package main

import (
	"context"
	"encoding/json"
	"html"
	"io/ioutil"
	"net/http"
	"regexp"
	"strings"
	"time"

	"github.com/microcosm-cc/bluemonday"
)

var p *bluemonday.Policy
var spaceReg *regexp.Regexp
var removeHTMLReg *regexp.Regexp
var re *regexp.Regexp
var matchurl *regexp.Regexp

type ImageType struct {
	Url string `json:"url"`
}

type PublicKeyType struct {
	PublicKeyPem string `json:"publicKeyPem"`
}

type ActorJson struct {
	id                int
	Uri               string        `json:"id"`
	Type              string        `json:"type"`
	Inbox             string        `json:"inbox"`
	Outbox            string        `json:"outbox"`
	Followers         string        `json:"followers"`
	Following         string        `json:"following"`
	Url               string        `json:"url"`
	PreferredUsername string        `json:"preferredUsername"`
	Name              string        `json:"name"`
	Summary           string        `json:"summary"`
	Icon              ImageType     `json:"icon"`
	Image             ImageType     `json:"image"`
	PublicKey         PublicKeyType `json:"publicKey"`

	bot      bool
	instance string
}

type TagType struct {
	Type string `json:"type"`
	Name string `json:"name"`
}

type PostJson struct {
	id        int
	Uri       string `json:"id"`
	InReplyTo string `json:"inReplyTo"`

	normalized string
	receivedAt time.Time `json:"created_at"`

	Content      string    `json:"content"`
	Conversation string    `json:"conversation"`
	Published    time.Time `json:"published"`
	Summary      string    `json:"summary"`
	Tag          []TagType `json:"tag"`
	To           []string  `json:"to"`
	Type         string    `json:"type"`

	Actor        string `json:"actor"`
	AttributedTo string `json:"attributedTo"`

	bot      bool
	instance string
}

func check_activity(uri string) {
	logDebug("Retrieving: " + uri)
	var activityjson PostJson

	// Ignore invalid URIs
	endslash := strings.Index(uri[8:], "/")
	if endslash == -1 {
		return
	}
	activityjson.instance = uri[8 : endslash+8]

	o, _ := GetRunner(activityjson.instance)
	if o.Banned == true {
		logDebug("Ignoring banned instance: ", uri)
		return // Banned instance
	}

	// Check if there were any recent requests on this
	o.Recentactivities.Mu.Lock()
	i, _ := o.Recentactivities.Contains(uri)
	if i != -1 {
		logDebug("Ignoring cached recent request: ", uri)
		o.Recentactivities.Mu.Unlock()
		return
	}

	o.Recentactivities.Add(uri, "") // Added blank entry
	o.Recentactivities.Mu.Unlock()
	var jsondocument string

	selectRet := pool.QueryRow(context.Background(), "SELECT FROM activities WHERE document->>'id' = $1", uri)
	err := selectRet.Scan()
	if err == nil {
		logDebug("Already in database, ignoring: ", uri)
		return
	}

	req, _ := http.NewRequest("GET", uri, nil)
	req.Header.Set("User-Agent", "Tusky")
	req.Header.Add("Accept", "application/ld+json")

	resp, err := DoTries(&o, req)
	if err != nil {
		logDebug("Gave up after multiple tries: ", uri)
		return
	}

	if resp.StatusCode != 200 {
		logDebug("Non-200 response code for ", uri, " was ", resp.StatusCode)
		resp.Body.Close()
		return
	}

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		logDebug("Failed to read the reply: ", uri)
		return
	}
	resp.Body.Close()
	jsondocument = string(body)
	err = json.Unmarshal(body, &activityjson)
	if err != nil {
		logDebug("Failed to Unmarshal, err: ", err, " uri: ", uri)
		return
	}

	if activityjson.InReplyTo != "" && activityjson.InReplyTo != uri {
		if activityjson.InReplyTo != uri {
			go check_activity(activityjson.InReplyTo)
		}
	}

	// If AttributedTo is blank, this is likely an authentication failure
	// For now, skip it...
	if activityjson.AttributedTo == "" {
		logDebug("AttributedTo field is blank, dropping for ", uri)
		return
	}

