package main

import (
	"github.com/microcosm-cc/bluemonday"
	"github.com/jackc/pgx/pgxpool"
	"encoding/json"
	"crypto/sha1"
	"io/ioutil"
	"net/http"
	"context"
	"strings"
	"time"
	"fmt"
	"net"
	"log"
	"io"
	"os"
)

const (
	NEW_INSTANCE =			0
	CLIENT_ISSUE =			600
	ONION_PROTOCOL =		601
	UNMARSHAL_ERROR	=		602
	NO_CONNECTION =			603
)

type PollMessage struct {
	from			string
	status			int
	min_id			string
	numposts		int
}

// Parsing Unmarshal JSON type
type ReportPost struct {

	// Retrieved values
	Id			string `json:"id"`
	Url			string `json:"url"`
	Account			AccountType
	Content			string `json:"content"`
	Created_at		string `json:"created_at"`

	// Derived values
	StrippedContent			string
	Posthash			[]byte
}

type AccountType struct {
	Acct			string	`json:"acct"`
	Avatar			string	`json:"avatar"`
	Bot			bool	`json:"bot"`
	Created_at		string	`json:"created_at"`
	Display_name		string	`json:"display_name"`
	Url			string	`json:"url"`
}

// Used to report a new instance to main
type ReportInstance struct {
	from			string
	endpoint		string
	status			int
}

// Instance's new min_id value
type RunningInstance struct {
	endpoint		string
	software		string
	min_id			string
	status			int
}

type NodeInfoSoftware struct {
	Name			string	`json:"name"`
	Version			string	`json:"version"`
}

type NodeInfo struct {
	Software		NodeInfoSoftware `json:"software"`
}

func handleClient(commandClient net.Conn) {
	rawCommand := make([]byte, 20)

	for {
		_, err := io.ReadFull(commandClient, rawCommand)
		if err != nil {
			fmt.Println(err)
			commandClient.Close()
		}
		fmt.Println(rawCommand)
	}
}

/*
 * This code can be refactored per
 * https://golang.org/pkg/encoding/binary/
 * But for now, this should be sufficient
 */
/*
func parseCommand(c net.Conn) {
	rawCommand := make([]byte, 1)
}
*/

func AppendIfMissing(hay []string, needle string) []string {
	for _, ele := range hay {
		if ele == needle {
			return hay
		}
	}
	return append(hay, needle)
}

func StartInstancePoll(endpoint string, min_id string, reportPostChan chan ReportPost, pollMessageChan chan PollMessage, reportInstanceChan chan ReportInstance) {
	p := bluemonday.NewPolicy()
	newposts := make([]ReportPost, 0)

	// Only placing this here to later have the option of using an HTTP client via a SOCKS5 Tor proxy
	if strings.Contains(endpoint, ".onion") == true {
		reportInstanceChan <- ReportInstance{endpoint, endpoint, ONION_PROTOCOL}
		return
	}

	api_timeline := "https://" + endpoint + "/api/v1/timelines/public?min_id=" + min_id
	resp, err := http.Get(api_timeline)
	if err != nil {
		reportInstanceChan <- ReportInstance{endpoint, endpoint, CLIENT_ISSUE}
		return
	}

	body, err := ioutil.ReadAll(resp.Body)
	err = json.Unmarshal(body, &newposts)
	if err != nil {
		fmt.Println("Unmarshal 3");
		// Perhaps get rid of this if-condition?
		if resp.StatusCode >= 400 && resp.StatusCode < 500 {
			reportInstanceChan <- ReportInstance{endpoint, endpoint, resp.StatusCode}
		} else if resp.StatusCode >= 500 && resp.StatusCode < 600 {
			reportInstanceChan <- ReportInstance{endpoint, endpoint, resp.StatusCode}
		} else {
			reportInstanceChan <- ReportInstance{endpoint, endpoint, UNMARSHAL_ERROR}
		}
		//log.Fatal(err)
		return
	}

	newinstances := make([]string, 0)
	numposts := 0
	for _, newpost := range newposts {
		posthash := sha1.New()

		at_sign := strings.Index(newpost.Account.Acct, "@")

		if at_sign == -1 {
			at_sign = len(newpost.Account.Acct)
			newpost.Account.Acct += "@" + endpoint
		}

