Add coffee bot (#2809)

* Add coffee bot

* fix order

samples/go/coffee/main.go

@@ -0,0 +1,126 @@
+// Copyright 2016 Attic Labs, Inc. All rights reserved.
+// Licensed under the Apache License, version 2.0:
+// http://www.apache.org/licenses/LICENSE-2.0
+
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/attic-labs/noms/go/config"
+	"github.com/attic-labs/noms/go/d"
+	"github.com/attic-labs/noms/go/datas"
+	"github.com/attic-labs/noms/go/marshal"
+	"github.com/attic-labs/noms/go/spec"
+	"github.com/attic-labs/noms/go/types"
+	"github.com/attic-labs/noms/go/util/verbose"
+	flag "github.com/juju/gnuflag"
+)
+
+var people = []string{
+	"aa",
+	"arv",
+	"dan",
+	"ehalpern",
+	"kalman",
+	"rafael",
+	"zane",
+}
+
+func main() {
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, "Usage: %s <ds>\n", os.Args[0])
+	}
+
+	verbose.RegisterVerboseFlags(flag.CommandLine)
+	flag.Parse(true)
+
+	if flag.NArg() != 1 {
+		fmt.Fprintln(os.Stderr, "Incorrect number of arguments")
+		return
+	}
+
+	cfg := config.NewResolver()
+	db, ds, err := cfg.GetDataset(flag.Arg(0))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Could not create dataset: %s\n", err)
+		return
+	}
+	defer db.Close()
+
+	now := time.Now()
+	lastTime, idx := getCurrent(ds)
+	if lastTime.YearDay() == now.YearDay() {
+		fmt.Println("Same day as last run, nothing to do. Peace.")
+		return
+	}
+
+	if now.Weekday() == time.Sunday || now.Weekday() == time.Saturday {
+		fmt.Println("No coffee on weekends.")
+		return
+	}
+
+	idx += 1
+	if idx == len(people) {
+		idx = 0
+	}
+	winner := people[idx]
+
+	pokeSlack(winner)
+
+	_, err = db.Commit(ds, types.String(winner), datas.CommitOptions{
+		Meta: types.NewStruct("", types.StructData{
+			"date": types.String(now.Format(spec.CommitMetaDateFormat)),
+		}),
+	})
+	d.CheckErrorNoUsage(err)
+}
+
+func getCurrent(ds datas.Dataset) (d time.Time, idx int) {
+	idx = -1
+
+	type Commit struct {
+		Meta struct {
+			Date string
+		}
+		Value string
+	}
+
+	h, ok := ds.MaybeHead()
+	if !ok {
+		return
+	}
+
+	var c Commit
+	err := marshal.Unmarshal(h, &c)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Got error unmarshaling: %+v\n", err)
+		return
+	}
+
+	t, err := time.Parse(spec.CommitMetaDateFormat, c.Meta.Date)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Got error parsing last date: %+v\n", err)
+		return
+	}
+
+	for i, _ := range people {
+		if people[i] == c.Value {
+			return t, i
+		}
+	}
+
+	fmt.Fprintf(os.Stderr, "Couldn't find person %s, resetting at beginning", c.Value)
+	return
+}
+
+func pokeSlack(winner string) {
+	r := strings.NewReader(fmt.Sprintf("{\"text\":\"Today @%s cleans the coffee machine. Thank-you! You are awesome!\"}", winner))
+	_, err := http.Post("https://hooks.slack.com/services/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",
+		"application/json", r)
+	d.CheckErrorNoUsage(err)
+}