1 files changed, 184 insertions, 0 deletions
diff --git a/backend/fetchers/app.bsky.actor.go b/backend/fetchers/app.bsky.actor.go
new file mode 100644
index 0000000..3c0154a
--- /dev/null
+++ b/backend/fetchers/app.bsky.actor.go
@@ -0,0 +1,184 @@
+package fetchers
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"llostre/backend/general"
+	"net"
+	"net/http"
+	"strings"
+)
+
+type DIDDocument struct {
+	AlsoKnownAs []string `json:"alsoKnownAs"`
+	Service     []struct {
+		ID              string `json:"id"`
+		Type            string `json:"type"`
+		ServiceEndpoint string `json:"serviceEndpoint"`
+	} `json:"service"`
+}
+
+func FetchDID(handle string) (string, error) {
+	// return if it's a DID already
+	if strings.HasPrefix(handle, "did:") {
+		return handle, nil
+	}
+
+	// resolve DNS record first
+	txtRecords, err := net.LookupTXT("_atproto." + handle)
+	if err == nil {
+		for _, txt := range txtRecords {
+			if after, ok := strings.CutPrefix(txt, "did="); ok {
+				return after, nil
+			}
+		}
+	}
+
+	// fallback to HTTPS well-known
+	resp, err := http.Get(fmt.Sprintf("https://%s/.well-known/atproto-did", handle))
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	did := strings.TrimSpace(string(body))
+	if !strings.HasPrefix(did, "did:") {
+		return "", fmt.Errorf("invalid DID returned: %s", did)
+	}
+
+	return did, nil
+}
+
+func FetchDidDoc(did string) (*DIDDocument, error) {
+	didDocURL := fmt.Sprintf("https://plc.directory/%s", did)
+
+	resp, err := http.Get(didDocURL)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("DID resolution failed: %d", resp.StatusCode)
+	}
+
+	var didDoc DIDDocument
+	if err := json.NewDecoder(resp.Body).Decode(&didDoc); err != nil {
+		return nil, err
+	}
+
+	return &didDoc, nil
+}
+
+func FetchHandle(did string) (string, error) {
+	var didDoc, err = FetchDidDoc(did)
+	if err != nil {
+		return "", err
+	}
+
+	if len(didDoc.AlsoKnownAs) == 0 {
+		return "", fmt.Errorf("no handle found")
+	}
+
+	handle := strings.TrimPrefix(didDoc.AlsoKnownAs[0], "at://")
+	return handle, nil
+}
+
+func FetchPDS(did string) (string, error) {
+	var didDoc, err = FetchDidDoc(did)
+	if err != nil {
+		return "", err
+	}
+
+	for _, svc := range didDoc.Service {
+		if svc.Type == "AtprotoPersonalDataServer" {
+			return svc.ServiceEndpoint, nil
+		}
+	}
+
+	return "", fmt.Errorf("no PDS found for DID %s", did)
+}
+
+func FetchHandleAndPDS(did string) (string, string, error) {
+	var didDoc, err = FetchDidDoc(did)
+	if err != nil {
+		return "", "", err
+	}
+
+	if len(didDoc.AlsoKnownAs) == 0 {
+		return "", "", fmt.Errorf("no handle found")
+	}
+
+	var pds string
+	for _, svc := range didDoc.Service {
+		if svc.Type == "AtprotoPersonalDataServer" {
+			pds = svc.ServiceEndpoint
+			break
+		}
+	}
+
+	handle := strings.TrimPrefix(didDoc.AlsoKnownAs[0], "at://")
+
+	return handle, pds, nil
+}
+
+func FetchProfile(did, pdsURL string, cache *Cache) (*general.Profile, error) {
+	recordURL := fmt.Sprintf("%s/xrpc/com.atproto.repo.getRecord?repo=%s&collection=app.bsky.actor.profile&rkey=self", pdsURL, did)
+
+	resp, err := http.Get(recordURL)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("profile fetch failed: %d", resp.StatusCode)
+	}
+
+	handle, err := FetchHandle(did)
+	if err != nil {
+		handle = "handle.invalid"
+	}
+
+	var response general.ProfileRecordResponse
+	if err := json.NewDecoder(resp.Body).Decode(&response); err != nil {
+		return nil, err
+	}
+
+	var avatarURL, bannerURL string
+	if response.Value.Avatar != nil {
+		avatarURL = fmt.Sprintf("https://cdn.bsky.app/img/avatar/plain/%s/%s@jpeg", did, response.Value.Avatar.Ref.Link)
+	}
+	if response.Value.Banner != nil {
+		bannerURL = fmt.Sprintf("https://cdn.bsky.app/img/banner/plain/%s/%s@jpeg", did, response.Value.Banner.Ref.Link)
+	}
+
+	profile := &general.Profile{
+		Handle:      handle,
+		DisplayName: response.Value.DisplayName,
+		AvatarURL:   avatarURL,
+		BannerURL:   bannerURL,
+		Pronouns:    response.Value.Pronouns,
+	}
+
+	cache.SetProfile(handle, profile)
+	return profile, nil
+}
+
+func FetchProfiles(dids []string, pdsURL string, cache *Cache) map[string]general.Profile {
+	profiles := make(map[string]general.Profile)
+	for _, did := range dids {
+		profile, err := FetchProfile(did, pdsURL, cache)
+		if err == nil {
+			cache.SetProfile(did, profile)
+			profiles[did] = *profile
+		}
+	}
+	return profiles
+}