$code:
    route = "/recipes"
    session = web.tx.user.session
    token = session.get("token")
    endpoint = str(session.get("endpoint") or "")
    if endpoint and "://" not in endpoint:
        endpoint = "https://" + endpoint

    fields = (
        ("name", "Name", 1),
        ("summary", "Summary", 3),
        ("ingredient", "Ingredients (one per line)", 12),
        ("yield", "Yield", 1),
        ("duration", "Duration", 1),
        ("instructions", "Instructions (HTML)", 16),
        ("content", "Additional content (HTML)", 8),
    )

    values = {key: "" for key, label, rows in fields}
    original = {}
    url = ""
    error = ""
    saved = False
    destination = ""
    method = web.tx.request.method

    def display_value(properties, key):
        items = properties.get(key, [])
        if key == "ingredient":
            return "\n".join(items)
        if not items:
            return ""
        value = items[0]
        if isinstance(value, dict):
            return value.get("html", value.get("value", ""))
        return str(value)

    if method == "GET":
        url = web.tx.request.uri.query.get("url", [""])[0].strip()
    elif method == "POST":
        form = web.form()
        #    "url",
        #    "name",
        #    "summary",
        #    "ingredient",
        #    "yield",
        #    "duration",
        #    "instructions",
        #    "content",
        #)
        if "url" in form:
            url = form["url"].strip()
            values = {key: form[key] for key, label, rows in fields}

    if not token or not endpoint:
        error = "Sign in with a Micropub account first."

    if not error:
        headers = {
            "Authorization": f"Bearer {token}",
            "Accept": "application/json",
        }

        if url and not url.startswith("https://"):
            error = "Enter the recipe's full HTTPS URL."

        if url and not error:
            source_response = web.get(
                endpoint,
                headers=headers,
                params={"q": "source", "url": url},
                allow_redirects=False,
            )
            if source_response.status != 200:
                error = f"Could not load recipe (HTTP {source_response.status})."
            else:
                source = source_response.json
                if not isinstance(source, dict):
                    error = "The source response must be a JSON object."
                elif "recipe" not in source.get("type", []):
                    error = "The source response does not identify this as an h-recipe."
                else:
                    original = source  # ["properties"]
                    if method == "GET":
                        values = {
                            key: display_value(original, key)
                            for key, label, rows in fields
                        }
                # XXX elif not isinstance(source.get("properties"), dict):
                # XXX    error = "The source response is missing its properties object."

        if method == "POST" and not error:
            if not values["name"].strip():
                error = "Enter a recipe name."
            else:
                properties = {}
                deleted = []

                for key, label, rows in fields:
                    value = values[key]

                    # Leave unchanged properties exactly as they were.
                    if url and value == display_value(original, key):
                        continue

                    if not value.strip():
                        if key in original:
                            deleted.append(key)
                        continue

                    if key == "ingredient":
                        properties[key] = [
                            line.strip()
                            for line in value.splitlines()
                            if line.strip()
                        ]
                    elif key in ("instructions", "content"):
                        properties[key] = [{"html": value}]
                    else:
                        properties[key] = [value.strip()]

                if url:
                    payload = {"action": "update", "url": url}
                    if properties:
                        payload["replace"] = properties
                    if deleted:
                        payload["delete"] = deleted
                else:
                    payload = {
                        "type": ["h-recipe"],
                        "properties": properties,
                    }

                if url and not properties and not deleted:
                    saved = True
                    destination = url
                else:
                    micropub_response = web.post(
                        endpoint,
                        headers=headers,
                        json=payload,
                        allow_redirects=False,
                    )
                    expected = (200, 201, 204) if url else (201, 202)
                    if micropub_response.status in expected:
                        saved = True
                        destination = micropub_response.headers.get(
                            "Location", url
                        )
                    else:
                        error = (
                            "Could not save recipe "
                            f"(HTTP {micropub_response.status})."
                        )

<h1>$("Edit recipe" if url else "New recipe")</h1>

$if saved:
    <p>Recipe saved.</p>
    $if destination:
        <p><a href="$destination">View recipe</a></p>
    <p><a href="$route">Create another recipe</a></p>
$else:
    $if error:
        <p role="alert"><strong>$error</strong></p>
    $if token and endpoint:
        <form method="get" action="$route">
            <p>
                <label>
                    Existing recipe URL:<br>
                    <input type="url" name="url" value="$url"
                           placeholder="https://ragt.ag/recipes/beef-burgandy"
                           style="width:100%;box-sizing:border-box">
                </label>
            </p>
            <button type="submit">Load for editing</button>
            <a href="$route">New recipe</a>
        </form>
        <hr>
        $if method == "POST" or not error:
            <form method="post" action="$route">
                <input type="hidden" name="url" value="$url">
                $if url:
                    <p>Editing <a href="$url">$url</a></p>
                $for key, label, rows in fields:
                    <p>
                        <label>
                            $label:<br>
                            $if rows == 1:
                                <input name="$key" value="$values[key]"
                                       style="width:100%;box-sizing:border-box"
                                       $("required" if key == "name" else "")>
                            $else:
                                <textarea name="$key" rows="$rows"
                                          style="width:100%;box-sizing:border-box">$values[key]</textarea>
                        </label>
                    </p>
                <button type="submit">
                    $("Save changes" if url else "Publish recipe")
                </button>
            </form>