"use client";

import { useState, useTransition } from "react";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Textarea } from "@/components/ui/textarea";
import { Switch } from "@/components/ui/switch";
import { submitInstallationAction, verifyInstallationTokenAction } from "../actions/install";
import type { InstallInput } from "../schema";

/**
 * Holds every wizard step's data as plain React state, not a signed
 * server-side draft — nothing is validated or written to the database
 * until the single final `submitInstallationAction` call on Step 9's
 * confirmation (see installer.service.ts's own header). That means a
 * page refresh loses progress, a deliberate simplification: this page is
 * only ever visited once, by the person physically standing up the
 * deployment, so "refresh loses your place" is a fair trade for not
 * needing a signed-cookie draft model and its own cleanup story.
 */

const WEEKDAYS = ["MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY", "SATURDAY", "SUNDAY"] as const;
type WeekdayCode = (typeof WEEKDAYS)[number];
const DAY_LABEL: Record<WeekdayCode, string> = {
  MONDAY: "Monday",
  TUESDAY: "Tuesday",
  WEDNESDAY: "Wednesday",
  THURSDAY: "Thursday",
  FRIDAY: "Friday",
  SATURDAY: "Saturday",
  SUNDAY: "Sunday",
};

interface HoursDayState {
  dayOfWeek: WeekdayCode;
  isClosed: boolean;
  startTime: string;
  endTime: string;
}

interface StarterServiceState {
  key: string;
  categoryName: string;
  name: string;
  description: string;
  price: string;
  durationMinutes: number;
  active: boolean;
  allowOnlineBooking: boolean;
}

function toMinutes(time: string): number {
  const [h, m] = time.split(":").map(Number);
  return (h ?? 0) * 60 + (m ?? 0);
}

const STEPS = [
  "Welcome",
  "Administrator",
  "Business Details",
  "Location & Contact",
  "Opening Hours",
  "Booking Settings",
  "Branding",
  "Starter Services",
  "Review",
] as const;

let starterServiceKeySeq = 0;
function newStarterServiceKey(): string {
  starterServiceKeySeq += 1;
  return `starter-${starterServiceKeySeq}`;
}

const DEFAULT_STARTER_SERVICES: StarterServiceState[] = [
  {
    key: newStarterServiceKey(),
    categoryName: "Haircuts",
    name: "Classic Haircut",
    description: "",
    price: "25.00",
    durationMinutes: 30,
    active: true,
    allowOnlineBooking: true,
  },
  {
    key: newStarterServiceKey(),
    categoryName: "Beard Services",
    name: "Beard Trim",
    description: "",
    price: "15.00",
    durationMinutes: 20,
    active: true,
    allowOnlineBooking: true,
  },
  {
    key: newStarterServiceKey(),
    categoryName: "Packages",
    name: "Haircut & Beard Combo",
    description: "",
    price: "35.00",
    durationMinutes: 45,
    active: true,
    allowOnlineBooking: true,
  },
];

export function InstallWizard() {
  const [step, setStep] = useState(1);
  const [isPending, startTransition] = useTransition();
  const [submitError, setSubmitError] = useState<string | null>(null);

  // Step 1
  const [token, setToken] = useState("");
  const [tokenError, setTokenError] = useState<string | null>(null);

  // Step 2
  const [admin, setAdmin] = useState({ firstName: "", lastName: "", email: "", phone: "", password: "", confirmPassword: "" });

  // Step 3
  const [business, setBusiness] = useState({ name: "", shortName: "", description: "", email: "", phone: "", website: "" });

  // Step 4
  const [location, setLocation] = useState({
    addressLine1: "",
    addressLine2: "",
    city: "",
    region: "",
    postalCode: "",
    country: "GB",
    timezone: "Europe/London",
    currency: "GBP",
    locale: "en-GB",
  });

  // Step 5
  const [hours, setHours] = useState<HoursDayState[]>(
    WEEKDAYS.map((dayOfWeek) => ({
      dayOfWeek,
      isClosed: dayOfWeek === "SUNDAY",
      startTime: "09:00",
      endTime: "18:00",
    })),
  );

