From 2a26e4fb3ae3ce827839e6b3eaf4dbab2ed86232 Mon Sep 17 00:00:00 2001
From: Jan Philipp Timme <jan.philipp@timme.it>
Date: Sat, 29 Dec 2018 01:42:50 +0100
Subject: [PATCH] Initial import

---
 main.go          | 24 ++++++++++++++
 parser/parser.go | 86 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 main.go
 create mode 100644 parser/parser.go

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..30078e2
--- /dev/null
+++ b/main.go
@@ -0,0 +1,24 @@
+package main
+
+import (
+    "bufio"
+    "fmt"
+    "os"
+    "mailq-inspector/parser"
+)
+
+
+func main() {
+    // Read data from stdin
+    scanner := bufio.NewScanner(os.Stdin)
+    entries, err := parser.ParseMailQ(scanner)
+    if err != nil {
+       fmt.Printf("Got error from parser: %s\n", err.Error())
+       os.Exit(1)
+    } else {
+        for _, entry := range entries {
+            fmt.Printf("%s\n", entry.String())
+        }
+        os.Exit(0)
+    }
+}
diff --git a/parser/parser.go b/parser/parser.go
new file mode 100644
index 0000000..30c043d
--- /dev/null
+++ b/parser/parser.go
@@ -0,0 +1,86 @@
+package parser
+
+import (
+    "bufio"
+    "errors"
+    "fmt"
+    "regexp"
+    "strconv"
+    "strings"
+    "time"
+)
+
+type Entry struct {
+    id string
+    status string
+    date time.Time
+    size int
+    sender string
+    recipients []string
+    reason string
+}
+
+func (m Entry) String() string {
+    return fmt.Sprintf("ID: %s, Status: %s, Size: %d bytes, Sender: %s, Recipients: %d", m.id, m.status, m.size, m.sender, len(m.recipients))
+}
+
+func ParseMailQ(scanner *bufio.Scanner) ([]Entry, error) {
+    const dateFormat = "2006 Mon Jan _2 15:04:05"
+    var messageIdStart = regexp.MustCompile("^[0-9A-Za-z]+[*!]? ")
+    scanner.Scan()
+    line := scanner.Text()
+    if strings.HasPrefix(line, "Mail queue is empty") {
+        // If mail queue is empty, there is nothing to do
+        return nil, errors.New(line)
+    } else if strings.HasPrefix(line, "-Queue ID-") == false {
+        // Abort if input does not look like output from mailq(1)
+        return nil, errors.New("Sorry, this does not look like output from mailq(1).")
+    }
+    var currentMail Entry
+    var queueEntries []Entry
+
+    for scanner.Scan() {
+        // Read input line by line
+        line := scanner.Text()
+        fields := strings.Fields(line)
+        if strings.HasPrefix(line, "--") {
+            // Handle the summary line at the end of mailq output
+            break
+        } else if messageIdStart.MatchString(line) {
+            // Handle line starting next mail in queue
+            messageId := fields[0]
+            if strings.HasSuffix(messageId, "*") {
+                currentMail.status = "active"
+            } else if strings.HasSuffix(messageId, "!") {
+                currentMail.status = "hold"
+            } else {
+                currentMail.status = "deferred"
+            }
+            dateString := strconv.Itoa(time.Now().Year()) + " " + strings.Join(fields[2:6], " ")
+            mailDate, _ := time.Parse(dateFormat, dateString)
+            currentMail.id = strings.TrimRight(messageId, "*!")
+            currentMail.size, _ = strconv.Atoi(fields[1])
+            currentMail.date = mailDate
+            currentMail.sender = fields[6]
+            continue
+        } else if strings.HasPrefix(line, "(") && strings.HasSuffix(line, ")") {
+            // Handle reason for deferred status (if deferred at all, may be missing)
+            currentMail.reason = strings.Trim(strings.TrimSpace(line), "()")
+            continue
+        } else if len(fields) == 1 {
+            // Handle line with one of the mail recipients
+            currentMail.recipients = append(currentMail.recipients, fields[0])
+            continue
+        } else if len(fields) == 0 {
+            // If the next line is empty, make sure to push current mail to list
+            // and create a new struct for the next mail to process
+            queueEntries = append(queueEntries, currentMail)
+            currentMail = Entry{}
+        }
+    }
+    if scanner.Err() != nil {
+        // If the scanner failed, let our caller know.
+        return nil, errors.New("Something went wrong with reading from stdin. Sorry!")
+    }
+    return queueEntries, nil
+}