package main

import (
	"encoding/json"
	"fmt"
	"os"
	"reflect"
	"regexp"
	"strings"
	"tildegit.org/sloum/swim/termios"
	"time"
)

const (
	swimLogo string   = "\033[7m ｓｗｉｍ ▟\033[27m "
	cursorHome string = "\033[0;0H"
	styleOff string   = "\033[0m"
	upAndLeft string  = "\033[1A\033[500D"
	cursorEnd string  = "\033[500;500H"
)

type Board struct {
	Title     string `json:"BoardTitle"`
	Lanes     []Lane `json:"Lanes"`
	Current   int    `json:"CurrentLane"` // Index of current lane
	laneOff   int
	message   string
	msgErr    bool
	width     int
	height    int
	Zoom      int    `json:"Zoom"`
	StoryOpen bool
}

func (b *Board) PollForTermSize() {
	for {
		var w, h = termios.GetWindowSize()
		if h != b.height || w != b.width {
			b.height = h
			b.width = w
			if b.StoryOpen {
				b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].offset = 0
				b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].Draw(b)
			} else {
				for l := range b.Lanes {
					if len(b.Lanes[l].Stories) == 0 {
						continue
					}
					b.Lanes[l].Current = 0
					b.Lanes[l].storyOff = 0
				}
				b.Draw()
			}
		}

		time.Sleep(500 * time.Millisecond)
	}
}

func (b *Board) Run() {
	defer termios.Restore()
	termios.SetCharMode()
	fmt.Print("\033[?25l")
	go b.PollForTermSize()

	var ch rune
	for {
		b.Draw()
		ch = Getch()

		switch ch {
		case 'Q':
			Quit()
		case 'N':
			b.CreateLane("")
		case 'n':
			b.CreateStory("")
		case '\n':
			b.StoryOpen = true
			b.ViewStory()
			b.StoryOpen = false
		case 'g':
			if len(b.Lanes[b.Current].Stories) > 0 {
				b.Lanes[b.Current].Current = 0
				b.Lanes[b.Current].storyOff = 0
			}
		case 'G':
			if len(b.Lanes[b.Current].Stories) > 0 {
				b.Lanes[b.Current].Current = len(b.Lanes[b.Current].Stories)-1
				if b.Lanes[b.Current].Current * 3 + 1 > b.height-5 {
					off := b.Lanes[b.Current].Current - 3 % (b.height-5)
					if off+1 > b.height-5 {
						b.Lanes[b.Current].storyOff = off
					} else {
						b.Lanes[b.Current].storyOff = off+1
					}
				} 
			}
		case 'h', 'j', 'k', 'l', 'H', 'L', 'K', 'J':
			b.ClearMessage()
			b.Move(ch)
		case ':':
			b.EnterCommand()
		case '+':
			b.ZoomIn()
		case '-':
			b.ZoomOut()
		default:
			b.SetMessage(fmt.Sprintf("There is no action bound to '%c'", ch), true)
		}
	}
}

func (b *Board) ClearMessage() {
	b.message = ""
	b.msgErr = false
}

func (b *Board) SetMessage(msg string, isError bool) {
	b.message = msg
	b.msgErr = isError
}

func (b *Board) CreateLane(name string) {
	if name == "" {
		name = GetEditableLine("Lane title: ", "")
		if name == "" {
			b.SetMessage("Lane creation canceled", true)
			return
		}
	}
	b.Lanes = append(b.Lanes, MakeLane(name))
	if b.Current < 0 {
		b.Current = 0
	}
	unsavedChanges = true
	b.SetMessage("Lane created", false)
}

func (b *Board) CreateStory(name string) {
	if b.Current < 0 {
		b.SetMessage("You must create a lane first", true)
		return
	}
	b.Lanes[b.Current].CreateStory(name, b)
}

func (b Board) PrintHeader() string {
	return fmt.Sprintf("%s%s%-*.*s%s\n", style.Header, swimLogo, b.width-12, b.width-12, b.Title, styleOff)
}

func (b Board) PrintInputArea() string {
	return fmt.Sprintf("%s%-*.*s%s\n", style.Input, b.width, b.width, " ", styleOff)
}