  // Step 6 — guest booking defaults OFF, per the brief.
  const [bookingRules, setBookingRules] = useState({
    allowGuestBooking: false,
    minNoticeMinutes: 120,
    maxAdvanceDays: 60,
    cancellationWindowHours: 24,
    rescheduleWindowHours: 24,
    slotIntervalMinutes: 30,
    bufferBeforeMinutes: 0,
    bufferAfterMinutes: 5,
    maxAppointmentsPerDay: null as number | null,
    maxAppointmentsPerStaffPerDay: null as number | null,
    customerCanChooseStaff: true,
    requireApproval: false,
  });

  // Step 7
  const [branding, setBranding] = useState({ logoUrl: "", coverImageUrl: "", themeColor: "", backgroundColor: "" });

  // Step 8
  const [starterServices, setStarterServices] = useState<StarterServiceState[]>(DEFAULT_STARTER_SERVICES);

  const verifyToken = () => {
    setTokenError(null);
    startTransition(async () => {
      const result = await verifyInstallationTokenAction(token);
      if (!result.valid) {
        setTokenError(result.error ?? "Incorrect installation token.");
        return;
      }
      setStep(2);
    });
  };

  const updateDay = (dayOfWeek: WeekdayCode, patch: Partial<HoursDayState>) => {
    setHours((prev) => prev.map((d) => (d.dayOfWeek === dayOfWeek ? { ...d, ...patch } : d)));
  };
  const copyMondayToWeekdays = () => {
    const monday = hours.find((d) => d.dayOfWeek === "MONDAY");
    if (!monday) return;
    setHours((prev) =>
      prev.map((d) =>
        d.dayOfWeek === "SATURDAY" || d.dayOfWeek === "SUNDAY" || d.dayOfWeek === "MONDAY"
          ? d
          : { ...d, isClosed: monday.isClosed, startTime: monday.startTime, endTime: monday.endTime },
      ),
    );
  };
  const copyMondayToAll = () => {
    const monday = hours.find((d) => d.dayOfWeek === "MONDAY");
    if (!monday) return;
    setHours((prev) =>
      prev.map((d) => (d.dayOfWeek === "MONDAY" ? d : { ...d, isClosed: monday.isClosed, startTime: monday.startTime, endTime: monday.endTime })),
    );
  };

  const updateStarter = (key: string, patch: Partial<StarterServiceState>) => {
    setStarterServices((prev) => prev.map((s) => (s.key === key ? { ...s, ...patch } : s)));
  };
  const removeStarter = (key: string) => {
    setStarterServices((prev) => prev.filter((s) => s.key !== key));
  };
  const addStarter = () => {
    setStarterServices((prev) => [
      ...prev,
      {
        key: newStarterServiceKey(),
        categoryName: "Haircuts",
        name: "",
        description: "",
        price: "0.00",
        durationMinutes: 30,
        active: true,
        allowOnlineBooking: true,
      },
    ]);
  };

  const submit = () => {
    setSubmitError(null);
    const input: InstallInput = {
      installationToken: token,
      administrator: admin,
      business,
      location,
      hours: hours.map((d) => ({
        dayOfWeek: d.dayOfWeek,
        isClosed: d.isClosed,
        ...(d.isClosed ? {} : { opensAtMinutes: toMinutes(d.startTime), closesAtMinutes: toMinutes(d.endTime) }),
      })),
      bookingRules,
      branding,
      starterServices: starterServices
        .filter((s) => s.name.trim())
        .map((s) => ({
          categoryName: s.categoryName,
          name: s.name,
          description: s.description,
          price: s.price,
          durationMinutes: s.durationMinutes,
          active: s.active,
          allowOnlineBooking: s.allowOnlineBooking,
        })),
    };

    startTransition(async () => {
      const result = await submitInstallationAction(input);
      if (!result.success) {
        setSubmitError(result.error ?? "Installation failed. Please try again.");
      }
      // On success, submitInstallationAction signs the administrator in
      // and redirects server-side — nothing else to do here.
    });
  };

