"""Admin endpoints for groups + their permission bindings."""

from __future__ import annotations

import logging
import uuid

from flask import Blueprint, jsonify, request
from pydantic import BaseModel, Field, ValidationError

from app.core.auth_decorators import require_auth, require_perm
from app.services import groups as groups_svc

bp = Blueprint("groups", __name__, url_prefix="/groups")
log = logging.getLogger("metamorph.api.groups")


def _serialize(g: groups_svc.GroupView) -> dict:
    return {
        "id": str(g.id),
        "name": g.name,
        "description": g.description,
        "is_system": g.is_system,
        "members_count": g.members_count,
        "permissions": g.permissions,
        "created_at": g.created_at.isoformat(),
        "updated_at": g.updated_at.isoformat(),
    }


class CreateGroupPayload(BaseModel):
    name: str = Field(min_length=1, max_length=80)
    description: str | None = Field(default=None, max_length=2000)

    model_config = {"extra": "forbid"}


class UpdateGroupPayload(BaseModel):
    name: str | None = Field(default=None, min_length=1, max_length=80)
    description: str | None = Field(default=None, max_length=2000)

    model_config = {"extra": "forbid"}


class SetPermissionsPayload(BaseModel):
    codes: list[str] = Field(default_factory=list)

    model_config = {"extra": "forbid"}


def _parse_uuid_or_400(raw: str):
    try:
        return uuid.UUID(raw)
    except ValueError:
        return None


@bp.get("")
@require_auth
@require_perm("group.read")
def list_groups():
    rows = groups_svc.list_groups()
    return jsonify({"items": [_serialize(g) for g in rows], "total": len(rows)})


@bp.get("/<group_id>")
@require_auth
@require_perm("group.read")
def get_group(group_id: str):
    gid = _parse_uuid_or_400(group_id)
    if gid is None:
        return jsonify({"error": "invalid_id"}), 400
    try:
        g = groups_svc.get_group(gid)
    except groups_svc.GroupNotFound:
        return jsonify({"error": "not_found"}), 404
    return jsonify(_serialize(g))


@bp.post("")
@require_auth
@require_perm("group.create")
def create_group():
    try:
        payload = CreateGroupPayload.model_validate(request.get_json(silent=True) or {})
    except ValidationError as e:
        return jsonify({"error": "invalid_request", "details": e.errors(include_context=False, include_url=False)}), 400
    try:
        g = groups_svc.create_group(name=payload.name, description=payload.description)
    except groups_svc.GroupNameConflict as e:
        return jsonify({"error": "name_conflict", "message": str(e)}), 409
    except ValueError as e:
        return jsonify({"error": "invalid_request", "message": str(e)}), 400
    log.info("metamorph.group.created", extra={"group_id": str(g.id), "group_name": g.name})
    return jsonify(_serialize(g)), 201


@bp.patch("/<group_id>")
@require_auth
@require_perm("group.update")
def update_group(group_id: str):
    gid = _parse_uuid_or_400(group_id)
    if gid is None:
        return jsonify({"error": "invalid_id"}), 400
    raw = request.get_json(silent=True) or {}
    try:
        payload = UpdateGroupPayload.model_validate(raw)
    except ValidationError as e:
        return jsonify({"error": "invalid_request", "details": e.errors(include_context=False, include_url=False)}), 400
    description_unset = "description" not in raw
    try:
        g = groups_svc.update_group(
            gid,
            name=payload.name,
            description=... if description_unset else payload.description,
        )
    except groups_svc.GroupNotFound:
        return jsonify({"error": "not_found"}), 404
    except groups_svc.SystemGroupProtected as e:
        return jsonify({"error": "system_group_protected", "message": str(e)}), 409
    except groups_svc.GroupNameConflict as e:
        return jsonify({"error": "name_conflict", "message": str(e)}), 409
    except ValueError as e:
        return jsonify({"error": "invalid_request", "message": str(e)}), 400
    log.info("metamorph.group.updated", extra={"group_id": str(gid), "fields": sorted(raw.keys())})
    return jsonify(_serialize(g))


@bp.delete("/<group_id>")
@require_auth
@require_perm("group.delete")
def soft_delete(group_id: str):
    gid = _parse_uuid_or_400(group_id)
    if gid is None:
        return jsonify({"error": "invalid_id"}), 400
    try:
        groups_svc.soft_delete_group(gid)
    except groups_svc.GroupNotFound:
        return jsonify({"error": "not_found"}), 404
    except groups_svc.SystemGroupProtected as e:
        return jsonify({"error": "system_group_protected", "message": str(e)}), 409
    log.info("metamorph.group.soft_deleted", extra={"group_id": str(gid)})
    return jsonify({"ok": True})


@bp.put("/<group_id>/permissions")
@require_auth
@require_perm("group.update")
def set_permissions(group_id: str):
    gid = _parse_uuid_or_400(group_id)
    if gid is None:
        return jsonify({"error": "invalid_id"}), 400
    try:
        payload = SetPermissionsPayload.model_validate(request.get_json(silent=True) or {})
    except ValidationError as e:
        return jsonify({"error": "invalid_request", "details": e.errors(include_context=False, include_url=False)}), 400
    try:
        g = groups_svc.set_group_permissions(gid, payload.codes)
    except groups_svc.GroupNotFound:
        return jsonify({"error": "not_found"}), 404
    except groups_svc.SystemGroupProtected as e:
        return jsonify({"error": "system_group_protected", "message": str(e)}), 409
    except ValueError as e:
        return jsonify({"error": "invalid_request", "message": str(e)}), 400
    log.info(
        "metamorph.group.permissions_set",
        extra={"group_id": str(gid), "count": len(payload.codes)},
    )
    return jsonify(_serialize(g))