"""Blog app fragment endpoints.

Exposes HTML fragments at ``/internal/fragments/<type>`` for consumption
by other coop apps via the fragment client.
"""

from __future__ import annotations

from quart import Blueprint, Response, g, render_template, request

from shared.infrastructure.fragments import FRAGMENT_HEADER
from shared.services.navigation import get_navigation_tree


def register():
    bp = Blueprint("fragments", __name__, url_prefix="/internal/fragments")

    # Registry of fragment handlers: type -> async callable returning HTML str
    _handlers: dict[str, object] = {}

    @bp.before_request
    async def _require_fragment_header():
        if not request.headers.get(FRAGMENT_HEADER):
            return Response("", status=403)

    @bp.get("/<fragment_type>")
    async def get_fragment(fragment_type: str):
        handler = _handlers.get(fragment_type)
        if handler is None:
            return Response("", status=200, content_type="text/html")
        html = await handler()
        return Response(html, status=200, content_type="text/html")

    # --- nav-tree fragment ---
    async def _nav_tree_handler():
        app_name = request.args.get("app_name", "")
        path = request.args.get("path", "/")
        first_seg = path.strip("/").split("/")[0]
        menu_items = list(await get_navigation_tree(g.s))

        # Append Art-DAG as a synthetic nav entry (not a DB MenuNode)
        class _NavItem:
            __slots__ = ("slug", "label", "feature_image")
            def __init__(self, slug, label, feature_image=None):
                self.slug = slug
                self.label = label
                self.feature_image = feature_image

        menu_items.append(_NavItem("artdag", "art-dag"))

        return await render_template(
            "fragments/nav_tree.html",
            menu_items=menu_items,
            frag_app_name=app_name,
            frag_first_seg=first_seg,
        )

    _handlers["nav-tree"] = _nav_tree_handler

    # --- link-card fragment ---
    async def _link_card_handler():
        from shared.services.registry import services
        from shared.infrastructure.urls import blog_url

        slug = request.args.get("slug", "")
        keys_raw = request.args.get("keys", "")

        # Batch mode
        if keys_raw:
            slugs = [k.strip() for k in keys_raw.split(",") if k.strip()]
            parts = []
            for s in slugs:
                parts.append(f"<!-- fragment:{s} -->")
                post = await services.blog.get_post_by_slug(g.s, s)
                if post:
                    parts.append(await render_template(
                        "fragments/link_card.html",
                        title=post.title,
                        feature_image=post.feature_image,
                        excerpt=post.custom_excerpt or post.excerpt,
                        published_at=post.published_at,
                        link=blog_url(f"/{post.slug}"),
                    ))
            return "\n".join(parts)

        # Single mode
        if not slug:
            return ""
        post = await services.blog.get_post_by_slug(g.s, slug)
        if not post:
            return ""
        return await render_template(
            "fragments/link_card.html",
            title=post.title,
            feature_image=post.feature_image,
            excerpt=post.custom_excerpt or post.excerpt,
            published_at=post.published_at,
            link=blog_url(f"/{post.slug}"),
        )

    _handlers["link-card"] = _link_card_handler

    # Store handlers dict on blueprint so app code can register handlers
    bp._fragment_handlers = _handlers

    return bp