package main

import (
	"database/sql"
	"encoding/gob"
	"fmt"
	"html/template"
	"net/http"
	"strconv"
	"time"

	"github.com/dustin/go-humanize"
	"github.com/gin-contrib/sessions"
	"github.com/gin-gonic/gin"
)

type OfflineIM struct {
	ID          string        `json:"ID"`
	PrincipalID string        `json:"PrincipalID"`
	Username    template.HTML `json:"Username"` // will be constructed by getting it from the UserAccounts table with some HTML (so, sanitize first!)
	Libravatar  string        `json:"Libravatar"`
	FromID      string        `json:"FromID"`
	Message     template.HTML `json:"Message"` // may contain HTML, so it will be sanitised later on (gwyneth 20200815)
	TMStamp     string        `json:"TMStamp"`
}
type OfflineIMList []OfflineIM

const MaxNumberMessages int = 5 // maximum number of messages to retrieve

// For some very, very, very stupid reason, we need to register our message type (and probably others) when starting...
func init() {
	gob.RegisterName("listOfOfflineIMs", OfflineIMList{})
}

// GetTopOfflineMessages will retrieve the top first 5 messages and put it on the session, to avoid constant reloading
func GetTopOfflineMessages(c *gin.Context) {
	session := sessions.Default(c)
	username := session.Get("Username")
	uuid := session.Get("UUID")

	if uuid == "" {
		config.LogWarn("GetTopOfflineMessages(): No UUID stored; messages for this user cannot get retrieved")
	}

	if *config["dsn"] == "" {
		config.LogFatal("Please configure the DSN for accessing your OpenSimulator database; this application won't work without that")
	}
	db, err := sql.Open("mysql", *config["dsn"]+"?parseTime=true") // this will allow parsing MySQL timestamps into Time vars; see https://stackoverflow.com/a/46613451/1035977
	checkErrFatal(err)

	defer db.Close()

	// first count how many messages we have, we will need this later.
	// According to the Internet, current versions of MariaDB/MySQL are actually much faster doing _two_ queries, one just for counting rows, since it's allegedly optimised; in this case, we can simplify the whole query as well.

	var numberMessages int

	err = db.QueryRow("SELECT COUNT(*) FROM im_offline WHERE im_offline.PrincipalID = ?", uuid).Scan(&numberMessages)
	checkErr(err)

	if numberMessages > 0 {
		rows, err := db.Query("SELECT ID, im_offline.PrincipalID, FromID, Message, TMStamp, FirstName, LastName, Email FROM im_offline, UserAccounts WHERE im_offline.PrincipalID = ? AND UserAccounts.PrincipalID = im_offline.FromID ORDER BY TMStamp ASC LIMIT ?", uuid, strconv.Itoa(MaxNumberMessages))
		checkErr(err)

		defer rows.Close()

		var (
			oneMessage                                OfflineIM
			messages                                  OfflineIMList
			firstName, lastName, email, unsafeMessage string
			messageTimeStamp                          sql.NullTime // sql.NullTime will match timestamps with NULLs without crashing; see https://stackoverflow.com/a/60293251/1035977
		)

		for /* i := 1; */ rows.Next() /* ; i++ */ { // uncomment for special
			err = rows.Scan(
				&oneMessage.ID,
				&oneMessage.PrincipalID,
				&oneMessage.FromID,
				&unsafeMessage,
				&messageTimeStamp,
				&firstName,
				&lastName,
				&email,
			)
			oneMessage.Message = template.HTML(bluemondaySafeHTML.Sanitize(unsafeMessage))
			username := firstName + " " + lastName
			oneMessage.Username = template.HTML(bluemondaySafeHTML.Sanitize(fmt.Sprintf("<span title=\"%s\"  data-toggle=\"tooltip\">%s</span>", oneMessage.FromID, username)))
			oneMessage.Libravatar = getLibravatar(email, username, 60)
			// do something to the time
			if messageTimeStamp.Valid {
				oneMessage.TMStamp = humanize.Time(messageTimeStamp.Time)
			} else {
				oneMessage.TMStamp = ""
			}
			config.LogTracef("message from user %q <%s> to %q is: %q\n",
				oneMessage.Username, email, username, oneMessage.Message)
			messages = append(messages, oneMessage)
		}
		checkErr(err)

		config.LogTracef("GetTopOfflineMessages(): All messages for user %q: %+v\n", username, messages)

		session.Set("Messages", messages)
		session.Set("numberMessages", numberMessages)
	} else { // no messages for this user
		session.Set("Messages", nil)
		session.Set("numberMessages", numberMessages)
	}
	config.LogDebugf(": GetTopOfflineMessages(): user %q(%s) has %d message(s).\n",
		username, uuid, numberMessages)

	if err := session.Save(); err != nil {
		config.LogWarnf("GetTopOfflineMessages(): Could not save messages to user %q on the session, error was: %q\n", username, err)
	}
}

