"use client";

import * as React from "react";
import {
  TextFieldRoot,
  TextFieldInput,
  SwitchRoot,
  SwitchControl,
  SwitchThumb,
  SwitchLabel,
  SwitchHiddenInput,
  Skeleton,
} from "@seed-design/react";
import { MercuryButton } from "@/ds/MercuryButton";
import { useSettings } from "@/api/hooks/reads";
import { useSaveSettings } from "@/api/hooks/mutations";
import type { Settings } from "@/api/schemas";
import { profileStrings } from "./strings";

interface FormState {
  holderName: string;
  employer: string;
  salaryKeywords: string;
  payDays: string;
  ownAccounts: string;
  peerAccounts: string;
  hideAmounts: boolean;
}

const EMPTY_FORM: FormState = {
  holderName: "",
  employer: "",
  salaryKeywords: "",
  payDays: "",
  ownAccounts: "",
  peerAccounts: "",
  hideAmounts: false,
};

function toFormState(settings: Settings | undefined): FormState {
  if (!settings) return EMPTY_FORM;
  return {
    holderName: settings.holderName,
    employer: settings.employer,
    salaryKeywords: settings.salaryKeywords.join(", "),
    payDays: settings.payDays.join(", "),
    ownAccounts: settings.ownAccounts.join(", "),
    peerAccounts: settings.peerAccounts.join(", "),
    hideAmounts: settings.hideAmounts ?? false,
  };
}

function splitList(value: string): string[] {
  return value
    .split(",")
    .map((v) => v.trim())
    .filter((v) => v.length > 0);
}

function splitNumberList(value: string): number[] {
  return splitList(value)
    .map((v) => Number(v))
    .filter((n) => Number.isFinite(n));
}

export interface SettingsFormProps {
  onBack?: () => void;
}

/** Edits the account-level settings (holder name, employer, salary detection
 * keywords/pay days, own/peer account lists, hide-amounts) that back the
 * backend's auto-categorization — not currently exposed anywhere in the iOS
 * app, but commissioned for the web app per the Task 13 brief. */
export function SettingsForm({ onBack }: SettingsFormProps) {
  const query = useSettings();
  const save = useSaveSettings();

  const initialized = React.useRef(Boolean(query.data));
  const [form, setForm] = React.useState<FormState>(() => toFormState(query.data));
  const [savedAt, setSavedAt] = React.useState<number | null>(null);

  React.useEffect(() => {
    if (!initialized.current && query.data) {
      setForm(toFormState(query.data));
      initialized.current = true;
    }
  }, [query.data]);

  function field(key: keyof Omit<FormState, "hideAmounts">) {
    return {
      value: form[key],
      onValueChange: (v: string) => setForm((f) => ({ ...f, [key]: v })),
    };
  }

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    setSavedAt(null);
    await save.mutateAsync({
      holderName: form.holderName.trim(),
      employer: form.employer.trim(),
      salaryKeywords: splitList(form.salaryKeywords),
      payDays: splitNumberList(form.payDays),
      ownAccounts: splitList(form.ownAccounts),
      peerAccounts: splitList(form.peerAccounts),
      hideAmounts: form.hideAmounts,
    });
    setSavedAt(Date.now());
  }

  if (query.isLoading && !query.data) {
    return (
      <div style={{ display: "flex", flexDirection: "column", gap: 12 }}>
        <Skeleton height="44px" />
        <Skeleton height="44px" />
        <Skeleton height="44px" />
      </div>
    );
  }

  return (
    <div style={{ display: "flex", flexDirection: "column", gap: 16 }}>
      <div style={{ display: "flex", alignItems: "center", gap: 12 }}>
        {onBack && (
          <button
            type="button"
            onClick={onBack}
            aria-label={profileStrings.settings.back}
            style={{ background: "none", border: "none", fontSize: 20, cursor: "pointer" }}
          >
            ←
          </button>
        )}
        <h1 style={{ fontSize: 16, fontWeight: 600, margin: 0 }}>{profileStrings.settings.title}</h1>
      </div>

      <form onSubmit={handleSubmit} style={{ display: "flex", flexDirection: "column", gap: 14 }}>
        <Labeled label={profileStrings.settings.holderName}>
          <TextFieldRoot {...field("holderName")} name="holderName">
            <TextFieldInput aria-label={profileStrings.settings.holderName} />
          </TextFieldRoot>
        </Labeled>

        <Labeled label={profileStrings.settings.employer}>
          <TextFieldRoot {...field("employer")} name="employer">
            <TextFieldInput aria-label={profileStrings.settings.employer} />
          </TextFieldRoot>
        </Labeled>

        <Labeled label={profileStrings.settings.salaryKeywords} hint={profileStrings.settings.salaryKeywordsHint}>
          <TextFieldRoot {...field("salaryKeywords")} name="salaryKeywords">
            <TextFieldInput aria-label={profileStrings.settings.salaryKeywords} />
          </TextFieldRoot>
        </Labeled>

        <Labeled label={profileStrings.settings.payDays} hint={profileStrings.settings.payDaysHint}>
          <TextFieldRoot {...field("payDays")} name="payDays">
            <TextFieldInput aria-label={profileStrings.settings.payDays} />
          </TextFieldRoot>
        </Labeled>

        <Labeled label={profileStrings.settings.ownAccounts} hint={profileStrings.settings.ownAccountsHint}>
          <TextFieldRoot {...field("ownAccounts")} name="ownAccounts">
            <TextFieldInput aria-label={profileStrings.settings.ownAccounts} />
          </TextFieldRoot>
        </Labeled>

        <Labeled label={profileStrings.settings.peerAccounts} hint={profileStrings.settings.peerAccountsHint}>
          <TextFieldRoot {...field("peerAccounts")} name="peerAccounts">
            <TextFieldInput aria-label={profileStrings.settings.peerAccounts} />
          </TextFieldRoot>
        </Labeled>

        <SwitchRoot
          checked={form.hideAmounts}
          onCheckedChange={(v: boolean) => setForm((f) => ({ ...f, hideAmounts: v }))}
        >
          {/* The actual interactive/accessible element (role="switch",
              checked/onChange) lives on the hidden input — SwitchControl and
              SwitchThumb are purely decorative (aria-hidden). Without this
              the switch renders but nothing is clickable or announced to
              assistive tech (same bug as ds/HideAmountsToggle.tsx). */}
          <SwitchHiddenInput />
          <SwitchControl>
            <SwitchThumb />
          </SwitchControl>
          <SwitchLabel>{profileStrings.settings.hideAmounts}</SwitchLabel>
        </SwitchRoot>

        {save.isError && (
          <p role="alert" style={{ fontSize: 13, color: "var(--seed-color-fg-critical)" }}>
            {profileStrings.settings.error}
          </p>
        )}
        {savedAt && !save.isPending && (
          <p style={{ fontSize: 13, color: "var(--seed-color-fg-muted, #6b7280)" }}>
            {profileStrings.settings.saved}
          </p>
        )}

        <MercuryButton type="submit" variant="primary" loading={save.isPending}>
          {profileStrings.settings.save}
        </MercuryButton>
      </form>
    </div>
  );
}

function Labeled({ label, hint, children }: { label: string; hint?: string; children: React.ReactNode }) {
  return (
    <label style={{ display: "flex", flexDirection: "column", gap: 4 }}>
      <span style={{ fontSize: 13, color: "var(--seed-color-fg-muted, #6b7280)" }}>{label}</span>
      {children}
      {hint && <span style={{ fontSize: 11, color: "var(--seed-color-fg-placeholder, #9ca3af)" }}>{hint}</span>}
    </label>
  );
}