"""Public discovery metadata, derived from the registry and live SDK tools.

The experimental MCP card and Cloudflare's earlier tool-bearing card are
different formats. Keep each at its own URL; neither exposes research data.
"""
from __future__ import annotations

import hashlib
import json
from pathlib import Path

from starlette.requests import Request
from starlette.responses import Response

REGISTRY = json.loads(Path(__file__).with_name("server.json").read_text())
CARD_PATH = "/mcp/server-card"
COMPAT_CARD_PATH = "/.well-known/mcp/server-card.json"
CATALOG_PATH = "/.well-known/ai-catalog.json"
DESCRIPTION = "Read-only U.S. household distress research: public indicators, ADI and county scorecards."


def server_card() -> dict:
    return {
        "$schema": "https://static.modelcontextprotocol.io/schemas/v1/server-card.schema.json",
        **{key: REGISTRY[key] for key in (
            "name", "title", "version", "websiteUrl", "repository", "remotes"
        )},
        "description": DESCRIPTION,
    }


def catalog() -> dict:
    return {"specVersion": "1.0", "host": {"displayName": REGISTRY["title"]}, "entries": [{
        "identifier": "urn:air:americandefault.org:mcp:research",
        "displayName": REGISTRY["title"],
        "type": "application/mcp-server-card+json",
        "url": REGISTRY["remotes"][0]["url"] + "/server-card",
        "representativeQueries": [
            "What is the latest U.S. personal saving rate and what month does it cover?",
            "How has the American Distress Index changed since 2020?",
            "What is the latest County Distress Index score for King County, Washington?",
        ],
    }, {
        "identifier": "urn:air:americandefault.org:skill:cite-american-default",
        "displayName": "Cite American Default Research",
        "type": "application/agent-skills+md",
        "url": "https://americandefault.org/.well-known/agent-skills/cite-american-default/SKILL.md",
        "representativeQueries": [
            "Find the original publisher, observation date and source link for a household savings statistic.",
            "How do I cite an American Distress Index release in an article?",
            "Find a public household distress chart and check its reuse terms.",
        ],
    }]}


async def compatibility_card() -> dict:
    # Import lazily: the server imports REGISTRY for its initialize identity.
    from scripts.machine_layer.mcp_server import mcp
    from mcp.types import LATEST_PROTOCOL_VERSION

    tools = await mcp.list_tools()
    return {
        "$schema": "https://static.modelcontextprotocol.io/schemas/mcp-server-card/v1.json",
        "version": "1.0",
        "protocolVersion": LATEST_PROTOCOL_VERSION,
        "serverInfo": {key: REGISTRY[key] for key in ("name", "title", "version")},
        "description": DESCRIPTION,
        "transport": {"type": "streamable-http", "endpoint": REGISTRY["remotes"][0]["url"]},
        "authentication": {"required": False},
        "capabilities": mcp._lowlevel_server.get_capabilities().model_dump(
            mode="json", by_alias=True, exclude_none=True
        ),
        "tools": [tool.model_dump(mode="json", by_alias=True, exclude_none=True) for tool in tools],
    }


async def discovery_response(request: Request) -> Response:
    headers = {
        "Access-Control-Allow-Origin": "*",
        "Access-Control-Allow-Methods": "GET, HEAD, OPTIONS",
        "Access-Control-Allow-Headers": "Content-Type, If-None-Match",
        "Access-Control-Expose-Headers": "ETag",
        "Cache-Control": "public, max-age=3600",
    }
    if request.method == "OPTIONS":
        return Response(status_code=204, headers=headers)
    path = request.url.path
    if path == CARD_PATH:
        payload, media_type = server_card(), "application/mcp-server-card+json"
    elif path == CATALOG_PATH:
        payload, media_type = catalog(), "application/ai-catalog+json"
    else:
        payload, media_type = await compatibility_card(), "application/json"
    body = json.dumps(payload, sort_keys=True, separators=(",", ":")).encode()
    etag = '"' + hashlib.sha256(body).hexdigest() + '"'
    headers["ETag"] = etag
    validators = [value.strip().removeprefix("W/") for value in request.headers.get("if-none-match", "").split(",")]
    if etag in validators or "*" in validators:
        return Response(status_code=304, headers=headers)
    headers["Content-Length"] = str(len(body))
    return Response(b"" if request.method == "HEAD" else body, media_type=media_type, headers=headers)