"""Rulebook / topic REST endpoints.

Wraps services/rulebooks.py. Standard Scribe auth: get_current_user_id() is the
authenticated owner; the service enforces ownership scoping.
"""
from __future__ import annotations

from quart import Blueprint, jsonify, request

from scribe.auth import get_current_user_id, login_required
import scribe.services.rulebooks as rulebooks_svc
from scribe.services.trash import delete as trash_delete
from scribe.services.rule_usage import (
    empty_rule_usage, record_rule_pulled, usage_for_rules,
)

rulebooks_bp = Blueprint("rulebooks", __name__, url_prefix="/api")



# ── Rulebooks ───────────────────────────────────────────────────────────

@rulebooks_bp.get("/rulebooks")
@login_required
async def list_rulebooks():
    rows = await rulebooks_svc.list_rulebooks(get_current_user_id())
    return jsonify({"rulebooks": [rb.to_dict() for rb in rows]})


@rulebooks_bp.post("/rulebooks")
@login_required
async def create_rulebook():
    data = await request.get_json() or {}
    title = (data.get("title") or "").strip()
    if not title:
        return jsonify({"error": "title is required"}), 400
    rb = await rulebooks_svc.create_rulebook(
        user_id=get_current_user_id(),
        title=title,
        description=data.get("description", ""),
    )
    return jsonify(rb.to_dict()), 201


@rulebooks_bp.get("/rulebooks/<int:rulebook_id>")
@login_required
async def get_rulebook(rulebook_id: int):
    rb = await rulebooks_svc.get_rulebook(rulebook_id, get_current_user_id())
    if rb is None:
        return jsonify({"error": "rulebook not found"}), 404
    return jsonify(rb.to_dict())


@rulebooks_bp.patch("/rulebooks/<int:rulebook_id>")
@login_required
async def update_rulebook(rulebook_id: int):
    data = await request.get_json() or {}
    fields = {k: v for k, v in data.items() if k in ("title", "description", "always_on")}
    rb = await rulebooks_svc.update_rulebook(rulebook_id, get_current_user_id(), **fields)
    if rb is None:
        return jsonify({"error": "rulebook not found"}), 404
    return jsonify(rb.to_dict())


@rulebooks_bp.delete("/rulebooks/<int:rulebook_id>")
@login_required
async def delete_rulebook(rulebook_id: int):
    await trash_delete(get_current_user_id(), "rulebook", rulebook_id)
    return "", 204


# ── Topics ──────────────────────────────────────────────────────────────

@rulebooks_bp.get("/rulebooks/<int:rulebook_id>/topics")
@login_required
async def list_topics(rulebook_id: int):
    try:
        rows = await rulebooks_svc.list_topics(rulebook_id, get_current_user_id())
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return jsonify({"topics": [t.to_dict() for t in rows]})


@rulebooks_bp.post("/rulebooks/<int:rulebook_id>/topics")
@login_required
async def create_topic(rulebook_id: int):
    data = await request.get_json() or {}
    title = (data.get("title") or "").strip()
    if not title:
        return jsonify({"error": "title is required"}), 400
    try:
        topic = await rulebooks_svc.create_topic(
            rulebook_id=rulebook_id,
            user_id=get_current_user_id(),
            title=title,
            description=data.get("description", ""),
            order_index=data.get("order_index", 0),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return jsonify(topic.to_dict()), 201


@rulebooks_bp.patch("/rulebook-topics/<int:topic_id>")
@login_required
async def update_topic(topic_id: int):
    data = await request.get_json() or {}
    fields = {
        k: v for k, v in data.items()
        if k in ("title", "description", "order_index")
    }
    topic = await rulebooks_svc.update_topic(topic_id, get_current_user_id(), **fields)
    if topic is None:
        return jsonify({"error": "topic not found"}), 404
    return jsonify(topic.to_dict())


@rulebooks_bp.delete("/rulebook-topics/<int:topic_id>")
@login_required
async def delete_topic(topic_id: int):
    if await trash_delete(get_current_user_id(), "topic", topic_id) is None:
        return jsonify({"error": "topic not found"}), 404
    return "", 204