// getOfflineMessages opens the template for offline messages and fills it with all data.
// It's conceptually similar to the above code, only using DataTables and its wn template instead.
func getOfflineMessages(c *gin.Context) {
	session := sessions.Default(c)
	username := session.Get("Username").(string)
	uuid := session.Get("UUID").(string)

	if uuid == "" {
		config.LogWarn("getOfflineMessages(): No UUID stored; messages for this user cannot get retrieved")
	}

	if *config["dsn"] == "" {
		config.LogFatal("Please configure the DSN for accessing your OpenSimulator database; this application won't work without that")
	}
	db, err := sql.Open("mysql", *config["dsn"]+"?parseTime=true") // this will allow parsing MySQL timestamps into Time vars; see https://stackoverflow.com/a/46613451/1035977
	checkErrFatal(err)

	defer db.Close()

	// first count how many messages we have, we will need this later.
	// According to the Internet, current versions of MariaDB/MySQL are actually much faster doing _two_ queries, one just for counting rows, since it's allegedly optimised; in this case, we can simplify the whole query as well.

	var numberMessages int

	err = db.QueryRow("SELECT COUNT(*) FROM im_offline WHERE im_offline.PrincipalID = ?", uuid).Scan(&numberMessages)
	checkErr(err)

	if numberMessages > 0 {
		rows, err := db.Query("SELECT ID, im_offline.PrincipalID, FromID, Message, TMStamp, FirstName, LastName, Email FROM im_offline, UserAccounts WHERE im_offline.PrincipalID = ? AND UserAccounts.PrincipalID = im_offline.FromID ORDER BY TMStamp ASC", uuid)
		checkErr(err)

		defer rows.Close()

		var (
			oneMessage                                OfflineIM
			messages                                  OfflineIMList
			firstName, lastName, email, unsafeMessage string
			messageTimeStamp                          sql.NullTime // sql.NullTime will match timestamps with NULLs without crashing; see https://stackoverflow.com/a/60293251/1035977
		)

		for rows.Next() { // uncomment for special
			err = rows.Scan(
				&oneMessage.ID,
				&oneMessage.PrincipalID,
				&oneMessage.FromID,
				&unsafeMessage,
				&messageTimeStamp,
				&firstName,
				&lastName,
				&email,
			)
			oneMessage.Message = template.HTML(bluemondaySafeHTML.Sanitize(unsafeMessage))
			username := firstName + " " + lastName
			oneMessage.Username = template.HTML(bluemondaySafeHTML.Sanitize(fmt.Sprintf("<span title=\"%s\"  data-toggle=\"tooltip\">%s</span>", oneMessage.FromID, username)))
			oneMessage.Libravatar = getLibravatar(email, username, 60)
			// do something to the time
			if messageTimeStamp.Valid {
				// No need to humanize timestamps here.
				// oneMessage.TMStamp = humanize.Time(messageTimeStamp.Time)
				oneMessage.TMStamp = messageTimeStamp.Time.Format(time.RFC1123)
			} else {
				oneMessage.TMStamp = ""
			}
			config.LogTracef("message from user %q <%s> to %q is: %q\n",
				oneMessage.Username, email, username, oneMessage.Message)
			messages = append(messages, oneMessage)
		}
		checkErr(err)

		config.LogTracef("getOfflineMessages(): All messages for user %q: %+v\n", username, messages)

		config.LogDebugf("getOfflineMessages(): user %q(%s) has %d message(s).\n",
			username, uuid, numberMessages)

		c.HTML(http.StatusOK, "tables.tpl", environment(c, gin.H{
			"needsTables":     true,
			"needsMap":        false,
			"moreValidation":  true,
			"titleCommon":     *config["titleCommon"] + "Offline Messages for: " + username,
			"offlineMessages": messages,
			"numberMessages":  numberMessages,
			"Debug":           *config["ginMode"] == "debug" || *config["ginMode"] == "trace",
			"BoxTitle":        "Debug info:",
			"BoxContent":      fmt.Sprintf("<p><b>Number of messages:</b>&nbsp;%d</p>", numberMessages), // for debug
		}))
		return
	}
	c.HTML(http.StatusOK, "generic.tpl", environment(c,
		gin.H{
			"needsTables":    false,
			"needsMap":       false,
			"moreValidation": true,
			"titleCommon":    *config["titleCommon"] + "Offline Messages for: " + username,
			"title":          "Offline Messages",
			"content":        "Good news! You have no pending offline messages to read!",
			"Debug":          *config["ginMode"] == "debug" || *config["ginMode"] == "trace",
		}))
}