4 files changed, 101 insertions, 0 deletions
diff --git a/src/twitch/client.cr b/src/twitch/client.cr
new file mode 100644
index 0000000..8502b90
--- /dev/null
+++ b/src/twitch/client.cr
@@ -0,0 +1,27 @@
+require "./rest"
+require "./mappings/*"
+
+module Twitcr::Client
+  include REST
+
+  getter token : String
+  getter client_id : String
+
+  def initialize(@token, @client_id)
+    @token = "Bearer" + @token
+  end
+
+  def user?(name : String)
+    true if get_user_by_login(name)
+  rescue EMPTY_RESULT
+    false
+  end
+
+  def user(name : String)
+    get_user_by_login(name)
+  end
+
+  def user(id : Int64)
+    get_user_by_id(id)
+  end
+end
diff --git a/src/twitch/mappings/converters.cr b/src/twitch/mappings/converters.cr
new file mode 100644
index 0000000..d9b57e9
--- /dev/null
+++ b/src/twitch/mappings/converters.cr
@@ -0,0 +1,3 @@
+module Twitcr
+  TIME_FORMAT = Time::Format.new("%FT%TZ")
+end
diff --git a/src/twitch/mappings/user.cr b/src/twitch/mappings/user.cr
new file mode 100644
index 0000000..6ddd08b
--- /dev/null
+++ b/src/twitch/mappings/user.cr
@@ -0,0 +1,21 @@
+require "./converters"
+
+module Twitcr
+  struct UserList
+    JSON.mapping({data: Array(User)})
+  end
+
+  struct User
+    JSON.mapping({
+      id:           {type: UInt64, converter: ID::Converter},
+      login:        String,
+      display_name: String,
+    })
+  end
+end
+
+module ID::Converter
+  def self.from_json(value : JSON::PullParser) : UInt64
+    UInt64.new(value.read_string)
+  end
+end
diff --git a/src/twitch/rest.cr b/src/twitch/rest.cr
new file mode 100644
index 0000000..1de8d6f
--- /dev/null
+++ b/src/twitch/rest.cr
@@ -0,0 +1,50 @@
+require "http"
+require "json"
+require "./mappings/*"
+
+module Twitcr::REST
+  # Mixin for interacting with Twitch's REST API
+  SSL_CONTEXT = OpenSSL::SSL::Context::Client.new
+  API_BASE    = "https://api.twitch.tv/helix"
+
+  EMPTY_RESULT = Exception.new("Empty Result")
+
+  # Executes an HTTP request against the API_BASE url
+  def request(method : String, route : String, version = "5", headers = HTTP::Headers.new, body : String? = nil)
+    headers["Authorization"] = @token
+    headers["Client-ID"] = @client_id
+
+    response = HTTP::Client.exec(
+      method,
+      API_BASE + route,
+      headers,
+      tls: SSL_CONTEXT
+    )
+
+    response.body
+  end
+
+  def get_user_by_login(login : String)
+    response = request(
+      "GET",
+      "/users?login=" + login
+    )
+
+    list = UserList.from_json(response)
+    raise EMPTY_RESULT if list.data.empty?
+
+    list.data.first
+  end
+
+  def get_user_by_id(id : Int64)
+    response = request(
+      "GET",
+      "/users?id=" + id.to_s
+    )
+
+    list = UserList.from_json(response)
+    raise EMPTY_RESULT if list.data.empty?
+
+    list.data.first
+  end
+end