func (b Board) GetLaneSlices(width int) [][]string {
	laneText := make([][]string, b.Zoom)
	for i := b.laneOff; i < b.laneOff + b.Zoom; i++ {
		var s []string
		if i < len(b.Lanes) {
			s = b.Lanes[i].StringSlice(width, i == b.Current)
		} else {
			s = make([]string, 0)
		}
		laneText[i-b.laneOff] = s
	}
	return laneText
}

func (b Board) LaneHeaderRow(width, pad int) string {
	var out strings.Builder
	for i := b.laneOff; i < b.laneOff + b.Zoom; i++ {
		if i < len(b.Lanes) {
			out.WriteString(b.Lanes[i].Header(width, i == b.Current))
		} else {
			out.WriteString(fmt.Sprintf("%s%*.*s%s", style.Lane, width, width, " ", styleOff))
		}
	}
	if pad > 0 {
		out.WriteString(fmt.Sprintf("%s%*.*s%s", style.Lane, pad, pad, " ", styleOff))
	}
	out.WriteRune('\n')
	return out.String()
}

func (b Board) PrintLanes() string {
	var out strings.Builder
	laneWidth := b.width / b.Zoom
	laneSlices := b.GetLaneSlices(laneWidth)
	pad := b.width - laneWidth * b.Zoom

	out.WriteString(b.LaneHeaderRow(laneWidth, pad))

	for row := 0; row < b.height - 4; row++ {
		for _, l := range laneSlices {
			if row < len(l) {
				out.WriteString(l[row])
			} else {
				out.WriteString(fmt.Sprintf("%s%*.*s%s", style.Lane, laneWidth, laneWidth, " ", styleOff))
			}
		}
		if pad > 0 {
			out.WriteString(fmt.Sprintf("%s%*.*s%s", style.Lane, pad, pad, " ", styleOff))
		}
		out.WriteRune('\n')
	}
	out.WriteString(styleOff)
	return out.String()
}

func (b *Board) EnterCommand() {
	command := GetEditableLine(":", "")
	if command == "" {
		return
	}
	f := strings.Fields(command)
	mainCom := strings.ToLower(f[0])
	switch mainCom {
	case "write", "wq", "w":
		b.Write(f)
		if mainCom == "wq" {
			Quit()
		}
	case "regex", "re", "regexp":
		if len(f) < 4 {
			b.SetMessage("Not enough arguments: regex [target] [location] [/pattern/replacement/]", true)
			return
		}
		b.Regex(f[1:])
	case "q", "quit":
		Quit()
	case "c", "create":
		if len(f) >= 2 {
			target := strings.ToLower(f[1])
				name := ""
				if len(f) > 2 {
					name = strings.Join(f[2:], " ")
				}
			switch target {
			case "lane", "l", "la", "lan":
				b.CreateLane(name)
			case "story", "s", "st", "sto", "stor":
				b.CreateStory(name)
			case "task", "tas", "ta", "t":
				b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].AddTask(name, b)
			case "comment", "com", "c":
				b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].AddComment(name, b)
			default:
				b.SetMessage(fmt.Sprintf("Unknown target %q", f[1]), true)
			}
		} else {
			b.SetMessage("More info needed: 'create [target|location] [[value]]'", true)
		}
	case "d", "del", "delete":
		if len(f) > 1 {
			target := strings.ToLower(f[1])
			switch target {
			case "lane", "l", "la", "lan":
				b.DeleteLane()
			case "story", "s", "st", "sto", "stor":
				b.Lanes[b.Current].DeleteStory(b)
			case "t", "ta", "tas", "task":
				val := ""
				if len(f) > 2 {
					val = f[2]
				}
				b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].DeleteTask(val, b)
			default:
				b.SetMessage(fmt.Sprintf("Unknown target %q", f[1]), true)
			}
		} else {
			b.SetMessage("More info needed: 'delete [target] [[location]]'", true)
		}
	case "set", "s":
		if len(f) > 2 {
			target := strings.ToLower(f[1])
			switch target {
			case "board", "b", "bo", "boa", "boar":
				b.Update(f[2:])
			case "lane", "l", "la", "lan":
				b.Lanes[b.Current].Update(f[2:], b)
			case "story", "s", "st", "sto", "stor":
				b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].Update(f[2:], b)
			default:
				b.SetMessage(fmt.Sprintf("Unknown target %q", f[1]), true)
			}
		} else {
			b.SetMessage("More info needed: 'set [target] [location] [[value]]'", true)
		}
	case "user", "toggle", "t", "u":
		b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].Update(f, b)
	default:
		b.SetMessage(fmt.Sprintf("Unknown command %q", f[0]), true)
	}
}

func (b *Board) Update(args []string) {
	location := strings.ToLower(args[0])
	switch location {
	case "title", "t", "name", "n":
		var title string
		var err error
		if len(args) == 1 {
			title = GetEditableLine("Board title: ", b.Title)
			if title == "" {
				b.SetMessage(err.Error(), true)
				break
			}
		} else {
			title = strings.Join(args[1:], " ")
		}
		b.Title = title
		b.SetMessage("Board title updated", false)
	}

