sjansen/mecha

package main

import (
    "fmt"
    "os"
    "path/filepath"
    "time"

    "github.com/sjansen/watchman"
)

func connect() *watchman.Client {
    os.Stdout.Write([]byte("Connecting to Watchman... "))
    os.Stdout.Sync()
    c, err := watchman.Connect()
    if err != nil {
        fmt.Println("FAILURE")
        die(err)
    }
    fmt.Println("SUCCESS")

    return c
}

func die(err error) {
    fmt.Fprintln(os.Stderr, err)
    os.Exit(1)
}

func loop(c *watchman.Client) {
    for n := range c.Notifications() {
        cn, ok := n.(*watchman.ChangeNotification)
        if !ok || cn.IsFreshInstance {
            continue
        }
        fmt.Printf(
            "Update: (clock=%q)\n",
            cn.Clock,
        )
        files := cn.Files
        for _, file := range files {
            switch file.Type {
            case "d":
                fmt.Printf("  %9s  %s/\n",
                    file.Change, file.Name,
                )
            case "l":
                fmt.Printf("  %9s  %s -> %s\n",
                    file.Change, file.Name, file.Target,
                )
            default:
                fmt.Printf("  %9s  %s\n",
                    file.Change, file.Name,
                )
            }
        }
        fmt.Println()
    }
}

func mkdir() (dir string, err error) {
    dir, err = os.MkdirTemp("", "watchman-client-test")
    if err != nil {
        return
    }

    dir, err = filepath.EvalSymlinks(dir)
    if err != nil {
        return
    }

    path := filepath.Join(dir, ".watchmanconfig")
    err = os.WriteFile(path, []byte(`{"idle_reap_age_seconds": 300}`+"\n"), os.ModePerm)
    return
}

func main() {
    c := connect()
    fmt.Printf("version: %s\n\n", c.Version())

    dir, err := mkdir()
    if err != nil {
        die(err)
    }
    defer os.RemoveAll(dir)

    fmt.Printf("Watching: %s\n\n", dir)
    watch, err := c.AddWatch(dir)
    if err != nil {
        die(err)
    }

    go func() {
        loop(c)
    }()

    _, err = watch.Subscribe("example", dir)
    if err != nil {
        die(err)
    }

    for i, basename := range []string{"foo", "bar", "baz"} {
        filename := filepath.Join(dir, basename)
        os.WriteFile(filename, []byte{}, os.ModePerm)
        time.Sleep(time.Duration(i) * time.Second)
        os.Remove(filename)
        time.Sleep(time.Second)
    }
}