  const canProceedFromStep = (s: number): boolean => {
    switch (s) {
      case 2:
        return (
          !!admin.firstName.trim() &&
          !!admin.lastName.trim() &&
          !!admin.email.trim() &&
          admin.password.length >= 8 &&
          admin.password === admin.confirmPassword
        );
      case 3:
        return !!business.name.trim();
      case 4:
        return (
          !!location.addressLine1.trim() &&
          !!location.city.trim() &&
          !!location.postalCode.trim() &&
          !!location.timezone.trim() &&
          location.currency.trim().length === 3
        );
      default:
        return true;
    }
  };

  return (
    <div className="space-y-6">
      <div>
        <p className="text-muted text-[10px] font-bold tracking-widest uppercase">
          Step {step} of {STEPS.length} — {STEPS[step - 1]}
        </p>
        <div className="bg-line mt-2 h-1.5 w-full overflow-hidden rounded-full">
          <div className="bg-ink h-full rounded-full transition-all" style={{ width: `${(step / STEPS.length) * 100}%` }} />
        </div>
      </div>

      {step === 1 && (
        <div className="space-y-4">
          <h1 className="text-2xl font-bold">Set up your business</h1>
          <p className="text-muted text-sm">
            This wizard creates the first administrator account and configures your business — opening hours,
            booking rules, and branding. It only needs to run once.
          </p>
          <Input
            label="Installation Token"
            type="password"
            value={token}
            onChange={(e) => setToken(e.target.value)}
            error={tokenError ?? undefined}
            required
            autoComplete="off"
          />
          <Button className="w-full" isLoading={isPending} disabled={!token} onClick={verifyToken}>
            Continue
          </Button>
        </div>
      )}

      {step === 2 && (
        <div className="space-y-4">
          <h2 className="text-xl font-bold">Administrator account</h2>
          <p className="text-muted text-sm">This becomes the first owner — full permissions, protected from removal.</p>
          <div className="grid grid-cols-2 gap-3">
            <Input label="First Name" value={admin.firstName} onChange={(e) => setAdmin({ ...admin, firstName: e.target.value })} required />
            <Input label="Last Name" value={admin.lastName} onChange={(e) => setAdmin({ ...admin, lastName: e.target.value })} required />
          </div>
          <Input label="Email Address" type="email" value={admin.email} onChange={(e) => setAdmin({ ...admin, email: e.target.value })} required />
          <Input label="Phone (optional)" type="tel" value={admin.phone} onChange={(e) => setAdmin({ ...admin, phone: e.target.value })} />
          <Input
            label="Password"
            type="password"
            value={admin.password}
            onChange={(e) => setAdmin({ ...admin, password: e.target.value })}
            hint="At least 8 characters."
            required
          />
          <Input
            label="Confirm Password"
            type="password"
            value={admin.confirmPassword}
            onChange={(e) => setAdmin({ ...admin, confirmPassword: e.target.value })}
            error={admin.confirmPassword && admin.password !== admin.confirmPassword ? "Passwords don't match" : undefined}
            required
          />
          <StepNav onBack={() => setStep(1)} onNext={() => setStep(3)} nextDisabled={!canProceedFromStep(2)} />
        </div>
      )}

      {step === 3 && (
        <div className="space-y-4">
          <h2 className="text-xl font-bold">Business details</h2>
          <Input label="Business Name" value={business.name} onChange={(e) => setBusiness({ ...business, name: e.target.value })} required />
          <Input
            label="Short Name (optional)"
            hint="Used where space is tight, e.g. the home-screen icon label."
            value={business.shortName}
            onChange={(e) => setBusiness({ ...business, shortName: e.target.value })}
          />
          <Textarea
            label="Description (optional)"
            value={business.description}
            onChange={(e) => setBusiness({ ...business, description: e.target.value })}
          />
          <Input label="Business Email (optional)" type="email" value={business.email} onChange={(e) => setBusiness({ ...business, email: e.target.value })} />
          <Input label="Phone Number (optional)" type="tel" value={business.phone} onChange={(e) => setBusiness({ ...business, phone: e.target.value })} />
          <Input label="Website (optional)" value={business.website} onChange={(e) => setBusiness({ ...business, website: e.target.value })} />
          <StepNav onBack={() => setStep(2)} onNext={() => setStep(4)} nextDisabled={!canProceedFromStep(3)} />
        </div>
      )}

