kanbante/app/digest.py

"""Weekly digest (roadmap #13): the week in Kanbante, as a note.

Composes a markdown digest from the event journal (last 7 days) and
the current focus snapshot, then — ONLY after a human approves on
/digest (standing rule: cross-app writes need approval) — delivers
it to ObsiGate through its MCP server (Kanbante as MCP *client*:
initialize → tools/call) or to a generic JSON webhook.

The ObsiGate tool contract is configurable (URL, tool name, JSON
argument template with {title}/{content} placeholders) because the
exact tool names of the target server are an operator decision, not
something to hardcode blindly.
"""

import json
import logging

import httpx

logger = logging.getLogger("kanbante.digest")

MCP_PROTOCOL_VERSION = "2024-11-05"


def format_digest_markdown(
    week_label: str,
    closed_items: list[dict],
    created_count: int,
    moved_count: int,
    focus_groups: list[dict],
) -> str:
    """Render the weekly digest as markdown (Obsidian-friendly)."""
    lines = [f"# 🧠 Kanbante — semaine du {week_label}", ""]
    lines.append(f"## ✅ Livré ({len(closed_items)})")
    if closed_items:
        for item in closed_items:
            title = item.get("title") or ""
            lines.append(
                f"- [{item['repo']}#{item['number']}]({item.get('html_url', '')})"
                f" {title}".rstrip()
            )
    else:
        lines.append("- Rien n'a été fermé cette semaine.")
    lines.append("")
    lines.append("## 🚧 En cours")
    total_focus = sum(len(g["cards"]) for g in focus_groups)
    if total_focus:
        for group in focus_groups:
            lines.append(f"### {group['full_name']}")
            for card in group["cards"]:
                issue = card["issue"]
                lines.append(
                    f"- #{issue['number']} {issue.get('title', '')}"
                    f" — *{card['column']}*"
                )
    else:
        lines.append("- Aucune carte en cours, en QA ou en révision.")
    lines.append("")
    lines.append("## 📈 Activité de la semaine")
    lines.append(f"- Issues créées : {created_count}")
    lines.append(f"- Déplacements de cartes : {moved_count}")
    lines.append(f"- Issues fermées : {len(closed_items)}")
    lines.append("")
    lines.append("*Digest composé par Kanbante à partir de son journal d'événements.*")
    return "\n".join(lines)


def render_mcp_args(template: str, title: str, content: str) -> dict:
    """Substitute {title}/{content} in a JSON template, safely."""
    def esc(value: str) -> str:
        return json.dumps(value, ensure_ascii=False)[1:-1]

    rendered = template.replace("{title}", esc(title)).replace(
        "{content}", esc(content)
    )
    try:
        args = json.loads(rendered)
    except ValueError as exc:
        raise ValueError(f"KANBANTE_OBSIGATE_MCP_ARGS is not valid JSON: {exc}")
    if not isinstance(args, dict):
        raise ValueError("KANBANTE_OBSIGATE_MCP_ARGS must be a JSON object")
    return args


async def send_webhook(url: str, title: str, markdown: str, week: str) -> tuple[bool, str]:
    """POST the digest as JSON to a generic webhook."""
    try:
        async with httpx.AsyncClient(timeout=20) as client:
            response = await client.post(
                url, json={"title": title, "markdown": markdown, "week": week}
            )
        if response.status_code < 300:
            return True, f"webhook HTTP {response.status_code}"
        return False, f"webhook HTTP {response.status_code}: {response.text[:200]}"
    except Exception as exc:
        return False, f"webhook error: {exc}"


def _mcp_headers(token: str) -> dict:
    headers = {
        "Accept": "application/json, text/event-stream",
        "Content-Type": "application/json",
    }
    if token:
        headers["Authorization"] = f"Bearer {token}"
    return headers


def _parse_mcp_body(response: httpx.Response) -> dict:
    """MCP streamable HTTP answers JSON or an SSE frame — accept both."""
    text = response.text.strip()
    if not text:
        return {}
    if text.startswith("{"):
        return json.loads(text)
    payload: dict = {}
    for line in text.splitlines():
        if line.startswith("data:"):
            chunk = line[5:].strip()
            if chunk.startswith("{"):
                payload = json.loads(chunk)
    return payload


async def _mcp_rpc(client: httpx.AsyncClient, url: str, token: str,
                   method: str, params: dict, req_id: int) -> dict:
    response = await client.post(
        url,
        json={"jsonrpc": "2.0", "id": req_id, "method": method, "params": params},
        headers=_mcp_headers(token),
    )
    response.raise_for_status()
    payload = _parse_mcp_body(response)
    if "error" in payload:
        err = payload["error"] or {}
        raise RuntimeError(f"MCP error {err.get('code')}: {err.get('message')}")
    return payload.get("result") or {}


async def _mcp_session(client: httpx.AsyncClient, url: str, token: str) -> None:
    await _mcp_rpc(
        client, url, token, "initialize",
        {
            "protocolVersion": MCP_PROTOCOL_VERSION,
            "capabilities": {},
            "clientInfo": {"name": "kanbante", "version": "0.16.0"},
        },
        req_id=1,
    )
    await client.post(
        url,
        json={"jsonrpc": "2.0", "method": "notifications/initialized"},
        headers=_mcp_headers(token),
    )


async def mcp_list_tools(url: str, token: str) -> tuple[bool, list[str] | str]:
    """(True, [tool names]) or (False, error message)."""
    try:
        async with httpx.AsyncClient(timeout=20) as client:
            await _mcp_session(client, url, token)
            result = await _mcp_rpc(client, url, token, "tools/list", {}, req_id=2)
        return True, [t.get("name", "?") for t in result.get("tools", [])]
    except Exception as exc:
        return False, f"MCP tools/list failed: {exc}"


async def mcp_call_tool(
    url: str, token: str, tool: str, arguments: dict
) -> tuple[bool, str]:
    """Call one tool; (True, short result) or (False, error message)."""
    try:
        async with httpx.AsyncClient(timeout=30) as client:
            await _mcp_session(client, url, token)
            result = await _mcp_rpc(
                client, url, token, "tools/call",
                {"name": tool, "arguments": arguments}, req_id=3,
            )
        if result.get("isError"):
            return False, f"tool {tool} reported an error: {str(result)[:300]}"
        texts = [
            block.get("text", "")
            for block in result.get("content", [])
            if isinstance(block, dict) and block.get("type") == "text"
        ]
        return True, (" ".join(texts)[:300] or f"tool {tool} OK")
    except Exception as exc:
        return False, f"MCP tools/call failed: {exc}"