// ─── pages/users/EditUser.jsx ─────────────────────────────────────────────────
import { useEffect, useState }    from "react";
import { useParams, useNavigate } from "react-router-dom";
import { useUsers }               from "@/contexts/AdminUserContext";
import { toast }                  from "sonner";

import { useForm, Controller, useFieldArray } from "react-hook-form";
import { zodResolver }                        from "@hookform/resolvers/zod";
import { z }                                  from "zod";

import { Button }  from "@/components/ui/button";
import { Input }   from "@/components/ui/input";
import { Label }   from "@/components/ui/label";
import { Spinner } from "@/components/ui/spinner";
import {
  Select, SelectContent, SelectItem,
  SelectTrigger, SelectValue,
} from "@/components/ui/select";
import { ArrowLeft, Save, Plus, Trash2, UserCircle2 } from "lucide-react";

// ─── Schema ───────────────────────────────────────────────────────────────────
const addressSchema = z.object({
  address_type: z.enum(["home", "work", "province", "other"]),
  street:       z.string().min(1, "Street is required."),
  city:         z.string().min(1, "City is required."),
  state:        z.string().min(1, "State is required."),
  country:      z.string().min(1, "Country is required."),
  zip:          z.string().min(1, "ZIP is required."),
});

const phoneSchema = z.object({
  phone_type:   z.enum(["mobile", "home", "work", "other"]),
  country_code: z.string().min(1, "Country code is required."),
  number:       z.string().min(1, "Number is required."),
});

const editUserSchema = z.object({
  acc_type:       z.enum(["user", "staff", "admin"]),
  is_active:      z.boolean(),
  given_name:     z.string().min(1, "First name is required."),
  middle_name:    z.string().optional(),
  last_name:      z.string().min(1, "Last name is required."),
  extension_name: z.string().optional(),
  date_of_birth:  z.string().optional(),
  occupation:     z.string().optional(),
  addresses:      z.array(addressSchema).optional(),
  phone_number:   z.array(phoneSchema).optional(),
});

// ─── Defaults ─────────────────────────────────────────────────────────────────
const DEFAULT_ADDRESS = {
  address_type: "home", street: "", city: "",
  state: "", country: "", zip: "",
};

const DEFAULT_PHONE = {
  phone_type: "mobile", country_code: "63", number: "",
};

export default function EditUser() {
  const { id }   = useParams();
  const navigate = useNavigate();
  const { user, fetchUser, updateUser, loading } = useUsers();

  const [avatarPreview, setAvatarPreview] = useState(null);
  const [avatarFile,    setAvatarFile]    = useState(null);

  const {
    register,
    handleSubmit,
    control,
    reset,
    formState: { errors, isDirty },
  } = useForm({
    resolver:      zodResolver(editUserSchema),
    defaultValues: {
      acc_type: "user", is_active: true,
      given_name: "", middle_name: "", last_name: "",
      extension_name: "", date_of_birth: "", occupation: "",
      addresses: [], phone_number: [],
    },
  });

  // ─── Field arrays ──────────────────────────────────────────────────────────
  const {
    fields:  addressFields,
    append:  appendAddress,
    remove:  removeAddress,
  } = useFieldArray({ control, name: "addresses" });

  const {
    fields:  phoneFields,
    append:  appendPhone,
    remove:  removePhone,
  } = useFieldArray({ control, name: "phone_number" });

  // ─── Fetch user ────────────────────────────────────────────────────────────
  useEffect(() => { fetchUser(id); }, [id]);

  // ─── Populate form ────────────────────────────────────────────────────────
  useEffect(() => {
    if (!user) return;
    const info = user.personal_info ?? {};
    const name = info.name          ?? {};

    setAvatarPreview(info.avatar?.url ?? null);

    reset({
      acc_type:       user.acc_type        ?? "user",
      is_active:      user.is_active       ?? true,
      given_name:     name.given_name      ?? "",
      middle_name:    name.middle_name     ?? "",
      last_name:      name.last_name       ?? "",
      extension_name: name.extension_name  ?? "",
      date_of_birth:  info.date_of_birth   ?? "",
      occupation:     info.occupation      ?? "",
      addresses:      (info.addresses ?? []).map(({ full_address: _, ...rest }) => rest),
      phone_number:   (info.phone_number ?? []).map(({ full_number: _, ...rest }) => rest),
    });
  }, [user, reset]);

  // ─── Avatar preview ───────────────────────────────────────────────────────
  const handleAvatarChange = (e) => {
    const file = e.target.files?.[0];
    if (!file) return;
    setAvatarFile(file);
    setAvatarPreview(URL.createObjectURL(file));
  };