		// Calculate the post hash
		fmt.Fprint(posthash, newpost.Url)
		fmt.Fprint(posthash, newpost.StrippedContent)
		fmt.Fprint(posthash, newpost.Account.Acct)
		fmt.Fprint(posthash, newpost.Account.Display_name)
		fmt.Fprint(posthash, newpost.Account.Url)
		newpost.Posthash = posthash.Sum(nil)

		newpost.StrippedContent = p.Sanitize(newpost.Content)

		reportPostChan <- newpost

		// Check min_id
		if newpost.Id > min_id {
			min_id = newpost.Id
		}
		numposts = numposts + 1

		newinstance := newpost.Account.Acct[at_sign+1:]

		newinstances = AppendIfMissing(newinstances, newinstance)
	}

	for _, newinstance := range newinstances {
		var q ReportInstance
		q.from = endpoint
		q.endpoint = newinstance
		q.status = NEW_INSTANCE
		reportInstanceChan <- q
	}

	fmt.Println(newinstances)

	pollMessageChan <- PollMessage{endpoint, resp.StatusCode, min_id, numposts}
}

func StartGetPeers(endpoint string, reportInstanceChan chan ReportInstance) {
	var newpeers	[]string

	api_peers := "https://" + endpoint + "/api/v1/instance/peers"
	resp, err := http.Get(api_peers)
	if err != nil {
		reportInstanceChan <- ReportInstance{endpoint, endpoint, NO_CONNECTION}
		return
//		os.Exit(1)
	}

	body, err := ioutil.ReadAll(resp.Body)

	err = json.Unmarshal([]byte(body), &newpeers)
	if err != nil {
		fmt.Println("Unmarshal 1");
		log.Fatal(err)
		reportInstanceChan <- ReportInstance{endpoint, endpoint, UNMARSHAL_ERROR}
		return
	}

	for _, newpeer := range newpeers {
		var q ReportInstance
		q.from = endpoint
		q.endpoint = newpeer
		q.status = NEW_INSTANCE
		reportInstanceChan <- q
	}
}

func DeferPollRun(pollmessage PollMessage, runninginstances *[]RunningInstance, reportInstanceChan chan ReportInstance, reportPostChan chan ReportPost, pollMessageChan chan PollMessage) {
	var min_id string

	for _, runninginstance := range *runninginstances {
		if runninginstance.endpoint == pollmessage.from {
			min_id = runninginstance.min_id
			break
		}
	}

	delay := 2
	if pollmessage.status == 200 && pollmessage.numposts <= 10 {
		delay = 2
	} else if pollmessage.status == 200 && pollmessage.numposts > 10 {
		delay = 5
	} else if pollmessage.status == 429 {
		delay = 30
	} else {
		fmt.Println("error, status code is: ", pollmessage.status)
	}
	time.Sleep(time.Second * time.Duration(delay))

	go StartInstancePoll(pollmessage.from, min_id, reportPostChan, pollMessageChan, reportInstanceChan)
}

// Change this to return a proper "err"
func GetNodeInfo(endpoint string, nodeinfo *NodeInfo) {
	api_nodeinfo := "https://" + endpoint + "/nodeinfo/2.0.json"
	resp, err := http.Get(api_nodeinfo)
	if err != nil {
		return
	}

	body, err := ioutil.ReadAll(resp.Body)
	err = json.Unmarshal(body, &nodeinfo)
	if err != nil {
		fmt.Println("Unmarshal 2");
		return
	}
}

func NewInstance(endpoint string, runninginstances *[]RunningInstance, reportInstanceChan chan ReportInstance, reportPostChan chan ReportPost, pollMessageChan chan PollMessage) {
	var nodeinfo NodeInfo
	// Check node type
	GetNodeInfo(endpoint, &nodeinfo)

	if endpoint == "" {
		return
	}
	for _, runninginstance := range *runninginstances {
		if runninginstance.endpoint == endpoint {
			return
		}
	}
	newinstance := RunningInstance{endpoint, "", "", NEW_INSTANCE}
	*runninginstances = append(*runninginstances, newinstance)

	fmt.Println(nodeinfo.Software)

	if nodeinfo.Software.Name == "pleroma" || nodeinfo.Software.Name == "mastodon" {
		go StartInstancePoll(endpoint, "", reportPostChan, pollMessageChan, reportInstanceChan)
//		fmt.Println("Temporarily disabled Peer Hunting")
//		go StartGetPeers(endpoint, reportInstanceChan)
	}
}

func writePost(pool *pgxpool.Pool, reportpost ReportPost) {
	conn, err := pool.Acquire(context.Background())
	if err != nil {
		fmt.Println("Error acquiring connection:", err)
		os.Exit(1)
	}
	defer conn.Release()

