"use client";

import { startTransition, useState } from "react";
import { useRouter } from "next/navigation";
import type { Locale } from "@/lib/i18n";
import type { CrosswordRequest } from "@/lib/types";

const DEFAULTS = {
  topic: "transport",
  difficulty: "medium",
  initialWordCount: 19,
  themedFillCount: 10,
  targetEmptyRatio: 0.1667,
  seed: 2,
  lexiconFile: "lexicon_it_curated_llm_aggressive.json",
};

type CrosswordConfigFormProps = {
  locale: Locale;
  dict: {
    topic: string;
    difficulty: string;
    initialWords: string;
    themedFillCount: string;
    targetEmptyRatio: string;
    seed: string;
    lexiconFile: string;
    submit: string;
    submitting: string;
    note: string;
  };
};

export function CrosswordConfigForm({ locale, dict }: CrosswordConfigFormProps) {
  const router = useRouter();
  const [topic, setTopic] = useState(DEFAULTS.topic);
  const [difficulty, setDifficulty] = useState(DEFAULTS.difficulty);
  const [initialWordCount, setInitialWordCount] = useState(DEFAULTS.initialWordCount);
  const [themedFillCount, setThemedFillCount] = useState(DEFAULTS.themedFillCount);
  const [targetEmptyRatio, setTargetEmptyRatio] = useState(DEFAULTS.targetEmptyRatio);
  const [seed, setSeed] = useState(DEFAULTS.seed);
  const [lexiconFile, setLexiconFile] = useState(DEFAULTS.lexiconFile);
  const [isSubmitting, setIsSubmitting] = useState(false);
  const [errorMessage, setErrorMessage] = useState("");

  async function handleSubmit(event: React.FormEvent<HTMLFormElement>) {
    event.preventDefault();
    setIsSubmitting(true);
    setErrorMessage("");

    const requestPayload: CrosswordRequest = {
      schema_version: "1.0",
      request_id: `req-${Date.now()}`,
      requested_at: new Date().toISOString(),
      generator: {
        topic: topic
          .split(",")
          .map((item) => item.trim())
          .filter(Boolean),
        difficulty,
        seed,
        initial_word_count: initialWordCount,
        themed_fill_count: themedFillCount,
        target_empty_ratio: targetEmptyRatio,
        diffxy: 7,
        time_limit_seconds: 8,
        max_candidates_per_word: 12,
        lexicon_file: lexiconFile,
        definitions_enabled: true,
        definition_style: "classic",
        preferred_output_language: locale,
      },
    };

    try {
      const response = await fetch("/api/crosswords/generate", {
        method: "POST",
        headers: {
          "Content-Type": "application/json",
        },
        body: JSON.stringify(requestPayload),
      });

      if (!response.ok) {
        const errorPayload = await response.json().catch(() => ({}));
        throw new Error(errorPayload.message || "Unable to generate crossword");
      }

      const generated = await response.json();

      startTransition(() => {
        router.push(`/${locale}/crosswords/${generated.crossword_id}`);
      });
    } catch (error) {
      setErrorMessage(error instanceof Error ? error.message : "Unexpected error");
      setIsSubmitting(false);
    }
  }

  return (
    <form className="config-form" onSubmit={handleSubmit}>
      <div className="config-form__grid">
        <div className="field">
          <label htmlFor="topic">{dict.topic}</label>
          <input id="topic" value={topic} onChange={(event) => setTopic(event.target.value)} />
        </div>

        <div className="field">
          <label htmlFor="difficulty">{dict.difficulty}</label>
          <select
            id="difficulty"
            value={difficulty}
            onChange={(event) => setDifficulty(event.target.value)}
          >
            <option value="easy">easy</option>
            <option value="medium">medium</option>
            <option value="hard">hard</option>
            <option value="expert">expert</option>
          </select>
        </div>

        <div className="field">
          <label htmlFor="initialWordCount">{dict.initialWords}</label>
          <input
            id="initialWordCount"
            type="number"
            value={initialWordCount}
            onChange={(event) => setInitialWordCount(Number(event.target.value))}
          />
        </div>

        <div className="field">
          <label htmlFor="themedFillCount">{dict.themedFillCount}</label>
          <input
            id="themedFillCount"
            type="number"
            value={themedFillCount}
            onChange={(event) => setThemedFillCount(Number(event.target.value))}
          />
        </div>

        <div className="field">
          <label htmlFor="targetEmptyRatio">{dict.targetEmptyRatio}</label>
          <input
            id="targetEmptyRatio"
            type="number"
            step="0.0001"
            value={targetEmptyRatio}
            onChange={(event) => setTargetEmptyRatio(Number(event.target.value))}
          />
        </div>

        <div className="field">
          <label htmlFor="seed">{dict.seed}</label>
          <input
            id="seed"
            type="number"
            value={seed}
            onChange={(event) => setSeed(Number(event.target.value))}
          />
        </div>
      </div>

      <div className="field">
        <label htmlFor="lexiconFile">{dict.lexiconFile}</label>
        <input
          id="lexiconFile"
          value={lexiconFile}
          onChange={(event) => setLexiconFile(event.target.value)}
        />
      </div>

      <div className="actions">
        <button className="button" type="submit" disabled={isSubmitting}>
          {isSubmitting ? dict.submitting : dict.submit}
        </button>
        <span className="muted">{dict.note}</span>
      </div>

      {errorMessage ? <p className="form-error">{errorMessage}</p> : null}
    </form>
  );
}