update to match new interface

3 files changed, 87 insertions, 183 deletions

diff --git a/lib/dispatch/adapter/copilot.rb b/lib/dispatch/adapter/copilot.rb
index b14c5c0..7355df8 100644
--- a/lib/dispatch/adapter/copilot.rb
+++ b/lib/dispatch/adapter/copilot.rb
@@ -51,14 +51,22 @@ module Dispatch
 
       VALID_THINKING_LEVELS = %w[low medium high].freeze
 
+      # Default Editor-Version header value. Mimics what codecompanion.nvim
+      # sends so that requests are indistinguishable on the wire from the
+      # well-known Neovim Copilot adapter (which is widely used and trusted).
+      # Override via the `editor_version:` constructor option if you need a
+      # different value (e.g. your actual running Neovim version).
+      DEFAULT_EDITOR_VERSION = "Neovim/0.10.4"
+
       def initialize(model: "gpt-4.1", github_token: nil, token_path: nil, max_tokens: 8192, thinking: "high",
-                     min_request_interval: 3.0, rate_limit: nil)
+                     min_request_interval: 3.0, rate_limit: nil, editor_version: DEFAULT_EDITOR_VERSION)
         super()
         @model = model
         @github_token = github_token
         @token_path = token_path || default_token_path
         @default_max_tokens = max_tokens
         @default_thinking = thinking
+        @editor_version = editor_version
         @copilot_token = nil
         @copilot_token_expires_at = 0
         @mutex = Mutex.new
@@ -295,13 +303,51 @@ module Dispatch
 
       # --- HTTP helpers ---
 
-      def apply_headers!(request)
+      # Apply the request headers used for Copilot chat completions.
+      #
+      # Header set is intentionally identical to what codecompanion.nvim's
+      # Copilot adapter sends (see lua/codecompanion/adapters/http/copilot/init.lua):
+      #
+      #   - Authorization: Bearer <copilot-token>
+      #   - Content-Type: application/json
+      #   - Copilot-Integration-Id: vscode-chat
+      #   - Editor-Version: Neovim/x.y.z (configurable)
+      #   - X-Initiator: user|agent (only added by callers via apply_headers!)
+      #
+      # We deliberately DO NOT send `Openai-Intent` because codecompanion
+      # does not, and matching that wire profile is the goal.
+      def apply_headers!(request, initiator: "user")
         request["Authorization"] = "Bearer #{@copilot_token}"
         request["Content-Type"] = "application/json"
         request["Accept"] = "application/json"
         request["Copilot-Integration-Id"] = "vscode-chat"
-        request["Editor-Version"] = "dispatch/#{VERSION}"
-        request["Openai-Intent"] = "conversation-panel"
+        request["Editor-Version"] = @editor_version
+        request["X-Initiator"] = initiator
+      end
+
+      # Decides the value of the `X-Initiator` header that GitHub Copilot uses
+      # to classify a request as a billable premium request ("user") or a
+      # non-billable agent continuation ("agent").
+      #
+      # Strategy: "savings" mode (matches ericc-ch/copilot-api default and is
+      # more aggressive than codecompanion.nvim / VS Code).
+      #
+      #   * If the wire payload contains ANY assistant or tool message, it means
+      #     the model has already produced at least one turn — therefore this
+      #     send is part of an ongoing agent loop (typically a tool-result
+      #     follow-up) and is NOT a fresh user-initiated turn. → "agent".
+      #   * Otherwise this is the very first send for a conversation (only
+      #     system + user messages present). → "user".
+      #
+      # Only the initial user prompt of an automation should be billed as a
+      # premium request; every subsequent tool-loop continuation is free.
+      #
+      # Rationale & references:
+      #   - codecompanion.nvim PR #1738 / Discussion #1717
+      #   - ericc-ch/copilot-api PR #85 ("savings" vs "per-user-prompt" modes)
+      #   - https://docs.github.com/en/copilot/concepts/billing/copilot-requests
+      def x_initiator_for(wire_messages)
+        wire_messages.any? { |m| %w[assistant tool].include?(m[:role].to_s) } ? "agent" : "user"
       end
 
       def execute_request(uri, request)
@@ -460,13 +506,13 @@ module Dispatch
       def merge_consecutive_roles(messages)
         return messages if messages.empty?
 
