package main

import (
	"errors"
	"fmt"
	"io"
	"net/http"
	"os"
	"sort"
	"strings"
	"time"
)

func appendToFile(filename, data string) error {
	f, err := os.OpenFile(filename, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
	if err != nil {
		return err
	}
	f.WriteString(data)
	f.Close()
	return nil
}

func prependToFile(filename, data string) error {
	ogData, err := os.ReadFile(filename)
	if err != nil {
		return err
	}

	fileData := string(ogData[:])

	f, err := os.Create(filename)
	if err != nil {
		return err
	}
	f.WriteString(data + fileData)
	f.Close()
	return nil
}

func Post(twt, feedFile string, ascend bool) error {
	fileInfo, err := os.Stat(feedFile)
	if err != nil {
		os.Create(feedFile)
	} else if fileInfo.IsDir() {
		return errors.New("Feed file is a directory")
	}

	if ascend {
		return appendToFile(feedFile, time.Now().Format(time.RFC3339)+"\t"+twt+"\n")
	}
	return prependToFile(feedFile, time.Now().Format(time.RFC3339)+"\t"+twt+"\n")
}

func buildFeedFromUrl(feed *Feed, nick, url string) error {
	resp, err := http.Get(url)
	if err != nil {
		return err
	}

	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return err
	}

	return buildFeed(feed, nick, string(body[:]))
}

func buildFeedFromPath(feed *Feed, nick, filename string) error {
	f, err := os.ReadFile(filename)
	if err != nil {
		return err
	}

	return buildFeed(feed, nick, string(f[:]))
}

func buildFeed(feed *Feed, nick, data string) error {
	lines := strings.Split(data, "\n")

	for _, l := range lines {
		parts := strings.Split(l, "\t")
		t, err := time.Parse(time.RFC3339, parts[0])
		if err != nil {
			continue
		}
		*feed = append(*feed, FeedEntry{
			Nick:      nick,
			Timestamp: t,
			Post:      parts[1],
		})
	}
	return nil
}

func printFeed(feed *Feed, max int64) {
	sort.Sort(*feed)
	for i, entry := range *feed {
		if int64(i) >= max {
			return
		}
		fmt.Printf("[%s] <%s> %s\n", entry.Timestamp.Format(time.Stamp), entry.Nick, entry.Post)
	}
}

func GetFeed(friend, friendsFile string, max int64) error {
	feed := &Feed{}

	f, err := os.ReadFile(friendsFile)
	if err != nil {
		return err
	}

	fileData := string(f[:])

	lines := strings.Split(fileData, "\n")

	for _, l := range lines {
		if len(l) == 0 {
			continue
		}
		if !strings.Contains(l, " ") {
			return errors.New("Malformed friends file not in the format 'FRIEND_NAME https://friend.site/path/to/feed.txt'")
		}

		kvp := strings.Split(l, " ")
		k := kvp[0]
		v := kvp[1]

		if k == friend || len(friend) == 0 {
			err = buildFeedFromUrl(feed, k, v)
			if err != nil {
				return err
			}
			if len(friend) > 0 {
				break
			}
		}
	}
	printFeed(feed, max)
	return nil
}

func GetOwnFeed(nick, feedFile string, max int64) error {
	feed := &Feed{}
	err := buildFeedFromPath(feed, nick, feedFile)
	if err != nil {
		return err
	}
	printFeed(feed, max)
	return nil
}