parking_solution/apps/web/src/TariffComposer.tsx

import { useEffect, useState } from "react";
import { useTranslation } from "react-i18next";
import {
  ApiError,
  fetchTariff,
  isTariffV2,
  publishTariffVersion,
  type TariffBlock,
  type TariffCard,
  type TariffStructure,
  type TariffState,
} from "./api.js";

// Tariff composer — the admin builds + edits the rate card at runtime. Publishing
// creates a new IMMUTABLE version (the active card); old versions are kept so past
// sessions reprice correctly. Amounts are entered in major units (e.g. euros) for
// usability and converted to integer minor units on submit. See wiki/concepts/tariff.md.

// Editable form mirror of TariffStructure, but money in major-unit strings.
// Blocks are edited as a DURATION in hours ("this band lasts N hours") — the
// owner thinks "first 2 hours, then next 3 hours", not in cumulative minutes.
// The LAST block is always open-ended ("thereafter"): its hours field is unused
// and it has no bound. On submit, per-block hours accumulate into the engine's
// cumulative `uptoMin` (minutes), and the last block emits uptoMin: null.
interface BlockForm {
  hours: string; // duration of THIS band, in hours (ignored for the last block)
  price: string; // major units, e.g. "2.00"
}
// A pricing body the form edits: either a flat rate or a block ladder.
interface PricingForm {
  mode: "ladder" | "flat";
  flat: string; // major units (used when mode==="flat")
  blocks: BlockForm[]; // hours-based ladder (used when mode==="ladder")
  dailyCap: string; // "" = no cap (ladder only)
}
// An optional time/category TIER (a V2 windowed card). Absent windows = unconstrained.
interface TierForm {
  name: string;
  priority: string;
  category: string; // "" = applies to all categories
  dow: number[]; // selected days 0..6; empty = every day
  fromHour: string; // "" = all day
  toHour: string;
  dateFrom: string; // "" = unbounded
  dateTo: string;
  pricing: PricingForm;
}
interface FormState {
  currency: string;
  gracePeriodEntryMin: string;
  incrementMin: string;
  lostTicket: string;
  gracePeriodExitMin: string;
  // The default (always-active) card — its own flat/ladder body + daily cap.
  base: PricingForm;
  // Optional time/category tiers. Empty ⇒ a bare V1 structure is published.
  tiers: TierForm[];
}

const toMinor = (major: string): number => Math.round(parseFloat(major || "0") * 100);
const toMajor = (minor: number): string => (minor / 100).toFixed(2);

function emptyLadder(): PricingForm {
  return { mode: "ladder", flat: "0.00", dailyCap: "", blocks: [{ hours: "1", price: "2.00" }, { hours: "", price: "1.00" }] };
}
function emptyTier(): TierForm {
  return { name: "", priority: "10", category: "", dow: [], fromHour: "", toHour: "", dateFrom: "", dateTo: "", pricing: { ...emptyLadder(), blocks: [{ hours: "", price: "1.00" }] } };
}

function emptyForm(): FormState {
  return {
    currency: "EUR",
    gracePeriodEntryMin: "15",
    incrementMin: "60",
    lostTicket: "20.00",
    gracePeriodExitMin: "15",
    base: emptyLadder(),
    tiers: [],
  };
}

// Convert a stored block ladder's cumulative `uptoMin` (minutes) into the per-band
// hours the form edits. Open-ended last band has no hours. Legacy bounded tails still
// load (shown as their own band).
function blocksToForm(blocks: TariffBlock[]): BlockForm[] {
  let prev = 0;
  return blocks.map((b) => {
    if (b.uptoMin == null) return { hours: "", price: toMajor(b.priceMinorPerIncrement) };
    const hours = (b.uptoMin - prev) / 60;
    prev = b.uptoMin;
    return { hours: String(hours), price: toMajor(b.priceMinorPerIncrement) };
  });
}

