package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"runtime/debug"
	"strings"
	"sync"

	"git.yetaga.in/alazyreader/library/book"
	"git.yetaga.in/alazyreader/library/config"
	"git.yetaga.in/alazyreader/library/database"
	"git.yetaga.in/alazyreader/library/importer"
	"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
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

// UI states
const (
	IN_MENU = iota
	IN_BOOK
	IN_IMPORT
)

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 == "" {
		if c.DBPass != "" { // obscure password
			c.DBPass = c.DBPass[0:max(3, len(c.DBPass))] + strings.Repeat("*", max(0, len(c.DBPass)-3))
		}
		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)
	}
	// cleanup our screen and log if we panic and crash out somewhere
	defer func() {
		if r := recover(); r != nil {
			if screen != nil {
				screen.Fini()
			}
			fmt.Println("fatal panic;", r)
			if c.Debug {
				fmt.Println("stacktrace: \n" + string(debug.Stack()))
			}
			return
		}
	}()

	// book list and options menu (left column)
	l := ui.NewList(Titles(state.Get("library").([]book.Book)), 0)
	menu := ui.NewBox(
		"library",
		[]string{"˄˅ select", "⏎ edit", "(n)ew", "(i)mport", "(q)uit"},
		ui.Contents{{
			Offsets:   ui.Offsets{Top: 1, Left: 2, Bottom: -2, Right: -2},
			Container: l,
		}},
		ui.StyleActive,
		false,
	)
	activeBookDetails := ui.NewBookDetails(&book.Book{})

	// book display (right column)
	activeBook := ui.NewBox(
		"book",
		[]string{"˄˅ select", "⏎ edit", "(esc) close"},
		ui.Contents{{
			Offsets:   ui.Offsets{Top: 1, Left: 2, Bottom: 0, Right: 0},
			Container: activeBookDetails,
		}},
		ui.StyleInactive,
		false,
	)

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

	// import pop-up
	wd, _ := os.Getwd()
	fileSelector := ui.NewEditableTextLine(wd)
	fileSelector.ResetCursor(false)
	fileSelector.SetStyle(ui.StyleActive.Underline(true))
	popup := ui.NewBox(
		"import csv file",
		[]string{"⏎ submit", "(esc)close"},
		ui.Contents{
			{Container: fileSelector, Offsets: ui.Offsets{Top: 2, Left: 2}},
		},
		ui.StyleActive,
		false,
	)
	popup.SetVisible(false)

	// error pop-up
	errorMessage := ui.NewEditableTextLine("")
	errorPopup := ui.NewBox(
		"error",
		[]string{"⏎ close"},
		ui.Contents{
			{Container: errorMessage, Offsets: ui.Offsets{Top: 1, Left: 1}},
		},
		ui.StyleActive.Bold(true).Foreground(tcell.ColorRed),
		false,
	)
	errorPopup.SetVisible(false)

	// 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.Key() == tcell.KeyEnter {
					screen.PostEvent(NewEventEnterBook())
				}
				if v.Rune() == 'i' {
					screen.PostEvent(NewEventOpenImport())
				}
				if v.Rune() == 'q' {
					screen.PostEvent(NewEventQuit())
				}
			} else if curr == IN_BOOK {
				if v.Key() == tcell.KeyEsc {
					screen.PostEvent(NewEventExitBook())
				}
			} else if curr == IN_IMPORT {
				if v.Key() == tcell.KeyEsc {
					fileSelector.SetText(wd)
					fileSelector.ResetCursor(false)
					screen.PostEvent(NewEventCloseImport())
				}
				if v.Key() == tcell.KeyBackspace || v.Key() == tcell.KeyBackspace2 {
					fileSelector.DeleteAtCursor()
				} else if v.Key() == tcell.KeyRight {
					fileSelector.MoveCursor(1)

				} else if v.Key() == tcell.KeyLeft {
					fileSelector.MoveCursor(-1)
				} else if v.Key() == tcell.KeyEnter {
					screen.PostEvent(NewEventAttemptImport(fileSelector.Text()))
				} else if v.Rune() != 0 {
					fileSelector.InsertAtCursor(v.Rune())
				}
			}
		case *tcell.EventResize: // screen redraw
			w, h := screen.Size()
			container.SetSize(0, 0, h, w)
		case *EventBookUpdate:
			// TK
		case *EventEnterBook:
			activeBook.SetStyle(ui.StyleActive)
			menu.SetStyle(ui.StyleInactive)
			state.Set("ui_state", IN_BOOK)
		case *EventExitBook:
			state.Set("ui_state", IN_MENU)
			activeBook.SetStyle(ui.StyleInactive)
			menu.SetStyle(ui.StyleActive)
		case *EventLoadBook:
			activeBookDetails.SetBook(GetBookByID(v.ID, books))
		case *EventOpenImport:
			state.Set("ui_state", IN_IMPORT)
			menu.SetStyle(ui.StyleInactive)
			popup.SetVisible(true)
			popup.SetSize(6, 3, 5, 80)
		case *EventAttemptImport:
			// this will block other events, but it shouldn't take too long...
			f, err := os.Open(v.filename)
			if err != nil {
				screen.PostEvent(NewEventError(err))
				continue
			}
			books, err := importer.CSVToBooks(f)
			if err != nil {
				screen.PostEvent(NewEventError(err))
				continue
			}
			for b := range books {
				err = lib.AddBook(context.Background(), &books[b])
				if err != nil {
					screen.PostEvent(NewEventError(err))
				}
			}
			screen.PostEvent(NewEventCloseImport())
			allbooks, err := lib.GetAllBooks(context.Background())
			if err != nil {
				screen.PostEvent(NewEventError(err))
			}
			state.Set("library", allbooks)
			state.Set("ui_state", IN_MENU)
		case *EventCloseImport:
			state.Set("ui_state", IN_MENU)
			screen.HideCursor()
			menu.SetStyle(ui.StyleActive)
			popup.SetVisible(false)
		case *EventError:
			errorMessage.SetText(v.err.Error())
			errorPopup.SetVisible(true)
		case *EventQuit:
			screen.Fini()
			fmt.Printf("Thank you for playing Wing Commander!\n\n")
			return
		case *tcell.EventInterrupt:
		case *tcell.EventMouse:
		case *tcell.EventTime:
		default:
		}
		// repaint
		l.SetMembers(Titles(state.Get("library").([]book.Book)))
		container.Draw(screen)
		popup.Draw(screen)
		errorPopup.Draw(screen)
		screen.Show()
	}
}

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{}
}