-        merged = [ messages.first.dup ]
+        merged = [messages.first.dup]
 
         messages[1..].each do |msg|
           prev = merged.last
 
           if prev[:role] == msg[:role] && prev[:role] != "tool" && !msg.key?(:tool_calls) && !prev.key?(:tool_calls)
-            prev[:content] = [ prev[:content], msg[:content] ].compact.join("\n\n")
+            prev[:content] = [prev[:content], msg[:content]].compact.join("\n\n")
           else
             merged << msg.dup
           end
@@ -504,8 +550,8 @@ module Dispatch
         @rate_limiter.wait!
         uri = URI("#{API_BASE}/chat/completions")
         request = Net::HTTP::Post.new(uri)
-        apply_headers!(request)
-        request.body = JSON.generate(body)
+        apply_headers!(request, initiator: x_initiator_for(body[:messages] || []))
+        request.body = JSON.generate(deep_utf8(body))
 
         response = execute_request(uri, request)
         data = parse_response!(response)
@@ -557,6 +603,35 @@ module Dispatch
         )
       end
 
+      # Recursively coerces every String inside a wire-body to valid UTF-8.
+      #
+      # Tool results (grep output, file reads, shell stdout) frequently arrive
+      # tagged as US-ASCII or BINARY/ASCII-8BIT even though the bytes are
+      # legitimate UTF-8 (e.g. an em-dash \xE2\x80\x94 inside a source
+      # comment). `JSON.generate` then raises
+      # `Encoding::InvalidByteSequenceError: "\xE2" on US-ASCII` because it
+      # tries to re-encode the mistagged string.
+      #
+      # We force_encoding to UTF-8 (no byte rewrite) and then `scrub` to
+      # replace any genuinely invalid sequences with the Unicode replacement
+      # character so JSON.generate can never fail on user-provided text.
+      def deep_utf8(obj)
+        case obj
+        when String
+          s = obj.dup
+          s.force_encoding(Encoding::UTF_8)
+          s.valid_encoding? ? s : s.scrub("\uFFFD")
+        when Array
+          obj.map { |v| deep_utf8(v) }
+        when Hash
+          obj.each_with_object({}) { |(k, v), h| h[k] = deep_utf8(v) }
+        when Symbol
+          obj
+        else
+          obj
+        end
+      end
+
       def parse_tool_arguments(args_string)
         return {} if args_string.nil? || args_string.empty?
 
@@ -571,8 +646,8 @@ module Dispatch
         @rate_limiter.wait!
         uri = URI("#{API_BASE}/chat/completions")
         request = Net::HTTP::Post.new(uri)
-        apply_headers!(request)
-        request.body = JSON.generate(body)
+        apply_headers!(request, initiator: x_initiator_for(body[:messages] || []))
+        request.body = JSON.generate(deep_utf8(body))
 
         collected = new_stream_collector
 
diff --git a/lib/dispatch/adapter/rate_limiter.rb b/lib/dispatch/adapter/rate_limiter.rb
index 1b05582..7b0e3ed 100644
--- a/lib/dispatch/adapter/rate_limiter.rb
+++ b/lib/dispatch/adapter/rate_limiter.rb
@@ -1,174 +1,3 @@
 # frozen_string_literal: true
 
