feat: fb and google oauth

internal/repository/oauth_account_repo.go

@@ -0,0 +1,69 @@
+package repository
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/prabhupadasays/spsays-bff/internal/model"
+)
+
+// ErrOAuthAccountNotFound mirrors the other repo sentinels.
+var ErrOAuthAccountNotFound = errors.New("oauth account not found")
+
+// OAuthAccountRepo manages provider linkage rows.
+type OAuthAccountRepo struct {
+	pg *Postgres
+}
+
+func NewOAuthAccountRepo(pg *Postgres) *OAuthAccountRepo {
+	return &OAuthAccountRepo{pg: pg}
+}
+
+// FindByProvider returns the linkage row for the given (provider, provider_user_id),
+// or ErrOAuthAccountNotFound. Use this first on every callback — a hit means
+// this provider identity has been seen before and we just log the user in.
+func (r *OAuthAccountRepo) FindByProvider(ctx context.Context, provider, providerUserID string) (*model.OAuthAccount, error) {
+	const q = `
+		SELECT id, user_id, provider, provider_user_id, email, name, avatar_url, created_at, updated_at
+		FROM oauth_accounts
+		WHERE provider = $1 AND provider_user_id = $2
+		LIMIT 1`
+	a := &model.OAuthAccount{}
+	err := r.pg.Pool.QueryRow(ctx, q, provider, providerUserID).Scan(
+		&a.ID, &a.UserID, &a.Provider, &a.ProviderUserID,
+		&a.Email, &a.Name, &a.AvatarURL, &a.CreatedAt, &a.UpdatedAt,
+	)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, ErrOAuthAccountNotFound
+		}
+		return nil, fmt.Errorf("find oauth account: %w", err)
+	}
+	return a, nil
+}
+
+// Link inserts a new oauth_accounts row tying a provider identity to an
+// existing user. Idempotent: a second call for the same (provider, sub)
+// returns the existing row instead of erroring on the unique constraint.
+func (r *OAuthAccountRepo) Link(ctx context.Context, userID, provider, providerUserID string, email, name, avatarURL *string) (*model.OAuthAccount, error) {
+	const q = `
+		INSERT INTO oauth_accounts (user_id, provider, provider_user_id, email, name, avatar_url)
+		VALUES ($1, $2, $3, $4, $5, $6)
+		ON CONFLICT (provider, provider_user_id) DO UPDATE
+		  SET email      = EXCLUDED.email,
+		      name       = EXCLUDED.name,
+		      avatar_url = EXCLUDED.avatar_url,
+		      updated_at = now()
+		RETURNING id, user_id, provider, provider_user_id, email, name, avatar_url, created_at, updated_at`
+	a := &model.OAuthAccount{}
+	err := r.pg.Pool.QueryRow(ctx, q, userID, provider, providerUserID, email, name, avatarURL).Scan(
+		&a.ID, &a.UserID, &a.Provider, &a.ProviderUserID,
+		&a.Email, &a.Name, &a.AvatarURL, &a.CreatedAt, &a.UpdatedAt,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("link oauth account: %w", err)
+	}
+	return a, nil
+}