from fastapi import APIRouter, Depends, HTTPException, Query, Request
from fastapi.responses import HTMLResponse
from fastapi.templating import Jinja2Templates
from typing import List, Optional
import os
import json

router = APIRouter(prefix="/logs", tags=["System Logs"])
templates = Jinja2Templates(directory="templates")

LOG_FILE_PATH = "logs/system.json.log"

@router.get("/view", response_class=HTMLResponse)
async def view_logs_page(request: Request):
    """
    Log Analysis Dashboard Page (UI)
    """
    return templates.TemplateResponse("log_viewer.html", {"request": request})

@router.get("/api")
async def get_logs_api(
    limit: int = 100,
    level: Optional[str] = None,
    keyword: Optional[str] = None
):
    """
    API to fetch parsed logs from system.json.log
    """
    if not os.path.exists(LOG_FILE_PATH):
        return {"logs": []}

    logs = []
    
    # Read file in reverse is tricky with JSON lines, so read all and filter (for now)
    # Optimization: Read file backwards or use `tail`. 
    # Since it's local file system, reading lines is okay for < 10MB.
    
    try:
        with open(LOG_FILE_PATH, 'r', encoding='utf-8') as f:
            lines = f.readlines()
            
        # Parse and Filter
        for line in reversed(lines): # Show newest first
            try:
                if not line.strip(): continue
                log_entry = json.loads(line)
                
                # Filter by Level
                if level and log_entry.get("level") != level.upper():
                    continue
                    
                # Filter by Keyword
                if keyword:
                    # Search in message or other fields
                    search_blobs = str(log_entry.values()).lower()
                    if keyword.lower() not in search_blobs:
                        continue
                
                logs.append(log_entry)
                
                if len(logs) >= limit:
                    break
            except json.JSONDecodeError:
                continue
                
        return {"logs": logs}
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))