"use client";

import { useState, useEffect } from "react";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { Textarea } from "@/components/ui/textarea";
import { Separator } from "@/components/ui/separator";
import { Sheet, SheetContent, SheetHeader, SheetTitle, SheetDescription, SheetFooter } from "@/components/ui/sheet";
import { toast } from "sonner";
import { Loader2, User, Building2, Mail, Phone, AtSign, MapPin, FileText } from "lucide-react";
import getPocketBase from "@/lib/pocketbase";
import { getAllCompanies } from "@/lib/pb-helpers";
import { CompanySearch } from "@/components/ui/company-search";
import { UserSearch } from "@/components/ui/user-search";
import type { Company, Customer } from "@/lib/types";

interface CustomerFormProps {
  open: boolean;
  onOpenChange: (open: boolean) => void;
  customer?: Customer | null;
  onSaved: () => void;
}

/**
 * Treat PB's `{ lon: 0, lat: 0 }` (Null Island) as "no coordinates".
 * PB geoPoint is non-nullable with this zero default — masking it
 * keeps every unset customer from showing up at sea.
 */
function hasRealCoordinates(c: Customer["coordinates"]): c is { lon: number; lat: number } {
  return !!c && (c.lon !== 0 || c.lat !== 0);
}

export function CustomerForm({ open, onOpenChange, customer, onSaved }: CustomerFormProps) {
  const [loading, setLoading] = useState(false);
  const [companies, setCompanies] = useState<Company[]>([]);
  const [form, setForm] = useState({
    customer: "",
    email: "",
    alternative_email: "",
    buyer_email: "",
    number: "",
    company: "",
    rep: "",
    lat: "",
    lon: "",
    description: "",
  });

  // Lazy-load companies for the company combobox the first time the
  // sheet opens. Cheap (small table) and the user opens the form
  // infrequently, so we don't bother with a context or page-level
  // prefetch.
  useEffect(() => {
    if (!open || companies.length > 0) return;
    let cancelled = false;
    getAllCompanies()
      .then((data) => {
        if (!cancelled) setCompanies(data);
      })
      .catch(() => {
        // best-effort — combobox will just show empty list
      });
    return () => {
      cancelled = true;
    };
  }, [open, companies.length]);

  useEffect(() => {
    if (customer) {
      setForm({
        customer: customer.customer || "",
        email: customer.email || "",
        alternative_email: customer.alternative_email || "",
        buyer_email: customer.buyer_email || "",
        number: customer.number || "",
        company: customer.company || "",
        rep: customer.rep || "",
        lat: hasRealCoordinates(customer.coordinates) ? String(customer.coordinates.lat) : "",
        lon: hasRealCoordinates(customer.coordinates) ? String(customer.coordinates.lon) : "",
        description: customer.description || "",
      });
    } else {
      setForm({
        customer: "",
        email: "",
        alternative_email: "",
        buyer_email: "",
        number: "",
        company: "",
        rep: "",
        lat: "",
        lon: "",
        description: "",
      });
    }
  }, [customer, open]);

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!form.customer.trim()) {
      toast.error("Customer name is required");
      return;
    }

    // Coordinates: blank → PB default {0,0}; both-or-neither, range-checked.
    const latTrim = form.lat.trim();
    const lonTrim = form.lon.trim();
    let coordinatesPayload: { lon: number; lat: number };
    if (!latTrim && !lonTrim) {
      coordinatesPayload = { lon: 0, lat: 0 };
    } else {
      if (!latTrim || !lonTrim) {
        toast.error("Enter both latitude and longitude, or leave both blank.");
        return;
      }
      const lat = Number(latTrim);
      const lon = Number(lonTrim);
      if (!Number.isFinite(lat) || !Number.isFinite(lon)) {
        toast.error("Coordinates must be numbers.");
        return;
      }
      if (lat < -90 || lat > 90) {
        toast.error("Latitude must be between -90 and 90.");
        return;
      }
      if (lon < -180 || lon > 180) {
        toast.error("Longitude must be between -180 and 180.");
        return;
      }
      coordinatesPayload = { lon, lat };
    }

    setLoading(true);
    try {
      const pb = getPocketBase();
      // `company` and `rep` are relation ids — PB stores them as
      // strings; passing "" unsets the relation. `dateadded` /
      // `lastvisiteddate` mirror the legacy fields (still useful for
      // sorting / display on the list page).
      const data = {
        customer: form.customer,
        email: form.email,
        alternative_email: form.alternative_email,
        buyer_email: form.buyer_email,
        number: form.number,
        company: form.company,
        rep: form.rep,
        coordinates: coordinatesPayload,
        description: form.description,
        dateadded: customer?.dateadded || new Date().toISOString(),
        lastvisiteddate: new Date().toISOString(),
      };
      if (customer) {
        await pb.collection("customers").update(customer.id, data);
        toast.success("Customer updated");
      } else {
        await pb.collection("customers").create(data);
        toast.success("Customer created");
      }
      onSaved();
      onOpenChange(false);
    } catch (err: unknown) {
      const message = err instanceof Error ? err.message : "Failed to save customer";
      toast.error(message);
    } finally {
      setLoading(false);
    }
  };