// A stored card (V2) or bare-V1 body → the form's PricingForm (flat or ladder).
function pricingFromCard(c: { flatMinor?: number; blocks?: TariffBlock[]; dailyCapMinor?: number | null }): PricingForm {
  if (c.flatMinor != null) {
    return { mode: "flat", flat: toMajor(c.flatMinor), dailyCap: "", blocks: emptyLadder().blocks };
  }
  return {
    mode: "ladder",
    flat: "0.00",
    dailyCap: c.dailyCapMinor == null ? "" : toMajor(c.dailyCapMinor),
    blocks: blocksToForm(c.blocks ?? []),
  };
}

function tierFromCard(c: TariffCard): TierForm {
  const w = c.window ?? {};
  return {
    name: c.name,
    priority: String(c.priority),
    category: c.category ?? "",
    dow: w.dow ? [...w.dow] : [],
    fromHour: w.fromHour ?? "",
    toHour: w.toHour ?? "",
    dateFrom: w.dateFrom ?? "",
    dateTo: w.dateTo ?? "",
    pricing: pricingFromCard(c),
  };
}

function formFromActive(s: TariffState): FormState {
  const v = s.active;
  if (!v) return emptyForm();
  const st = v.structure;
  const common = {
    currency: v.currency,
    gracePeriodEntryMin: String(st.gracePeriodEntryMin),
    incrementMin: String(st.incrementMin),
    lostTicket: toMajor(st.lostTicketMinor),
    gracePeriodExitMin: String(st.gracePeriodExitMin),
  };
  if (isTariffV2(st)) {
    return { ...common, base: pricingFromCard(st.defaultCard), tiers: (st.windowedCards ?? []).map(tierFromCard) };
  }
  // V1: the bare ladder becomes the default card body; no tiers.
  return { ...common, base: pricingFromCard(st), tiers: [] };
}

// Build a tariff card's pricing body (flat XOR ladder) from a PricingForm.
function pricingToCardBody(p: PricingForm): Pick<TariffCard, "flatMinor" | "blocks" | "dailyCapMinor"> {
  if (p.mode === "flat") return { flatMinor: toMinor(p.flat) };
  // Accumulate each band's hours into cumulative uptoMin (min); last band open-ended.
  const last = p.blocks.length - 1;
  let cum = 0;
  const blocks: TariffBlock[] = p.blocks.map((b, i) => {
    if (i === last) return { uptoMin: null, priceMinorPerIncrement: toMinor(b.price) };
    cum += Math.round(Number(b.hours || "0") * 60);
    return { uptoMin: cum, priceMinorPerIncrement: toMinor(b.price) };
  });
  return { blocks, dailyCapMinor: p.dailyCap.trim() === "" ? null : toMinor(p.dailyCap) };
}

function tierToCard(tr: TierForm): TariffCard {
  const window: TariffCard["window"] = {};
  if (tr.dow.length > 0) window.dow = [...tr.dow].sort((a, b) => a - b);
  if (tr.fromHour && tr.toHour) {
    window.fromHour = tr.fromHour;
    window.toHour = tr.toHour;
  }
  if (tr.dateFrom) window.dateFrom = tr.dateFrom;
  if (tr.dateTo) window.dateTo = tr.dateTo;
  const card: TariffCard = {
    name: tr.name.trim() || "tier",
    priority: Math.round(Number(tr.priority || "0")),
    ...pricingToCardBody(tr.pricing),
  };
  if (tr.category.trim()) card.category = tr.category.trim();
  if (Object.keys(window).length > 0) card.window = window;
  return card;
}

function toStructure(f: FormState): TariffStructure {
  const common = {
    gracePeriodEntryMin: Math.round(Number(f.gracePeriodEntryMin)),
    incrementMin: Math.round(Number(f.incrementMin)),
    lostTicketMinor: toMinor(f.lostTicket),
    gracePeriodExitMin: Math.round(Number(f.gracePeriodExitMin)),
    overstay: "reprice" as const,
  };
  const baseBody = pricingToCardBody(f.base);

  // NO tiers ⇒ publish a BARE V1 structure (back-compat: a site that never wants
  // tiers gets exactly today's shape; the server leaves it untouched).
  if (f.tiers.length === 0) {
    if (f.base.mode === "flat") {
      // A flat V1: a single open-ended block at the flat rate (V1 has no flat field).
      return { ...common, blocks: [{ uptoMin: null, priceMinorPerIncrement: toMinor(f.base.flat) }], dailyCapMinor: null };
    }
    return { ...common, blocks: baseBody.blocks ?? [], dailyCapMinor: baseBody.dailyCapMinor ?? null };
  }

  // Tiers present ⇒ V2. tz is stamped server-side from site config (left blank here).
  return {
    ...common,
    version: 2,
    tz: "",
    defaultCard: { name: "default", priority: 0, ...baseBody },
    windowedCards: f.tiers.map(tierToCard),
  };
}

export function TariffComposer() {
  const { t } = useTranslation();
  const [state, setState] = useState<TariffState | null>(null);
  const [form, setForm] = useState<FormState>(emptyForm);
  const [saving, setSaving] = useState(false);
  const [msg, setMsg] = useState<{ kind: "ok" | "err"; text: string } | null>(null);

  useEffect(() => {
    fetchTariff()
      .then((s) => {
        setState(s);
        setForm(formFromActive(s));
      })
      .catch((e) => setMsg({ kind: "err", text: (e as Error).message }));
  }, []);

  function set<K extends keyof FormState>(key: K, value: FormState[K]) {
    setForm((f) => ({ ...f, [key]: value }));
  }

