1 files changed, 345 insertions, 0 deletions
diff --git a/internal/github/client.go b/internal/github/client.go
new file mode 100644
index 0000000..c864a8c
--- /dev/null
+++ b/internal/github/client.go
@@ -0,0 +1,345 @@
+package github
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	maxRetries = 3
+	retryDelay = 2 * time.Second
+)
+
+// Client implements the GitHub API client.
+type Client struct {
+	httpClient *http.Client
+	token      string
+	apiURL     string
+}
+
+// NewClient creates a new GitHub API client.
+func NewClient(token, apiURL string) *Client {
+	apiURL = strings.TrimRight(apiURL, "/")
+	if !strings.HasSuffix(apiURL, "/api/v3") {
+		apiURL = strings.TrimRight(apiURL, "/api")
+		apiURL = apiURL + "/api/v3"
+	}
+
+	return &Client{
+		httpClient: &http.Client{
+			Timeout: 10 * time.Second,
+		},
+		token:  token,
+		apiURL: apiURL,
+	}
+}
+
+// GetPullRequests fetches pull requests created within the specified date range.
+func (c *Client) GetPullRequests(
+	ctx context.Context,
+	owner, repo string,
+	since, until time.Time,
+) ([]PullRequest, error) {
+	url := fmt.Sprintf("%s/repos/%s/%s/pulls", c.apiURL, owner, repo)
+
+	params := []string{
+		"state=all",
+		"sort=created",
+		"direction=desc",
+		"per_page=100", // Maximum allowed by GitHub
+	}
+
+	log.Printf("Fetching PRs from: %s with params: %v", url, params)
+
+	req, err := http.NewRequestWithContext(ctx, "GET", url+"?"+strings.Join(params, "&"), nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating request: %w", err)
+	}
+
+	var allPRs []PullRequest
+	for {
+		prs, nextPage, err := c.doGetPullRequests(req)
+		if err != nil {
+			return nil, fmt.Errorf("fetching PRs: %w", err)
+		}
+		allPRs = append(allPRs, prs...)
+
+		// Check if we've reached PRs outside our date range
+		if len(prs) > 0 && prs[len(prs)-1].CreatedAt.Before(since) {
+			break
+		}
+
+		if nextPage == "" {
+			break
+		}
+
+		req.URL.RawQuery = nextPage
+	}
+
+	var filteredPRs []PullRequest
+	for _, pr := range allPRs {
+		if pr.CreatedAt.After(since) && pr.CreatedAt.Before(until) {
+			filteredPRs = append(filteredPRs, pr)
+		}
+	}
+
+	log.Printf("Found %d PRs in date range", len(filteredPRs))
+	return filteredPRs, nil
+}
+
+// GetPullRequestReviews fetches all reviews for a specific pull request.
+func (c *Client) GetPullRequestReviews(
+	ctx context.Context,
+	owner, repo string,
+	prNumber int,
+) ([]Review, error) {
+	url := fmt.Sprintf("%s/repos/%s/%s/pulls/%d/reviews", c.apiURL, owner, repo, prNumber)
+
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating request: %w", err)
+	}
+
+	var reviews []Review
+	err = c.doRequest(req, &reviews)
+	if err != nil {
+		return nil, err
+	}
+
+	return reviews, nil
+}
+
+// GetPullRequestReviewComments fetches all review comments for a specific pull request.
+func (c *Client) GetPullRequestReviewComments(
+	ctx context.Context,
+	owner, repo string,
+	prNumber int,
+) ([]ReviewComment, error) {
+	url := fmt.Sprintf("%s/repos/%s/%s/pulls/%d/reviews", c.apiURL, owner, repo, prNumber)
+
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating request: %w", err)
+	}
+
+	var reviews []Review
+	err = c.doRequest(req, &reviews)
+	if err != nil {
+		return nil, err
+	}
+
+	var allComments []ReviewComment
+	for _, review := range reviews {
+		comments, err := c.getReviewComments(ctx, owner, repo, prNumber, review.ID)
+		if err != nil {
+			return nil, err
+		}
+		allComments = append(allComments, comments...)
+	}
+
+	return allComments, nil
+}
+
+// GetRateLimit returns the current rate limit information.
