core/plugin/wasmguest/context.go

package wasmguest

import (
	"context"
	"encoding/json"
	"net/http"
	"net/url"

	abiv1 "git.dev.alexdunmow.com/block/core/abi/v1"
	"git.dev.alexdunmow.com/block/core/blocks"
	"github.com/google/uuid"
)

// contextFromRenderContext rebuilds the context.Context that block and
// template code expects, applying each RenderContext field through the same
// context keys core/blocks/context.go defines. Existing render code reading
// via blocks.Get* works unchanged inside the guest.
//
// Function-valued context entries (SlotRenderer, MediaResolver,
// EmbedResolver, Queries) do not cross the wire; their v1 mappings are
// documented in core/docs/wasm-abi.md. RenderContext.theme_json and .locale
// have no core/blocks context key yet and are ignored here until a consumer
// key exists.
func contextFromRenderContext(ctx context.Context, rc *abiv1.RenderContext) context.Context {
	if rc == nil {
		return ctx
	}

	if req := requestFromInfo(rc.GetRequest()); req != nil {
		ctx = blocks.WithRequest(ctx, req)
	}
	if bc := blockContextFromProto(rc.GetBlockContext()); bc != nil {
		ctx = blocks.WithBlockContext(ctx, bc)
	}
	if rc.GetTemplateKey() != "" {
		ctx = blocks.WithTemplateKey(ctx, rc.GetTemplateKey())
	}
	if p := rc.GetPage(); p != nil {
		ctx = blocks.WithCurrentPage(ctx, &blocks.PageContext{
			ID:       parseUUID(p.GetId()),
			Slug:     p.GetSlug(),
			Title:    p.GetTitle(),
			PostType: p.GetPostType(),
			Status:   p.GetStatus(),
		})
	}
	if p := rc.GetPost(); p != nil {
		post := &blocks.PostContext{
			ID:               parseUUID(p.GetId()),
			Slug:             p.GetSlug(),
			Title:            p.GetTitle(),
			Excerpt:          p.GetExcerpt(),
			FeaturedImageURL: p.GetFeaturedImageUrl(),
			AuthorID:         parseUUID(p.GetAuthorId()),
			ReadingTime:      int(p.GetReadingTime()),
			IsFeatured:       p.GetIsFeatured(),
		}
		if ts := p.GetPublishedAt(); ts != nil {
			post.PublishedAt = ts.AsTime()
		}
		ctx = blocks.WithCurrentBlogPost(ctx, post)
	}
	if a := rc.GetAuthor(); a != nil {
		ctx = blocks.WithCurrentAuthor(ctx, &blocks.AuthorContext{
			ID:        parseUUID(a.GetId()),
			Name:      a.GetName(),
			Slug:      a.GetSlug(),
			Bio:       a.GetBio(),
			AvatarURL: a.GetAvatarUrl(),
		})
	}
	if c := rc.GetCategory(); c != nil {
		ctx = blocks.WithCurrentCategory(ctx, &blocks.CategoryContext{
			ID:   parseUUID(c.GetId()),
			Name: c.GetName(),
			Slug: c.GetSlug(),
		})
	}
	if mp := rc.GetMasterPage(); mp != nil {
		ctx = blocks.WithMasterPage(ctx, &blocks.MasterPageContext{
			ID:    parseUUID(mp.GetId()),
			Slug:  mp.GetSlug(),
			Title: mp.GetTitle(),
		})
	}
	if rc.GetRequestedPath() != "" {
		ctx = blocks.WithRequestedPath(ctx, rc.GetRequestedPath())
	}
	if slots := rc.GetInjectedSlots(); len(slots) > 0 {
		ctx = blocks.WithInjectedSlots(ctx, slots)
	}
	if rc.GetIsEditor() {
		ctx = blocks.WithIsEditor(ctx, true)
	}
	if slots := rc.GetExpectedSlots(); len(slots) > 0 {
		ctx = blocks.WithExpectedSlots(ctx, slots)
	}
	if id := parseUUID(rc.GetBlockId()); id != uuid.Nil {
		ctx = blocks.WithBlockID(ctx, id)
	}
	if id := parseUUID(rc.GetCurrentPageId()); id != uuid.Nil {
		ctx = blocks.WithCurrentPageID(ctx, id)
	}
	if hp := rc.GetHumanProofBanner(); hp != nil {
		ctx = blocks.WithHumanProofBanner(ctx, &blocks.HumanProofBannerData{
			ActiveTimeMinutes: int(hp.GetActiveTimeMinutes()),
			KeystrokeCount:    int(hp.GetKeystrokeCount()),
			SessionCount:      int(hp.GetSessionCount()),
			PostSlug:          hp.GetPostSlug(),
		})
	}
	if dr := rc.GetDetailRow(); dr != nil {
		ctx = blocks.WithDetailRow(ctx, dr.GetTableId(), dr.GetRowId(), unmarshalMap(dr.GetDataJson()))
	}
	return ctx
}