  // --- pricing-body editing (used by the default card AND each tier) ---
  // `update` maps the old PricingForm to a new one; `target` selects which body:
  // the base card, or tier index N.
  function updatePricing(target: "base" | number, update: (p: PricingForm) => PricingForm) {
    setForm((f) => {
      if (target === "base") return { ...f, base: update(f.base) };
      return { ...f, tiers: f.tiers.map((tr, j) => (j === target ? { ...tr, pricing: update(tr.pricing) } : tr)) };
    });
  }
  function setBlock(target: "base" | number, i: number, patch: Partial<BlockForm>) {
    updatePricing(target, (p) => ({ ...p, blocks: p.blocks.map((b, j) => (j === i ? { ...b, ...patch } : b)) }));
  }
  // Insert a bounded band just BEFORE the open-ended tail, so the last block stays open-ended.
  function addBlock(target: "base" | number) {
    updatePricing(target, (p) => {
      const next = [...p.blocks];
      next.splice(p.blocks.length - 1, 0, { hours: "1", price: "0.00" });
      return { ...p, blocks: next };
    });
  }
  function removeBlock(target: "base" | number, i: number) {
    updatePricing(target, (p) => (i === p.blocks.length - 1 || p.blocks.length <= 1 ? p : { ...p, blocks: p.blocks.filter((_, j) => j !== i) }));
  }

  // --- tier editing ---
  function setTier(i: number, patch: Partial<TierForm>) {
    setForm((f) => ({ ...f, tiers: f.tiers.map((tr, j) => (j === i ? { ...tr, ...patch } : tr)) }));
  }
  function addTier() {
    setForm((f) => ({ ...f, tiers: [...f.tiers, emptyTier()] }));
  }
  function removeTier(i: number) {
    setForm((f) => ({ ...f, tiers: f.tiers.filter((_, j) => j !== i) }));
  }
  function toggleDow(i: number, d: number) {
    setForm((f) => ({
      ...f,
      tiers: f.tiers.map((tr, j) =>
        j === i ? { ...tr, dow: tr.dow.includes(d) ? tr.dow.filter((x) => x !== d) : [...tr.dow, d] } : tr,
      ),
    }));
  }

  async function publish() {
    setSaving(true);
    setMsg(null);
    try {
      await publishTariffVersion({ currency: form.currency.trim().toUpperCase(), structure: toStructure(form) });
      const fresh = await fetchTariff();
      setState(fresh);
      setMsg({ kind: "ok", text: t("tariff.publishedOk") });
    } catch (e) {
      const text =
        e instanceof ApiError && (e as ApiError & { problems?: string[] }).problems
          ? `${e.message}: ${((e as ApiError & { problems?: string[] }).problems ?? []).join("; ")}`
          : (e as Error).message;
      setMsg({ kind: "err", text });
    } finally {
      setSaving(false);
    }
  }

  return (
    <section className="mx-auto max-w-3xl px-4 py-6">
      <h2 className="mb-1 text-h4 font-semibold text-term-text">{t("tariff.title")}</h2>
      {!state?.active ? (
        <p className="mb-4 rounded-term border border-term-amber/50 bg-term-amber/10 px-3 py-2 text-[12px] text-term-amber">
          {t("tariff.noRateCard")}
        </p>
      ) : (
        <p className="mb-4 text-[12px] text-term-muted">
          {t("tariff.activeSince", {
            date: new Date(state.active.effectiveFrom).toLocaleString(),
            count: state.versions.length,
          })}
        </p>
      )}

      <div className="card card-body grid grid-cols-[max-content_1fr] items-center gap-x-4 gap-y-2">
        <label className="label">{t("tariff.currency")}</label>
        <input className="input w-24" value={form.currency} onChange={(e) => set("currency", e.target.value)} maxLength={3} />
        <label className="label">{t("tariff.freeEntryGrace")}</label>
        <input className="input w-32" value={form.gracePeriodEntryMin} onChange={(e) => set("gracePeriodEntryMin", e.target.value)} />
        <label className="label">{t("tariff.billingIncrement")}</label>
        <input className="input w-32" value={form.incrementMin} onChange={(e) => set("incrementMin", e.target.value)} />
        <label className="label">{t("tariff.lostTicketFee")}</label>
        <input className="input w-32" value={form.lostTicket} onChange={(e) => set("lostTicket", e.target.value)} />
        <label className="label">{t("tariff.exitGrace")}</label>
        <input className="input w-32" value={form.gracePeriodExitMin} onChange={(e) => set("gracePeriodExitMin", e.target.value)} />
      </div>