+func (c *Client) GetRateLimit(ctx context.Context) (*RateLimit, error) {
+	url := fmt.Sprintf("%s/rate_limit", c.apiURL)
+
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating request: %w", err)
+	}
+
+	var response struct {
+		Resources struct {
+			Core struct {
+				Limit     int       `json:"limit"`
+				Remaining int       `json:"remaining"`
+				Reset     time.Time `json:"reset"`
+			} `json:"core"`
+		} `json:"resources"`
+	}
+
+	err = c.doRequest(req, &response)
+	if err != nil {
+		return nil, err
+	}
+
+	return &RateLimit{
+		Limit:     response.Resources.Core.Limit,
+		Remaining: response.Resources.Core.Remaining,
+		Reset:     response.Resources.Core.Reset,
+	}, nil
+}
+
+func (c *Client) doGetPullRequests(req *http.Request) ([]PullRequest, string, error) {
+	var prs []PullRequest
+	nextPage, err := c.doRequestWithPagination(req, &prs)
+	if err != nil {
+		return nil, "", err
+	}
+	return prs, nextPage, nil
+}
+
+func (c *Client) getReviewComments(
+	ctx context.Context,
+	owner, repo string,
+	prNumber int,
+	reviewID int64,
+) ([]ReviewComment, error) {
+	url := fmt.Sprintf(
+		"%s/repos/%s/%s/pulls/%d/reviews/%d/comments",
+		c.apiURL,
+		owner,
+		repo,
+		prNumber,
+		reviewID,
+	)
+
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating request: %w", err)
+	}
+
+	var comments []ReviewComment
+	err = c.doRequest(req, &comments)
+	if err != nil {
+		return nil, err
+	}
+
+	return comments, nil
+}
+
+func (c *Client) doRequest(req *http.Request, v any) error {
+	req.Header.Set("Authorization", "token "+c.token)
+	req.Header.Set("Accept", "application/vnd.github.v3+json")
+
+	var lastErr error
+	for i := range maxRetries {
+		resp, err := c.httpClient.Do(req)
+		if err != nil {
+			lastErr = err
+			log.Printf("Request failed (attempt %d/%d): %v", i+1, maxRetries, err)
+			time.Sleep(retryDelay * time.Duration(i+1))
+			continue
+		}
+		defer func() {
+			err := resp.Body.Close()
+			if err != nil {
+				log.Fatal(err)
+			}
+		}()
+
+		// Check rate limit
+		if resp.StatusCode == http.StatusForbidden {
+			resetTime := resp.Header.Get("X-RateLimit-Reset")
+			if resetTime != "" {
+				reset, err := strconv.ParseInt(resetTime, 10, 64)
+				if err == nil {
+					waitTime := time.Until(time.Unix(reset, 0))
+					if waitTime > 0 {
+						log.Printf("Rate limit exceeded. Waiting %v before retry", waitTime)
+						time.Sleep(waitTime)
+						continue
+					}
+				}
+			}
+		}
+
+		if resp.StatusCode != http.StatusOK {
+			body, _ := io.ReadAll(resp.Body)
+			var apiErr APIError
+			if err := json.Unmarshal(body, &apiErr); err == nil {
+				log.Printf("API Error Response: %+v", apiErr)
+				return fmt.Errorf("API error: %s (Status: %d)", apiErr.Message, resp.StatusCode)
+			}
+			log.Printf("Unexpected response body: %s", string(body))
+			return fmt.Errorf("unexpected status code: %d", resp.StatusCode)
+		}
+
+		if err := json.NewDecoder(resp.Body).Decode(v); err != nil {
+			return fmt.Errorf("decoding response: %w", err)
+		}
+
+		return nil
+	}
+
+	return fmt.Errorf("max retries exceeded: %w", lastErr)
+}
+
+func (c *Client) doRequestWithPagination(req *http.Request, v any) (string, error) {
+	req.Header.Set("Authorization", "token "+c.token)
+	req.Header.Set("Accept", "application/vnd.github.v3+json")
+
+	var lastErr error
+	for i := range maxRetries {
+		resp, err := c.httpClient.Do(req)
+		if err != nil {
+			lastErr = err
+			log.Printf("Request failed (attempt %d/%d): %v", i+1, maxRetries, err)
+			time.Sleep(retryDelay * time.Duration(i+1))
+			continue
+		}
+		defer func() {
+			err := resp.Body.Close()
+			if err != nil {
+				log.Fatal(err)
+			}
+		}()
+
+		if resp.StatusCode == http.StatusForbidden {
+			resetTime := resp.Header.Get("X-RateLimit-Reset")
+			if resetTime != "" {
+				reset, err := strconv.ParseInt(resetTime, 10, 64)
+				if err == nil {
+					waitTime := time.Until(time.Unix(reset, 0))
+					if waitTime > 0 {
+						log.Printf("Rate limit exceeded. Waiting %v before retry", waitTime)
+						time.Sleep(waitTime)
+						continue
+					}
+				}
+			}
+		}
+
+		if resp.StatusCode != http.StatusOK {
+			body, _ := io.ReadAll(resp.Body)
+			var apiErr APIError
+			if err := json.Unmarshal(body, &apiErr); err == nil {
+				log.Printf("API Error Response: %+v", apiErr)
+				return "", fmt.Errorf("API error: %s (Status: %d)", apiErr.Message, resp.StatusCode)
+			}
+			log.Printf("Unexpected response body: %s", string(body))
+			return "", fmt.Errorf("unexpected status code: %d", resp.StatusCode)
+		}
+
+		if err := json.NewDecoder(resp.Body).Decode(v); err != nil {
+			return "", fmt.Errorf("decoding response: %w", err)
+		}
+
+		nextPage := ""
+		if link := resp.Header.Get("Link"); link != "" {
+			parts := strings.SplitSeq(link, ",")
+			for part := range parts {
+				if strings.Contains(part, "rel=\"next\"") {
+					start := strings.Index(part, "<")
+					end := strings.Index(part, ">")
+					if start >= 0 && end > start {
+						nextPage = part[start+1 : end]
+						break
+					}
+				}
+			}
+		}
+
+		return nextPage, nil
+	}
+
+	return "", fmt.Errorf("max retries exceeded: %w", lastErr)
+}