package configui

import (
	"bytes"
	"errors"
	"fmt"
	"os"
	"os/exec"
	"runtime"
	"sync"
	"time"
)

type File struct {
	Path   string `json:"path"`
	Name   string `json:"name"`
	Action string `json:"action"`
	// RO is readonly
	RO   bool   `json:"ro"`
	Lang string `json:"lang"`

	// Order order of the display on ui
	Order int `json:"order"`

	// used for parsing post data
	Data string `json:"data,omitempty"`

	lock  sync.RWMutex  `json:"-"`
	owner *ConfigUI     `json:"-"`
	run   chan struct{} `json:"-"`
	pid   int           `json:"-"`
}

func (f *File) Read() ([]byte, error) {
	f.lock.RLock()
	defer f.lock.RUnlock()
	data, err := os.ReadFile(f.Path)
	if err != nil {
		f.owner.log.Error(err)
		return nil, err
	}
	return data, nil
}

func (f *File) Write(data []byte) error {
	if f.RO {
		return errors.New("this file has readonly set")
	}
	f.lock.Lock()
	defer f.lock.Unlock()
	info, err := os.Stat(f.Path)
	if err != nil {
		return err
	}
	return os.WriteFile(f.Path, data, info.Mode())
}

func (f *File) Do(CmdTimeout time.Duration) (string, error) {
	if f.Action == "" {
		return "", nil
	}
	f.lock.RLock()
	defer f.lock.RUnlock()

	// limit running instance to 1
	if cap(f.run) == 0 {
		f.run = make(chan struct{}, 1)
	}
	select {
	case f.run <- struct{}{}:
		defer func() { <-f.run }()
	default:
		f.owner.log.Error("task is running: ", f.Name)
		return "", fmt.Errorf("another task of %s is running with pid: %d", f.Name, f.pid)
	}

	// prepare cmd
	cmd := &exec.Cmd{}
	if runtime.GOOS == "windows" {
		cmd = exec.Command(WIN_SHELL, "/c", f.Action)
	} else {
		cmd = exec.Command(UNIX_SHELL, "-c", f.Action)
	}
	f.owner.log.Info("DO: ", f.Action)
	done := make(chan string, 1)
	go func() {

		var b bytes.Buffer
		cmd.Stdout = &b
		cmd.Stderr = &b
		cmd.Start()
		f.pid = cmd.Process.Pid
		cmd.Wait()
		done <- b.String()
	}()
	select {
	case <-time.After(CmdTimeout):
		cmd.Process.Kill()
		f.owner.log.Error("timeout")
		return "", errors.New("command timeout")
	case out := <-done:
		f.owner.log.Info("\n", out)
		return out, nil
	}
}