  // ─── Submit ───────────────────────────────────────────────────────────────
  const onSubmit = async (values) => {
    const payload = {
      acc_type:  values.acc_type,
      is_active: values.is_active,
      personal_info: {
        ...user.personal_info,
        date_of_birth: values.date_of_birth,
        occupation:    values.occupation,
        name: {
          ...user.personal_info?.name,
          given_name:     values.given_name,
          middle_name:    values.middle_name,
          last_name:      values.last_name,
          extension_name: values.extension_name,
        },
        addresses:    values.addresses,
        phone_number: values.phone_number,
        // ─── avatar handled separately via file upload API ────────────────
      },
    };

    const res = await updateUser(id, payload);
    if (res) {
      toast("User updated successfully.", {
        action: {
          label: "Close",
          onClick: () => {}
        }
      });
      navigate(`../view/${id}`);
    } else {
      toast("Failed to update user.", {
        action: {
          label: "Close",
          onClick: () => {}
        }
      });
    }
  };

  if (loading && !user) return (
    <div className="flex items-center justify-center h-screen">
      <Spinner className="size-8" />
    </div>
  );

  return (
    <form
      onSubmit={handleSubmit(onSubmit)}
      className="lg:container lg:mx-auto px-4 py-6 flex flex-col gap-6"
    >
      {/* ─── Header ──────────────────────────────────────────────────────── */}
      <div className="flex items-center justify-between">
        <div className="flex items-center gap-3">
          <Button type="button" variant="ghost" size="icon" onClick={() => navigate(`/admin/users`)}>
            <ArrowLeft className="size-4" />
          </Button>
          <div>
            <h1 className="text-2xl font-semibold tracking-tight">Edit User</h1>
            <p className="text-muted-foreground text-sm">{user?.email}</p>
          </div>
        </div>
        <Button type="submit" disabled={loading || !isDirty}>
          {loading ? <Spinner className="size-4 mr-2" /> : <Save className="size-4 mr-2" />}
          Save Changes
        </Button>
      </div>

      {/* ─── Avatar ──────────────────────────────────────────────────────── */}
      <EditSection title="Profile Picture">
        <div className="col-span-full flex items-center gap-6">
          {/* Preview */}
          <div className="size-24 rounded-full border-2 border-border overflow-hidden bg-muted flex items-center justify-center shrink-0">
            {avatarPreview
              ? <img src={avatarPreview} alt="Avatar" className="object-cover w-full h-full" />
              : <UserCircle2 className="size-12 text-muted-foreground" />
            }
          </div>

          {/* Upload */}
          <div className="flex flex-col gap-2">
            <Label className="text-xs text-muted-foreground">
              Upload new photo
            </Label>
            <Input
              type="file"
              accept="image/*"
              onChange={handleAvatarChange}
              className="w-fit cursor-pointer text-xs"
            />
            <p className="text-xs text-muted-foreground">
              JPG, PNG or WEBP. Avatar upload requires a separate file upload API.
            </p>
          </div>
        </div>
      </EditSection>

      {/* ─── Account Information ─────────────────────────────────────────── */}
      <EditSection title="Account Information">
        <EditField label="Account Type" error={errors.acc_type?.message} required>
          <Controller
            name="acc_type"
            control={control}
            render={({ field }) => (
              <Select value={field.value} onValueChange={field.onChange}>
                <SelectTrigger className={errors.acc_type ? "border-destructive" : ""}>
                  <SelectValue placeholder="Select type" />
                </SelectTrigger>
                <SelectContent>
                  <SelectItem value="user">User</SelectItem>
                  <SelectItem value="staff">Staff</SelectItem>
                  <SelectItem value="admin">Admin</SelectItem>
                </SelectContent>
              </Select>
            )}
          />
        </EditField>

        <EditField label="Status" error={errors.is_active?.message}>
          <Controller
            name="is_active"
            control={control}
            render={({ field }) => (
              <Select
                value={String(field.value)}
                onValueChange={(v) => field.onChange(v === "true")}
              >
                <SelectTrigger>
                  <SelectValue placeholder="Select status" />
                </SelectTrigger>
                <SelectContent>
                  <SelectItem value="true">Active</SelectItem>
                  <SelectItem value="false">Inactive</SelectItem>
                </SelectContent>
              </Select>
            )}
          />
        </EditField>
      </EditSection>

      {/* ─── Personal Information ─────────────────────────────────────────── */}
      <EditSection title="Personal Information">
        <EditField label="First Name" error={errors.given_name?.message} required>
          <Input {...register("given_name")} className={errors.given_name ? "border-destructive" : ""} placeholder="First name" />
        </EditField>
        <EditField label="Middle Name" error={errors.middle_name?.message}>
          <Input {...register("middle_name")} placeholder="Middle name" />
        </EditField>
        <EditField label="Last Name" error={errors.last_name?.message} required>
          <Input {...register("last_name")} className={errors.last_name ? "border-destructive" : ""} placeholder="Last name" />
        </EditField>
        <EditField label="Extension Name" error={errors.extension_name?.message}>
          <Input {...register("extension_name")} placeholder="e.g. Jr., Sr." />
        </EditField>
        <EditField label="Date of Birth" error={errors.date_of_birth?.message}>
          <Input type="date" {...register("date_of_birth")} />
        </EditField>
        <EditField label="Occupation" error={errors.occupation?.message}>
          <Input {...register("occupation")} placeholder="Occupation" />
        </EditField>
      </EditSection>

