feat(pierre): sanity check

internal/gitadapters/bitbucket/resource.go

@@ -1,6 +1,10 @@
 package bitbucket
 
 import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
 	"strings"
 
 	"git.schreifuchs.ch/schreifuchs/pierre-bot/internal/gitadapters/baseadapter"
@@ -18,3 +22,43 @@ func NewBitbucket(baseURL string, bearerToken string) *BitbucketAdapter {
 		Rest: baseadapter.NewRest(baseURL, bearerToken),
 	}
 }
+
+// GetFileContent returns the raw file content at the given ref (commit SHA) or HEAD if ref is empty.
+func (b *BitbucketAdapter) GetFileContent(ctx context.Context, projectKey, repositorySlug, path, ref string) (string, error) {
+	// Use the Rest helper to build the base URL, then add the "at" query param if needed.
+	r, err := b.CreateRequest(ctx, http.MethodGet, nil,
+		"/projects/", projectKey, "repos", repositorySlug, "raw", path)
+	if err != nil {
+		return "", err
+	}
+	if ref != "" {
+		q := r.URL.Query()
+		q.Set("at", ref)
+		r.URL.RawQuery = q.Encode()
+	}
+
+	resp, err := http.DefaultClient.Do(r)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		sb := &strings.Builder{}
+		io.Copy(sb, resp.Body)
+		return "", fmt.Errorf("error fetching file %s status %d, body %s", path, resp.StatusCode, sb.String())
+	}
+	content, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+	return string(content), nil
+}
+
+// GetPRHeadSHA fetches the PR and returns the SHA of the source (to) branch.
+func (b *BitbucketAdapter) GetPRHeadSHA(ctx context.Context, projectKey, repositorySlug string, pullRequestID int) (string, error) {
+	pr, err := b.GetPR(ctx, projectKey, repositorySlug, pullRequestID)
+	if err != nil {
+		return "", err
+	}
+	return pr.ToRef.LatestCommit, nil
+}