package main

import (
	"fmt"
	"io"
	"strings"

	"hilbish/util"

	"github.com/maxlandon/readline"
	rt "github.com/arnodel/golua/runtime"
)

type lineReader struct {
	rl *readline.Instance
	fileHist *fileHistory
}
var hinter *rt.Closure
var highlighter *rt.Closure

func newLineReader(prompt string, noHist bool) *lineReader {
	rl := readline.NewInstance()
	lr := &lineReader{
		rl: rl,
	}

	// we don't mind hilbish.read rl instances having completion,
	// but it cant have shared history
	if !noHist {
		lr.fileHist = newFileHistory(defaultHistPath)
		rl.SetHistoryCtrlR("History", &luaHistory{})
		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, readline.VimReplaceMany: modeStr = "replace"
		}
		setVimMode(modeStr)
	}
	rl.ViActionCallback = func(action readline.ViAction, args []string) {
		actionStr := ""
		switch action {
			case readline.VimActionPaste: actionStr = "paste"
			case readline.VimActionYank: actionStr = "yank"
		}
		hooks.Emit("hilbish.vimAction", actionStr, args)
	}
	rl.HintText = func(line []rune, pos int) []rune {
		if hinter == nil {
			return []rune{}
		}

		retVal, err := rt.Call1(l.MainThread(), rt.FunctionValue(hinter),
		rt.StringValue(string(line)), rt.IntValue(int64(pos)))
		if err != nil {
			fmt.Println(err)
			return []rune{}
		}
		
		hintText := ""
		if luaStr, ok := retVal.TryString(); ok {
			hintText = luaStr
		}
		
		return []rune(hintText)
	}
	rl.SyntaxHighlighter = func(line []rune) string {
		if highlighter == nil {
			return string(line)
		}
		retVal, err := rt.Call1(l.MainThread(), rt.FunctionValue(highlighter),
		rt.StringValue(string(line)))
		if err != nil {
			fmt.Println(err)
			return string(line)
		}
		
		highlighted := ""
		if luaStr, ok := retVal.TryString(); ok {
			highlighted = luaStr
		}
		
		return highlighted
	}
	rl.TabCompleter = func(line []rune, pos int, _ readline.DelayedTabContext) (string, []*readline.CompletionGroup) {
		term := rt.NewTerminationWith(l.MainThread().CurrentCont(), 2, false)
		compHandle := hshMod.Get(rt.StringValue("completion")).AsTable().Get(rt.StringValue("handler"))
		err := rt.Call(l.MainThread(), compHandle, []rt.Value{rt.StringValue(string(line)),
		rt.IntValue(int64(pos))}, term)

		var compGroups []*readline.CompletionGroup
		if err != nil {
			return "", compGroups
		}

		luaCompGroups := term.Get(0)
		luaPrefix := term.Get(1)

		if luaCompGroups.Type() != rt.TableType {
			return "", compGroups
		}

		groups := luaCompGroups.AsTable()
		// prefix is optional
		pfx, _ := luaPrefix.TryString()

		util.ForEach(groups, func(key rt.Value, val rt.Value) {
			if key.Type() != rt.IntType || val.Type() != rt.TableType {
				return
			}

			valTbl := val.AsTable()
			luaCompType := valTbl.Get(rt.StringValue("type"))
			luaCompItems := valTbl.Get(rt.StringValue("items"))

			if luaCompType.Type() != rt.StringType || luaCompItems.Type() != rt.TableType {
				return
			}

			items := []string{}
			itemDescriptions := make(map[string]string)

			util.ForEach(luaCompItems.AsTable(), func(lkey rt.Value, lval rt.Value) {
				if keytyp := lkey.Type(); keytyp == rt.StringType {
					// ['--flag'] = {'description', '--flag-alias'}
					itemName, ok := lkey.TryString()
					vlTbl, okk := lval.TryTable()
					if !ok && !okk {
						// TODO: error
						return
					}

					items = append(items, itemName)
					itemDescription, ok := vlTbl.Get(rt.IntValue(1)).TryString()
					if !ok {
						// TODO: error
						return
					}
					itemDescriptions[itemName] = itemDescription
				} else if keytyp == rt.IntType {
					vlStr, ok := lval.TryString()
						if !ok {
							// TODO: error
							return
						}
						items = append(items, vlStr)
				} else {
					// TODO: error
					return
				}
			})

			var dispType readline.TabDisplayType
			switch luaCompType.AsString() {
				case "grid": dispType = readline.TabDisplayGrid
				case "list": dispType = readline.TabDisplayList
				// need special cases, will implement later
				//case "map": dispType = readline.TabDisplayMap
			}

			compGroups = append(compGroups, &readline.CompletionGroup{
				DisplayType: dispType,
				Descriptions: itemDescriptions,
				Suggestions: items,
				TrimSlash: false,
				NoSpace: true,
			})
		})

		return pfx, compGroups
	}

	return lr
}

func (lr *lineReader) Read() (string, error) {
	hooks.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.MultilinePrompt = ""
		lr.rl.SetPrompt(p)
	}
	if initialized && !running {
		lr.rl.RefreshPromptInPlace("")
	}
}

func (lr *lineReader) SetRightPrompt(p string) {
	lr.rl.SetRightPrompt(p)
	if initialized && !running {
		lr.rl.RefreshPromptInPlace("")
	}
}

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

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

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

// #interface history
// command history
// The history interface deals with command history. 
// This includes the ability to override functions to change the main
// method of saving history.
func (lr *lineReader) Loader(rtm *rt.Runtime) *rt.Table {
	lrLua := map[string]util.LuaExport{
		"add": {lr.luaAddHistory, 1, false},
		"all": {lr.luaAllHistory, 0, false},
		"clear": {lr.luaClearHistory, 0, false},
		"get": {lr.luaGetHistory, 1, false},
		"size": {lr.luaSize, 0, false},
	}

	mod := rt.NewTable()
	util.SetExports(rtm, mod, lrLua)

	return mod
}

// #interface history
// add(cmd)
// Adds a command to the history.
// --- @param cmd string
func (lr *lineReader) luaAddHistory(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
	if err := c.Check1Arg(); err != nil {
		return nil, err
	}
	cmd, err := c.StringArg(0)
	if err != nil {
		return nil, err
	}
	lr.AddHistory(cmd)

	return c.Next(), nil
}

// #interface history
// size()
// Returns the amount of commands in the history.
// --- @returns number
func (lr *lineReader) luaSize(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
	return c.PushingNext1(t.Runtime, rt.IntValue(int64(lr.fileHist.Len()))), nil
}

// #interface history
// get(idx)
// Retrieves a command from the history based on the `idx`.
// --- @param idx number
func (lr *lineReader) luaGetHistory(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
	if err := c.Check1Arg(); err != nil {
		return nil, err
	}
	idx, err := c.IntArg(0)
	if err != nil {
		return nil, err
	}

	cmd, _ := lr.fileHist.GetLine(int(idx))

	return c.PushingNext1(t.Runtime, rt.StringValue(cmd)), nil
}

func (lr *lineReader) luaAllHistory(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
	tbl := rt.NewTable()
	size := lr.fileHist.Len()

	for i := 1; i < size; i++ {
		cmd, _ := lr.fileHist.GetLine(i)
		tbl.Set(rt.IntValue(int64(i)), rt.StringValue(cmd))
	}

	return c.PushingNext1(t.Runtime, rt.TableValue(tbl)), nil
}

// #interface history
// clear()
// Deletes all commands from the history.
func (lr *lineReader) luaClearHistory(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
	lr.fileHist.clear()
	return c.Next(), nil
}