// requestFromInfo rebuilds a *http.Request carrying the subset of fields
// render code reads via blocks.GetRequest.
func requestFromInfo(ri *abiv1.RequestInfo) *http.Request {
	if ri == nil {
		return nil
	}
	u, err := url.Parse(ri.GetUrl())
	if err != nil || ri.GetUrl() == "" {
		u = &url.URL{Path: ri.GetPath(), RawQuery: ri.GetRawQuery()}
	}
	req := &http.Request{
		Method:     ri.GetMethod(),
		URL:        u,
		Proto:      "HTTP/1.1",
		ProtoMajor: 1,
		ProtoMinor: 1,
		Header:     make(http.Header, len(ri.GetHeaders())+2),
		Host:       ri.GetHost(),
		RemoteAddr: ri.GetRemoteIp(),
		RequestURI: u.RequestURI(),
	}
	for k, v := range ri.GetHeaders() {
		req.Header.Set(k, v)
	}
	if ri.GetReferrer() != "" && req.Header.Get("Referer") == "" {
		req.Header.Set("Referer", ri.GetReferrer())
	}
	if ri.GetUserAgent() != "" && req.Header.Get("User-Agent") == "" {
		req.Header.Set("User-Agent", ri.GetUserAgent())
	}
	for name, value := range ri.GetCookies() {
		req.AddCookie(&http.Cookie{Name: name, Value: value})
	}
	return req
}

func blockContextFromProto(pb *abiv1.BlockContext) *blocks.BlockContext {
	if pb == nil {
		return nil
	}
	bc := &blocks.BlockContext{
		URL:                 pb.GetUrl(),
		Path:                pb.GetPath(),
		Slug:                pb.GetSlug(),
		PageID:              pb.GetPageId(),
		PageTitle:           pb.GetPageTitle(),
		TemplateKey:         pb.GetTemplateKey(),
		IsEditor:            pb.GetIsEditor(),
		Timestamp:           pb.GetTimestamp(),
		IsLoggedIn:          pb.GetIsLoggedIn(),
		UserID:              pb.GetUserId(),
		UserEmail:           pb.GetUserEmail(),
		UserRole:            pb.GetUserRole(),
		Method:              pb.GetMethod(),
		Host:                pb.GetHost(),
		Query:               pb.GetQuery(),
		Referrer:            pb.GetReferrer(),
		UserAgent:           pb.GetUserAgent(),
		IP:                  pb.GetIp(),
		Cookies:             pb.GetCookies(),
		Headers:             pb.GetHeaders(),
		Country:             pb.GetCountry(),
		City:                pb.GetCity(),
		Timezone:            pb.GetTimezone(),
		CurrentAuthor:       unmarshalMap(pb.GetCurrentAuthorJson()),
		CurrentPost:         unmarshalMap(pb.GetCurrentPostJson()),
		CurrentCategory:     unmarshalMap(pb.GetCurrentCategoryJson()),
		Site:                unmarshalMap(pb.GetSiteJson()),
		IsPublicLoggedIn:    pb.GetIsPublicLoggedIn(),
		PublicUserID:        pb.GetPublicUserId(),
		PublicUsername:      pb.GetPublicUsername(),
		PublicDisplayName:   pb.GetPublicDisplayName(),
		PublicEmailVerified: pb.GetPublicEmailVerified(),
		DetailRowID:         pb.GetDetailRowId(),
		DetailTableID:       pb.GetDetailTableId(),
		DetailRowData:       unmarshalMap(pb.GetDetailRowDataJson()),
		BlogIndexURL:        pb.GetBlogIndexUrl(),
		CategoryPageURL:     pb.GetCategoryPageUrl(),
	}
	if ts := pb.GetNow(); ts != nil {
		bc.Now = ts.AsTime()
	}
	return bc
}

// unmarshalMap decodes a JSON object into map[string]any, returning nil for
// empty or undecodable input (render code treats absent maps as nil).
func unmarshalMap(raw []byte) map[string]any {
	if len(raw) == 0 {
		return nil
	}
	var m map[string]any
	if err := json.Unmarshal(raw, &m); err != nil {
		return nil
	}
	return m
}

func parseUUID(s string) uuid.UUID {
	if s == "" {
		return uuid.Nil
	}
	id, err := uuid.Parse(s)
	if err != nil {
		return uuid.Nil
	}
	return id
}