      {step === 4 && (
        <div className="space-y-4">
          <h2 className="text-xl font-bold">Location & contact</h2>
          <Input label="Address Line 1" value={location.addressLine1} onChange={(e) => setLocation({ ...location, addressLine1: e.target.value })} required />
          <Input label="Address Line 2 (optional)" value={location.addressLine2} onChange={(e) => setLocation({ ...location, addressLine2: e.target.value })} />
          <div className="grid grid-cols-2 gap-3">
            <Input label="Town / City" value={location.city} onChange={(e) => setLocation({ ...location, city: e.target.value })} required />
            <Input label="County (optional)" value={location.region} onChange={(e) => setLocation({ ...location, region: e.target.value })} />
          </div>
          <div className="grid grid-cols-2 gap-3">
            <Input label="Postcode" value={location.postalCode} onChange={(e) => setLocation({ ...location, postalCode: e.target.value })} required />
            <Input label="Country" value={location.country} onChange={(e) => setLocation({ ...location, country: e.target.value })} required />
          </div>
          <div className="grid grid-cols-3 gap-3">
            <Input label="Timezone" value={location.timezone} onChange={(e) => setLocation({ ...location, timezone: e.target.value })} required />
            <Input label="Currency" value={location.currency} onChange={(e) => setLocation({ ...location, currency: e.target.value.toUpperCase() })} maxLength={3} required />
            <Input label="Locale" value={location.locale} onChange={(e) => setLocation({ ...location, locale: e.target.value })} required />
          </div>
          <StepNav onBack={() => setStep(3)} onNext={() => setStep(5)} nextDisabled={!canProceedFromStep(4)} />
        </div>
      )}

      {step === 5 && (
        <div className="space-y-4">
          <h2 className="text-xl font-bold">Opening hours</h2>
          <div className="flex gap-4">
            <button type="button" onClick={copyMondayToWeekdays} className="text-accent text-xs font-bold tracking-widest uppercase underline">
              Copy Monday to weekdays
            </button>
            <button type="button" onClick={copyMondayToAll} className="text-accent text-xs font-bold tracking-widest uppercase underline">
              Copy Monday to all days
            </button>
          </div>
          <div className="divide-line rounded-md border-line divide-y border bg-white">
            {hours.map((day) => (
              <div key={day.dayOfWeek} className="flex items-center justify-between gap-4 px-5 py-4">
                <div className="flex items-center gap-3">
                  <Switch checked={!day.isClosed} onCheckedChange={(checked) => updateDay(day.dayOfWeek, { isClosed: !checked })} aria-label={`${DAY_LABEL[day.dayOfWeek]} open`} />
                  <p className="text-sm font-bold">{DAY_LABEL[day.dayOfWeek]}</p>
                </div>
                {day.isClosed ? (
                  <span className="text-muted text-xs">Closed</span>
                ) : (
                  <div className="flex items-center gap-2">
                    <input type="time" value={day.startTime} onChange={(e) => updateDay(day.dayOfWeek, { startTime: e.target.value })} className="border-line rounded-lg border px-2 py-1.5 text-xs" aria-label={`${DAY_LABEL[day.dayOfWeek]} opening time`} />
                    <span className="text-muted text-xs">to</span>
                    <input type="time" value={day.endTime} onChange={(e) => updateDay(day.dayOfWeek, { endTime: e.target.value })} className="border-line rounded-lg border px-2 py-1.5 text-xs" aria-label={`${DAY_LABEL[day.dayOfWeek]} closing time`} />
                  </div>
                )}
              </div>
            ))}
          </div>
          <StepNav onBack={() => setStep(4)} onNext={() => setStep(6)} />
        </div>
      )}