# ── Rules ───────────────────────────────────────────────────────────────

@rulebooks_bp.get("/rules")
@login_required
async def list_rules():
    def _opt_int(name):
        raw = request.args.get(name)
        return int(raw) if raw else None

    try:
        rulebook_id = _opt_int("rulebook_id")
        topic_id = _opt_int("topic_id")
        project_id = _opt_int("project_id")
    except ValueError:
        return jsonify({"error": "rulebook_id, topic_id, project_id must be integers"}), 400

    uid = get_current_user_id()
    rows = await rulebooks_svc.list_rules(
        user_id=uid,
        rulebook_id=rulebook_id,
        topic_id=topic_id,
        project_id=project_id,
    )
    items = [r.to_dict() for r in rows]
    # One aggregate for the whole page — a per-row lookup here would be N+1 by
    # construction, the same reason the snippet list does it this way. Every
    # row gets the key, zero-filled, so the UI renders "never surfaced" rather
    # than having to treat a missing field as a state. That matters more here
    # than for snippets: every rule on every install predates this table, so
    # for a while the zero-filled shape IS the common case.
    usage = await usage_for_rules([int(it["id"]) for it in items])
    for it in items:
        it["usage"] = usage.get(int(it["id"]), empty_rule_usage())
    return jsonify({"rules": items})


@rulebooks_bp.post("/rulebook-topics/<int:topic_id>/rules")
@login_required
async def create_rule(topic_id: int):
    data = await request.get_json() or {}
    title = (data.get("title") or "").strip()
    statement = (data.get("statement") or "").strip()
    if not title or not statement:
        return jsonify({"error": "title and statement are required"}), 400
    try:
        rule = await rulebooks_svc.create_rule(
            topic_id=topic_id,
            user_id=get_current_user_id(),
            title=title,
            statement=statement,
            why=data.get("why", ""),
            how_to_apply=data.get("how_to_apply", ""),
            order_index=data.get("order_index", 0),
            when_to_apply=data.get("when_to_apply", ""),
            tier=data.get("tier", "always_on"),
            # The human door carries `kind` too, and without the MCP door's
            # required provenance: an operator editing their own preference
            # owes nobody an explanation. That requirement is about auditing
            # what the AGENT changed, not what they did themselves.
            kind=data.get("kind", "rule"),
            arose_from_id=data.get("arose_from_id", 0) or 0,
            verify_with=data.get("verify_with", ""),
            expires_when=data.get("expires_when", ""),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return jsonify(await rulebooks_svc.rule_detail(
        get_current_user_id(), rule, data.get("system_ids"),
    )), 201


@rulebooks_bp.get("/rules/<int:rule_id>")
@login_required
async def get_rule(rule_id: int):
    uid = get_current_user_id()
    rule = await rulebooks_svc.get_rule(rule_id, uid)
    if rule is None:
        return jsonify({"error": "rule not found"}), 404
    # `rest_` rather than `mcp_`, and the prefix is load-bearing: "is this rule
    # dead weight?" is served by any pull, but "did that injected hint land?"
    # — the question this arm exists to answer — is served by AGENT pulls only.
    # A person clicking through the rule list says nothing about the hint.
    record_rule_pulled(user_id=uid, rule_id=int(rule.id), source="rest_rule")
    return jsonify(await rulebooks_svc.rule_detail(uid, rule))


@rulebooks_bp.patch("/rules/<int:rule_id>")
@login_required
async def update_rule(rule_id: int):
    data = await request.get_json() or {}
    uid = get_current_user_id()
    fields = {
        k: v for k, v in data.items()
        if k in ("title", "statement", "why", "how_to_apply", "order_index",
                 "when_to_apply", "tier", "kind", "arose_from_id",
                 "verify_with", "expires_when")
    }
    # No clear_fields here: a form sends "" for an emptied input, and the
    # service normalises "" to NULL for every nullable text column. The MCP
    # door needs the explicit list only because "" already means "unchanged"
    # there — two idioms, one outcome.
    rule = await rulebooks_svc.update_rule(rule_id, uid, **fields)
    if rule is None:
        return jsonify({"error": "rule not found"}), 404
    return jsonify(await rulebooks_svc.rule_detail(uid, rule, data.get("system_ids")))


@rulebooks_bp.get("/rules/<int:rule_id>/versions")
@login_required
async def list_rule_versions(rule_id: int):
    """A rule's edit history, newest first.

