feat: get evaluation get result

Gemfile.lock

@@ -4,6 +4,7 @@ PATH
     flagsmith (4.3.0)
       faraday (>= 2.0.1)
       faraday-retry
+      jsonpath (~> 1.1)
       semantic
 
 GEM
@@ -21,8 +22,11 @@ GEM
       faraday (~> 2.0)
     gem-release (2.2.2)
     json (2.7.1)
+    jsonpath (1.1.5)
+      multi_json
     language_server-protocol (3.17.0.3)
     method_source (1.0.0)
+    multi_json (1.17.0)
     net-http (0.4.1)
       uri
     parallel (1.24.0)

flagsmith.gemspec

@@ -34,6 +34,7 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency 'faraday', '>= 2.0.1'
   spec.add_dependency 'faraday-retry'
+  spec.add_dependency 'jsonpath', '~> 1.1'
   spec.add_dependency 'semantic'
   spec.metadata['rubygems_mfa_required'] = 'true'
 end

lib/flagsmith/engine/core.rb

@@ -12,6 +12,7 @@
 require_relative 'segments/models'
 require_relative 'utils/hash_func'
 require_relative 'evaluation/mappers'
+require_relative 'evaluation/core'
 
 module Flagsmith
   module Engine

lib/flagsmith/engine/evaluation/core.rb

@@ -1,20 +1,173 @@
 # frozen_string_literal: true
 
+require_relative '../utils/hash_func'
+require_relative '../features/constants'
+require_relative '../segments/evaluator'
+
 module Flagsmith
   module Engine
     module Evaluation
+      # Core evaluation logic module
       module Core
+        extend self
+        include Flagsmith::Engine::Utils::HashFunc
+        include Flagsmith::Engine::Features::TargetingReasons
+        include Flagsmith::Engine::Segments::Evaluator
         # Get evaluation result from evaluation context
         #
         # @param evaluation_context [Hash] The evaluation context
         # @return [Hash] Evaluation result with flags and segments
-        def self.get_evaluation_result(_evaluation_context)
-          # TODO: Implement core evaluation logic
+        # returns EvaluationResultWithMetadata
+        def get_evaluation_result(evaluation_context)
+          segments, segment_overrides = evaluate_segments(evaluation_context)
+          flags = evaluate_features(evaluation_context, segment_overrides)
           {
-            flags: {},
-            segments: []
+            flags: flags,
+            segments: segments
           }
         end
+
+        # Returns { segments: EvaluationResultSegments; segmentOverrides: Record<string, SegmentOverride>; }
+        def evaluate_segments(evaluation_context)
+          return [], {} if evaluation_context[:identity].nil? || evaluation_context[:segments].nil?
+
+          identity_segments = get_identity_segments_from_context(evaluation_context)
+
+          segments = identity_segments.map do |segment|
+            result = {
+              name: segment[:name]
+            }
+
+            result[:metadata] = segment[:metadata] if segment[:metadata]
+
+            result
+          end
+
+          segment_overrides = process_segment_overrides(identity_segments)
+
+          [segments, segment_overrides]
+        end
+
+        # Returns Record<string: override.name, SegmentOverride>
+        def process_segment_overrides(identity_segments)
+          segment_overrides = {}
+
+          identity_segments.each do |segment|
+            next unless segment[:overrides]
+
+            overrides_list = segment[:overrides].is_a?(Array) ? segment[:overrides] : []
+
+            overrides_list.each do |override|
+              next unless should_apply_override(override, segment_overrides)
+
+              segment_overrides[override[:name]] = {
+                feature: override,
+                segment_name: segment[:name]
+              }
+            end
+          end
+
+          segment_overrides
+        end
+
+        # returns EvaluationResultFlags<Metadata>
+        def evaluate_features(evaluation_context, segment_overrides)
+          flags = {}
+
+          (evaluation_context[:features] || {}).each_value do |feature|
+            segment_override = segment_overrides[feature[:name]]
+            final_feature = segment_override ? segment_override[:feature] : feature
+            has_override = !segment_override.nil?
+
+            # Evaluate feature value
+            evaluated = if has_override
+                          { value: final_feature[:value], reason: nil }
+                        else