	// This must be done BEFORE the `INSERT INTO activities'` below
	actorjson := check_actor(activityjson.AttributedTo)
	if actorjson == nil {
		logDebug("Failed to add actor, dropping post: ", uri)
		return
	}
	if actorjson.bot || o.Alwaysbot {
		activityjson.bot = true
	}

	activityjson.normalized = removeHTMLReg.ReplaceAllString(activityjson.Content, " ")
	activityjson.normalized = html.UnescapeString(strings.ToLower(p.Sanitize(activityjson.normalized)))
	activityjson.normalized = matchurl.ReplaceAllString(activityjson.normalized, "")
	activityjson.normalized = spaceReg.ReplaceAllString(activityjson.normalized, " ")

	var hashtags []string
	for _, tag := range activityjson.Tag {
		if tag.Type == "Hashtag" {
			hashtags = append(hashtags, strings.ToLower(tag.Name))
		}
	}
	_, err = pool.Exec(context.Background(), "INSERT INTO activities (document, normalized, instance, hashtags, bot) VALUES($1, $2, $3, $4, $5)", jsondocument, activityjson.normalized, activityjson.instance, hashtags, activityjson.bot)
	if err != nil {
		logWarn("Error inserting ", uri, " into `activities`: ", err)
		return
	}

	for _, to := range activityjson.To {
		if to != "https://www.w3.org/ns/activitystreams#Public" && to != "" {
			if strings.HasSuffix(to, "/followers") {
				// This check is very much a bad solution, may consider removing the entire for-loop
				continue
			}
			go check_actor(to)
		}
	}

}

/* Test: TestCheck_actor */
func check_actor(uri string) *ActorJson {
	actorjson := &ActorJson{}

	if len(uri) <= 7 {
		return nil // Bad actor
	}

	endslash := strings.Index(uri[8:], "/")
	if endslash == -1 {
		return nil // Bad actor
	}
	actorjson.instance = uri[8 : endslash+8]

	// Check if there were any recent requests on this
	o, _ := GetRunner(actorjson.instance)
	if o.Banned {
		logDebug("Banned actor: ", uri)
		return nil // Banned actor
	}
	o.Recentactors.Mu.Lock()
	i, cachedactorjson := o.Recentactors.Contains(uri)
	if i != -1 {
		o.Recentactors.Mu.Unlock()
		cachedactorjson := cachedactorjson.(*ActorJson)
		return cachedactorjson
	}
	o.Recentactors.Mu.Unlock()

	selectRet := pool.QueryRow(context.Background(), "SELECT document FROM actors WHERE document->>'id' = $1", uri)
	err := selectRet.Scan(&actorjson)
	if err == nil {
		return actorjson // Actor already in database, good!
	}

	req, _ := http.NewRequest("GET", uri, nil)
	req.Header.Set("User-Agent", "Tusky")
	req.Header.Add("Accept", "application/ld+json")

	var resp *http.Response
	tries := 0
	for {
		resp, err = o.Client.Do(req)
		if err != nil {
			if tries > 10 {
				logErr("Unable to connect to " + uri + " attempt 10/10, giving up.")
				return nil // Unable to connect to host after 10 attempts
			}
			logWarn("Unable to connect to "+uri+", attempt ", tries+1, "+/10 sleeping for 30 seconds.")
			time.Sleep(time.Second * 30)
			tries = tries + 1
			continue
		}
		break
	}

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		logWarn("Unable to read body from ", uri)
		return nil // Unable to read body of message
	}
	resp.Body.Close()

	jsondocument := string(body)

	err = json.Unmarshal(body, &actorjson)
	if err != nil {
		logWarn("Unable to unmarshal body from ", uri)
		return nil // Unable to unmarshal body of message
	}
	o.Recentactors.Add(uri, actorjson)

	var bot bool
	if actorjson.Type == "Service" {
		actorjson.bot = true
	} else {
		actorjson.bot = o.Alwaysbot // default on host's classification
	}

	_, err = pool.Exec(context.Background(), "INSERT INTO actors (document, instance, bot) VALUES($1, $2, $3)", jsondocument, actorjson.instance, bot)
	if err != nil {
		logWarn("Error inserting ", uri, " into `actors`: ", err)
		return nil // Unable to insert actor
	}

	o.Recentactors.Add(uri, actorjson)
	return actorjson // Successful
}