    Listing form only — a rule's `statement` and `why` run to thousands of
    characters, so a history list carrying every field would be unreadable
    and expensive to send. Open one for the text.
    """
    uid = get_current_user_id()
    versions = await rulebooks_svc.list_rule_versions(rule_id, uid)
    if versions is None:
        return jsonify({"error": "rule not found"}), 404
    return jsonify({
        "versions": [v.to_dict(include_text=False) for v in versions],
    })


@rulebooks_bp.get("/rules/<int:rule_id>/versions/<int:version_id>")
@login_required
async def get_rule_version(rule_id: int, version_id: int):
    """One snapshot in full — what the rule said before that edit."""
    uid = get_current_user_id()
    version = await rulebooks_svc.get_rule_version(rule_id, version_id, uid)
    if version is None:
        return jsonify({"error": "version not found"}), 404
    return jsonify(version.to_dict(include_text=True))


# NO restore route, deliberately (milestone 323). A note version can be
# restored; a binding instruction should not be revertible in one click.
# Putting a rewrite back goes through update_rule, which takes its own
# snapshot and leaves the undo in the history like any other edit — a silent
# revert would erase the only record of why the rewrite happened.


@rulebooks_bp.post("/rules/<int:rule_id>/relations")
@login_required
async def relate_rules(rule_id: int):
    """Draw a typed edge FROM this rule to another.

    Body: {"to_rule_id": N, "kind": "co_surfaces"|"overrides"|"elaborates",
    "note": "..."}. Idempotent — re-drawing an edge returns the existing one.
    """
    data = await request.get_json() or {}
    to_rule_id = data.get("to_rule_id")
    if not isinstance(to_rule_id, int):
        return jsonify({"error": "to_rule_id is required"}), 400
    try:
        relation = await rulebooks_svc.add_rule_relation(
            get_current_user_id(), rule_id, to_rule_id,
            data.get("kind", ""), data.get("note", ""),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 400
    if relation is None:
        return jsonify({"error": "rule not found"}), 404
    return jsonify(relation.to_dict()), 201


@rulebooks_bp.delete("/rule-relations/<int:relation_id>")
@login_required
async def unrelate_rules(relation_id: int):
    if not await rulebooks_svc.remove_rule_relation(get_current_user_id(), relation_id):
        return jsonify({"error": "relation not found"}), 404
    return "", 204


@rulebooks_bp.delete("/rules/<int:rule_id>")
@login_required
async def delete_rule(rule_id: int):
    if await trash_delete(get_current_user_id(), "rule", rule_id) is None:
        return jsonify({"error": "rule not found"}), 404
    return "", 204


# ── Subscriptions ──────────────────────────────────────────────────────

@rulebooks_bp.post("/projects/<int:project_id>/rulebook-subscriptions")
@login_required
async def subscribe_project(project_id: int):
    data = await request.get_json() or {}
    rulebook_id = data.get("rulebook_id")
    if not rulebook_id:
        return jsonify({"error": "rulebook_id is required"}), 400
    try:
        await rulebooks_svc.subscribe_project(
            project_id=project_id, rulebook_id=int(rulebook_id), user_id=get_current_user_id(),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return "", 204


@rulebooks_bp.delete(
    "/projects/<int:project_id>/rulebook-subscriptions/<int:rulebook_id>"
)
@login_required
async def unsubscribe_project(project_id: int, rulebook_id: int):
    try:
        await rulebooks_svc.unsubscribe_project(
            project_id=project_id, rulebook_id=rulebook_id, user_id=get_current_user_id(),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return "", 204


@rulebooks_bp.get("/projects/<int:project_id>/rules")
@login_required
async def get_project_rules(project_id: int):
    result = await rulebooks_svc.get_applicable_rules(
        project_id=project_id, user_id=get_current_user_id(),
    )
    return jsonify(result)


@rulebooks_bp.post("/projects/<int:project_id>/suppressions/rules/<int:rule_id>")
@login_required
async def suppress_project_rule(project_id: int, rule_id: int):
    try:
        await rulebooks_svc.suppress_rule_for_project(
            project_id=project_id, rule_id=rule_id, user_id=get_current_user_id(),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return "", 204


@rulebooks_bp.delete("/projects/<int:project_id>/suppressions/rules/<int:rule_id>")
@login_required
async def unsuppress_project_rule(project_id: int, rule_id: int):
    try:
        await rulebooks_svc.unsuppress_rule_for_project(
            project_id=project_id, rule_id=rule_id, user_id=get_current_user_id(),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return "", 204


@rulebooks_bp.post("/projects/<int:project_id>/suppressions/topics/<int:topic_id>")
@login_required
async def suppress_project_topic(project_id: int, topic_id: int):
    try:
        await rulebooks_svc.suppress_topic_for_project(
            project_id=project_id, topic_id=topic_id, user_id=get_current_user_id(),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return "", 204


@rulebooks_bp.delete("/projects/<int:project_id>/suppressions/topics/<int:topic_id>")
@login_required
async def unsuppress_project_topic(project_id: int, topic_id: int):
    try:
        await rulebooks_svc.unsuppress_topic_for_project(
            project_id=project_id, topic_id=topic_id, user_id=get_current_user_id(),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return "", 204


