package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"sort"
	"strings"
	"time"

	"github.com/br0xen/user-config"
	"github.com/jroimartin/gocui"
)

const (
	AppName    = "gocal"
	AppVersion = 1
)

type AppState struct {
	Name             string
	Version          int
	ClientSecret     []byte
	cfg              *userConfig.Config
	account          *Account
	defaultCalendars []string

	StatusMsg string
}

var state *AppState

func main() {
	var err error
	var op string
	state = &AppState{Name: AppName, Version: AppVersion}
	state.cfg, err = userConfig.NewConfig(state.Name)

	if err != nil {
		panic(err)
	}

	if len(os.Args) > 1 {
		op = os.Args[1]
	} else {
		op = "today"
	}

	DoVersionCheck()

	switch op {
	case "--reinit":
		// Reset all config
		for _, v := range state.cfg.GetKeyList() {
			fmt.Println("Deleting Key: " + v)
			state.cfg.DeleteKey(v)
		}

	case "today":
		// Show everything on the calendar for today
		InitComm()
		// TODO: Get calendars flagged as default
		list := state.account.GetCalendarList()
		var todayEvents []Event
		if len(list) > 0 {
			for defIdx := range state.defaultCalendars {
				for i := range list {
					if list[i].Deleted {
						// Deleted calendar, next please
						continue
					}
					if state.defaultCalendars[defIdx] == list[i].Id {
						todayEvents = append(todayEvents, list[i].GetTodaysEvents()...)
					}
				}
			}
			sort.Sort(ByStartTime(todayEvents))
			for _, e := range todayEvents {
				if e.GetStartTime() == "00:00:00" {
					fmt.Println("[All Day ]  " + e.Summary)
				} else {
					fmt.Println("[" + e.GetStartTime() + "]  " + e.Summary)
				}
			}
		} else {
			fmt.Printf("No calendars found.\n")
		}

	case "config":
		InitComm()
		DoConfig()

	case "defaults":
		// Show Defaults
		InitComm()

	case "add":
		// Quick event add to primary calendar
		quickAddText := strings.Join(os.Args[2:], " ")
		e, err := state.account.GetDefaultCalendar().QuickAdd(quickAddText)
		if err != nil {
			fmt.Println(err.Error())
		} else {
			fmt.Println(e.ToCLIString())
		}
	case "bail":
		// Just initialize communications and bail
		InitComm()
	}
	// All done, save the account state
	saveAccountState()
}

func InitComm() {
	var err error
	sec := state.cfg.GetBytes("ClientSecret")
	tkn := state.cfg.GetBytes("Token")

	state.account, err = GetAccount(sec, tkn)
	if err != nil {
		log.Fatalf("Unable to get Account: %v", err)
	}

	// Save the Raw Token
	state.cfg.SetBytes("Token", state.account.CC.GetRawToken())

	// If the 'defaultCalendars' cfg is set to 'primary' (or not at all)
	// we need to actually but the primary cal id in there
	var defCal []string
	defCal, err = state.cfg.GetArray("defaultCalendars")
	if len(defCal) == 0 || (len(defCal) == 1 && defCal[0] == "primary") {
		gCal, err := state.account.Service.CalendarList.Get("primary").Do()
		if err == nil {
			defCal = []string{gCal.Id}
			state.cfg.SetArray("defaultCalendars", defCal)
		}
	}
	state.defaultCalendars = defCal

	loadAccountState()
}

func DoVersionCheck() {
	confVer, _ := state.cfg.GetInt("version")
	for confVer < state.Version {
		// Update from confVer to state.Version
		switch confVer {
		case 0: // Initializing the app
			fmt.Println("Initializing gocal")
			for {
				fmt.Println("Client Secret Filename (Ctrl-C to exit): ")
				var fn string
				if _, err := fmt.Scan(&fn); err == nil {
					var b []byte
					b, err = ioutil.ReadFile(fn)
					if len(b) > 0 && err == nil {
						state.cfg.SetBytes("ClientSecret", b)
						break
					}
				}
			}
			state.cfg.SetInt("version", 1)
			state.cfg.SetArray("defaultCalendars", []string{"primary"})
		}
		state.ClientSecret = state.cfg.GetBytes("ClientSecret")
		// Refetch the version from the config
		confVer, _ = state.cfg.GetInt("version")
	}
}

// saveAccountState saves all the bits of cache from the account
// into our config
func saveAccountState() {
	var err error
	var calListJson []byte
	if calListJson, err = json.Marshal(state.account.CalendarList); err == nil {
		if err = state.cfg.SetBytes("calendarList", calListJson); err != nil {
			fmt.Println("saveAccountState:calendarList error:", err)
		}
		if err = state.cfg.SetDateTime("calListUseBy", state.account.CalListUseBy); err != nil {
			fmt.Println("saveAccountState:calListUseBy error:", err)
		}
	}
	if err = state.cfg.SetArray("defaultCalendars", state.defaultCalendars); err != nil {
		fmt.Println("saveAccountState:defaultCalendars error:", err)
	}
}