	// Insert new account if new
	var acctid int
	err = conn.QueryRow(context.Background(), "INSERT INTO accounts (acct, avatar, bot, created_at, display_name, url) VALUES($1, $2, $3, $4, $5, $6) ON CONFLICT(acct) DO UPDATE SET acct=EXCLUDED.acct RETURNING id", reportpost.Account.Acct, reportpost.Account.Avatar, reportpost.Account.Bot, reportpost.Account.Created_at, reportpost.Account.Display_name, reportpost.Account.Url).Scan(&acctid)
	if err != nil {
		fmt.Println("First ", err)
		fmt.Println(reportpost.Account.Acct, reportpost.Account.Avatar, reportpost.Account.Bot, reportpost.Account.Created_at, reportpost.Account.Display_name, reportpost.Account.Url)
		os.Exit(1) // For now I want this to die and learn why it failed
		return
	}

	// Insert new post if new
	_, err = conn.Exec(context.Background(), "INSERT INTO posts (url, content, created_at, strippedcontent, acct_id, posthash) VALUES ($1, $2, $3, $4, $5, $6) ON CONFLICT (posthash) DO NOTHING", reportpost.Url, reportpost.Content, reportpost.Created_at, reportpost.StrippedContent, acctid, reportpost.Posthash)
	if err != nil { // For now I want to know why this failed.
		fmt.Println("Second ", err)
		os.Exit(1) // For now I want this to die and learn why it failed
		return
	}
}

func SuspendInstance(suspendinstance ReportInstance, runninginstances *[]RunningInstance) {
	fmt.Println("Suspend")
	for _, runninginstance := range *runninginstances {
		if runninginstance.endpoint == suspendinstance.endpoint {
			runninginstance.status = suspendinstance.status
			return
		}
	}
}

func main() {

	// Current instances
	runninginstances := make([]RunningInstance, 0)

	// Initial Setup
	reportPostChan := make(chan ReportPost, 100)
	reportInstanceChan := make(chan ReportInstance, 100)
	pollMessageChan := make (chan PollMessage, 100)

	// Setup Database
	pool, err := pgxpool.Connect(context.Background(), "postgres://postgres@127.0.0.1/tutorial")
	if err != nil {
		fmt.Fprintln(os.Stderr, "Unable to connect to database:", err)
		os.Exit(1)
	}

	l, err := net.Listen("tcp", "127.0.0.1:5555")
	if err != nil {
		fmt.Println(err)
		return
	}
	defer l.Close()

	var q ReportInstance
	q.from = ""
	q.endpoint = "mastodon.social"
	q.status = NEW_INSTANCE
	reportInstanceChan <- q

	for {
		commandClient := make(chan net.Conn)

		go func(l net.Listener) {
			for {
				c, err := l.Accept()
				if err != nil {
					commandClient <- nil
					return
				}
				commandClient <- c
			}
		}(l)

		for {
			select {
			case c := <-commandClient:		// New client connection
				go handleClient(c)
			case p := <-pollMessageChan:		// A poller ended
				for i, runninginstance := range runninginstances {
					if runninginstance.endpoint == p.from {
						runninginstances[i].min_id = p.min_id
					}
				}
				go DeferPollRun(p, &runninginstances, reportInstanceChan, reportPostChan, pollMessageChan)
			case v := <-reportPostChan:		// New Post
				go writePost(pool, v)
			case w := <-reportInstanceChan:		// Start or suspend instance
				if w.status == NEW_INSTANCE {
					fmt.Println("NEW INSTANCE: ", w.endpoint)
					NewInstance(w.endpoint, &runninginstances, reportInstanceChan, reportPostChan, pollMessageChan)
				} else {
					SuspendInstance(w, &runninginstances)
				}
			}
		}
	}
}