  const FieldLabel = ({ icon: Icon, label }: { icon: React.ElementType; label: string }) => (
    <Label className="flex items-center gap-1.5 text-xs font-medium text-muted-foreground mb-1">
      <Icon className="h-3 w-3" />
      {label}
    </Label>
  );

  return (
    <Sheet open={open} onOpenChange={onOpenChange}>
      <SheetContent className="w-full sm:max-w-lg overflow-y-auto p-0 flex flex-col">
        <SheetHeader className="px-6 pt-6 pb-2 border-b">
          <SheetTitle className="text-lg flex items-center gap-2">
            <div className="flex h-8 w-8 items-center justify-center rounded-md bg-primary/10 text-primary">
              <User className="h-4 w-4" />
            </div>
            {customer ? "Edit Customer" : "New Customer"}
          </SheetTitle>
          <SheetDescription>
            {customer ? "Update customer details" : "Add a new customer to your CRM"}
          </SheetDescription>
        </SheetHeader>

        <form onSubmit={handleSubmit} className="flex-1 overflow-y-auto">
          <div className="space-y-6 px-6 py-5">
            <div className="space-y-4">
              <div>
                <FieldLabel icon={User} label="Customer Name *" />
                <Input
                  value={form.customer}
                  onChange={(e) => setForm({ ...form, customer: e.target.value })}
                  required
                  placeholder="Full name or business name"
                  className="h-9"
                />
              </div>
              <div>
                <FieldLabel icon={Building2} label="Company" />
                <CompanySearch
                  value={form.company}
                  onValueChange={(id) => setForm({ ...form, company: id })}
                  companies={companies}
                  placeholder="Select company..."
                />
                <p className="text-[11px] text-muted-foreground mt-1.5">
                  The company the customer works for. Delivery address
                  is captured below — different shafts may share the
                  same company but deliver to different coordinates.
                </p>
              </div>
            </div>

            <Separator />

            <div className="space-y-4">
              <p className="text-xs font-medium text-muted-foreground uppercase tracking-wider">Contact</p>
              <div className="grid grid-cols-2 gap-4">
                <div>
                  <FieldLabel icon={Mail} label="Email" />
                  <Input
                    type="email"
                    value={form.email}
                    onChange={(e) => setForm({ ...form, email: e.target.value })}
                    placeholder="email@example.com"
                    className="h-9"
                  />
                </div>
                <div>
                  <FieldLabel icon={Phone} label="Phone" />
                  <Input
                    value={form.number}
                    onChange={(e) => setForm({ ...form, number: e.target.value })}
                    placeholder="Phone number"
                    className="h-9"
                  />
                </div>
              </div>
              <div className="grid grid-cols-2 gap-4">
                <div>
                  <FieldLabel icon={AtSign} label="Alt Email" />
                  <Input
                    type="email"
                    value={form.alternative_email}
                    onChange={(e) => setForm({ ...form, alternative_email: e.target.value })}
                    placeholder="alternative@example.com"
                    className="h-9"
                  />
                </div>
                <div>
                  <FieldLabel icon={AtSign} label="Buyer Email" />
                  <Input
                    type="email"
                    value={form.buyer_email}
                    onChange={(e) => setForm({ ...form, buyer_email: e.target.value })}
                    placeholder="buyer@example.com"
                    className="h-9"
                  />
                </div>
              </div>
            </div>

            <Separator />

            <div className="space-y-4">
              <p className="text-xs font-medium text-muted-foreground uppercase tracking-wider">Details</p>
              <div>
                <FieldLabel icon={User} label="Sales Rep" />
                <UserSearch
                  value={form.rep}
                  onValueChange={(id) => setForm({ ...form, rep: id })}
                  placeholder="Select sales rep..."
                />
              </div>
              <div>
                <FieldLabel icon={MapPin} label="Delivery Coordinates" />
                <div className="grid grid-cols-2 gap-3">
                  <Input
                    value={form.lat}
                    onChange={(e) => setForm({ ...form, lat: e.target.value })}
                    type="number"
                    step="any"
                    placeholder="Latitude"
                    className="h-9"
                    aria-label="Latitude"
                  />
                  <Input
                    value={form.lon}
                    onChange={(e) => setForm({ ...form, lon: e.target.value })}
                    type="number"
                    step="any"
                    placeholder="Longitude"
                    className="h-9"
                    aria-label="Longitude"
                  />
                </div>
                <p className="text-[11px] text-muted-foreground mt-1.5">
                  Leave both blank if unknown. Used later for routing /
                  delivery. Example: -26.2041, 28.0473 (Johannesburg).
                </p>
              </div>
              <div>
                <FieldLabel icon={FileText} label="Description" />
                <Textarea
                  value={form.description}
                  onChange={(e) => setForm({ ...form, description: e.target.value })}
                  rows={2}
                  placeholder="Optional notes..."
                  className="resize-none text-sm"
                />
              </div>
            </div>
          </div>

          <SheetFooter className="px-6 pb-6 border-t pt-4">
            <Button type="submit" disabled={loading} className="w-full">
              {loading && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
              {customer ? "Save Changes" : "Create Customer"}
            </Button>
          </SheetFooter>
        </form>
      </SheetContent>
    </Sheet>
  );
}