From 7c6009abd22d8461039be15d0fd069a460340585 Mon Sep 17 00:00:00 2001
From: Jake Mannens <jake@asger.xyz>
Date: Fri, 20 Sep 2024 16:13:30 +1000
Subject: v0.1

---
 PagerMessage.cs | 124 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 PagerMessage.cs

(limited to 'PagerMessage.cs')

diff --git a/PagerMessage.cs b/PagerMessage.cs
new file mode 100644
index 0000000..dc30a05
--- /dev/null
+++ b/PagerMessage.cs
@@ -0,0 +1,124 @@
+using Microsoft.EntityFrameworkCore;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+using System.Text.RegularExpressions;
+
+namespace PagerParser;
+
+public enum AlertLevel {
+    Code1 = 1,
+    Code3 = 3
+}
+
+[Flags]
+public enum EmergencyService {
+    Ambulance = 1,
+    Fire      = 2,
+    Police    = 3,
+    Rescue    = 4,
+    SES       = 5
+}
+
+[Index(nameof(Message))]
+public class PagerMessage {
+    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+    public int      PagerMessageId { get; set; }
+    public DateTime Timestamp      { get; set; }
+    public string   Message        { get; set; }
+
+    public virtual ParsedPagerMessage? ParsedMessage { get; set; }
+
+    public override int GetHashCode() =>
+        (Timestamp, Message).GetHashCode();
+}
+
+[Index(nameof(FirecomJobNo))]
+public class ParsedPagerMessage {
+    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+    public int              ParsedPagerMessageId { get; set; }
+    public int              FirecomJobNo         { get; set; }
+    public string           AssignmentArea       { get; set; }
+    public string           JobType              { get; set; }
+    public AlertLevel       AlertLevel           { get; set; }
+    public string           Description          { get; set; }
+    public int?             MelwaysMapNo         { get; set; }
+    public string?          MelwaysGrid          { get; set; }
+    public int?             GridReference        { get; set; }
+    public EmergencyService AttendingServices    { get; set; }
+    public string?          Note                 { get; set; }
+    public int?             FireGroundChannel    { get; set; }
+    public string           PageDestination      { get; set; }
+
+    public virtual GpsPosition? GpsPosition { get; set; }
+
+    [ForeignKey(nameof(PagerMessage))]
+    public virtual PagerMessage OriginalMessage { get; set; }
+}
+
+public interface IPagerMessageParserService {
+    public ParsedPagerMessage  Parse(string message);
+    public ParsedPagerMessage? TryParse(string message);
+}
+
+// We run the pager message parser as a service with a single instance
+// as this allows us to pre-compile the parsing regular expression
+// which will help when potentially processing 1000's of pager messages.
+//
+// Running a single instance of the service isn't an issue, as this
+// service is only used by the fetch service for parsing new messages.
+public class PagerMessageParserService : IPagerMessageParserService {
+    private const string Pattern =
+        @"^@@ALERT\s+([A-Z]+[0-9]+)\s+([A-Z&]+)C([13])\s+(.*)\s+M\s+(\d+)\s+([A-Z]\d+)\s+\((\d+)\)\s+(\*\s+[^*]+\*\s+)?([AFPRS]+)\s+((C[A-Z]+)\s+)+FGD(\d+)\s+(P\d+\s+)?F(\d+)\s+\[([A-Z]+)\]$";
+
+    private Regex pageMessageRegex = new Regex(Pattern, RegexOptions.Compiled | RegexOptions.IgnoreCase);
+
+    public ParsedPagerMessage Parse(string message) {
+        ParsedPagerMessage m = new();
+
+        var match = pageMessageRegex.Match(message);
+
+        if(!match.Success)
+            throw new ArgumentException();
+
+        // Parse non-optional message components
+        m.AssignmentArea  = match.Groups[1].Value;
+        m.JobType         = match.Groups[2].Value;
+        m.Description     = match.Groups[4].Value;
+        m.FirecomJobNo    = Int32.Parse(match.Groups[14].Value);
+        m.PageDestination = match.Groups[15].Value;
+
+        // Parse optional message components
+        if(match.Groups[5].Success)  m.MelwaysMapNo      = Int32.Parse(match.Groups[5].Value);
+        if(match.Groups[6].Success)  m.MelwaysGrid       = match.Groups[6].Value;
+        if(match.Groups[7].Success)  m.GridReference     = Int32.Parse(match.Groups[7].Value);
+        if(match.Groups[8].Success)  m.Note              = match.Groups[8].Value;
+        if(match.Groups[12].Success) m.FireGroundChannel = Int32.Parse(match.Groups[12].Value);
+
+        switch(match.Groups[3].Value) {
+            case "1": m.AlertLevel = AlertLevel.Code1; break;
+            case "3": m.AlertLevel = AlertLevel.Code3; break;
+            default: throw new ArgumentException();
+        }
+
+        // Handle each character to construct a bitmap of attending services
+        foreach(char c in match.Groups[9].Value) {
+            switch(c) {
+                case 'A': m.AttendingServices |= EmergencyService.Ambulance; break;
+                case 'F': m.AttendingServices |= EmergencyService.Fire;      break;
+                case 'P': m.AttendingServices |= EmergencyService.Police;    break;
+                case 'R': m.AttendingServices |= EmergencyService.Rescue;    break;
+                case 'S': m.AttendingServices |= EmergencyService.SES;       break;
+            }
+        }
+
+        return m;
+    }
+
+    public ParsedPagerMessage? TryParse(string message) {
+        try {
+            return Parse(message);
+        } catch {
+            return null;
+        }
+    }
+}
\ No newline at end of file
-- 
cgit v1.3