+                          evaluate_feature_value(final_feature, get_identity_key(evaluation_context))
+                        end
+
+            # Build flag result
+            flag_result = {
+              name: final_feature[:name],
+              enabled: final_feature[:enabled],
+              value: evaluated[:value]
+            }
+
+            # Add metadata if present
+            flag_result[:metadata] = final_feature[:metadata] if final_feature[:metadata]
+
+            # Set reason
+            flag_result[:reason] = evaluated[:reason] ||
+                                   get_targeting_match_reason({ type: 'SEGMENT', override: segment_override })
+
+            flags[final_feature[:name].to_sym] = flag_result
+          end
+
+          flags
+        end
+
+        # Returns {value: any; reason?: string}
+        def evaluate_feature_value(feature, identity_key = nil)
+          return get_multivariate_feature_value(feature, identity_key) if feature[:variants]&.any? && identity_key
+
+          { value: feature[:value], reason: nil }
+        end
+
+        # Returns {value: any; reason?: string}
+        def get_multivariate_feature_value(feature, identity_key)
+          percentage_value = hashed_percentage_for_object_ids([feature[:key], identity_key])
+          sorted_variants = (feature[:variants] || []).sort_by { |v| v[:priority] || Float::INFINITY }
+
+          start_percentage = 0
+          sorted_variants.each do |variant|
+            limit = start_percentage + variant[:weight]
+            if start_percentage <= percentage_value && percentage_value < limit
+              return {
+                value: variant[:value],
+                reason: get_targeting_match_reason({ type: 'SPLIT', weight: variant[:weight] })
+              }
+            end
+            start_percentage = limit
+          end
+
+          { value: feature[:value], reason: nil }
+        end
+
+        # returns boolean
+        def should_apply_override(override, existing_overrides)
+          current_override = existing_overrides[override[:name]]
+          !current_override || higher_priority?(override[:priority], current_override[:feature][:priority])
+        end
+
+        private
+
+        # Extract identity key from evaluation context
+        #
+        # @param evaluation_context [Hash] The evaluation context
+        # @return [String, nil] The identity key or nil if no identity
+        def get_identity_key(evaluation_context)
+          return nil unless evaluation_context[:identity]
+
+          evaluation_context[:identity][:key] ||
+            "#{evaluation_context[:environment][:key]}_#{evaluation_context[:identity][:identifier]}"
+        end
+
+        # returns boolean
+        def higher_priority?(priority_a, priority_b)
+          (priority_a || Float::INFINITY) < (priority_b || Float::INFINITY)
+        end
+
+        def get_targeting_match_reason(match_object)
+          type = match_object[:type]
+
+          if type == 'SEGMENT'
+            return match_object[:override] ? "#{TARGETING_REASON_TARGETING_MATCH}; segment=#{match_object[:override][:segment_name]}" : TARGETING_REASON_DEFAULT
+          end
+
+          return "#{TARGETING_REASON_SPLIT}; weight=#{match_object[:weight]}" if type == 'SPLIT'
+
+          TARGETING_REASON_DEFAULT
+        end
       end
     end
   end

lib/flagsmith/engine/evaluation/mappers.rb

@@ -161,7 +161,7 @@ def self.map_identity_overrides_to_segments(identity_overrides)
           features_to_identifiers = {}
 
           identity_overrides.each do |identity|
-            next if identity.identity_features.nil? || !identity.identity_features.any?
+            next if identity.identity_features.nil? || identity.identity_features.none?
 
             # Sort features by name for consistent hashing
             sorted_features = identity.identity_features.to_a.sort_by { |fs| fs.feature.name }

lib/flagsmith/engine/features/constants.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module Flagsmith
+  module Engine
+    module Features
+      # Targeting reason constants for evaluation results
+      module TargetingReasons
+        TARGETING_REASON_DEFAULT = 'DEFAULT'
+        TARGETING_REASON_TARGETING_MATCH = 'TARGETING_MATCH'
+        TARGETING_REASON_SPLIT = 'SPLIT'
+      end
+    end
+  end
+end