import { useMemo, useState, type FormEvent } from "react";
import {
  GENERATOR_VARIANTS,
  type DifficultyAssessment,
  type GeneratedVariantPuzzle,
  type GenerationDifficultyTarget,
  type GeneratorVariant,
  type GenerateVariantOptions,
} from "../solver";

const difficultyTargets: readonly GenerationDifficultyTarget[] = [
  "beginner",
  "easy",
  "medium",
  "hard",
  "expert",
];

function techniqueLabel(value: string | undefined): string {
  return value === undefined
    ? "Direct placements"
    : value
        .split("-")
        .map((part) => `${part[0]?.toUpperCase() ?? ""}${part.slice(1)}`)
        .join(" ");
}

export function GeneratorWorkspace({
  busy,
  assessment,
  generation,
  onGenerate,
  onRate,
}: {
  busy: boolean;
  assessment?: DifficultyAssessment;
  generation?: GeneratedVariantPuzzle;
  onGenerate: (options: GenerateVariantOptions) => void;
  onRate: () => void;
}) {
  const [variant, setVariant] = useState<GeneratorVariant>("classic");
  const definition = useMemo(
    () => GENERATOR_VARIANTS.find((item) => item.id === variant)!,
    [variant],
  );
  const [size, setSize] = useState(9);
  const [targetDifficulty, setTargetDifficulty] =
    useState<GenerationDifficultyTarget>("medium");
  const [symmetry, setSymmetry] = useState<"none" | "rotational">("rotational");
  const [constraintCount, setConstraintCount] = useState(8);
  const [seed, setSeed] = useState("");
  const usesMarkingCount = ![
    "classic",
    "diagonal",
    "killer",
    "anti-knight",
    "anti-king",
    "non-consecutive",
  ].includes(variant);

  const submit = (event: FormEvent<HTMLFormElement>) => {
    event.preventDefault();
    onGenerate({
      variant,
      size,
      targetDifficulty,
      symmetry,
      ...(usesMarkingCount ? { constraintCount } : {}),
      seed: seed.trim() || `local-${Date.now().toString(36)}`,
    });
  };

  return (
    <div className="generator-workspace stack">
      <div>
        <p className="eyebrow">Bounded local construction</p>
        <h2>Sudoku generator</h2>
        <p className="muted">
          Build a seedable, uniquely checked puzzle in the worker. The requested
          level guides clue removal; the finished puzzle receives an independent
          evidence-based rating.
        </p>
      </div>

      <form className="panel-section generator-form" onSubmit={submit}>
        <div className="field-grid">
          <label>
            Variant
            <select
              value={variant}
              onChange={(event) => {
                const next = event.target.value as GeneratorVariant;
                const nextDefinition = GENERATOR_VARIANTS.find(
                  (item) => item.id === next,
                )!;
                setVariant(next);
                if (
                  !(
                    nextDefinition.supportedSizes as readonly number[]
                  ).includes(size)
                ) {
                  setSize(nextDefinition.supportedSizes[0]);
                }
              }}
            >
              {GENERATOR_VARIANTS.map((item) => (
                <option key={item.id} value={item.id}>
                  {item.label}
                </option>
              ))}
            </select>
          </label>
          <label>
            Grid
            <select
              value={size}
              onChange={(event) => setSize(Number(event.target.value))}
            >
              {definition.supportedSizes.map((supportedSize) => (
                <option key={supportedSize} value={supportedSize}>
                  {supportedSize} × {supportedSize}
                </option>
              ))}
            </select>
          </label>
          <label>
            Requested profile
            <select
              value={targetDifficulty}
              onChange={(event) =>
                setTargetDifficulty(
                  event.target.value as GenerationDifficultyTarget,
                )
              }
            >
              {difficultyTargets.map((target) => (
                <option key={target} value={target}>
                  {target[0]!.toUpperCase() + target.slice(1)}
                </option>
              ))}
            </select>
          </label>
          <label>
            Given symmetry
            <select
              value={symmetry}
              onChange={(event) =>
                setSymmetry(event.target.value as "none" | "rotational")
              }
            >
              <option value="rotational">Rotational</option>
              <option value="none">None</option>
            </select>
          </label>
          {usesMarkingCount && (
            <label>
              Requested markings
              <input
                type="number"
                min="1"
                max={size * size * 2}
                value={constraintCount}
                onChange={(event) =>
                  setConstraintCount(Number(event.target.value))
                }
              />
            </label>
          )}
          <label>
            Seed
            <input
              value={seed}
              maxLength={128}
              placeholder="blank = fresh local seed"
              onChange={(event) => setSeed(event.target.value)}
            />
          </label>
        </div>
        <p className="generator-description">{definition.description}</p>
        <div className="action-row">
          <button className="primary-button" type="submit" disabled={busy}>
            {busy ? "Working locally…" : `Generate ${definition.label}`}
          </button>
          <button type="button" disabled={busy} onClick={onRate}>
            Rate current puzzle
          </button>
        </div>
        <p className="muted">
          Difficulty is an estimate from reproducible solver evidence, not a
          universal promise. Uniqueness is never claimed after a safety limit.
        </p>
      </form>

      {assessment && (
        <section
          className="analysis-summary difficulty-card"
          aria-live="polite"
        >
          <div className="section-heading">
            <div>
              <p className="eyebrow">Difficulty assessment</p>
              <h3>{assessment.label}</h3>
            </div>
            <span
              className={`status-pill${assessment.uniqueness === "unique" ? " status-solved" : " status-invalid"}`}
            >
              {assessment.uniqueness}
            </span>
          </div>
          <div className="metric-row">
            <span>
              Score <strong>{assessment.score ?? "—"}/100</strong>
            </span>
            <span>
              Givens <strong>{assessment.clueCount}</strong>
            </span>
            <span>
              Logical steps <strong>{assessment.logicalSteps}</strong>
            </span>
            <span>
              Hardest{" "}
              <strong>{techniqueLabel(assessment.hardestTechnique)}</strong>
            </span>
            <span>
              Search nodes <strong>{assessment.exactNodes}</strong>
            </span>
            {generation && (
              <span>
                Markings <strong>{generation.generatedConstraintCount}</strong>
              </span>
            )}
          </div>
          <p>{assessment.summary}</p>
          {generation && (
            <p className="muted">
              Seed: <code>{String(generation.seed)}</code>
            </p>
          )}
        </section>
      )}
    </div>
  );
}