = await file.read()
    try:
        DbManager.import_db(contents, db, user_id=current_admin.sub)
        return {"status": "success", "message": "Database successfully imported and replaced."}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

import os
from ..database import BASE_DIR
PROJECT_ROOT = os.path.dirname(BASE_DIR)
PROMPT_FILE_PATH = os.path.join(PROJECT_ROOT, "config", "ai_prompt.md")

@router.get("/settings/prompt")
def get_ai_prompt(
    db: Session = Depends(get_db),
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """Get the current AI extraction prompt (prioritizes config file)."""
    # 1. Try file first
    if os.path.exists(PROMPT_FILE_PATH):
        try:
            with open(PROMPT_FILE_PATH, 'r', encoding='utf-8') as f:
                return {"value": f.read().strip(), "source": "file"}
        except Exception as e:
            print(f"Error reading prompt file: {e}")

    # 2. Fallback to DB
    setting = db.query(models.SystemSetting).filter(models.SystemSetting.key == "ai_extraction_prompt").first()
    if not setting:
        return {"value": "", "source": "none"}
    return {"value": setting.value, "source": "database"}

@router.post("/settings/prompt")
def update_ai_prompt(
    payload: dict,
    db: Session = Depends(get_db),
    current_admin: auth.TokenData = Depends(auth.get_current_admin)
):
    """Update the AI extraction prompt (writes to both file and DB)."""
    value = payload.get("value")
    if value is None:
        raise HTTPException(status_code=400, detail="Value required")
    
    # 1. Update File (Primary)
    try:
        os.makedirs(os.path.dirname(PROMPT_FILE_PATH), exist_ok=True)
        with open(PROMPT_FILE_PATH, 'w', encoding='utf-8') as f:
            f.write(value)
    except Exception as e:
        print(f"Failed to write prompt file: {e}")
        # We continue to DB update anyway

    # 2. Update DB (Backup/Sync)
    existing = db.query(models.SystemSetting).filter(models.SystemSetting.key == "ai_extraction_prompt").first()
    if existing:
        existing.value = value
    else:
        db.add(models.SystemSetting(key="ai_extraction_prompt", value=value))
    
    db.commit()
    return {"status": "success", "file_updated": os.path.exists(PROMPT_FILE_PATH)}