-require "json"
-require "fileutils"
-
-module Dispatch
-  module Adapter
-    class RateLimiter
-      def initialize(rate_limit_path:, min_request_interval:, rate_limit:)
-        validate_min_request_interval!(min_request_interval)
-        validate_rate_limit!(rate_limit)
-
-        @rate_limit_path = rate_limit_path
-        @min_request_interval = min_request_interval
-        @rate_limit = rate_limit
-      end
-
-      def wait!
-        return if disabled?
-
-        loop do
-          wait_time = 0.0
-          done = false
-
-          File.open(rate_limit_file, File::RDWR | File::CREAT) do |file|
-            file.flock(File::LOCK_EX)
-            state = read_state(file)
-            now = Time.now.to_f
-            wait_time = compute_wait(state, now)
-
-            if wait_time <= 0
-              record_request(state, now)
-              write_state(file, state)
-              done = true
-            end
-          end
-
-          return if done
-
-          sleep(wait_time)
-        end
-      end
-
-      private
-
-      def disabled?
-        effective_min_interval.nil? && @rate_limit.nil?
-      end
-
-      def effective_min_interval
-        return nil if @min_request_interval.nil?
-        return nil if @min_request_interval.zero?
-
-        @min_request_interval
-      end
-
-      def rate_limit_file
-        FileUtils.mkdir_p(File.dirname(@rate_limit_path))
-        File.chmod(0o600, @rate_limit_path) if File.exist?(@rate_limit_path)
-        @rate_limit_path
-      end
-
-      def read_state(file)
-        file.rewind
-        content = file.read
-        return default_state if content.nil? || content.strip.empty?
-
-        parsed = JSON.parse(content)
-        {
-          "last_request_at" => parsed["last_request_at"]&.to_f,
-          "request_log" => Array(parsed["request_log"]).map(&:to_f)
-        }
-      rescue JSON::ParserError
-        default_state
-      end
-
-      def default_state
-        { "last_request_at" => nil, "request_log" => [] }
-      end
-
-      def write_state(file, state)
-        file.rewind
-        file.truncate(0)
-        file.write(JSON.generate(state))
-        file.flush
-
-        File.chmod(0o600, @rate_limit_path)
-      end
-
-      def compute_wait(state, now)
-        cooldown_wait = compute_cooldown_wait(state, now)
-        window_wait = compute_window_wait(state, now)
-        [ cooldown_wait, window_wait ].max
-      end
-
-      def compute_cooldown_wait(state, now)
-        interval = effective_min_interval
-        return 0.0 if interval.nil?
-
-        last = state["last_request_at"]
-        return 0.0 if last.nil?
-
-        elapsed = now - last
-        remaining = interval - elapsed
-        remaining.positive? ? remaining : 0.0
-      end
-
-      def compute_window_wait(state, now)
-        return 0.0 if @rate_limit.nil?
-
-        max_requests = @rate_limit[:requests]
-        period = @rate_limit[:period]
-        window_start = now - period
-
-        log = state["request_log"].select { |t| t > window_start }
-
-        return 0.0 if log.size < max_requests
-
-        oldest_in_window = log.min
-        wait = oldest_in_window + period - now
-        wait.positive? ? wait : 0.0
-      end
-
-      def record_request(state, now)
-        state["last_request_at"] = now
-        state["request_log"] << now
-        prune_log(state, now)
-      end
-
-      def prune_log(state, now)
-        if @rate_limit
-          period = @rate_limit[:period]
-          cutoff = now - period
-          state["request_log"] = state["request_log"].select { |t| t > cutoff }
-        else
-          state["request_log"] = []
-        end
-      end
-
-      def validate_min_request_interval!(value)
-        return if value.nil?
-
-        unless value.is_a?(Numeric)
-          raise ArgumentError,
-                "min_request_interval must be nil or a Numeric >= 0, got #{value.inspect}"
-        end
-
-        return unless value.negative?
-
-        raise ArgumentError,
-              "min_request_interval must be nil or a Numeric >= 0, got #{value.inspect}"
-      end
-
-      def validate_rate_limit!(value)
-        return if value.nil?
-
-        unless value.is_a?(Hash)
-          raise ArgumentError,
-                "rate_limit must be nil or a Hash with :requests and :period keys, got #{value.inspect}"
-        end
-
-        unless value.key?(:requests) && value[:requests].is_a?(Integer) && value[:requests].positive?
-          raise ArgumentError,
-                "rate_limit[:requests] must be a positive Integer, got #{value[:requests].inspect}"
-        end
-
-        return if value.key?(:period) && value[:period].is_a?(Numeric) && value[:period].positive?
-
-        raise ArgumentError,
-              "rate_limit[:period] must be a positive Numeric, got #{value[:period].inspect}"
-      end
-    end
-  end
-end
+require "dispatch/adapter/interface/rate_limiter"
diff --git a/lib/dispatch/adapter/version.rb b/lib/dispatch/adapter/version.rb
index cde8614..967c0c3 100644
--- a/lib/dispatch/adapter/version.rb
+++ b/lib/dispatch/adapter/version.rb
@@ -3,7 +3,7 @@
 module Dispatch
   module Adapter
     module CopilotVersion
-      VERSION = "0.3.0"
+      VERSION = "0.5.0"
     end
   end
 end