}

func (b Board) PrintMessage() string {
	var out strings.Builder
	if b.msgErr {
		out.WriteString(style.MessageErr)
	} else {
		out.WriteString(style.Message)
	}
	msg := b.message
	if len(msg) > b.width {
		msg = msg[:b.width] + "…"
	}
	out.WriteString(fmt.Sprintf("%-*s%s", b.width, msg, styleOff))
	return out.String()
}

func (b *Board) ZoomIn() {
	if b.Zoom > 1 {
		b.Zoom -= 1
		if b.Current + 1 > b.laneOff + b.Zoom {
			b.laneOff += 1
		}
	}
}

func (b *Board) ZoomOut() {
	if b.width / (b.Zoom+1) > 15 {
		b.Zoom += 1
		if len(b.Lanes) < b.laneOff + b.Zoom {
			b.laneOff -= 1
			if b.laneOff < 0 {
				b.laneOff = 0
			}
		}
	}
}

func (b *Board) Move(ch rune) {
	if len(b.Lanes) == 0 {
		return
	}
	switch ch {
	case 'h':
		// move left a lane
		if b.Current > 0 {
			b.Current -= 1
			if b.Current < b.laneOff {
				b.laneOff -= 1
			}
		} else {
			b.SetMessage("Cannot move further left", true)
		}
	case 'l':
		// move selection right a lane
		if b.Current < len(b.Lanes)-1 {
			b.Current += 1
			if b.Current > b.laneOff + b.Zoom - 1 {
				b.laneOff += 1
			}
		} else {
			b.SetMessage("Cannot move further right", true)
		}
	case 'j':
		// move selection down a story
		if b.Lanes[b.Current].Current < len(b.Lanes[b.Current].Stories)-1 {
			b.Lanes[b.Current].Current += 1
			if b.Lanes[b.Current].Current * 3 + 1 - (b.Lanes[b.Current].storyOff*3) >= b.height-4 {
				b.Lanes[b.Current].storyOff += 1
			} 
		} else {
			b.SetMessage("Cannot move further down", true)
		}
	case 'k':
		// move selection up a story
		if b.Lanes[b.Current].Current > 0 {
			b.Lanes[b.Current].Current -= 1
			if b.Lanes[b.Current].Current < b.Lanes[b.Current].storyOff {
				b.Lanes[b.Current].storyOff -= 1
			}
		} else {
			b.SetMessage("Cannot move further up", true)
		}
	case 'H':
		// move story left a lane
		if b.Current == 0 {
			b.SetMessage("Cannot move story left", true)
			break
		}
		storyIndex := b.Lanes[b.Current].Current
		if len(b.Lanes[b.Current].Stories) <= 0 {
			goto MoveLeft
		}
		b.Lanes[b.Current-1].Stories = append(b.Lanes[b.Current-1].Stories, b.Lanes[b.Current].Stories[storyIndex].Duplicate())
		if storyIndex == len(b.Lanes[b.Current].Stories)-1 {
			b.Lanes[b.Current].Stories = b.Lanes[b.Current].Stories[:len(b.Lanes[b.Current].Stories)-1]
			b.Lanes[b.Current].Current -= 1
		} else {
			b.Lanes[b.Current].Stories[storyIndex] = b.Lanes[b.Current].Stories[len(b.Lanes[b.Current].Stories)-1]
			b.Lanes[b.Current].Stories = b.Lanes[b.Current].Stories[:len(b.Lanes[b.Current].Stories)-1]
		}
		b.Lanes[b.Current-1].Current = len(b.Lanes[b.Current-1].Stories)-1
		MoveLeft: b.Move('h')
		unsavedChanges = true
	case 'L':
		// move story right a lane
		if b.Current == len(b.Lanes)-1 {
			b.SetMessage("Cannot move story right", true)
			break
		}
		storyIndex := b.Lanes[b.Current].Current
		if len(b.Lanes[b.Current].Stories) <= 0 {
			goto MoveRight
		}
		b.Lanes[b.Current+1].Stories = append(b.Lanes[b.Current+1].Stories, b.Lanes[b.Current].Stories[storyIndex].Duplicate())
		if storyIndex == len(b.Lanes[b.Current].Stories)-1 {
			b.Lanes[b.Current].Stories = b.Lanes[b.Current].Stories[:len(b.Lanes[b.Current].Stories)-1]
			b.Lanes[b.Current].Current -= 1
		} else {
			b.Lanes[b.Current].Stories[storyIndex] = b.Lanes[b.Current].Stories[len(b.Lanes[b.Current].Stories)-1]
			b.Lanes[b.Current].Stories = b.Lanes[b.Current].Stories[:len(b.Lanes[b.Current].Stories)-1]
		}
		b.Lanes[b.Current+1].Current = len(b.Lanes[b.Current+1].Stories)-1
		MoveRight: b.Move('l')
		unsavedChanges = true
	case 'K':
		// moves story up
		storyIndex := b.Lanes[b.Current].Current
		if storyIndex <= 0 {
			b.SetMessage("Cannot move story up", true)
			break
		}
		swapper := reflect.Swapper(b.Lanes[b.Current].Stories)
		swapper(storyIndex, storyIndex-1)
		b.Move('k')
		unsavedChanges = true
	case 'J':
		// moves story down
		storyIndex := b.Lanes[b.Current].Current
		if storyIndex > len(b.Lanes[b.Current].Stories)-2 {
			b.SetMessage("Cannot move story down", true)
			break
		}
		swapper := reflect.Swapper(b.Lanes[b.Current].Stories)
		swapper(storyIndex, storyIndex+1)
		b.Move('j')
		unsavedChanges = true
	}
}

