package main

import (
	"fmt"
	"io"
	"strings"

	"github.com/maxlandon/readline"
	"github.com/yuin/gopher-lua"
)

type lineReader struct {
	rl *readline.Instance
}
var fileHist *fileHistory

// other gophers might hate this naming but this is local, shut up
func newLineReader(prompt string, noHist bool) *lineReader {
	rl := readline.NewInstance()
	// we don't mind hilbish.read rl instances having completion,
	// but it cant have shared history
	if !noHist {
		fileHist = newFileHistory()
		rl.SetHistoryCtrlR("file", fileHist)
		rl.HistoryAutoWrite = false
	}
	rl.ShowVimMode = false
	rl.ViModeCallback = func(mode readline.ViMode) {
		modeStr := ""
		switch mode {
			case readline.VimKeys: modeStr = "normal"
			case readline.VimInsert: modeStr = "insert"
			case readline.VimDelete: modeStr = "delete"
			case readline.VimReplaceOnce:
			case readline.VimReplaceMany: modeStr = "replace"
		}
		setVimMode(modeStr)
	}
	rl.TabCompleter = func(line []rune, pos int, _ readline.DelayedTabContext) (string, []*readline.CompletionGroup) {
		ctx := string(line)
		var completions []string

		var compGroup []*readline.CompletionGroup

		ctx = strings.TrimLeft(ctx, " ")
		if len(ctx) == 0 {
			return "", compGroup
		}

		fields := strings.Split(ctx, " ")
		if len(fields) == 0 {
			return "", compGroup
		}
		query := fields[len(fields) - 1]

		ctx = aliases.Resolve(ctx)

		if len(fields) == 1 {
			completions, prefix := binaryComplete(query, ctx, fields)

			compGroup = append(compGroup, &readline.CompletionGroup{
				TrimSlash: false,
				NoSpace: true,
				Suggestions: completions,
			})

			return prefix, compGroup
		} else {
			if completecb, ok := luaCompletions["command." + fields[0]]; ok {
				luaFields := l.NewTable()
				for _, f := range fields {
					luaFields.Append(lua.LString(f))
				}
				err := l.CallByParam(lua.P{
					Fn: completecb,
					NRet: 1,
					Protect: true,
				}, lua.LString(query), lua.LString(ctx), luaFields)

				if err != nil {
					return "", compGroup
				}

				luacompleteTable := l.Get(-1)
				l.Pop(1)

				/*
					as an example with git,
					completion table should be structured like:
					{
						{
							items = {
								'add',
								'clone',
								'init'
							},
							type = 'grid'
						},
						{
							items = {
								'-c',
								'--git-dir'
							},
							type = 'list'
						}
					}
					^ a table of completion groups.
					it is the responsibility of the completer
					to work on subcommands and subcompletions
				*/
				if cmpTbl, ok := luacompleteTable.(*lua.LTable); ok {
					cmpTbl.ForEach(func(key lua.LValue, value lua.LValue) {
						if key.Type() == lua.LTNumber {
							// completion group
							if value.Type() == lua.LTTable {
								luaCmpGroup := value.(*lua.LTable)
								compType := luaCmpGroup.RawGet(lua.LString("type"))
								compItems := luaCmpGroup.RawGet(lua.LString("items"))
								if compType.Type() != lua.LTString {
									l.RaiseError("bad type name for completion (expected string, got %v)", compType.Type().String())
								}
								if compItems.Type() != lua.LTTable {
									l.RaiseError("bad items for completion (expected table, got %v)", compItems.Type().String())
								}
								var items []string
								itemDescriptions := make(map[string]string)
								compItems.(*lua.LTable).ForEach(func(k lua.LValue, v lua.LValue) {
									if k.Type() == lua.LTString {
										// ['--flag'] = {'description', '--flag-alias'}
										itm := v.(*lua.LTable)
										items = append(items, k.String())
										itemDescriptions[k.String()] = itm.RawGet(lua.LNumber(1)).String()
									} else {
										items = append(items, v.String())
									}
								})

								var dispType readline.TabDisplayType
								switch compType.String() {
									case "grid": dispType = readline.TabDisplayGrid
									case "list": dispType = readline.TabDisplayList
									// need special cases, will implement later
									//case "map": dispType = readline.TabDisplayMap
								}
								compGroup = append(compGroup, &readline.CompletionGroup{
									DisplayType: dispType,
									Descriptions: itemDescriptions,
									Suggestions: items,
									TrimSlash: false,
									NoSpace: true,
								})
							}
						}
					})
				}
			}

			if len(compGroup) == 0 {
				completions = fileComplete(query, ctx, fields)
				compGroup = append(compGroup, &readline.CompletionGroup{
					TrimSlash: false,
					NoSpace: true,
					Suggestions: completions,
				})
			}
		}
		return "", compGroup
	}

	return &lineReader{
		rl,
	}
}

func (lr *lineReader) Read() (string, error) {
	hooks.Em.Emit("command.precmd", nil)
	s, err := lr.rl.Readline()
	// this is so dumb
	if err == readline.EOF {
		fmt.Println("")
		return "", io.EOF
	}

	return s, err // might get another error
}

func (lr *lineReader) SetPrompt(p string) {
	halfPrompt := strings.Split(p, "\n")
	if len(halfPrompt) > 1 {
		lr.rl.Multiline = true
		lr.rl.SetPrompt(strings.Join(halfPrompt[:len(halfPrompt) - 1], "\n"))
		lr.rl.MultilinePrompt = halfPrompt[len(halfPrompt) - 1:][0]
	} else {
		lr.rl.Multiline = false
		lr.rl.SetPrompt(p)
	}
	if initialized && !running {
		lr.rl.RefreshPromptInPlace("")
	}
}

func (lr *lineReader) AddHistory(cmd string) {
	fileHist.Write(cmd)
}

func (lr *lineReader) ClearInput() {
	return
}

func (lr *lineReader) Resize() {
	return
}

// lua module
func (lr *lineReader) Loader(L *lua.LState) *lua.LTable {
	lrLua := map[string]lua.LGFunction{
		"add": lr.luaAddHistory,
		"all": lr.luaAllHistory,
		"clear": lr.luaClearHistory,
		"get": lr.luaGetHistory,
		"size": lr.luaSize,
	}

	mod := l.SetFuncs(l.NewTable(), lrLua)

	return mod
}

func (lr *lineReader) luaAddHistory(l *lua.LState) int {
	cmd := l.CheckString(1)
	lr.AddHistory(cmd)

	return 0
}

func (lr *lineReader) luaSize(L *lua.LState) int {
	L.Push(lua.LNumber(fileHist.Len()))

	return 1
}

func (lr *lineReader) luaGetHistory(L *lua.LState) int {
	idx := L.CheckInt(1)
	cmd, _ := fileHist.GetLine(idx)
	L.Push(lua.LString(cmd))

	return 0
}

func (lr *lineReader) luaAllHistory(L *lua.LState) int {
	tbl := L.NewTable()
	size := fileHist.Len()

	for i := 1; i < size; i++ {
		cmd, _ := fileHist.GetLine(i)
		tbl.Append(lua.LString(cmd))
	}

	L.Push(tbl)

	return 0
}

func (lr *lineReader) luaClearHistory(l *lua.LState) int {
	return 0

}