//
// Copyright (c) 2019 Ted Unangst <tedu@tedunangst.com>
//
// Permission to use, copy, modify, and distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

package main

import (
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"regexp"
	"strings"

	"github.com/andybalholm/cascadia"
	"golang.org/x/net/html"
	"humungus.tedunangst.com/r/webs/htfilter"
)

var tweetsel = cascadia.MustCompile("p.tweet-text")
var linksel = cascadia.MustCompile(".time a.tweet-timestamp")
var authorregex = regexp.MustCompile("twitter.com/([^/]+)")

var re_hoots = regexp.MustCompile(`hoot: ?https://\S+`)

func hooterize(noise string) string {
	seen := make(map[string]bool)

	hootfixer := func(r io.Reader, url string) string {
		root, err := html.Parse(r)
		if err != nil {
			log.Printf("error parsing hoot: %s", err)
			return url
		}
		divs := tweetsel.MatchAll(root)

		wantmatch := authorregex.FindStringSubmatch(url)
		if len(wantmatch) < 2 {
			log.Printf("no wanted author?")
		}
		wanted := wantmatch[1]
		var buf strings.Builder

		var htf htfilter.Filter
		fmt.Fprintf(&buf, "%s\n", url)
		for _, div := range divs {
			twp := div.Parent.Parent.Parent
			alink := linksel.MatchFirst(twp)
			if alink == nil {
				log.Printf("missing link")
				continue
			}
			link := "https://twitter.com" + htfilter.GetAttr(alink, "href")
			authormatch := authorregex.FindStringSubmatch(link)
			if len(authormatch) < 2 {
				log.Printf("no author?")
				continue
			}
			author := authormatch[1]
			if author != wanted {
				continue
			}
			text := htf.TextOnly(div)
			text = strings.Replace(text, "\n", " ", -1)
			text = strings.Replace(text, "pic.twitter.com", "https://pic.twitter.com", -1)

			if seen[text] {
				continue
			}

			fmt.Fprintf(&buf, "> @%s: %s\n", author, text)
			seen[text] = true
		}
		return buf.String()
	}

	hootfetcher := func(hoot string) string {
		url := hoot[5:]
		if url[0] == ' ' {
			url = url[1:]
		}
		url = strings.Replace(url, "mobile.twitter.com", "twitter.com", -1)
		log.Printf("hooterizing %s", url)
		req, err := http.NewRequest("GET", url, nil)
		if err != nil {
			log.Printf("error: %s", err)
			return hoot
		}
		req.Header.Set("User-Agent", "OpenBSD ftp")
		req.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
		req.Header.Set("Accept-Language", "en-US,en;q=0.9")
		resp, err := http.DefaultClient.Do(req)
		if err != nil {
			log.Printf("error: %s", err)
			return hoot
		}
		defer resp.Body.Close()
		if resp.StatusCode != 200 {
			log.Printf("error getting %s: %d", url, resp.StatusCode)
			return hoot
		}
		ld, _ := os.Create("lasthoot.html")
		r := io.TeeReader(resp.Body, ld)
		return hootfixer(r, url)
	}

	return re_hoots.ReplaceAllStringFunc(noise, hootfetcher)
}