capture.rb in tlapse-0.3.0

- old
+ new
@@ -1,7 +1,73 @@
+require "active_support/core_ext/numeric/time.rb"
+
 module Tlapse
   module Capture
-    def capture_single
+    def self.capture_single(format: nil)
+      puts "The format key is not yet supported" if format
+
       `gphoto2 --capture-image-and-download`
+    end
+
+    ##
+    # Calculate how many captures are needed given a duration of capture
+    # time and a desired interval between captures.
+    #
+    # @example
+    #   captures_needed duration: 5.minutes, interval: 30.seconds # => 10
+    #
+    # Specify either `start_time` and `end_time` or `duration`. If both
+    # are given, `duration` is preferred.
+    #
+    # @param start_time: [Time] when to start capturing
+    # @param end_time: [Time] when to end capturing
+    # @param duration: [Duration] duration over which images are captured.
+    #  If specifying, do not also specify `end_time
+    # @param interval: [Duration] time between each capture
+    # @return how many captures will be taken over the duration and interval
+    def self.captures_needed(start_time: Time.now, end_time: Time.now,
+                             duration: nil, interval:)
+      unless duration
+        start_time = start_time.to_i
+        end_time   = end_time.to_i
+        duration   = end_time - start_time
+      end
+
+      duration / interval
+    end
+
+    ##
+    # Capture a series of timelapse images over the given duration
+    # and at the given interval.
+    #
+    # @return [String] a gphoto2 command with the desired arguments
+    def self.timelapse_command(from: Time.now, to:, interval:)
+      captures = self.captures_needed(
+        start_time: from,
+        end_time:   to,
+        interval:   interval
+      )
+      "gphoto2 --capture-image-and-download -I #{interval} -F #{captures}"
+    end
+
+    ##
+    # Capture a timelapse image once per interval while the sun is up.
+    #
+    # @param interval [Duration] how frequently to capture images
+    # @return [String] a gphoto2 command with the desired arguments
+    def self.timelapse_command_while_sun_is_up(interval: 5.minutes)
+      sunrise = SolarEvent.sunrise
+      sunset  = SolarEvent.sunset
+      now     = Time.now
+
+      # Use now as starting time if sunrise has passed
+      sunrise = now > sunrise ? now : sunrise
+
+      captures = self.captures_needed(
+        start_time: sunrise,
+        end_time:   sunset,
+        interval:   interval
+      )
+      "gphoto2 --capture-image-and-download -I #{interval} -F #{captures}"
     end
   end # Capture
 end # Tlapse