      {step === 6 && (
        <div className="space-y-4">
          <h2 className="text-xl font-bold">Booking settings</h2>
          <div className="rounded-md border-line border bg-white p-5">
            <Switch
              checked={bookingRules.allowGuestBooking}
              onCheckedChange={(checked) => setBookingRules({ ...bookingRules, allowGuestBooking: checked })}
              label="Allow customers to book as guests"
              description="When enabled, customers can book without creating an account. When disabled, customers must sign in or create an account before confirming their booking. Off is recommended — you can turn this on later in Booking Settings."
            />
          </div>
          <div className="grid grid-cols-2 gap-3">
            <Input
              label="Minimum Notice (minutes)"
              type="number"
              value={bookingRules.minNoticeMinutes}
              onChange={(e) => setBookingRules({ ...bookingRules, minNoticeMinutes: Number(e.target.value) })}
            />
            <Input
              label="Max Advance Booking (days)"
              type="number"
              value={bookingRules.maxAdvanceDays}
              onChange={(e) => setBookingRules({ ...bookingRules, maxAdvanceDays: Number(e.target.value) })}
            />
            <Input
              label="Cancellation Window (hours)"
              type="number"
              value={bookingRules.cancellationWindowHours}
              onChange={(e) => setBookingRules({ ...bookingRules, cancellationWindowHours: Number(e.target.value) })}
            />
            <Input
              label="Reschedule Window (hours)"
              type="number"
              value={bookingRules.rescheduleWindowHours}
              onChange={(e) => setBookingRules({ ...bookingRules, rescheduleWindowHours: Number(e.target.value) })}
            />
            <Input
              label="Slot Interval (minutes)"
              type="number"
              value={bookingRules.slotIntervalMinutes}
              onChange={(e) => setBookingRules({ ...bookingRules, slotIntervalMinutes: Number(e.target.value) })}
            />
          </div>
          <div className="rounded-md border-line space-y-3 border bg-white p-5">
            <Switch
              checked={bookingRules.customerCanChooseStaff}
              onCheckedChange={(checked) => setBookingRules({ ...bookingRules, customerCanChooseStaff: checked })}
              label="Customers can choose their barber"
            />
            <Switch
              checked={bookingRules.requireApproval}
              onCheckedChange={(checked) => setBookingRules({ ...bookingRules, requireApproval: checked })}
              label="New bookings require staff approval"
            />
          </div>
          <StepNav onBack={() => setStep(5)} onNext={() => setStep(7)} />
        </div>
      )}

      {step === 7 && (
        <div className="space-y-4">
          <h2 className="text-xl font-bold">Branding</h2>
          <p className="text-muted text-sm">
            Optional — every screen in the app uses your business name and these images/colours instead of the
            product name. You can add or change all of this later in Business Settings.
          </p>
          <Input label="Logo URL (optional)" placeholder="https://…" value={branding.logoUrl} onChange={(e) => setBranding({ ...branding, logoUrl: e.target.value })} />
          <Input label="Cover Image URL (optional)" placeholder="https://…" value={branding.coverImageUrl} onChange={(e) => setBranding({ ...branding, coverImageUrl: e.target.value })} />
          <div className="grid grid-cols-2 gap-3">
            <Input label="Theme Colour (optional)" placeholder="#111b15" value={branding.themeColor} onChange={(e) => setBranding({ ...branding, themeColor: e.target.value })} />
            <Input label="Background Colour (optional)" placeholder="#f4f6f4" value={branding.backgroundColor} onChange={(e) => setBranding({ ...branding, backgroundColor: e.target.value })} />
          </div>
          <StepNav onBack={() => setStep(6)} onNext={() => setStep(8)} />
        </div>
      )}