// loadAccountState loads all the bits of cache from the config
// into the account
func loadAccountState() {
	var err error
	var calListJson []byte
	calListJson = state.cfg.GetBytes("calendarList")
	if err = json.Unmarshal(calListJson, &state.account.CalendarList); err == nil {
		if len(state.account.CalendarList) > 0 {
			if err != nil {
				fmt.Println("error: ", err)
			}
			if state.account.CalListUseBy, err = state.cfg.GetDateTime("calListUseBy"); err != nil {
				fmt.Println("error: ", err)
			}
		}
	} else {
		fmt.Println("error: ", err)
	}
}

// BEGIN CONFIG SCREEN FUNCTIONS //
func DoConfig() {
	g, err := gocui.NewGui(gocui.Output256)
	if err != nil {
		log.Panicln(err)
	}
	defer g.Close()
	g.Cursor = true
	g.SetManagerFunc(configLayout)

	// Set up some keybindings
	if err := g.SetKeybinding("", gocui.KeyCtrlC, gocui.ModNone, quit); err != nil {
		log.Panicln(err)
	}
	if err := g.SetKeybinding("default_calendars", gocui.KeyArrowUp, gocui.ModNone, cursorUp); err != nil {
		log.Panicln(err)
	}
	if err := g.SetKeybinding("default_calendars", 'k', gocui.ModNone, cursorUp); err != nil {
		log.Panicln(err)
	}
	if err := g.SetKeybinding("default_calendars", gocui.KeyArrowDown, gocui.ModNone, cursorDown); err != nil {
		log.Panicln(err)
	}
	if err := g.SetKeybinding("default_calendars", 'j', gocui.ModNone, cursorDown); err != nil {
		log.Panicln(err)
	}
	if err := g.SetKeybinding("default_calendars", gocui.KeySpace, gocui.ModNone, toggleCalendar); err != nil {
		log.Panicln(err)
	}
	if err := g.SetKeybinding("default_calendars", gocui.KeyEnter, gocui.ModNone, toggleCalendar); err != nil {
		log.Panicln(err)
	}

	// Kick off the main loop
	if err := g.MainLoop(); err != nil && err != gocui.ErrQuit {
		log.Panicln(err)
	}
}

func configLayout(g *gocui.Gui) error {
	list := state.account.GetCalendarList()
	height := len(list) + 4
	width, _ := g.Size()
	if v, err := g.SetView("default_calendars", 0, 0, width-1, height); err != nil {
		v.Highlight = true
		v.SelBgColor = gocui.ColorGreen
		v.SelFgColor = gocui.ColorBlack
		if err != gocui.ErrUnknownView {
			return err
		}
		drawCalList(g, v)

		if _, err := g.SetCurrentView("default_calendars"); err != nil {
			return err
		}
	}
	return nil
}

func quit(g *gocui.Gui, v *gocui.View) error {
	return gocui.ErrQuit
}

func toggleCalendar(g *gocui.Gui, v *gocui.View) error {
	_, cy := v.Cursor()
	calList := state.account.GetCalendarList()
	if v != nil {
		for i := range state.defaultCalendars {
			state.StatusMsg = time.Now().Format(time.RFC3339)
			if state.defaultCalendars[i] == calList[cy].Id {
			}
		}
	}
	drawCalList(g, v)
	return nil
}

func cursorUp(g *gocui.Gui, v *gocui.View) error {
	if v != nil {
		ox, oy := v.Origin()
		cx, cy := v.Cursor()
		if err := v.SetCursor(cx, cy-1); err != nil && oy > 0 {
			if err := v.SetOrigin(ox, oy-1); err != nil {
				return err
			}
		}
	}
	return nil
}

func cursorDown(g *gocui.Gui, v *gocui.View) error {
	if v != nil {
		cx, cy := v.Cursor()
		if err := v.SetCursor(cx, cy+1); err != nil {
			ox, oy := v.Origin()
			if err := v.SetOrigin(ox, oy+1); err != nil {
				return err
			}
		}
	}
	return nil
}

func drawCalList(g *gocui.Gui, v *gocui.View) error {
	width, _ := g.Size()
	list := state.account.GetCalendarList()
	for i := range list {
		isDef := false
		for defIdx := range state.defaultCalendars {
			if list[i].Id == state.defaultCalendars[defIdx] {
				isDef = true
				break
			}
		}
		calSumTxt := "["
		if isDef {
			calSumTxt += "*"
		} else {
			calSumTxt += " "
		}
		calSumTxt += "] " + list[i].Summary
		spc := strings.Repeat(" ", width-len(calSumTxt)-2)
		fmt.Fprintln(v, calSumTxt+spc)
	}
	fmt.Fprintln(v, "Status: "+state.StatusMsg)
	return nil
}

// END CONFIG SCREEN FUNCTIONS //