package main

import (
	"encoding/json"
	"errors"
	"io/ioutil"
	"os"
	"reflect"
	"strings"

	"github.com/flynn/json5"
	"github.com/zyedidia/glob"
)

type optionValidator func(string, interface{}) error

// The options that the user can set
var globalSettings map[string]interface{}

// This is the raw parsed json
var parsedSettings map[string]interface{}

// Options with validators
var optionValidators = map[string]optionValidator{
	"tabsize":      validatePositiveValue,
	"scrollmargin": validateNonNegativeValue,
	"scrollspeed":  validateNonNegativeValue,
	"colorscheme":  validateColorscheme,
	"colorcolumn":  validateNonNegativeValue,
	"fileformat":   validateLineEnding,
}

func ReadSettings() error {
	filename := configDir + "/settings.json"
	if _, e := os.Stat(filename); e == nil {
		input, err := ioutil.ReadFile(filename)
		if err != nil {
			return errors.New("Error reading settings.json file: " + err.Error())
		}
		if !strings.HasPrefix(string(input), "null") {
			// Unmarshal the input into the parsed map
			err = json5.Unmarshal(input, &parsedSettings)
			if err != nil {
				return errors.New("Error reading settings.json: " + err.Error())
			}
		}
	}
	return nil
}

// InitGlobalSettings initializes the options map and sets all options to their default values
// Must be called after ReadSettings
func InitGlobalSettings() {
	globalSettings = DefaultGlobalSettings()

	for k, v := range parsedSettings {
		if !strings.HasPrefix(reflect.TypeOf(v).String(), "map") {
			globalSettings[k] = v
		}
	}
}

// InitLocalSettings scans the json in settings.json and sets the options locally based
// on whether the buffer matches the glob
// Must be called after ReadSettings
func InitLocalSettings(buf *Buffer) error {
	var parseError error
	for k, v := range parsedSettings {
		if strings.HasPrefix(reflect.TypeOf(v).String(), "map") {
			if strings.HasPrefix(k, "ft:") {
				if buf.Settings["filetype"].(string) == k[3:] {
					for k1, v1 := range v.(map[string]interface{}) {
						buf.Settings[k1] = v1
					}
				}
			} else {
				g, err := glob.Compile(k)
				if err != nil {
					parseError = errors.New("Error with glob setting " + k + ": " + err.Error())
					continue
				}

				if g.MatchString(buf.Path) {
					for k1, v1 := range v.(map[string]interface{}) {
						buf.Settings[k1] = v1
					}
				}
			}
		}
	}
	return parseError
}

// WriteSettings writes the settings to the specified filename as JSON
func WriteSettings(filename string) error {
	var err error
	if _, e := os.Stat(configDir); e == nil {
		for k, v := range globalSettings {
			parsedSettings[k] = v
		}

		txt, _ := json.MarshalIndent(parsedSettings, "", "    ")
		err = ioutil.WriteFile(filename, append(txt, '\n'), 0644)
	}
	return err
}

// AddOption creates a new option. This is meant to be called by plugins to add options.
func AddOption(name string, value interface{}) error {
	globalSettings[name] = value
	err := WriteSettings(configDir + "/settings.json")
	if err != nil {
		return errors.New("Error writing settings.json file: " + err.Error())
	}
	return nil
}

// GetGlobalOption returns the global value of the given option
func GetGlobalOption(name string) interface{} {
	return globalSettings[name]
}

// GetLocalOption returns the local value of the given option
func GetLocalOption(name string, buf *Buffer) interface{} {
	return buf.Settings[name]
}

