feat: Add the initial Anthropic SDK implementation

.editorconfig

@@ -13,3 +13,8 @@ trim_trailing_whitespace = true
 [*.{go,mod}]
 indent_size = 4
 tab_width = 4
+
+[*.md]
+indent_size = 4
+tab_width = 4
+trim_trailing_whitespace = false

.github/workflows/pr.yaml

@@ -0,0 +1,37 @@
+name: PR
+
+on:
+  pull_request:
+    branches:
+    - main
+    paths-ignore:
+    - .editorconfig
+    - .gitignore
+    - LICENSE.md
+    - README.md
+
+jobs:
+  verify:
+    name: Verify
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+    - name: Setup Go
+      uses: actions/setup-go@v5
+      with:
+        go-version-file: go.mod
+    - name: Check formatting
+      run: test -z "$(go fmt ./...)"
+
+  build:
+    name: Build
+    needs: [ verify ]
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+    - name: Setup Go
+      uses: actions/setup-go@v5
+      with:
+        go-version-file: go.mod

README.md

@@ -8,7 +8,24 @@
 
 ### Installation and usage
 
-TODO
+```go
+package main
+
+import (
+    "os"
+
+    "github.com/unfunco/anthropic-sdk-go"
+)
+
+func main() {
+    transport := &anthropic.Transport{APIKey: os.Getenv("ANTHROPIC_API_KEY")}
+    claude := anthropic.NewClient(transport.Client())
+
+    _, _, _, = claude.Messages.Create(&anthropic.CreateMessageOptions{
+        Model: anthropic.Claude3Sonnet20240229,
+    })
+}
+```
 
 ### Development and testing
 

anthropic.go

@@ -0,0 +1,34 @@
+// Package anthropic provides a client library for interacting with the
+// Anthropic safety-first language model REST APIs.
+package anthropic
+
+import (
+	"context"
+	"net/http"
+)
+
+// Client manages communication with the Anthropic REST API.
+type Client struct {
+	client *http.Client
+}
+
+// NewClient returns a new Anthropic REST API client.
+func NewClient(client *http.Client) *Client {
+	if client == nil {
+		client = &http.Client{}
+	}
+
+	return &Client{
+		client: client,
+	}
+}
+
+// NewRequest creates an API request.
+func (c *Client) NewRequest(url string) (*http.Request, error) {
+	return http.NewRequest(http.MethodGet, url, nil)
+}
+
+// Do sends an API request and returns the API response.
+func (c *Client) Do(ctx context.Context, req *http.Request) (*http.Response, error) {
+	return c.client.Do(req.WithContext(ctx))
+}

anthropic_test.go

@@ -0,0 +1,11 @@
+package anthropic
+
+import "testing"
+
+func TestNewClient(t *testing.T) {
+	c1 := NewClient(nil)
+	c2 := NewClient(nil)
+	if c1.client == c2.client {
+		t.Errorf("NewClient() = %v, want %v", c1.client, c2.client)
+	}
+}

message.go

@@ -0,0 +1,44 @@
+package anthropic
+
+import "net/http"
+
+type MessagesService struct{}
+
+// Message defines ...
+type Message struct {
+	Content string
+	Role    string
+}
+
+// CreateMessageOptions defines ...
+type CreateMessageOptions struct {
+	// MaxTokens defines the maximum number of tokens to generate before
+	// stopping. Token generation may stop before reaching this limit, this only
+	// specifies the absolute maximum number of tokens to generate. Different
+	// models have different maximum token limits.
+	MaxTokens int
+	// Messages ...
+	Messages []Message
+	// Model defines the language model that will be used to complete the
+	// prompt. See model.go for a list of available models.
+	Model LanguageModel
+	// StopSequences defines custom text sequences that will cause the model to
+	// stop generating.
+	StopSequences []string
+	// System provides a means of specifying context and instructions to the
+	// model, such as specifying a particular goal or role.
+	System string
+	// Temperature defines the amount of randomness injected into the response.
+	// Note that even with a temperature of 0.0, results will not be fully
+	// deterministic.
+	Temperature *float64
+	// TopK is used to remove long tail low probability responses.
+	TopK *int
+	// TopP defines the cumulative probability of the highest probability.
+	TopP *float64
+}
+
+// Create creates a new message using the provided options.
+func (c *MessagesService) Create(options *CreateMessageOptions) (*Message, *http.Response, error) {
+	return nil, nil, nil
+}

message_test.go

@@ -0,0 +1 @@
+package anthropic

model.go

@@ -0,0 +1,15 @@
+package anthropic
+
+// LanguageModel represents a language model that can be used to complete
+// a prompt.
+// https://docs.anthropic.com/claude/docs/models-overview
+type LanguageModel string
+
+const (
+	Claude3Opus20240229   LanguageModel = "claude-3-opus-20240229"
+	Claude3Sonnet20240229 LanguageModel = "claude-3-sonnet-20240229"
+	Claude3Haiku20240229  LanguageModel = "claude-3-haiku-20240307"
+	Claude21              LanguageModel = "claude-2.1"
+	Claude20              LanguageModel = "claude-2.0"
+	ClaudeInstant12       LanguageModel = "claude-instant-1.2"
+)

transport.go

@@ -0,0 +1,10 @@
+package anthropic
+
+// Transport provides ...
+type Transport struct {
+	APIKey string
+}
+
+func (t *Transport) Client() *Client {
+	return NewClient(nil)
+}

transport_test.go

@@ -0,0 +1 @@
+package anthropic