package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"sync"

	"git.yetaga.in/alazyreader/library/book"
	"git.yetaga.in/alazyreader/library/config"
	"git.yetaga.in/alazyreader/library/database"
	"git.yetaga.in/alazyreader/library/ui"
	"github.com/gdamore/tcell"
	"github.com/kelseyhightower/envconfig"
)

// State holds the UI state keys=>value map and manages access to the map with a mutex
type State struct {
	m        sync.Mutex
	stateMap map[string]interface{}
}

// key, present
func (s *State) Get(key string) interface{} {
	s.m.Lock()
	defer s.m.Unlock()
	if s.stateMap == nil {
		s.stateMap = make(map[string]interface{})
	}
	k, ok := s.stateMap[key]
	if !ok {
		return nil
	}
	return k
}

// key, value
func (s *State) Set(key string, value interface{}) {
	s.m.Lock()
	defer s.m.Unlock()
	if s.stateMap == nil {
		s.stateMap = make(map[string]interface{})
	}
	s.stateMap[key] = value
}

const (
	IN_MENU = iota
	IN_BOOK
)

type EventBookUpdate struct {
	tcell.EventTime
	book *book.Book
}

func NewEventBookUpdate(b *book.Book) *EventBookUpdate {
	e := &EventBookUpdate{book: b}
	e.SetEventNow()
	return e
}

func (e *EventBookUpdate) Book() *book.Book {
	return e.book
}

type EventLoadBook struct {
	tcell.EventTime
	ID int
}

func NewEventLoadBook(id int) *EventLoadBook {
	e := &EventLoadBook{ID: id}
	e.SetEventNow()
	return e
}

func main() {
	var c config.Config
	err := envconfig.Process("library", &c)
	if err != nil {
		log.Fatalln(err)
	}

	// create state
	state := State{}

	// set up DB connection
	if c.DBUser == "" || c.DBPass == "" || c.DBHost == "" || c.DBPort == "" || c.DBName == "" {
		log.Fatalf("vars: %+v", c)
	}
	lib, err := database.NewMySQLConnection(c.DBUser, c.DBPass, c.DBHost, c.DBPort, c.DBName)
	if err != nil {
		log.Fatalln(err)
	}
	err = lib.PrepareDatabase(context.Background())
	if err != nil {
		log.Fatalln(err)
	}
	_, _, err = lib.RunMigrations(context.Background())
	if err != nil {
		log.Fatalln(err)
	}
	books, err := lib.GetAllBooks(context.Background())
	if err != nil {
		log.Fatalln(err)
	}
	state.Set("library", books)

	screen, err := tcell.NewScreen()
	if err != nil {
		log.Fatalln(err)
	}
	err = screen.Init()
	if err != nil {
		log.Fatalln(err)
	}

	l := ui.NewList(Titles(state.Get("library").([]book.Book)), 0)
	menu := ui.NewBox(
		"library",
		[]string{"(n)ew", "(i)mport", "(q)uit"},
		ui.Contents{{
			Offsets:   ui.Offsets{Top: 1, Left: 2, Bottom: -2, Right: -2},
			Container: l,
		}},
		ui.StyleActive,
		false,
	)
	book := ui.NewBookDetails(&book.Book{
		Title: "test title",
	})
	activeBook := ui.NewBox(
		"book",
		nil,
		ui.Contents{{
			Offsets:   ui.Offsets{Top: 1, Left: 2, Bottom: 0, Right: 0},
			Container: book,
		}},
		ui.StyleInactive,
		false,
	)

	container := ui.NewContainer(
		ui.Contents{
			{Container: menu, Offsets: ui.Offsets{Percent: 1}},
			{Container: activeBook, Offsets: ui.Offsets{Percent: 2}},
		},
		ui.LayoutHorizontalPercent,
	)

	// init
	screen.Clear()
	w, h := screen.Size()
	container.SetSize(0, 0, h, w)
	container.Draw(screen)
	screen.Sync()

	// init UI state
	state.Set("ui_state", IN_MENU)
	screen.PostEvent(NewEventLoadBook(l.SelectedID()))

	// UI loop
	for {
		e := screen.PollEvent()
		switch v := e.(type) {
		case *tcell.EventError:
			fmt.Fprintf(os.Stderr, "%v", v)
			screen.Beep()
		case *tcell.EventKey: // input handling
			curr := state.Get("ui_state").(int)
			if curr == IN_MENU {
				if v.Key() == tcell.KeyUp && l.Selected() > 0 {
					l.SetSelected(l.Selected() - 1)
					screen.PostEvent(NewEventLoadBook(l.SelectedID()))
				}
				if v.Key() == tcell.KeyDown && l.Selected() < len(l.ListMembers())-1 {
					l.SetSelected(l.Selected() + 1)
					screen.PostEvent(NewEventLoadBook(l.SelectedID()))
				}
				if v.Rune() == 'q' {
					screen.Fini()
					fmt.Printf("Thank you for playing Wing Commander!\n\n")
					return
				}
				if v.Key() == tcell.KeyEnter {
					activeBook.SetStyle(ui.StyleActive)
					menu.SetStyle(ui.StyleInactive)
					state.Set("ui_state", IN_BOOK)
				}
			} else if curr == IN_BOOK {
				if v.Key() == tcell.KeyEsc {
					activeBook.SetStyle(ui.StyleInactive)
					menu.SetStyle(ui.StyleActive)
					state.Set("ui_state", IN_MENU)
				}
			}
			screen.Clear()
			container.Draw(screen)
		case *tcell.EventResize: // screen redraw
			w, h := screen.Size()
			container.SetSize(0, 0, h, w)
			screen.Clear()
			container.Draw(screen)
		case *EventBookUpdate:
			// TK
		case *EventLoadBook:
			book.SetBook(GetBookByID(v.ID, books))
			screen.Clear()
			container.Draw(screen)
		case *tcell.EventInterrupt:
		case *tcell.EventMouse:
		case *tcell.EventTime:
		default:
		}
		screen.Show() // repaint
	}
}

func Titles(lb []book.Book) []ui.ListKeyValue {
	r := []ui.ListKeyValue{}
	for i := range lb {
		r = append(r, ui.ListKeyValue{
			Key:   lb[i].ID,
			Value: lb[i].Title,
		})
	}
	return r
}

func GetBookByID(id int, lb []book.Book) *book.Book {
	for i := range lb {
		if lb[i].ID == id {
			return &lb[i]
		}
	}
	return &book.Book{}
}