package main

import (
	"fmt"
	"net/http"
	"github.com/mattermost/mattermost-server/plugin"
	"github.com/pkg/errors"
	"sync"
	"reflect"
	"github.com/google/go-cmp/cmp"
	"os"
	"github.com/fatih/structs"
	"github.com/hashicorp/go-multierror"
	"github.com/kr/pretty"
	"strings"
)

type Config struct {
	NumDoors uint8 `json:",string"`
	WatchPath string
}

func (c *Config) configMap() map[string]interface{} {
	var configMap map[string]interface{} = structs.Map(c)
	var lowerConfigMap map[string]interface{} = make(map[string]interface{})
	for k, v := range(configMap) {
		lowerConfigMap[strings.ToLower(k)] = fmt.Sprintf("%v", v)
	}

	return lowerConfigMap
}

type HelloWorldPlugin struct {
	plugin.MattermostPlugin
	config *Config
	configLock sync.RWMutex
	configChanged chan struct{}
	doors map[uint8]bool
	configUpdates int
}

func (p *HelloWorldPlugin) initDoors() {
	p.doors = make(map[uint8]bool)
	for i := uint8(0); i < p.config.NumDoors; i++ {
		p.doors[i] = false
	}
}

func (p *HelloWorldPlugin) init() *HelloWorldPlugin {
	p.config = &Config{NumDoors: 1, WatchPath: "./"}
	p.configChanged = make(chan struct{})

	p.initDoors()

	return p;
}

func (p *HelloWorldPlugin) ServeHTTP(c *plugin.Context, w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, "Hello, world!")
}

func (p *HelloWorldPlugin) confChangedEvent() {
	select {
	case p.configChanged <- struct{}{}:
	default:
	}
}

func (p *HelloWorldPlugin) checkCorrectConfig() {
	var currentConfig map[string]interface{} = p.getLowerCasePluginConfig()
	var goodConfig map[string]interface{} = p.config.configMap()
	if !cmp.Equal(currentConfig, goodConfig) {
		p.API.LogInfo(fmt.Sprintf("%d: Saving un-matching config\n%# v\n%# v", p.configUpdates, pretty.Formatter(currentConfig), pretty.Formatter(goodConfig)))
		p.API.SavePluginConfig(goodConfig)
	}
}

func (p *HelloWorldPlugin) getLowerCasePluginConfig() map[string]interface{} {
	var currentConfig map[string]interface{} = p.API.GetPluginConfig()
	var lowerConfig map[string]interface{} = make(map[string]interface{})
	for k, v := range(currentConfig) {
		lowerConfig[strings.ToLower(k)] = fmt.Sprintf("%v", v)
	}
	return lowerConfig
}

func (p *HelloWorldPlugin) OnConfigurationChange() error {

	p.configLock.Lock()
	defer p.configLock.Unlock()

	var currentConfig map[string]interface{} = p.getLowerCasePluginConfig()
	if cmp.Equal(currentConfig, p.config.configMap()) {
		p.API.LogInfo(fmt.Sprintf("%d: Skipping matching config", p.configUpdates))
		return nil
	}

	defer p.checkCorrectConfig()

	var newConfig *Config = new(Config);
	if err := p.API.LoadPluginConfiguration(newConfig); err != nil {
		return errors.Wrap(err, fmt.Sprintf("%d: Failed to load configuration", p.configUpdates))
	}

	if newConfig == p.config || reflect.ValueOf(*newConfig).NumField() == 0 || cmp.Equal(*newConfig, *p.config) {
		p.API.LogInfo("Passed same config, or empty?")
		return nil;
	}

	var configErr error = nil

	if _, err := os.Stat(newConfig.WatchPath); err != nil {
		newConfig.WatchPath = "./"
		configErr = multierror.Append(configErr, errors.Wrap(err, "Invalid watch path"))
	}

	p.config = newConfig

	p.configUpdates++

	p.initDoors()

	p.API.LogInfo(fmt.Sprintf("%d: Config: %d %s", p.configUpdates, p.config.NumDoors, p.config.WatchPath))

	return configErr
}

func watchLoop(p *HelloWorldPlugin) {
	for {
		p.configLock.Lock()
		p.configLock.Unlock()
		select {
		case <- p.configChanged:
			p.API.LogInfo(fmt.Sprintf("CONFIG CHANGED, RESTARTING %d", p.configUpdates))
		}
	}
}


func (p *HelloWorldPlugin) OnActivate() error {
	go watchLoop(p)
	return nil
}

// This example demonstrates a plugin that handles HTTP requests which respond by greeting the
// world.
func main() {
	plugin.ClientMain((&HelloWorldPlugin{}).init())
}