      {/* The DEFAULT card — always-active rate. Front-and-centre; a site that never
          wants tiers just edits this and publishes a bare V1 structure. */}
      <h3 className="mt-6 mb-0.5 text-h6 font-semibold uppercase tracking-wider text-term-text">{t("tariff.defaultCard")}</h3>
      <p className="hint mb-2">{t("tariff.defaultCardHint")}</p>
      <div className="card card-body">
        <PricingEditor
          t={t}
          pricing={form.base}
          onMode={(mode) => updatePricing("base", (p) => ({ ...p, mode }))}
          onFlat={(flat) => updatePricing("base", (p) => ({ ...p, flat }))}
          onCap={(dailyCap) => updatePricing("base", (p) => ({ ...p, dailyCap }))}
          onBlock={(i, patch) => setBlock("base", i, patch)}
          onAddBlock={() => addBlock("base")}
          onRemoveBlock={(i) => removeBlock("base", i)}
        />
      </div>

      {/* Advanced: time & seasonal/category TIERS (opt-in). Empty ⇒ V1 is published. */}
      <details className="mt-6" open={form.tiers.length > 0}>
        <summary className="cursor-pointer text-h6 font-semibold uppercase tracking-wider text-term-text">{t("tariff.tiersAdvanced")}</summary>
        <p className="hint mt-1.5 mb-2">{t("tariff.tiersHint")}</p>
        {form.tiers.map((tr, i) => (
          <fieldset key={i} className="card mb-3 p-4">
            <legend className="flex items-center gap-2 px-1">
              <input
                className="input w-40"
                value={tr.name}
                onChange={(e) => setTier(i, { name: e.target.value })}
                placeholder={t("tariff.tierName")}
              />
              <button type="button" className="btn btn-danger btn-sm" onClick={() => removeTier(i)}>
                {t("tariff.remove")}
              </button>
            </legend>
            <div className="grid grid-cols-[max-content_1fr] items-center gap-x-4 gap-y-2">
              <label className="label">{t("tariff.tierPriority")}</label>
              <input className="input w-20" value={tr.priority} onChange={(e) => setTier(i, { priority: e.target.value })} />
              <label className="label">{t("tariff.tierCategory")}</label>
              <input className="input w-40" value={tr.category} onChange={(e) => setTier(i, { category: e.target.value })} placeholder={t("tariff.tierCategoryPh")} />
              <label className="label">{t("tariff.tierDays")}</label>
              <span className="flex flex-wrap gap-2">
                {[1, 2, 3, 4, 5, 6, 0].map((d) => (
                  <label key={d} className="inline-flex items-center gap-1 text-[12px] text-term-text">
                    <input type="checkbox" className="accent-term-amber" checked={tr.dow.includes(d)} onChange={() => toggleDow(i, d)} />
                    {t(`tariff.dow${d}`)}
                  </label>
                ))}
              </span>
              <label className="label">{t("tariff.tierHours")}</label>
              <span className="inline-flex items-center gap-2">
                <input className="input w-20" value={tr.fromHour} onChange={(e) => setTier(i, { fromHour: e.target.value })} placeholder="22:00" />
                <span className="text-term-muted">–</span>
                <input className="input w-20" value={tr.toHour} onChange={(e) => setTier(i, { toHour: e.target.value })} placeholder="06:00" />
                {tr.fromHour && tr.toHour && tr.toHour <= tr.fromHour && (
                  <span className="text-[11px] text-term-muted">{t("tariff.tierOvernight")}</span>
                )}
              </span>
              <label className="label">{t("tariff.tierDates")}</label>
              <span className="inline-flex items-center gap-2">
                <input type="date" className="input w-40" value={tr.dateFrom} onChange={(e) => setTier(i, { dateFrom: e.target.value })} />
                <span className="text-term-muted">–</span>
                <input type="date" className="input w-40" value={tr.dateTo} onChange={(e) => setTier(i, { dateTo: e.target.value })} />
              </span>
            </div>
            <div className="mt-3 border-t border-term-border pt-3">
              <PricingEditor
                t={t}
                pricing={tr.pricing}
                onMode={(mode) => updatePricing(i, (p) => ({ ...p, mode }))}
                onFlat={(flat) => updatePricing(i, (p) => ({ ...p, flat }))}
                onCap={(dailyCap) => updatePricing(i, (p) => ({ ...p, dailyCap }))}
                onBlock={(bi, patch) => setBlock(i, bi, patch)}
                onAddBlock={() => addBlock(i)}
                onRemoveBlock={(bi) => removeBlock(i, bi)}
              />
            </div>
          </fieldset>
        ))}
        <button type="button" className="btn btn-sm" onClick={addTier}>
          {t("tariff.addTier")}
        </button>
      </details>

