package webcmd

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"regexp"
	"sync"
)

var APP_VERSION string = "x.x.x" // Overridden by makefile

type App struct {
	cfg AppConfig

	rxTaskInfo *regexp.Regexp

	tasksMtx sync.RWMutex
	tasks    map[string]Task
}

func NewApp(configPath string) (*App, error) {

	confBytes, err := ioutil.ReadFile(configPath)
	if err != nil {
		return nil, fmt.Errorf("Couldn't open configuration file '%s': %s", configPath, err.Error())
	}

	cfg := AppConfig{}
	err = json.Unmarshal(confBytes, &cfg)
	if err != nil {
		return nil, fmt.Errorf("Invalid configuration file: %s", err.Error())
	}

	return NewAppFromConfig(cfg), nil
}

func NewAppFromConfig(cfg AppConfig) *App {
	return &App{
		cfg:        cfg,
		rxTaskInfo: regexp.MustCompile(`^/task/([A-Z0-9]+)$`),
		tasks:      make(map[string]Task),
	}
}

func (this *App) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Server", "webcmd/"+APP_VERSION)

	if r.Method == "GET" {
		if r.URL.Path == "/" {
			this.Serve_Homepage(w)

		} else if r.URL.Path == "/style.css" {
			this.Serve_StyleCSS(w)

		} else if r.URL.Path == "/tasks" {
			this.Serve_Tasks(w)

		} else if matches := this.rxTaskInfo.FindStringSubmatch(r.URL.Path); len(matches) == 2 {
			this.Serve_TaskInfo(w, matches[1])

		} else {
			http.Error(w, "No matching route for request", 404)

		}

	} else if r.Method == "POST" {
		if r.URL.Path == "/x-new-task" {
			this.Action_NewTask(w, r)

		} else if r.URL.Path == "/x-abandon-task" {
			this.Action_AbandonTask(w, r)

		} else if r.URL.Path == "/x-clear-completed-tasks" {
			this.Action_ClearCompleted(w, r)

		} else {
			http.Error(w, "No matching route for request", 404)

		}

	} else {
		http.Error(w, "Invalid method", 400)

	}
}

func (this *App) Run() {
	mux := http.NewServeMux()
	mux.Handle("/", this)

	log.Printf("Listening on '%s'...", this.cfg.ListenAddress)
	err := http.ListenAndServe(this.cfg.ListenAddress, mux)
	if err != nil {
		log.Fatalf("Network error: %s", err.Error())
	}
}