@rulebooks_bp.post("/projects/<int:project_id>/exclusions/rulebooks/<int:rulebook_id>")
@login_required
async def exclude_project_rulebook(project_id: int, rulebook_id: int):
    """Opt the project out of a whole always-on rulebook (milestone 297)."""
    try:
        await rulebooks_svc.exclude_always_on_rulebook_for_project(
            project_id=project_id, rulebook_id=rulebook_id, user_id=get_current_user_id(),
        )
    except ValueError as exc:
        msg = str(exc)
        return jsonify({"error": msg}), (400 if "not always-on" in msg else 404)
    return "", 204


@rulebooks_bp.delete("/projects/<int:project_id>/exclusions/rulebooks/<int:rulebook_id>")
@login_required
async def include_project_rulebook(project_id: int, rulebook_id: int):
    try:
        await rulebooks_svc.include_always_on_rulebook_for_project(
            project_id=project_id, rulebook_id=rulebook_id, user_id=get_current_user_id(),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return "", 204


@rulebooks_bp.post("/projects/<int:project_id>/rules")
@login_required
async def create_project_rule(project_id: int):
    """Create a rule scoped to a single project. Frontend fast path."""
    data = await request.get_json() or {}
    statement = (data.get("statement") or "").strip()
    if not statement:
        return jsonify({"error": "statement is required"}), 400
    title = (data.get("title") or "").strip() or statement.split(".")[0][:50]
    try:
        rule = await rulebooks_svc.create_project_rule(
            project_id=project_id,
            user_id=get_current_user_id(),
            title=title,
            statement=statement,
            why=data.get("why", ""),
            how_to_apply=data.get("how_to_apply", ""),
            order_index=data.get("order_index", 0),
            when_to_apply=data.get("when_to_apply", ""),
            tier=data.get("tier", "always_on"),
            # The human door carries `kind` too, and without the MCP door's
            # required provenance: an operator editing their own preference
            # owes nobody an explanation. That requirement is about auditing
            # what the AGENT changed, not what they did themselves.
            kind=data.get("kind", "rule"),
            arose_from_id=data.get("arose_from_id", 0) or 0,
            verify_with=data.get("verify_with", ""),
            expires_when=data.get("expires_when", ""),
        )
    except ValueError as exc:
        return jsonify({"error": str(exc)}), 404
    return jsonify(await rulebooks_svc.rule_detail(
        get_current_user_id(), rule, data.get("system_ids"),
    )), 201


# ── The staleness sweep (milestone 312) ────────────────────────────────

@rulebooks_bp.get("/rules-due-for-verification")
@login_required
async def rules_due_for_verification():
    """Rules that carry a check, oldest verification first, never-checked top.

    Query params: older_than_days, tier, never_only. A rule with no
    `verify_with` never appears — it is a decision, not a fact.
    """
    uid = get_current_user_id()
    args = request.args
    try:
        older = int(args.get("older_than_days", 0) or 0)
    except ValueError:
        return jsonify({"error": "older_than_days must be an integer"}), 400
    try:
        rules = await rulebooks_svc.rules_due_for_verification(
            uid,
            older_than_days=older,
            tier=args.get("tier", ""),
            never_only=args.get("never_only", "").lower() in ("1", "true", "yes"),
        )
    except ValueError as exc:
        # An unrecognised tier is a 400, not a silently narrowed result set:
        # a filter that quietly answers a different question is the failure
        # this whole surface exists to catch.
        return jsonify({"error": str(exc)}), 400
    return jsonify({
        "rules": [rulebooks_svc.verification_row(r) for r in rules],
        "total": len(rules),
    })


@rulebooks_bp.post("/rules/<int:rule_id>/verify")
@login_required
async def mark_rule_verified(rule_id: int):
    """Record that the rule's check was run. Body: {"still_true": bool}.

    `still_true: false` writes nothing — a rule whose check failed is wrong,
    not in a recordable state — so it stays at the top of the sweep.
    """
    data = await request.get_json() or {}
    uid = get_current_user_id()
    still_true = data.get("still_true", True)
    rule = await rulebooks_svc.mark_rule_verified(rule_id, uid, bool(still_true))
    if rule is None:
        return jsonify({"error": "rule not found, or carries no verify_with"}), 404
    payload = await rulebooks_svc.rule_detail(uid, rule)
    payload["verified"] = bool(still_true)
    return jsonify(payload)