Add invidious companion support (#4985)

* add support for invidious companion

* redirect latest_version and dash manifest to invidious companion

* fix Shadowing outer local variable `response`

* fixing condition for Content-Security-Policy

* throw error if inv_sig_helper and invidious_companion used same time

* Use sample instead of Random.rand

Co-authored-by: syeopite <70992037+syeopite@users.noreply.github.com>

* Remove debug puts functions

Co-authored-by: syeopite <70992037+syeopite@users.noreply.github.com>

* modify the description for config.example.yaml about invidious companion

* move config checks for invidious companion

* separate invidious_companion logic + better config.yaml config

* fixing "end" misplacement

* fix linting + use .empty?

* crystal handle decompression already by itself

* fix download function when invidious companion used

* fix linting

* invidious companion always used so always add CSP and redirect latest_version

* apply all the suggestions + rework invidious_companion parameter

* format watch.cr

* fix ameba Redundant use of `Object#to_s` in interpolation

* add ability for invidious companion to check request from invidious

* Better document private_url and public_url

* Better doc for invidious_companion_key

* !empty? to present?

* skip proxy for invidious companion

* fixing format

* missing ,

* add companion pooling http

* fix: don't use http proxy when sending requests to companion

* fix: logic where we want to have the invidious logic if companion is not used

* chore: remove baseurl usage from invidious companion

* chore: change from inv-sig-helper to companion for required playback

* fix: use puts + add warning for inv-sig-helper deprecated

---------

Co-authored-by: syeopite <70992037+syeopite@users.noreply.github.com>

src/invidious/yt_backend/youtube_api.cr

@@ -500,7 +500,11 @@ module YoutubeAPI
       data["params"] = params
     end
 
-    return self._post_json("/youtubei/v1/player", data, client_config)
+    if CONFIG.invidious_companion.present?
+      return self._post_invidious_companion("/youtubei/v1/player", data)
+    else
+      return self._post_json("/youtubei/v1/player", data, client_config)
+    end
   end
 
   ####################################################################
@@ -666,6 +670,49 @@ module YoutubeAPI
     return initial_data
   end
 
+  ####################################################################
+  # _post_invidious_companion(endpoint, data)
+  #
+  # Internal function that does the actual request to Invidious companion
+  # and handles errors.
+  #
+  # The requested data is an endpoint (URL without the domain part)
+  # and the data as a Hash object.
+  #
+  def _post_invidious_companion(
+    endpoint : String,
+    data : Hash,
+  ) : Hash(String, JSON::Any)
+    headers = HTTP::Headers{
+      "Content-Type"  => "application/json; charset=UTF-8",
+      "Authorization" => "Bearer #{CONFIG.invidious_companion_key}",
+    }
+
+    # Logging
+    LOGGER.debug("Invidious companion: Using endpoint: \"#{endpoint}\"")
+    LOGGER.trace("Invidious companion: POST data: #{data}")
+
+    # Send the POST request
+
+    begin
+      response = COMPANION_POOL.client &.post(endpoint, headers: headers, body: data.to_json)
+      body = response.body
+      if (response.status_code != 200)
+        raise Exception.new(
+          "Error while communicating with Invidious companion: \
+          status code: #{response.status_code} and body: #{body.dump}"
+        )
+      end
+    rescue ex
+      raise InfoException.new("Error while communicating with Invidious companion: " + (ex.message || "no extra info found"))
+    end
+
+    # Convert result to Hash
+    initial_data = JSON.parse(body).as_h
+
+    return initial_data
+  end
+
   ####################################################################
   # _decompress(body_io, headers)
   #