package main

import (
	"fmt"
	"io"
	"log"
	"os"
	"sync"
	"time"
)

type RssFeed struct {
	Url       string
	Id        string
	LastSeen  time.Time
	fileMutex sync.Mutex
}

func (f *RssFeed) UpdateLastSeen() error {
	log.Printf("[%s]: Updating last seen time", f.Id)
	lastSeen, err := f.ReadLastSeen()
	if err != nil {
		return fmt.Errorf("failed to read lastseen file for feed %s: %w", f.Id, err)
	}
	f.LastSeen = lastSeen
	log.Printf("[%s]: Last seen time updated to: %s", f.Id, f.LastSeen)
	return nil
}
func (f *RssFeed) ReadLastSeen() (time.Time, error) {
	f.fileMutex.Lock()
	defer f.fileMutex.Unlock()

	lastSeen := time.Now()
	log.Printf("[%s]: Attempting to open lastseen file...", f.Id)
	lastSeenFile, err := os.Open("lastseen" + f.Id)
	if err != nil {
		if os.IsNotExist(err) {
			log.Printf("[%s]: lastseen file does not exist, creating a new one...", f.Id)
			lastSeenFile, err = os.Create("lastseen" + f.Id)
			if err != nil {
				return lastSeen, fmt.Errorf("failed to create lastseen file: %w", err)
			}
			log.Printf("[%s]: Writing current time to lastseen file...", f.Id)
			lastSeenFile.Write([]byte(lastSeen.Format(time.RFC3339)))
			lastSeenFile.Sync()
			log.Printf("[%s]: Successfully created lastseen file with current time.", f.Id)
			return lastSeen, nil
		} else {
			log.Printf("[%s]: Error opening lastseen file: %v", f.Id, err)
			return lastSeen, fmt.Errorf("failed to read lastseen file: %w", err)
		}
	}
	log.Printf("[%s]: Reading contents of lastseen file...", f.Id)
	lastSeenBytes, err := io.ReadAll(lastSeenFile)
	if err != nil {
		log.Printf("[%s]: Error reading lastseen file: %v", f.Id, err)
		return lastSeen, fmt.Errorf("failed to read lastseen file: %w", err)
	}
	log.Printf("[%s]: Parsing lastseen time...", f.Id)
	lastSeen, err = time.Parse(time.RFC3339, string(lastSeenBytes))
	if err != nil {
		log.Printf("[%s]: Error parsing lastseen file: %v", f.Id, err)
		return lastSeen, fmt.Errorf("failed to parse lastseen file: %w", err)
	}
	lastSeenFile.Close()
	log.Printf("[%s]: Last seen time read: %s", f.Id, lastSeen)
	return lastSeen, nil
}

func (f *RssFeed) WriteLastSeen(when time.Time) error {
	f.fileMutex.Lock()
	defer f.fileMutex.Unlock()

	log.Printf("[%s]: Attempting to create lastseen file...", f.Id)
	lastSeenFile, err := os.Create("lastseen" + f.Id)
	if err != nil {
		log.Printf("[%s]: Error creating lastseen file: %v", f.Id, err)
		return fmt.Errorf("failed to create lastseen file: %w", err)
	}
	log.Printf("[%s]: Successfully created lastseen file: lastseen%s", f.Id, f.Id)

	log.Printf("[%s]: Writing last seen time to file: %s", f.Id, when.Format(time.RFC3339))
	_, err = lastSeenFile.Write([]byte(when.Format(time.RFC3339)))
	if err != nil {
		log.Printf("[%s]: Error writing to lastseen file: %v", f.Id, err)
		return fmt.Errorf("failed to write to lastseen file: %w", err)
	}
	log.Printf("[%s]: Successfully wrote last seen time to file.", f.Id)

	err = lastSeenFile.Close()
	if err != nil {
		log.Printf("[%s]: Error closing lastseen file: %v", f.Id, err)
		return fmt.Errorf("failed to close lastseen file: %w", err)
	}
	log.Printf("[%s]: Lastseen file closed successfully.", f.Id)
	return nil
}