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"
)

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

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

	return configMap
}

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) persistGoodConfig() {
	var configMap map[string]interface{} = structs.Map(p.config)
	for k, v := range(configMap) {
		configMap[k] = fmt.Sprintf("%v", v)
	}

	p.API.SavePluginConfig(configMap)
}

func (p *HelloWorldPlugin) OnConfigurationChange() error {
	var newConfig *Config = new(Config);
	if err := p.API.LoadPluginConfiguration(newConfig); err != nil {
		defer p.persistGoodConfig()
		return errors.Wrap(err, "failed to load configuration")
	}

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

	if _, err := os.Stat(newConfig.WatchPath); err != nil {
		defer p.persistGoodConfig()
		return errors.Wrap(err, "Invalid watch path")
	}

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

	p.config = newConfig

	p.configUpdates++

	p.initDoors()

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

	return nil
}

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())
}