"use client";

import { useMemo, useState } from "react";
import { useRouter } from "next/navigation";

import type { BoundaryQuestionSummary } from "@pipeline/shared";

import { ApiError, generateBoundaryQuestions, submitBoundaryQuestions, updateBoundaryQuestion } from "@/shared/pipeline-api";
import {
  buildBoundaryQuestionRows,
  validateRequiredAnswers,
  type BoundaryQuestionErrors,
  type BoundaryQuestionFormRow,
} from "./model";

type BoundaryQuestionsEditorProps = {
  articleId: string;
  initialQuestions: readonly BoundaryQuestionSummary[];
};

export function BoundaryQuestionsEditor({
  articleId,
  initialQuestions,
}: BoundaryQuestionsEditorProps) {
  const router = useRouter();
  const [rows, setRows] = useState<BoundaryQuestionFormRow[]>(() =>
    buildBoundaryQuestionRows(initialQuestions),
  );
  const [errors, setErrors] = useState<BoundaryQuestionErrors>({});
  const [formMessage, setFormMessage] = useState("");
  const [isBusy, setBusy] = useState(false);

  const requiredProgress = useMemo(() => {
    const requiredRows = rows.filter((row) => row.isRequired);
    const answeredRows = requiredRows.filter((row) => row.answer.trim());
    return `${answeredRows.length}/${requiredRows.length}`;
  }, [rows]);

  function updateRow(questionId: string, answer: string) {
    setRows((current) =>
      current.map((row) => (row.id === questionId ? { ...row, answer } : row)),
    );
  }

  async function handleGenerate() {
    setBusy(true);
    setFormMessage("");
    try {
      const response = await generateBoundaryQuestions(articleId);
      setRows(buildBoundaryQuestionRows(response.questions));
      setErrors({});
      router.refresh();
    } catch (error) {
      setFormMessage(error instanceof ApiError ? error.message : "Unable to generate questions");
    } finally {
      setBusy(false);
    }
  }

  async function handleSave(row: BoundaryQuestionFormRow) {
    setBusy(true);
    setFormMessage("");
    try {
      const response = await updateBoundaryQuestion(articleId, row.id, {
        answer: row.answer.trim() || null,
      });
      setRows((current) =>
        current.map((candidate) =>
          candidate.id === row.id
            ? buildBoundaryQuestionRows([response.question])[0]
            : candidate,
        ),
      );
      setErrors((current) => {
        const next = { ...current };
        delete next[row.id];
        return next;
      });
    } catch (error) {
      setFormMessage(error instanceof ApiError ? error.message : "Unable to save answer");
    } finally {
      setBusy(false);
    }
  }

  async function handleSubmit() {
    const nextErrors = validateRequiredAnswers(rows);
    if (Object.keys(nextErrors).length > 0) {
      setErrors(nextErrors);
      return;
    }

    setBusy(true);
    setFormMessage("");
    try {
      await submitBoundaryQuestions(articleId);
      router.push(`/articles/${articleId}`);
      router.refresh();
    } catch (error) {
      setFormMessage(error instanceof ApiError ? error.message : "Unable to submit answers");
    } finally {
      setBusy(false);
    }
  }

  return (
    <section className="boundaryQuestions">
      <div className="sectionHeader">
        <div>
          <h2>Boundary questions</h2>
          <p>Required answers: {requiredProgress}</p>
        </div>
        <button type="button" onClick={handleGenerate} disabled={isBusy}>
          {rows.length > 0 ? "Regenerate" : "Generate"}
        </button>
      </div>

      {formMessage ? <p className="formError">Error: {formMessage}</p> : null}

      {rows.length === 0 ? (
        <p className="emptyState">No boundary questions generated yet.</p>
      ) : (
        <div className="questionList">
          {rows.map((row) => (
            <article className="questionItem" key={row.id}>
              <div className="questionHeader">
                <div>
                  <strong>{row.category.replaceAll("_", " ")}</strong>
                  <p>{row.question}</p>
                </div>
                <span className={row.isRequired ? "requiredBadge" : "optionalBadge"}>
                  {row.stateLabel}
                </span>
              </div>
              <textarea
                value={row.answer}
                onChange={(event) => updateRow(row.id, event.target.value)}
              />
              {errors[row.id] ? <p className="fieldError">{errors[row.id]}</p> : null}
              <div className="formActions">
                <button type="button" onClick={() => handleSave(row)} disabled={isBusy}>
                  Save
                </button>
              </div>
            </article>
          ))}
        </div>
      )}

      <div className="formActions">
        <button type="button" onClick={handleSubmit} disabled={isBusy || rows.length === 0}>
          Submit boundary answers
        </button>
      </div>
    </section>
  );
}