cli: add option for timestamp line header format

4 files changed, 30 insertions, 3 deletions

diff --git a/changelog.md b/changelog.md
index 3f6aebc..b8af052 100644
--- a/changelog.md
+++ b/changelog.md
@@ -3,6 +3,7 @@ Changelog
 
 ## Next release
 * Fixed issue emitting pings when the system's IP address changed during exec
+* Added `--timestamp=datetime|unix|none` param to set line header format
 
 ## v2.0 (2024-11-25)
 * Fused the `--min` and `--max` display options into `--range=MIN:MAX`
diff --git a/logger.nim b/logger.nim
index a4d90a0..48aedf2 100644
--- a/logger.nim
+++ b/logger.nim
@@ -40,9 +40,22 @@ proc puts(f: File, s: string) =
 proc puts(f: File, r: Rune) =
   f.puts r.toUTF8
 
-proc loop*(probe: (timeout: Duration) -> int, getSymbol: (int) -> Rune) =
+func formatTimestampDateTime*(dt: DateTime): string =
+  dt.format(TIMESTAMP_FORMAT)
+
+func formatTimestampUnix*(dt: DateTime): string =
+  ($dt.toTime.toUnix) & " "
+
+func formatTimestampNone*(dt: DateTime): string =
+  ""
+
+proc loop*(
+  probe: (timeout: Duration) -> int,
+  getSymbol: (int) -> Rune,
+  timestampHeader: (DateTime) -> string,
+) =
   while true:
-    stdout.puts now().format(TIMESTAMP_FORMAT)
+    stdout.puts timestampHeader(now())
 
     for tick in 0..<60:
       let t = now()
diff --git a/main.nim b/main.nim
index 3128bac..cca5528 100644
--- a/main.nim
+++ b/main.nim
@@ -37,6 +37,7 @@ proc main() =
   var
     scale: Scale = log2
     symbols = UNICODE_SYMBOLS
+    timestampHeader = formatTimestampDateTime
     (min, max) = (0, 1000)
     probe: (timeout: Duration) -> int
 
@@ -66,6 +67,12 @@ proc main() =
       of "unicode", "utf8", "utf-8": symbols = UNICODE_SYMBOLS
       of "numeric", "ascii": symbols = NUMERIC_SYMBOLS
 
+    of "timestamp":
+      case val:
+      of "datetime", "date-time": timestampHeader = formatTimestampDateTime
+      of "unix", "epoch": timestampHeader = formatTimestampUnix
+      of "none", "false": timestampHeader = formatTimestampNone
+
     of "range":
       let parts = val.split(':', 1)
       if parts.len != 2: raise newException(ValueError, "Invalid range")
@@ -87,7 +94,11 @@ proc main() =
   if probe == nil:
     raise newException(ValueError, "Missing monitor argument")
 
-  loop(probe, (val: int) => symbols.indicator(min, max, val, scale))
+  loop(
+    probe,
+    (val: int) => symbols.indicator(min, max, val, scale),
+    timestampHeader,
+  )
 
 
 when not defined(test):
diff --git a/readme.md b/readme.md
index c82ba18..a105b43 100644
--- a/readme.md
+++ b/readme.md
@@ -36,6 +36,8 @@ Display options:
                       Choices: log2 (default), log10, ln, linear
   --symbols=CHOICE    Set output symbol set
                       Choices: unicode (default), numeric
+  --timestamp=CHOICE  Set line header timestamp format
+                      Choices: datetime (default), unix, none
 
 Other options:
   --help, -h          Display this help message