package reveil

import (
	"bytes"
	"crypto/sha512"
	"fmt"
	"io/fs"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"git.nemunai.re/nemunaire/reveil/config"
)

type RoutineStep struct {
	Delay  uint64   `json:"delay"`
	Action string   `json:"action"`
	Args   []string `json:"args,omitempty"`
}

func (s *RoutineStep) GetAction(cfg *config.Config) (*Action, error) {
	return LoadAction(cfg, s.Action)
}

type Routine struct {
	Id    Identifier    `json:"id"`
	Name  string        `json:"name"`
	Path  string        `json:"path"`
	Steps []RoutineStep `json:"steps"`
}

func LoadRoutine(path string, cfg *config.Config) ([]RoutineStep, error) {
	ds, err := ioutil.ReadDir(path)
	if err != nil {
		return nil, err
	}

	actionsDir, err := filepath.Abs(cfg.ActionsDir)
	if err != nil {
		return nil, err
	}

	var steps []RoutineStep

	for _, f := range ds {
		fullpath := filepath.Join(path, f.Name())
		if f.Mode()&os.ModeSymlink == 0 {
			continue
		}

		dst, err := os.Readlink(fullpath)
		if err != nil {
			return nil, err
		}

		if adst, err := filepath.Abs(filepath.Join(path, dst)); err == nil {
			dst = adst
		}

		args := strings.Split(f.Name(), "_")

		delay, err := strconv.ParseUint(args[0], 10, 64)

		step := RoutineStep{
			Delay:  delay,
			Action: strings.TrimPrefix(dst, actionsDir+"/"),
		}
		if len(args) > 1 {
			step.Args = args[1:]
		}

		steps = append(steps, step)
	}

	return steps, nil
}

func LoadRoutineFromId(id Identifier, cfg *config.Config) (*Routine, error) {
	routines, err := LoadRoutines(cfg)
	if err != nil {
		return nil, err
	}

	for _, routine := range routines {
		if bytes.Equal(routine.Id, id) {
			return routine, nil
		}
	}

	return nil, fmt.Errorf("Unable to find routine %x", id)
}

func LoadRoutines(cfg *config.Config) (routines []*Routine, err error) {
	err = filepath.Walk(cfg.RoutinesDir, func(path string, d fs.FileInfo, err error) error {
		if d.IsDir() && path != cfg.RoutinesDir {
			hash := sha512.Sum512([]byte(path))

			// Explore directory
			steps, err := LoadRoutine(path, cfg)
			if err != nil {
				log.Printf("Invalid routine directory (trying to walk through %s): %s", path, err.Error())
				// Ignore invalid routines
				return nil
			}

			routines = append(routines, &Routine{
				Id:    hash[:],
				Name:  d.Name(),
				Path:  path,
				Steps: steps,
			})
		}

		return nil
	})

	return
}

func (r *Routine) Rename(newName string) error {
	newPath := filepath.Join(filepath.Dir(r.Path), newName)

	err := os.Rename(
		r.Path,
		newPath,
	)
	if err != nil {
		return err
	}

	r.Path = newPath
	return nil
}

func (a *Routine) Remove() error {
	return os.Remove(a.Path)
}

func (a *Routine) Launch(cfg *config.Config) error {
	for _, s := range a.Steps {
		act, err := s.GetAction(cfg)
		if err != nil {
			log.Printf("Unable to get action: %s: %s", s.Action, err.Error())
			continue
		}

		settings, err := ReadSettings(cfg.SettingsFile)
		if err != nil {
			log.Printf("Unable to read settings: %s", err.Error())
			continue
		}

		time.Sleep(time.Duration(s.Delay) * time.Second)

		cmd, err := act.Launch(settings)
		if err != nil {
			log.Printf("Unable to launch the action %q: %s", s.Action, err.Error())
			continue
		}

		err = cmd.Wait()
		if err != nil {
			log.Printf("Something goes wrong when waiting for the action %q's end: %s", s.Action, err.Error())
		}
	}

	return nil
}