import os
import uuid
from flask import Blueprint, request, jsonify, current_app
from flask_login import login_required, current_user
from werkzeug.utils import secure_filename
from models import db, Document
from services.document_parser import parse_document
from services import rag_service

documents_bp = Blueprint("documents", __name__, url_prefix="/api/documents")


def _allowed(filename: str) -> bool:
    allowed = current_app.config["ALLOWED_EXTENSIONS"]
    return "." in filename and filename.rsplit(".", 1)[1].lower() in allowed


@documents_bp.route("/", methods=["GET"])
@login_required
def list_documents():
    docs = Document.query.filter_by(user_id=current_user.id).order_by(Document.created_at.desc()).all()
    return jsonify([d.to_dict() for d in docs])


@documents_bp.route("/upload", methods=["POST"])
@login_required
def upload():
    if "file" not in request.files:
        return jsonify({"error": "No file provided"}), 400

    file = request.files["file"]
    if not file.filename:
        return jsonify({"error": "No filename"}), 400

    if not _allowed(file.filename):
        return jsonify({"error": "File type not allowed"}), 400

    original_name = secure_filename(file.filename)
    ext = original_name.rsplit(".", 1)[1].lower()
    stored_name = f"{uuid.uuid4().hex}.{ext}"
    file_path = os.path.join(current_app.config["UPLOAD_FOLDER"], stored_name)
    file.save(file_path)

    doc = Document(
        user_id=current_user.id,
        filename=stored_name,
        original_name=original_name,
        file_type=ext,
        indexed=False,
    )
    db.session.add(doc)
    db.session.commit()

    # Index in background (synchronous for simplicity — fast enough for normal docs)
    try:
        text = parse_document(file_path, ext)
        rag_service.index_source(
            text=text,
            user_id=current_user.id,
            source_id=doc.id,
            source_type="doc",
            chunk_size=current_app.config["RAG_CHUNK_SIZE"],
            chunk_overlap=current_app.config["RAG_CHUNK_OVERLAP"],
        )
        doc.indexed = True
        db.session.commit()
    except Exception as e:
        current_app.logger.error(f"Indexing failed for doc {doc.id}: {e}")

    return jsonify(doc.to_dict()), 201


@documents_bp.route("/<int:doc_id>", methods=["DELETE"])
@login_required
def delete_document(doc_id):
    doc = Document.query.filter_by(id=doc_id, user_id=current_user.id).first_or_404()

    # Remove from vector store
    rag_service.delete_source(current_user.id, doc.id, "doc")

    # Remove file
    file_path = os.path.join(current_app.config["UPLOAD_FOLDER"], doc.filename)
    if os.path.exists(file_path):
        os.remove(file_path)

    db.session.delete(doc)
    db.session.commit()
    return jsonify({"success": True})


@documents_bp.route("/<int:doc_id>/content", methods=["GET"])
@login_required
def get_content(doc_id):
    doc = Document.query.filter_by(id=doc_id, user_id=current_user.id).first_or_404()
    file_path = os.path.join(current_app.config["UPLOAD_FOLDER"], doc.filename)
    try:
        text = parse_document(file_path, doc.file_type)
    except Exception as e:
        return jsonify({"error": str(e)}), 500
    return jsonify({"id": doc.id, "name": doc.original_name, "content": text})