// TODO: get option for current buffer
// GetOption returns the value of the given option
// If there is a local version of the option, it returns that
// otherwise it will return the global version
// func GetOption(name string) interface{} {
// 	if GetLocalOption(name, CurView().Buf) != nil {
// 		return GetLocalOption(name, CurView().Buf)
// 	}
// 	return GetGlobalOption(name)
// }

func DefaultCommonSettings() map[string]interface{} {
	return map[string]interface{}{
		"autoindent":     true,
		"autosave":       false,
		"basename":       false,
		"colorcolumn":    float64(0),
		"cursorline":     true,
		"eofnewline":     false,
		"fastdirty":      true,
		"fileformat":     "unix",
		"hidehelp":       false,
		"ignorecase":     false,
		"indentchar":     " ",
		"keepautoindent": false,
		"matchbrace":     false,
		"matchbraceleft": false,
		"rmtrailingws":   false,
		"ruler":          true,
		"savecursor":     false,
		"saveundo":       false,
		"scrollbar":      false,
		"scrollmargin":   float64(3),
		"scrollspeed":    float64(2),
		"softwrap":       false,
		"smartpaste":     true,
		"splitbottom":    true,
		"splitright":     true,
		"statusline":     true,
		"syntax":         true,
		"tabmovement":    false,
		"tabsize":        float64(4),
		"tabstospaces":   false,
		"useprimary":     true,
	}
}

// DefaultGlobalSettings returns the default global settings for micro
// Note that colorscheme is a global only option
func DefaultGlobalSettings() map[string]interface{} {
	common := DefaultCommonSettings()
	common["colorscheme"] = "default"
	common["infobar"] = true
	common["keymenu"] = false
	common["mouse"] = true
	common["pluginchannels"] = []string{"https://raw.githubusercontent.com/micro-editor/plugin-channel/master/channel.json"}
	common["pluginrepos"] = []string{}
	common["savehistory"] = true
	common["sucmd"] = "sudo"
	common["termtitle"] = false
	return common
}

// DefaultLocalSettings returns the default local settings
// Note that filetype is a local only option
func DefaultLocalSettings() map[string]interface{} {
	common := DefaultCommonSettings()
	common["filetype"] = "Unknown"
	return common
}

