api/endpoints/karma.py

import os
import logging
import time
import datetime
import traceback
import aiosqlite as sqlite3
from typing import LiteralString, Optional, Union
from fastapi import FastAPI, Request, HTTPException
from fastapi.responses import JSONResponse
from .constructors import ValidTopKarmaRequest, ValidKarmaRetrievalRequest,\
    ValidKarmaUpdateRequest

class KarmaDB:
    """Karma DB Util"""
    def __init__(self) -> None:
        self.db_path: LiteralString = os.path.join("/", "usr", "local", "share",
                                    "sqlite_dbs", "karma.db")

    async def get_karma(self, keyword: str) -> Union[int,  dict]:
        """Get Karma Value for Keyword
        Args:
            keyword (str): The keyword to search
        Returns:
            Union[int, dict]
        """
        async with sqlite3.connect(self.db_path, timeout=2) as db_conn:
            async with await db_conn.execute("SELECT score FROM karma WHERE keyword LIKE ? LIMIT 1", (keyword,)) as db_cursor:
                try:
                    (score,) = await db_cursor.fetchone()
                    return score
                except TypeError:
                    return {
                        'err': True,
                        'errorText': f'No records for {keyword}',
                    }
                
    async def get_top(self, n: Optional[int] = 10) -> Optional[list[tuple]]:
        """
        Get Top n=10 Karma Entries
        Args:
            n (Optional[int]) = 10: The number of top results to return
        Returns:
            list[tuple]
        """
        try:
            async with sqlite3.connect(self.db_path, timeout=2) as db_conn:
                async with await db_conn.execute("SELECT keyword, score FROM karma ORDER BY score DESC LIMIT ?", (n,)) as db_cursor:
                    return await db_cursor.fetchall()
        except:
            traceback.print_exc()
            return None
        
    async def update_karma(self, granter: str, keyword: str,
                           flag: int) -> Optional[bool]:
        """
        Update Karma for Keyword
        Args:
            granter (str): The user who granted (increased/decreased) the karma
            keyword (str): The keyword to update
            flag (int): 0 to increase karma, 1 to decrease karma
        Returns:
            Optional[bool]
        """
        
        if not flag in [0, 1]:
            return None
        
        modifier: str = "score + 1" if not flag else "score - 1"
        query: str = f"UPDATE karma SET score = {modifier}, last_change = ? WHERE keyword LIKE ?"
        new_keyword_query: str = "INSERT INTO karma(keyword, score, last_change) VALUES(?, ?, ?)"
        friendly_flag: str = "++" if not flag else "--"
        audit_message: str = f"{granter} adjusted karma for {keyword} @ {datetime.datetime.now().isoformat()}: {friendly_flag}"
        audit_query: str = "INSERT INTO karma_audit(impacted_keyword, comment) VALUES(?, ?)"
        now: int = int(time.time())

        logging.debug("Audit message: %s{audit_message}\nKeyword: %s{keyword}")

        async with sqlite3.connect(self.db_path, timeout=2) as db_conn:
            async with await db_conn.execute(audit_query, (keyword, audit_message,)) as db_cursor:
                await db_conn.commit()          
            async with await db_conn.execute(query, (now, keyword,)) as db_cursor:
                if db_cursor.rowcount:
                    await db_conn.commit()
                    return True
                if db_cursor.rowcount < 1:  # Keyword does not already exist
                    await db_cursor.close()
                    new_val = 1 if not flag else -1
                    async with await db_conn.execute(new_keyword_query, (keyword, new_val, now,)) as db_cursor:
                        if db_cursor.rowcount >= 1:
                            await db_conn.commit()
                            return True
                        else:
                            return False
                return False
                    
class Karma(FastAPI):
    """
    Karma Endpoints
    """   
    def __init__(self, app: FastAPI, util, constants) -> None:
        self.app: FastAPI = app
        self.util = util
        self.constants = constants
        self.db = KarmaDB()

        self.endpoints: dict = {
            "karma/get": self.get_karma_handler,
            "karma/modify": self.modify_karma_handler,
            "karma/top": self.top_karma_handler,
            }

        for endpoint, handler in self.endpoints.items():
            app.add_api_route(f"/{endpoint}", handler, methods=["POST"],
                              include_in_schema=True)

    
    async def top_karma_handler(self, request: Request,
                                data: Optional[ValidTopKarmaRequest] = None) -> JSONResponse:
        """
        Get top keywords for karma
         - **n**: Number of top results to return (default: 10)
        """

        if not self.util.check_key(request.url.path, request.headers.get('X-Authd-With')):
            raise HTTPException(status_code=403, detail="Unauthorized")
                
        n: int = 10
        if data and data.n:
            n = int(data.n)
            

        try:
            top10: Optional[list[tuple]] = await self.db.get_top(n=n)
            if not top10:
                return JSONResponse(status_code=500, content={
                    'err': True,
                    'errorText': 'General failure',
                    })
            return JSONResponse(content=top10)
        except:
            traceback.print_exc()
            return JSONResponse(status_code=500, content={
                'err': True,
                'errorText': 'Exception occurred.',
                })
    
    async def get_karma_handler(self, data: ValidKarmaRetrievalRequest,
                                request: Request) -> JSONResponse:
        """
        Get current karma value
        - **keyword**: Keyword to retrieve karma value for
        """
        
        if not self.util.check_key(request.url.path, request.headers.get('X-Authd-With')):
            raise HTTPException(status_code=403, detail="Unauthorized")        

        keyword: str = data.keyword
        try:
            count: Union[int, dict] = await self.db.get_karma(keyword)
            return JSONResponse(content={
                'keyword': keyword,
                'count': count,
                })
        except:
            traceback.print_exc()
            return JSONResponse(status_code=500, content={
                'err': True,
                'errorText': "Exception occurred.",
                })
    
    async def modify_karma_handler(self, data: ValidKarmaUpdateRequest,
                                   request: Request) -> JSONResponse:
        """
        Update karma count
        - **granter**: User who granted the karma
        - **keyword**: The keyword to modify
        - **flag**: 0 to decrement (--), 1 to increment (++) 
        """

        if not self.util.check_key(request.url.path, request.headers.get('X-Authd-With'), 2):
            raise HTTPException(status_code=403, detail="Unauthorized")
        
        if not data.flag in [0, 1]:
            return JSONResponse(status_code=500, content={
                'err': True,
                'errorText': 'Invalid request',
            })
        
        return JSONResponse(content={
            'success': await self.db.update_karma(data.granter,
                                                  data.keyword, data.flag)
            })