From d0c104aceb6ff96e4debf6b721cf8376d2d72503 Mon Sep 17 00:00:00 2001
From: Eric Callahan <arksine.code@gmail.com>
Date: Sat, 7 Aug 2021 11:39:15 -0400
Subject: [PATCH] job_state: initial implementation

This module adds a helper to track Klippy's "print_stats" module.  It
stores the current stats and emits events for changes in job state.

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>
---
 moonraker/components/job_state.py | 76 +++++++++++++++++++++++++++++++
 moonraker/moonraker.py            |  2 +-
 2 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 moonraker/components/job_state.py

diff --git a/moonraker/components/job_state.py b/moonraker/components/job_state.py
new file mode 100644
index 0000000..af76cd5
--- /dev/null
+++ b/moonraker/components/job_state.py
@@ -0,0 +1,76 @@
+# Klippy job state event handlers
+#
+# Copyright (C) 2021 Eric Callahan <arksine.code@gmail.com>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+from __future__ import annotations
+import logging
+
+# Annotation imports
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Optional,
+    Dict,
+    List,
+)
+if TYPE_CHECKING:
+    from confighelper import ConfigHelper
+    from .klippy_apis import KlippyAPI
+
+class JobState:
+    def __init__(self, config: ConfigHelper) -> None:
+        self.server = config.get_server()
+        self.last_print_stats: Dict[str, Any] = {}
+        self.server.register_event_handler(
+            "server:klippy_ready", self._handle_ready)
+        self.server.register_event_handler(
+            "server:status_update", self._status_update)
+
+    async def _handle_ready(self) -> None:
+        kapis: KlippyAPI = self.server.lookup_component('klippy_apis')
+        sub: Dict[str, Optional[List[str]]] = {"print_stats": None}
+        try:
+            result = await kapis.subscribe_objects(sub)
+        except self.server.error as e:
+            logging.info(f"Error subscribing to print_stats")
+        self.last_print_stats = result.get("print_stats", {})
+
+    async def _status_update(self, data: Dict[str, Any]) -> None:
+        if 'print_stats' not in data:
+            return
+        ps = data['print_stats']
+        if "state" in ps:
+            prev_ps = dict(self.last_print_stats)
+            old_state: str = prev_ps['state']
+            new_state: str = ps['state']
+            new_ps = dict(self.last_print_stats)
+            new_ps.update(ps)
+            if new_state is not old_state:
+                if new_state == "printing":
+                    # The "printing" state needs some special handling
+                    # to detect "resets" and a transition from pause to resume
+                    if self._check_resumed(prev_ps, new_ps):
+                        new_state = "resumed"
+                    else:
+                        new_state = "started"
+                self.server.send_event(
+                    f"job_state:{new_state}", prev_ps, new_ps)
+        self.last_print_stats.update(ps)
+
+    def _check_resumed(self,
+                       prev_ps: Dict[str, Any],
+                       new_ps: Dict[str, Any]
+                       ) -> bool:
+        return (
+            prev_ps['state'] == "paused" and
+            prev_ps['filename'] == new_ps['filename'] and
+            prev_ps['total_duration'] < new_ps['total_duration']
+        )
+
+    def get_last_stats(self) -> Dict[str, Any]:
+        return dict(self.last_print_stats)
+
+def load_component(config: ConfigHelper) -> JobState:
+    return JobState(config)
diff --git a/moonraker/moonraker.py b/moonraker/moonraker.py
index 7681993..7d01332 100755
--- a/moonraker/moonraker.py
+++ b/moonraker/moonraker.py
@@ -53,7 +53,7 @@ MAX_LOG_ATTEMPTS = 10 * LOG_ATTEMPT_INTERVAL
 
 CORE_COMPONENTS = [
     'database', 'file_manager', 'klippy_apis', 'machine',
-    'data_store', 'shell_command', 'proc_stats']
+    'data_store', 'shell_command', 'proc_stats', 'job_state']
 
 SENTINEL = SentinelClass.get_instance()