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/config.cr

@@ -74,6 +74,16 @@ end
 class Config
   include YAML::Serializable
 
+  class CompanionConfig
+    include YAML::Serializable
+
+    @[YAML::Field(converter: Preferences::URIConverter)]
+    property private_url : URI = URI.parse("")
+
+    @[YAML::Field(converter: Preferences::URIConverter)]
+    property public_url : URI = URI.parse("")
+  end
+
   # Number of threads to use for crawling videos from channels (for updating subscriptions)
   property channel_threads : Int32 = 1
   # Time interval between two executions of the job that crawls channel videos (subscriptions update).
@@ -160,6 +170,12 @@ class Config
   # poToken for passing bot attestation
   property po_token : String? = nil
 
+  # Invidious companion
+  property invidious_companion : Array(CompanionConfig) = [] of CompanionConfig
+
+  # Invidious companion API key
+  property invidious_companion_key : String = ""
+
   # Saved cookies in "name1=value1; name2=value2..." format
   @[YAML::Field(converter: Preferences::StringToCookies)]
   property cookies : HTTP::Cookies = HTTP::Cookies.new
@@ -240,6 +256,27 @@ class Config
         end
     {% end %}
 
+    if config.invidious_companion.present?
+      # invidious_companion and signature_server can't work together
+      if config.signature_server
+        puts "Config: You can not run inv_sig_helper and invidious_companion at the same time."
+        exit(1)
+      elsif config.invidious_companion_key.empty?
+        puts "Config: Please configure a key if you are using invidious companion."
+        exit(1)
+      elsif config.invidious_companion_key == "CHANGE_ME!!"
+        puts "Config: The value of 'invidious_companion_key' needs to be changed!!"
+        exit(1)
+      elsif config.invidious_companion_key.size < 16
+        puts "Config: The value of 'invidious_companion_key' needs to be a size of 16 or more."
+        exit(1)
+      end
+    elsif config.signature_server
+      puts("WARNING: inv-sig-helper is deprecated. Please switch to Invidious companion: https://docs.invidious.io/companion-installation/")
+    else
+      puts("WARNING: Invidious companion is required to view and playback videos. For more information see https://docs.invidious.io/companion-installation/")
+    end
+
     # HMAC_key is mandatory
     # See: https://github.com/iv-org/invidious/issues/3854
     if config.hmac_key.empty?