main.py

from fastapi import FastAPI, Request, Form, Path
from fastapi.responses import RedirectResponse
from fastapi.templating import Jinja2Templates
import logging, scheduler, uvicorn, executor
from typing import Optional
import threading, sqlite3
from datetime import datetime

# initialize FastAPI and Jinja2 instances
app = FastAPI()
templates = Jinja2Templates(directory="HTMLfiles")

logging.basicConfig(level=logging.INFO) #set up logging

@app.get("/")
def root(request: Request):
    tasks = scheduler.get_scheduled_tasks()  # Get the scheduled tasks from the scheduler
    return templates.TemplateResponse("index.html", 
                                      {"request": request, "task_table": tasks}) # render index.html

@app.post("/delete/{task_id}")
async def delete_task(task_id: int = Path(...)):
    scheduler.delete_task(task_id)
    return RedirectResponse("/", status_code=303)

@app.post("/schedule")
async def schedule(
    request: Request,
    trigger_type: str = Form(...), # Gets value from name="trigger_type"
    run_date: Optional[str] = Form(None), # Gets value from name="run_date"
    interval_seconds: Optional[str] = Form(None), # Gets value from name="interval_seconds"
    cron_hour: Optional[str] = Form(None), # Gets value from name="cron_hour"
    cron_minute: Optional[str] = Form(None), # Gets value from name="cron_minute"
    cron_second: Optional[str] = Form(None), # Gets value from name="cron_second"
    command: str = Form(...), # Gets value from name="command"
):
    try:
        trigger_kwargs = {}
        error_msg = None
        if trigger_type == 'date':
            trigger_kwargs['trigger_type'] = trigger_type
            if not run_date:
                raise ValueError("Run date cannot be empty for date trigger")
            # strptime() will raise an error if the date format is incorrect
            trigger_kwargs['run_date'] = datetime.strptime(run_date, "%Y-%m-%dT%H:%M:%S")
            trigger_kwargs['interval_seconds'] =  None
            trigger_kwargs['cron_hour'] = None
            trigger_kwargs['cron_minute'] = None
            trigger_kwargs['cron_second'] = None
            trigger_kwargs['last_run'] = None
            if not command:
                raise ValueError("Command cannot be empty for date trigger")
            trigger_kwargs['command'] = command # Command to run
        elif trigger_type == 'interval':
            trigger_kwargs['trigger_type'] = trigger_type
            trigger_kwargs['run_date'] = None
            trigger_kwargs['interval_seconds'] = int(interval_seconds) # Run every interval seconds from now
            trigger_kwargs['cron_hour'] = None
            trigger_kwargs['cron_minute'] = None
            trigger_kwargs['cron_second'] = None
            trigger_kwargs['last_run'] = None
            if not command:
                raise ValueError("Command cannot be empty for date trigger")
            trigger_kwargs['command'] = command # Command to run
        elif trigger_type == 'cron':
            trigger_kwargs['trigger_type'] = trigger_type
            trigger_kwargs['run_date'] = None
            trigger_kwargs['interval_seconds'] = None
            #check for empty values and values of out range
            if not cron_hour or not cron_minute or not cron_second:
                raise ValueError("Cron hour, minute, and second cannot be empty for cron trigger")
            if int(cron_hour) < 0 or int(cron_hour) > 23:
                raise ValueError("Cron hour must be between 0 and 23")
            if int(cron_minute) < 0 or int(cron_minute) > 59:
                raise ValueError("Cron minute must be between 0 and 59")
            if int(cron_second) < 0 or int(cron_second) > 59:
                raise ValueError("Cron second must be between 0 and 59")
            trigger_kwargs['cron_hour'] = int(cron_hour)
            trigger_kwargs['cron_minute'] = int(cron_minute)
            trigger_kwargs['cron_second'] = int(cron_second)
            trigger_kwargs['last_run'] = None
            if not command:
                raise ValueError("Command cannot be empty for date trigger")
            trigger_kwargs['command'] = command # Command to run

        scheduler.schedule_task(**trigger_kwargs) #schedule task
        return RedirectResponse("/", status_code=303) #redirect back to root page
    
    except Exception as e:
        # type error found, return error message and load index.html w/ error
        error_msg = str(e)
        tasks = scheduler.get_scheduled_tasks()
        return templates.TemplateResponse("index.html", {"request": request, "task_table": tasks, "error_msg": error_msg})

if __name__ == "__main__":
    # connect to SQLite DB and create the task table if it doesn't exist
    with sqlite3.connect('task_db.db') as connection:
        cursor = connection.cursor()
        #check if the task table exists. If not, create it
        create_table_query = '''
            CREATE TABLE IF NOT EXISTS task_table (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                command TEXT,
                trigger_type TEXT,
                run_date TEXT,
                interval_seconds INT,
                last_run TEXT,
                cron_hour INT,
                cron_minute INT,
                cron_second INT
            );
            '''
        cursor.execute(create_table_query)
        connection.commit()

    #make threads for executor and uvicorn server
    threads = []
    # 1 Thread for executor
    t_executor = threading.Thread(target=executor.run_executor)
    threads.append(t_executor)
    t_executor.start()

    # 1 Thread for uvicorn server
    t_uvicorn = threading.Thread(target=uvicorn.run, args=(app,), kwargs={"host": "127.0.0.1", "port": 8000})
    threads.append(t_uvicorn)
    t_uvicorn.start()

    # Wait for both threads to finish
    for t in threads:
        t.join()