package runner

import (
	"encoding/json"
	"fmt"
	"io"
	"sync"
	"time"

	"ewintr.nl/gte/cmd/android-app/component"
	"ewintr.nl/gte/cmd/android-app/screen"
	"ewintr.nl/gte/internal/task"
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/storage"
)

var runnerLock = sync.Mutex{}

type Runner struct {
	fyneApp    fyne.App
	fyneWindow fyne.Window
	conf       *component.Configuration
	logger     *component.Logger
	tasks      *component.Tasks
	status     string
	requests   chan interface{}
	refresh    chan bool
	fileURI    fyne.URI
	screenSet  *screen.ScreenSet
}

func NewRunner(conf *component.Configuration, fileURI fyne.URI, logger *component.Logger) *Runner {
	return &Runner{
		status:   "init",
		conf:     conf,
		logger:   logger,
		requests: make(chan interface{}),
		refresh:  make(chan bool),
		fileURI:  fileURI,
	}
}

func (r *Runner) Init() fyne.CanvasObject {
	stored, err := load(r.fileURI)
	if err != nil {
		r.logger.Log(err.Error())
	}
	r.logger.Log(fmt.Sprintf("loaded %d tasks from file", len(stored)))
	r.tasks = component.NewTasks(r.conf, stored)

	r.screenSet = screen.NewScreenSet(r.requests)

	return r.screenSet.Content()
}

func (r *Runner) Run() {
	go r.screenSet.Run()
	go r.refresher()
	go r.processRequest()
	r.backgroundSync()
}

func (r *Runner) processRequest() {
	for req := range r.requests {
		switch v := req.(type) {
		case screen.SaveConfigRequest:
			r.status = "saving..."
			r.refresh <- true
			for k, val := range v.Fields {
				r.conf.Set(k, val)
			}
			r.status = "config saved"
			r.logger.Log("config saved")
		case screen.SyncTasksRequest:
			r.status = "syncing..."
			r.refresh <- true
			countDisp, countFetch, err := r.tasks.Sync()
			if err != nil {
				r.logger.Log(err.Error())
			}
			if countDisp > 0 || countFetch > 0 {
				r.logger.Log(fmt.Sprintf("task sync: dispatched: %d, fetched: %d", countDisp, countFetch))
			}
			r.status = "synced"
			all, err := r.tasks.All()
			if err != nil {
				r.logger.Log(err.Error())
				break
			}
			if err := save(r.fileURI, all); err != nil {
				r.logger.Log(err.Error())
				break
			}
		case screen.MarkTaskDoneRequest:
			r.status = "marking done..."
			r.refresh <- true
			if err := r.tasks.MarkDone(v.ID); err != nil {
				r.logger.Log(err.Error())
			}
			r.logger.Log(fmt.Sprintf("marked task %q done", v.ID))
			r.status = "marked done"
		default:
			r.logger.Log("request unknown")
		}
		r.refresh <- true
	}
}

func (r *Runner) refresher() {
	for <-r.refresh {
		tasks, err := r.tasks.Today()
		if err != nil {
			r.logger.Log(err.Error())
		}
		sTasks := []screen.Task{}
		for id, action := range tasks {
			sTasks = append(sTasks, screen.Task{
				ID:     id,
				Action: action,
			})
		}

		state := screen.State{
			Status: r.status,
			Tasks:  sTasks,
			Config: r.conf.Fields(),
			Logs:   r.logger.Lines(),
		}

		r.screenSet.Refresh(state)
	}
}

func (r *Runner) backgroundSync() {
	ticker := time.NewTicker(15 * time.Second)
	for {
		r.requests <- screen.SyncTasksRequest{}
		<-ticker.C
	}
}

func load(fu fyne.URI) ([]*task.Task, error) {
	fr, err := storage.Reader(fu)
	if err != nil {
		return []*task.Task{}, err
	}
	defer fr.Close()

	exists, err := storage.Exists(fu)
	if !exists {
		return []*task.Task{}, fmt.Errorf("uri does not exist")
	}
	if err != nil {
		return []*task.Task{}, err
	}
	data, err := io.ReadAll(fr)
	if err != nil {
		return []*task.Task{}, err
	}

	storedTasks := []*task.Task{}
	if err := json.Unmarshal(data, &storedTasks); err != nil {
		return []*task.Task{}, err
	}

	return storedTasks, nil
}

func save(fu fyne.URI, tasks []*task.Task) error {
	fw, err := storage.Writer(fu)
	if err != nil {
		return err
	}

	data, err := json.Marshal(tasks)
	if err != nil {
		return err
	}
	if _, err := fw.Write(data); err != nil {
		return err
	}
	defer fw.Close()

	return nil
}