      <div className="mt-6 flex items-center gap-3">
        <button type="button" className="btn btn-primary btn-lg" onClick={publish} disabled={saving}>
          {saving ? t("tariff.publishing") : t("tariff.publishNewVersion")}
        </button>
        {msg && (
          <span className={msg.kind === "ok" ? "text-[12px] text-term-green" : "text-[12px] text-term-red"}>{msg.text}</span>
        )}
      </div>
    </section>
  );
}

// A reusable flat/ladder pricing-body editor — used by the default card and each tier.
function PricingEditor(props: {
  t: (k: string) => string;
  pricing: PricingForm;
  onMode: (m: "ladder" | "flat") => void;
  onFlat: (v: string) => void;
  onCap: (v: string) => void;
  onBlock: (i: number, patch: Partial<BlockForm>) => void;
  onAddBlock: () => void;
  onRemoveBlock: (i: number) => void;
}) {
  const { t, pricing: p } = props;
  return (
    <div>
      <div className="mb-3 flex gap-4 text-[12px]">
        <label className="inline-flex items-center gap-1.5 text-term-text">
          <input type="radio" className="accent-term-amber" checked={p.mode === "ladder"} onChange={() => props.onMode("ladder")} />
          {t("tariff.modeLadder")}
        </label>
        <label className="inline-flex items-center gap-1.5 text-term-text">
          <input type="radio" className="accent-term-amber" checked={p.mode === "flat"} onChange={() => props.onMode("flat")} />
          {t("tariff.modeFlat")}
        </label>
      </div>

      {p.mode === "flat" ? (
        <div className="inline-flex items-center gap-2">
          <span className="label">{t("tariff.pricePerIncrement")}</span>
          <input className="input w-28" value={p.flat} onChange={(e) => props.onFlat(e.target.value)} />
        </div>
      ) : (
        <>
          <table className="w-full border-collapse">
            <thead>
              <tr className="text-left">
                <th className="label px-2 pb-1 font-normal">{t("tariff.bandDuration")}</th>
                <th className="label px-2 pb-1 font-normal">{t("tariff.pricePerIncrement")}</th>
                <th />
              </tr>
            </thead>
            <tbody>
              {p.blocks.map((b, i) => {
                const isTail = i === p.blocks.length - 1;
                return (
                  <tr key={i}>
                    <td className="px-2 py-1">
                      {isTail ? (
                        <span className="italic text-term-muted">{t("tariff.thereafter")}</span>
                      ) : (
                        <span className="inline-flex items-center gap-2">
                          <input className="input w-20" value={b.hours} onChange={(e) => props.onBlock(i, { hours: e.target.value })} placeholder={t("tariff.egHours")} />
                          <span className="text-[11px] text-term-muted">{t("tariff.hoursUnit")}</span>
                        </span>
                      )}
                    </td>
                    <td className="px-2 py-1">
                      <input className="input w-28" value={b.price} onChange={(e) => props.onBlock(i, { price: e.target.value })} />
                    </td>
                    <td className="px-2">
                      {!isTail && (
                        <button type="button" className="btn btn-ghost btn-sm" onClick={() => props.onRemoveBlock(i)}>
                          {t("tariff.remove")}
                        </button>
                      )}
                    </td>
                  </tr>
                );
              })}
            </tbody>
          </table>
          <div className="mt-3 flex items-center gap-4">
            <button type="button" className="btn btn-sm" onClick={props.onAddBlock}>
              {t("tariff.addBlock")}
            </button>
            <span className="inline-flex items-center gap-2">
              <span className="label">{t("tariff.dailyCap")}</span>
              <input className="input w-28" value={p.dailyCap} onChange={(e) => props.onCap(e.target.value)} placeholder={t("tariff.dailyCapPh")} />
            </span>
          </div>
        </>
      )}
    </div>
  );
}