      {step === 8 && (
        <div className="space-y-4">
          <h2 className="text-xl font-bold">Starter services</h2>
          <p className="text-muted text-sm">
            A small editable starting point so your booking page isn&apos;t empty on day one. Edit, remove, or add
            your own before finishing setup.
          </p>
          <div className="space-y-3">
            {starterServices.map((s) => (
              <div key={s.key} className="rounded-md border-line space-y-3 border bg-white p-4">
                <div className="flex items-center justify-between">
                  <p className="text-muted text-[10px] font-bold tracking-widest uppercase">Service</p>
                  <button type="button" onClick={() => removeStarter(s.key)} className="text-danger text-xs font-bold uppercase">
                    Remove
                  </button>
                </div>
                <div className="grid grid-cols-2 gap-3">
                  <Input label="Category" value={s.categoryName} onChange={(e) => updateStarter(s.key, { categoryName: e.target.value })} />
                  <Input label="Service Name" value={s.name} onChange={(e) => updateStarter(s.key, { name: e.target.value })} />
                </div>
                <div className="grid grid-cols-2 gap-3">
                  <Input label="Price" value={s.price} onChange={(e) => updateStarter(s.key, { price: e.target.value })} />
                  <Input label="Duration (minutes)" type="number" value={s.durationMinutes} onChange={(e) => updateStarter(s.key, { durationMinutes: Number(e.target.value) })} />
                </div>
              </div>
            ))}
          </div>
          <Button variant="secondary" className="w-full" onClick={addStarter}>
            Add Another Service
          </Button>
          <StepNav onBack={() => setStep(7)} onNext={() => setStep(9)} />
        </div>
      )}

      {step === 9 && (
        <div className="space-y-4">
          <h2 className="text-xl font-bold">Review</h2>
          <ReviewSection title="Administrator">
            {admin.firstName} {admin.lastName} · {admin.email}
          </ReviewSection>
          <ReviewSection title="Business">{business.name}</ReviewSection>
          <ReviewSection title="Location">
            {location.addressLine1}, {location.city}, {location.postalCode} · {location.timezone} · {location.currency}
          </ReviewSection>
          <ReviewSection title="Opening Hours">
            {hours.filter((d) => !d.isClosed).length} day{hours.filter((d) => !d.isClosed).length === 1 ? "" : "s"} open
          </ReviewSection>
          <ReviewSection title="Booking Settings">
            Guest booking {bookingRules.allowGuestBooking ? "enabled" : "disabled"} · {bookingRules.requireApproval ? "requires approval" : "auto-confirms"}
          </ReviewSection>
          <ReviewSection title="Branding">{branding.logoUrl ? "Logo set" : "No logo yet — add one later in Business Settings"}</ReviewSection>
          <ReviewSection title="Starter Services">
            {starterServices.filter((s) => s.name.trim()).length} service{starterServices.filter((s) => s.name.trim()).length === 1 ? "" : "s"}
          </ReviewSection>

          {submitError && (
            <p role="alert" className="text-danger text-sm font-medium">
              {submitError}
            </p>
          )}

          <div className="flex gap-3">
            <Button variant="secondary" className="flex-1" onClick={() => setStep(8)} disabled={isPending}>
              Back
            </Button>
            <Button className="flex-1" isLoading={isPending} onClick={submit}>
              Confirm & Install
            </Button>
          </div>
        </div>
      )}
    </div>
  );
}

function StepNav({ onBack, onNext, nextDisabled }: { onBack: () => void; onNext: () => void; nextDisabled?: boolean }) {
  return (
    <div className="flex gap-3">
      <Button variant="secondary" className="flex-1" onClick={onBack}>
        Back
      </Button>
      <Button className="flex-1" onClick={onNext} disabled={nextDisabled}>
        Continue
      </Button>
    </div>
  );
}

function ReviewSection({ title, children }: { title: string; children: React.ReactNode }) {
  return (
    <div className="rounded-md border-line border bg-white p-4">
      <p className="text-muted text-[10px] font-bold tracking-widest uppercase">{title}</p>
      <p className="mt-1 text-sm">{children}</p>
    </div>
  );
}