func (b *Board) DeleteLane() {
	if len(b.Lanes) < 1 {
		b.SetMessage("There are no lanes to delete", true)
		return
	}
	cont, err := GetConfirmation("Are you sure? Type 'yes' to delete: ")
	if err != nil {
		b.SetMessage(err.Error(), true)
		return
	} else if !cont {
		b.SetMessage("Deletion canceled", true)
		return
	}
	if len(b.Lanes[b.Current].Stories) > 0 {
		cont, err = GetConfirmation("Are you really sure? There are stories in the lane... ")
		if err != nil {
			b.SetMessage(err.Error(), true)
			return
		} else if !cont {
			b.SetMessage("Deletion canceled", true)
			return
		}
	}
	if b.Current == len(b.Lanes)-1 {
		b.Lanes = b.Lanes[:len(b.Lanes)-1]
	} else {
		b.Lanes = append(b.Lanes[:b.Current], b.Lanes[b.Current+1:]...)
	}
	if b.Current > len(b.Lanes)-1 {
		b.Current -= 1
	}
	unsavedChanges = true
	b.SetMessage("Lane deleted", false)
}

func (b *Board) ViewStory() {
	if b.Current > -1 {
		if b.Lanes[b.Current].Current > -1 {
			b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].View(b)
		}
	} else {
		b.SetMessage("There is no story to view", true)
	}
}

