/*
    MastoGem, A Mastodon proxy for Gemini
    Copyright (C) 2021 Romain de Laage

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
package main

import (
	"html"
	"regexp"
	"strings"
	"os"
	"io/ioutil"
	"encoding/json"
	"log"
	"time"
	"net/url"
)

func getConfig() Config {
	configPath := os.Getenv("MASTOGEM_CONFIG_PATH")
	if configPath == "" {
		log.Println("MASTOGEM_CONFIG_PATH was not set, using default settings")

		config := Config{
			Listen: "127.0.0.1:1965",
			CertPath: "certs/cert.pem",
			KeyPath: "certs/key.rsa",
			BaseURL: "https://mamot.fr",
			Title: "MastoGem",
			HomeMessage: "Welcome on MastoGem, this is a Mastodon proxy for Gemini. You can view the last 20 toots of a Mastodon account by providing its ID.",
			RateLimit: 45,
		}

		return config
	}

	configFile, err := ioutil.ReadFile(configPath)
	if err != nil {
		log.Fatalln("config file: %s", err)
	}

	var config Config

	err = json.Unmarshal(configFile, &config)
	if err != nil {
		log.Fatalln("config file: %s", err)
	}

	return config
}

func removeHTMLTags(content string) string {
	text := strings.ReplaceAll(content, "<p>", "")
	text = strings.ReplaceAll(text, "</p>", "\n\n")
	text = strings.ReplaceAll(text, "<br />", "\n")
	text = strings.ReplaceAll(text, "<br>", "\n")
	text = strings.ReplaceAll(text, "</a>", "")
	text = strings.ReplaceAll(text, "</span>", "")
	regexString := "<a( [^>]*)?>"
	regex, err := regexp.Compile(regexString)
	if err != nil {
		log.Println("regex: %s", err)
		return ""
	}
	text = regex.ReplaceAllLiteralString(text, "")
	regexString = "<span( [^>]*)?>"
	regex, err = regexp.Compile(regexString)
	if err != nil {
		log.Println("regex: %s", err)
		return ""
	}
	text = regex.ReplaceAllLiteralString(text, "")
	text = html.UnescapeString(text)

	return text
}

func formatBlog(toot Blog) string {
	var content string
	if toot.Reblog == nil {
		content = toot.Content
	} else {
		content = toot.Reblog.Content
	}
	content = removeHTMLTags(content)
	content = strings.Trim(content, " \n\r")
	content = strings.ReplaceAll(content, "\n#", "\n[#]")
	if strings.HasPrefix(content, "#") {
		content = "[#]" + content[1:]
	}

	var author string

	if toot.Author.DisplayName == "" {
		author = toot.Author.Name
	} else {
		author = toot.Author.DisplayName
	}

	var header string

	if toot.Reblog == nil {
		header = "### Written by " + author + " on " + toot.Date[0:10] + " at " + toot.Date[11:16]
	} else {
		var originalAuthor string
		if toot.Reblog.Author.DisplayName == "" {
			originalAuthor = toot.Reblog.Author.Name
		} else {
			originalAuthor = toot.Reblog.Author.DisplayName
		}

		header = "### Shared by " + author + " on " + toot.Date[0:10] + " at " + toot.Date[11:16] + " (original by " + originalAuthor + ")"
	}

	footer := "\n"
	for _, media := range toot.Medias {
		mediaURL := url.QueryEscape(media.Url)
		footer += "=> /media?" + mediaURL + " View attached media\n"
	}
	footer += "\n=> /toot/" + toot.Id + " More informations about this toot"

	return header + "\n" + content + "\n" + footer
}

func rateIsOk(tab map[string]Rate, remoteIP string, limit int) bool {
	elmt, ok := tab[remoteIP]
	if ok == false {
		tab[remoteIP] = Rate{time.Now(), 1}
		return true
	} else {
		if time.Since(elmt.Date).Minutes() >= 1 {
			tab[remoteIP] = Rate{time.Now(), 1}
			return true
		} else {
			if elmt.Count < limit {
				tab[remoteIP] = Rate{elmt.Date, elmt.Count + 1}
				return true
			} else {
				return false
			}
		}
	}
}