// TODO: everything else

// SetOption attempts to set the given option to the value
// By default it will set the option as global, but if the option
// is local only it will set the local version
// Use setlocal to force an option to be set locally
// func SetOption(option, value string) error {
// 	if _, ok := globalSettings[option]; !ok {
// 		if _, ok := CurView().Buf.Settings[option]; !ok {
// 			return errors.New("Invalid option")
// 		}
// 		SetLocalOption(option, value, CurView())
// 		return nil
// 	}
//
// 	var nativeValue interface{}
//
// 	kind := reflect.TypeOf(globalSettings[option]).Kind()
// 	if kind == reflect.Bool {
// 		b, err := ParseBool(value)
// 		if err != nil {
// 			return errors.New("Invalid value")
// 		}
// 		nativeValue = b
// 	} else if kind == reflect.String {
// 		nativeValue = value
// 	} else if kind == reflect.Float64 {
// 		i, err := strconv.Atoi(value)
// 		if err != nil {
// 			return errors.New("Invalid value")
// 		}
// 		nativeValue = float64(i)
// 	} else {
// 		return errors.New("Option has unsupported value type")
// 	}
//
// 	if err := optionIsValid(option, nativeValue); err != nil {
// 		return err
// 	}
//
// 	globalSettings[option] = nativeValue
//
// 	if option == "colorscheme" {
// 		// LoadSyntaxFiles()
// 		InitColorscheme()
// 		for _, tab := range tabs {
// 			for _, view := range tab.Views {
// 				view.Buf.UpdateRules()
// 			}
// 		}
// 	}
//
// 	if option == "infobar" || option == "keymenu" {
// 		for _, tab := range tabs {
// 			tab.Resize()
// 		}
// 	}
//
// 	if option == "mouse" {
// 		if !nativeValue.(bool) {
// 			screen.DisableMouse()
// 		} else {
// 			screen.EnableMouse()
// 		}
// 	}
//
// 	if len(tabs) != 0 {
// 		if _, ok := CurView().Buf.Settings[option]; ok {
// 			for _, tab := range tabs {
// 				for _, view := range tab.Views {
// 					SetLocalOption(option, value, view)
// 				}
// 			}
// 		}
// 	}
//
// 	return nil
// }
//
// // SetLocalOption sets the local version of this option
// func SetLocalOption(option, value string, view *View) error {
// 	buf := view.Buf
// 	if _, ok := buf.Settings[option]; !ok {
// 		return errors.New("Invalid option")
// 	}
//
// 	var nativeValue interface{}
//
// 	kind := reflect.TypeOf(buf.Settings[option]).Kind()
// 	if kind == reflect.Bool {
// 		b, err := ParseBool(value)
// 		if err != nil {
// 			return errors.New("Invalid value")
// 		}
// 		nativeValue = b
// 	} else if kind == reflect.String {
// 		nativeValue = value
// 	} else if kind == reflect.Float64 {
// 		i, err := strconv.Atoi(value)
// 		if err != nil {
// 			return errors.New("Invalid value")
// 		}
// 		nativeValue = float64(i)
// 	} else {
// 		return errors.New("Option has unsupported value type")
// 	}
//
// 	if err := optionIsValid(option, nativeValue); err != nil {
// 		return err
// 	}
//
// 	if option == "fastdirty" {
// 		// If it is being turned off, we have to hash every open buffer
// 		var empty [md5.Size]byte
// 		var wg sync.WaitGroup
//
// 		for _, tab := range tabs {
// 			for _, v := range tab.Views {
// 				if !nativeValue.(bool) {
// 					if v.Buf.origHash == empty {
// 						wg.Add(1)
//
// 						go func(b *Buffer) { // calculate md5 hash of the file
// 							defer wg.Done()
//
// 							if file, e := os.Open(b.AbsPath); e == nil {
// 								defer file.Close()
//
// 								h := md5.New()
//
// 								if _, e = io.Copy(h, file); e == nil {
// 									h.Sum(b.origHash[:0])
// 								}
// 							}
// 						}(v.Buf)
// 					}
// 				} else {
// 					v.Buf.IsModified = v.Buf.Modified()
// 				}
// 			}
// 		}
//
// 		wg.Wait()
// 	}
//
// 	buf.Settings[option] = nativeValue
//
// 	if option == "statusline" {
// 		view.ToggleStatusLine()
// 	}
//
// 	if option == "filetype" {
// 		// LoadSyntaxFiles()
// 		InitColorscheme()
// 		buf.UpdateRules()
// 	}
//
// 	if option == "fileformat" {
// 		buf.IsModified = true
// 	}
//
// 	if option == "syntax" {
// 		if !nativeValue.(bool) {
// 			buf.ClearMatches()
// 		} else {
// 			if buf.highlighter != nil {
// 				buf.highlighter.HighlightStates(buf)
// 			}
// 		}
// 	}
//
// 	return nil
// }
//
// // SetOptionAndSettings sets the given option and saves the option setting to the settings config file
// func SetOptionAndSettings(option, value string) {
// 	filename := configDir + "/settings.json"
//
// 	err := SetOption(option, value)
//
// 	if err != nil {
// 		messenger.Error(err.Error())
// 		return
// 	}
//
// 	err = WriteSettings(filename)
// 	if err != nil {
// 		messenger.Error("Error writing to settings.json: " + err.Error())
// 		return
// 	}
// }

func optionIsValid(option string, value interface{}) error {
	if validator, ok := optionValidators[option]; ok {
		return validator(option, value)
	}

	return nil
}

// Option validators

func validatePositiveValue(option string, value interface{}) error {
	tabsize, ok := value.(float64)

	if !ok {
		return errors.New("Expected numeric type for " + option)
	}

	if tabsize < 1 {
		return errors.New(option + " must be greater than 0")
	}

	return nil
}

func validateNonNegativeValue(option string, value interface{}) error {
	nativeValue, ok := value.(float64)

	if !ok {
		return errors.New("Expected numeric type for " + option)
	}

	if nativeValue < 0 {
		return errors.New(option + " must be non-negative")
	}

	return nil
}

func validateColorscheme(option string, value interface{}) error {
	colorscheme, ok := value.(string)

	if !ok {
		return errors.New("Expected string type for colorscheme")
	}

	if !ColorschemeExists(colorscheme) {
		return errors.New(colorscheme + " is not a valid colorscheme")
	}

	return nil
}

func validateLineEnding(option string, value interface{}) error {
	endingType, ok := value.(string)

	if !ok {
		return errors.New("Expected string type for file format")
	}

	if endingType != "unix" && endingType != "dos" {
		return errors.New("File format must be either 'unix' or 'dos'")
	}

	return nil
}