import json
import logging

from fastapi import APIRouter
from rest_api.schema import FilterRequest, LabelSerialized
from rest_api.controller.search import DOCUMENT_STORE


router = APIRouter()

logger = logging.getLogger(__name__)


@router.post("/feedback")
def post_feedback(feedback: LabelSerialized):
    """
    This endpoint allows the API user to submit feedback on 
    an answer for a particular query. For example, the user 
    can send feedback on whether the answer was correct and 
    whether the right snippet was identified as the answer. 
    Information submitted through this endpoint is used to 
    train the underlying QA model.
    """
    if feedback.origin is None:
        feedback.origin = "user-feedback"
    DOCUMENT_STORE.write_labels([feedback])


@router.get("/feedback")
def get_feedback():
    """
    This endpoint allows the API user to retrieve all the
    feedback that has been sumbitted through the 
    `POST /feedback` endpoint
    """
    labels = DOCUMENT_STORE.get_all_labels()
    return labels


@router.post("/eval-feedback")
def get_feedback_metrics(filters: FilterRequest = None):
    """
    This endpoint returns basic accuracy metrics based on user feedback, 
    e.g., the ratio of correct answers or correctly identified documents. 
    You can filter the output by document or label.

    Example:
    `curl --location --request POST 'http://127.0.0.1:8000/eval-doc-qa-feedback' \
     --header 'Content-Type: application/json' \
     --data-raw '{ "filters": {"document_id": ["XRR3xnEBCYVTkbTystOB"]} }'`
    """

    if filters:
        filters = filters.filters
        filters["origin"] = ["user-feedback"]
    else:
        filters = {"origin": ["user-feedback"]}

    labels = DOCUMENT_STORE.get_all_labels(filters=filters)

    if len(labels) > 0:
        answer_feedback = [1 if l.is_correct_answer else 0 for l in labels]
        doc_feedback = [1 if l.is_correct_document else 0 for l in labels]

        answer_accuracy = sum(answer_feedback) / len(answer_feedback)
        doc_accuracy = sum(doc_feedback) / len(doc_feedback)

        res = {"answer_accuracy": answer_accuracy, "document_accuracy": doc_accuracy, "n_feedback": len(labels)}
    else:
        res = {"answer_accuracy": None, "document_accuracy": None, "n_feedback": 0}
    return res


@router.get("/export-feedback")
def export_feedback(
    context_size: int = 100_000, full_document_context: bool = True, only_positive_labels: bool = False
):
    """
    This endpoint returns JSON output in the SQuAD format for question/answer pairs 
    that were marked as "relevant" by user feedback through the `POST /feedback` endpoint.

    The context_size param can be used to limit response size for large documents.
    """
    if only_positive_labels:
        labels = DOCUMENT_STORE.get_all_labels(filters={"is_correct_answer": [True], "origin": ["user-feedback"]})
    else:
        labels = DOCUMENT_STORE.get_all_labels(filters={"origin": ["user-feedback"]})
        # Filter out the labels where the passage is correct but answer is wrong (in SQuAD this matches
        # neither a "positive example" nor a negative "is_impossible" one)
        labels = [l for l in labels if not (l.is_correct_document is True and l.is_correct_answer is False)]

    export_data = []

    for label in labels:
        if full_document_context:
            context = label.document.content

            answer_start = label.answer.offsets_in_document[0].start
        else:
            text = label.document.content
            # the final length of context(including the answer string) is 'context_size'.
            # we try to add equal characters for context before and after the answer string.
            # if either beginning or end of text is reached, we correspondingly
            # append more context characters at the other end of answer string.
            context_to_add = int((context_size - len(label.answer.answer)) / 2)
            start_pos = max(label.answer.offsets_in_document[0].start - context_to_add, 0)
            additional_context_at_end = max(context_to_add - label.answer.offsets_in_document[0].start, 0)
            end_pos = min(label.answer.offsets_in_document[0].start + len(label.answer.answer) + context_to_add, len(text) - 1)
            additional_context_at_start = max(
                label.answer.offsets_in_document[0].start + len(label.answer.answer) + context_to_add - len(text), 0
            )
            start_pos = max(0, start_pos - additional_context_at_start)
            end_pos = min(len(text) - 1, end_pos + additional_context_at_end)
            context = text[start_pos:end_pos]
            answer_start = label.answer.offsets_in_document[0].start - start_pos

        if label.is_correct_answer is False and label.is_correct_document is False:  # No answer
            squad_label = {
                "paragraphs": [
                    {
                        "context": context,
                        "id": label.document.id,
                        "qas": [{"question": label.query, "id": label.id, "is_impossible": True, "answers": []}],
                    }
                ]
            }
        else:
            squad_label = {
                "paragraphs": [
                    {
                        "context": context,
                        "id": label.document.id,
                        "qas": [
                            {
                                "question": label.query,
                                "id": label.id,
                                "is_impossible": False,
                                "answers": [{"text": label.answer.answer, "answer_start": answer_start}],
                            }
                        ],
                    }
                ]
            }

            # quality check
            start = squad_label["paragraphs"][0]["qas"][0]["answers"][0]["answer_start"]
            answer = squad_label["paragraphs"][0]["qas"][0]["answers"][0]["text"]
            context = squad_label["paragraphs"][0]["context"]
            if not context[start: start + len(answer)] == answer:
                logger.error(
                    f"Skipping invalid squad label as string via offsets "
                    f"('{context[start:start + len(answer)]}') does not match answer string ('{answer}') "
                )
        export_data.append(squad_label)

    export = {"data": export_data}

    with open("feedback_squad_direct.json", "w", encoding="utf8") as f:
        json.dump(export_data, f, ensure_ascii=False, sort_keys=True, indent=4)
    return export