from flask import Blueprint, request, jsonify, abort
from sqlalchemy.orm import scoped_session
from .dsl import QuerySpec
from .service import CrudService
from .eager import default_eager_policy
from .serialize import serialize

def make_blueprint(db_session_factory, registry):
    bp = Blueprint("crud", __name__)
    def session(): return scoped_session(db_session_factory)()

    @bp.get("/<model>/list")
    def list_items(model):
        Model = registry.get(model) or abort(404)
        spec = QuerySpec(
            filters=_parse_filters(request.args),
            order_by=request.args.getlist("sort"),
            page=request.args.get("page", type=int),
            per_page=request.args.get("per_page", type=int),
            expand=request.args.getlist("expand"),
            fields=request.args.get("fields", type=lambda s: [x.strip() for x in s.split(",")] if s else None),
        )
        s = session(); svc = CrudService(s, default_eager_policy)
        rows, total = svc.list(Model, spec)
        data = [serialize(r, fields=spec.fields, expand=spec.expand) for r in rows]
        return jsonify({"data": data, "total": total})

    @bp.post("/<model>")
    def create_item(model):
        Model = registry.get(model) or abort(404)
        payload = request.get_json() or {}
        s = session(); svc = CrudService(s, default_eager_policy)
        obj = svc.create(Model, payload)
        s.commit()
        return jsonify(serialize(obj)), 201

    @bp.get("/<model>/<int:id>")
    def read_item(model, id):
        Model = registry.get(model) or abort(404)
        spec = QuerySpec(expand=request.args.getlist("expand"),
                         fields=request.args.get("fields", type=lambda s: s.split(",")))
        s = session(); svc = CrudService(s, default_eager_policy)
        obj = svc.get(Model, id, spec) or abort(404)
        return jsonify(serialize(obj, fields=spec.fields, expand=spec.expand))

    @bp.patch("/<model>/<int:id>")
    def update_item(model, id):
        Model = registry.get(model) or abort(404)
        s = session(); svc = CrudService(s, default_eager_policy)
        obj = svc.get(Model, id, QuerySpec()) or abort(404)
        payload = request.get_json() or {}
        svc.update(obj, payload)
        s.commit()
        return jsonify(serialize(obj))

    @bp.delete("/<model>/<int:id>")
    def delete_item(model, id):
        Model = registry.get(model) or abort(404)
        s = session(); svc = CrudService(s, default_eager_policy)
        obj = svc.get(Model, id, QuerySpec()) or abort(404)
        svc.soft_delete(obj)
        s.commit()
        return jsonify({"status": "deleted"})

    @bp.post("/<model>/<int:id>/undelete")
    def undelete_item(model, id):
        Model = registry.get(model) or abort(404)
        s = session(); svc = CrudService(s, default_eager_policy)
        obj = svc.get(Model, id, QuerySpec()) or abort(404)
        svc.undelete(obj)
        s.commit()
        return jsonify({"status": "restored"})
    return bp

def _parse_filters(args):
    out = {}
    for k, v in args.items():
        if k in {"page", "per_page", "sort", "expand", "fields"}:
            continue
        out[k] = v
    return out