// MediNET - session repository and community portal for Meditation Assistant
// https://gitlab.com/tslocum/medinet
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"math/rand"
	"os"
	"regexp"
	"time"

	"github.com/jessevdk/go-flags"
	"gopkg.in/yaml.v2"
)

type configuration struct {
	TimeZone string
	DBDriver string
	DBSource string
	Om       string
	Web      string
}

type statistics struct {
	AccountsCreated int
	ActiveAccounts  []int

	SessionsPosted int
	TopStreak      int
}

var (
	db             *database
	config         *configuration
	printDebug     bool
	stats          *statistics
	serverLocation *time.Location

	regexpNumbers = regexp.MustCompile("[0-9]+")
	regexpMarket  = regexp.MustCompile(".*?([a-zA-Z]+)$")
)

func logDebug(message string) {
	if printDebug {
		log.Println(message)
	}
}

func logDebugf(format string, a ...interface{}) {
	logDebug(fmt.Sprintf(format, a...))
}

func atWindowStart(t time.Time, streakBuffer int) time.Time {
	year, month, day := t.Date()
	return time.Date(year, month, day, streakBuffer/3600, (streakBuffer%3600)/60, streakBuffer%60, 0, t.Location())
}

func beforeWindowStart(t time.Time, streakBuffer int) bool {
	return t.Before(atWindowStart(t, streakBuffer))
}

func failOnError(err error) {
	if err != nil {
		log.Fatal(err)
	}
}

func trackActiveAccount(accountID int) {
	active := false
	for _, aID := range stats.ActiveAccounts {
		if aID == accountID {
			active = true
		}
	}
	if !active {
		stats.ActiveAccounts = append(stats.ActiveAccounts, accountID)
	}
	err := db.updateLastActive(accountID)
	failOnError(err)
}

func printStatistics() {
	for {
		stats.ActiveAccounts = nil
		stats.AccountsCreated, stats.SessionsPosted, stats.TopStreak = 0, 0, 0

		now := time.Now().In(serverLocation)
		fourAM := time.Date(now.Year(), now.Month(), now.Day(), 4, 0, 0, 0, serverLocation)
		if !fourAM.After(now) {
			fourAM = fourAM.AddDate(0, 0, 1)
		}

		time.Sleep(time.Until(fourAM))
		log.Printf("%d accounts (%d new) posted %d sessions (top streak %d)", len(stats.ActiveAccounts), stats.AccountsCreated, stats.SessionsPosted, stats.TopStreak)
	}
}

func main() {
	var opts struct {
		ConfigFile string `short:"c" long:"config" description:"Configuration file"`
		Debug      bool   `short:"d" long:"debug" description:"Print debug information"`
	}
	_, err := flags.Parse(&opts)
	failOnError(err)

	rand.Seed(time.Now().UTC().UnixNano())

	if opts.ConfigFile == "" {
		log.Fatal("Please specify configuration file with:  medinet -c <config file>")
	}
	if _, err = os.Stat(opts.ConfigFile); err != nil {
		log.Fatalf("Configuration file %s does not exist: %s", opts.ConfigFile, err)
	}

	configData, err := ioutil.ReadFile(opts.ConfigFile)
	if err != nil {
		log.Fatalf("Failed to read %s: %v", opts.ConfigFile, err)
	}

	config = new(configuration)
	err = yaml.Unmarshal(configData, config)
	if err != nil {
		log.Fatalf("Failed to read %s: %v", opts.ConfigFile, err)
	} else if config.DBDriver == "" {
		log.Fatal("Specify database driver in configuration file")
	} else if config.Om == "" {
		log.Fatal("Specify Om host:port in configuration file")
	} else if config.Web == "" {
		log.Fatal("Specify Web directory in configuration file")
	}

	tz := "Local"
	if config.TimeZone != "" {
		tz = config.TimeZone
	}
	loc, err := time.LoadLocation(tz)
	failOnError(err)
	serverLocation = loc

	printDebug = opts.Debug

	stats = new(statistics)
	go printStatistics()

	db, err = connect(config.DBDriver, config.DBSource)
	failOnError(err)

	initWeb()
	listenWeb()
}