func (b *Board) Regex(args []string) {
	target := strings.ToLower(args[0])
	location := strings.ToLower(args[1])
	exp := strings.Join(args[2:], " ")
	if !strings.HasPrefix(exp, "/") {
		b.SetMessage("Invalid expression, must start with \"/\"", true)
		return
	}
	if len(exp) < 5 {
		b.SetMessage("Invalid expression", true)
		return
	}
	exp = strings.Replace(exp, "\\/", "~@!", -1)
	findReplaceFlag := strings.Split(exp[1:], "/")
	if len(findReplaceFlag) < 2 {
		b.SetMessage("Invalid expression, no replacement value", true)
		return
	}
	for i := range findReplaceFlag {
		findReplaceFlag[i] = strings.Replace(findReplaceFlag[i], "~@!", "\\/", -1)
	}
	re, err := regexp.Compile(findReplaceFlag[0])
	if err != nil {
		b.SetMessage(err.Error(), true)
		return
	}
	var src string
	switch target {
	case "board", "b", "bo", "boa", "boar":
		if !strings.HasPrefix(location, "t") {
			b.SetMessage(fmt.Sprintf("Invalid location, %q, for %s", location, target), true)
			return
		}
		src = b.Title
		b.Title = re.ReplaceAllLiteralString(src, findReplaceFlag[1])
	case "lanes":
		if !strings.HasPrefix(location, "t") {
			b.SetMessage(fmt.Sprintf("Invalid location, %q, for %s", location, target), true)
			return
		}
		for i := range b.Lanes {
			src = b.Lanes[i].Title
			b.Lanes[i].Title = re.ReplaceAllLiteralString(src, findReplaceFlag[1])
		}
	case "lane", "l", "la", "lan":
		if !strings.HasPrefix(location, "t") {
			b.SetMessage(fmt.Sprintf("Invalid location, %q, for %s", location, target), true)
			return
		}
		src = b.Lanes[b.Current].Title
		b.Lanes[b.Current].Title = re.ReplaceAllLiteralString(src, findReplaceFlag[1])
	case "stories!":
		for l := range b.Lanes {
			for i := range b.Lanes[l].Stories {
				switch location {
				case "title", "t", "ti", "tit", "titl":
					src = b.Lanes[l].Stories[i].Title
					b.Lanes[l].Stories[i].Title = re.ReplaceAllLiteralString(src, findReplaceFlag[1])
				case "description", "desc", "d", "de":
					src = b.Lanes[l].Stories[i].Body
					b.Lanes[l].Stories[i].Body = re.ReplaceAllLiteralString(src, findReplaceFlag[1])
				default:
					b.SetMessage(fmt.Sprintf("Invalid location, %q, for %s", location, target), true)
					return
				}
			}
		}
	case "stories":
		for i := range b.Lanes[b.Current].Stories {
			switch location {
			case "title", "t", "ti", "tit", "titl":
				src = b.Lanes[b.Current].Stories[i].Title
				b.Lanes[b.Current].Stories[i].Title = re.ReplaceAllLiteralString(src, findReplaceFlag[1])
			case "description", "desc", "d", "de":
				src = b.Lanes[b.Current].Stories[i].Body
				b.Lanes[b.Current].Stories[i].Body = re.ReplaceAllLiteralString(src, findReplaceFlag[1])
			default:
				b.SetMessage(fmt.Sprintf("Invalid location, %q, for %s", location, target), true)
				return
			}
		}
	case "story", "s", "st", "sto", "stor":
		switch location {
		case "title", "t", "ti", "tit", "titl":
			src = b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].Title
			b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].Title = re.ReplaceAllLiteralString(src, findReplaceFlag[1])
		case "description", "desc", "d", "de":
			src = b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].Body
			b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].Body = re.ReplaceAllLiteralString(src, findReplaceFlag[1])
		default:
			b.SetMessage(fmt.Sprintf("Invalid location, %q, for %s", location, target), true)
			return
		}
	default:
		b.SetMessage(fmt.Sprintf("Invalid target %q", target), true)
		return
	}
	if b.StoryOpen && strings.HasPrefix(target, "s") {
		b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].BuildStorySlice(b.width)
		b.Lanes[b.Current].Stories[b.Lanes[b.Current].Current].Draw(b)
	}
	unsavedChanges = true
	b.SetMessage("Regular expression applied", false)
}

func (b Board) Draw() {
	var out strings.Builder
	out.WriteString(cursorHome)
	out.WriteString(b.PrintHeader())
	out.WriteString(b.PrintLanes())
	out.WriteString(b.PrintInputArea())
	out.WriteString(b.PrintMessage())
	fmt.Print(out.String())
}

func (b *Board) Write(com []string) {
	j, err := json.Marshal(b)
	if err != nil {
		b.SetMessage(err.Error(), true)
		return
	}
	var path string
	if len(com) < 2 && fp == "" {
		b.SetMessage("No path was provided for file write", true)
		return
	} else if len(com) < 2 {
		path = fp
	} else {
		path = ExpandedAbsFilepath(strings.Join(com[1:], " "))
	}

	var perms os.FileMode = 0664
	fstats, err := os.Stat(path)
	if err == nil {
		perms = fstats.Mode()
	}
	f, err := os.OpenFile(path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, perms)
	if err != nil {
		b.SetMessage(err.Error(), true)
		return
	}
	fp = path
	defer f.Close()
	f.Write(j)
	b.SetMessage("File written", false)
	unsavedChanges = false
}