      {/* ─── Addresses ───────────────────────────────────────────────────── */}
      <div className="bg-card border rounded-lg p-6 flex flex-col gap-4">
        <div className="flex items-center justify-between">
          <h2 className="text-sm font-semibold text-muted-foreground uppercase tracking-wide">
            Addresses
          </h2>
          <Button
            type="button"
            variant="outline"
            size="sm"
            onClick={() => appendAddress(DEFAULT_ADDRESS)}
          >
            <Plus className="size-3.5 mr-1" /> Add Address
          </Button>
        </div>

        {addressFields.length === 0 && (
          <p className="text-sm text-muted-foreground">No addresses added.</p>
        )}

        {addressFields.map((field, i) => (
          <div key={field.id} className="border rounded-lg p-4 flex flex-col gap-4">
            {/* ─── Address Header ──────────────────────────────────────── */}
            <div className="flex items-center justify-between">
              <span className="text-sm font-medium">Address {i + 1}</span>
              <Button
                type="button"
                variant="ghost"
                size="icon"
                className="text-destructive hover:text-destructive"
                onClick={() => removeAddress(i)}
              >
                <Trash2 className="size-4" />
              </Button>
            </div>

            <div className="grid xs:grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-4">
              <EditField label="Type" error={errors.addresses?.[i]?.address_type?.message} required>
                <Controller
                  name={`addresses.${i}.address_type`}
                  control={control}
                  render={({ field }) => (
                    <Select value={field.value} onValueChange={field.onChange}>
                      <SelectTrigger><SelectValue placeholder="Select type" /></SelectTrigger>
                      <SelectContent>
                        <SelectItem value="home">Home</SelectItem>
                        <SelectItem value="work">Work</SelectItem>
                        <SelectItem value="province">Province</SelectItem>
                        <SelectItem value="other">Other</SelectItem>
                      </SelectContent>
                    </Select>
                  )}
                />
              </EditField>
              <EditField label="Street" error={errors.addresses?.[i]?.street?.message} required>
                <Input {...register(`addresses.${i}.street`)} placeholder="Street" />
              </EditField>
              <EditField label="City" error={errors.addresses?.[i]?.city?.message} required>
                <Input {...register(`addresses.${i}.city`)} placeholder="City" />
              </EditField>
              <EditField label="State / Region" error={errors.addresses?.[i]?.state?.message} required>
                <Input {...register(`addresses.${i}.state`)} placeholder="State / Region" />
              </EditField>
              <EditField label="Country" error={errors.addresses?.[i]?.country?.message} required>
                <Input {...register(`addresses.${i}.country`)} placeholder="Country" />
              </EditField>
              <EditField label="ZIP Code" error={errors.addresses?.[i]?.zip?.message} required>
                <Input {...register(`addresses.${i}.zip`)} placeholder="ZIP Code" />
              </EditField>
            </div>
          </div>
        ))}
      </div>

      {/* ─── Phone Numbers ───────────────────────────────────────────────── */}
      <div className="bg-card border rounded-lg p-6 flex flex-col gap-4">
        <div className="flex items-center justify-between">
          <h2 className="text-sm font-semibold text-muted-foreground uppercase tracking-wide">
            Phone Numbers
          </h2>
          <Button
            type="button"
            variant="outline"
            size="sm"
            onClick={() => appendPhone(DEFAULT_PHONE)}
          >
            <Plus className="size-3.5 mr-1" /> Add Phone
          </Button>
        </div>

        {phoneFields.length === 0 && (
          <p className="text-sm text-muted-foreground">No phone numbers added.</p>
        )}

        {phoneFields.map((field, i) => (
          <div key={field.id} className="border rounded-lg p-4 flex flex-col gap-4">
            <div className="flex items-center justify-between">
              <span className="text-sm font-medium">Phone {i + 1}</span>
              <Button
                type="button"
                variant="ghost"
                size="icon"
                className="text-destructive hover:text-destructive"
                onClick={() => removePhone(i)}
              >
                <Trash2 className="size-4" />
              </Button>
            </div>

            <div className="grid xs:grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-4">
              <EditField label="Type" error={errors.phone_number?.[i]?.phone_type?.message} required>
                <Controller
                  name={`phone_number.${i}.phone_type`}
                  control={control}
                  render={({ field }) => (
                    <Select value={field.value} onValueChange={field.onChange}>
                      <SelectTrigger><SelectValue placeholder="Select type" /></SelectTrigger>
                      <SelectContent>
                        <SelectItem value="mobile">Mobile</SelectItem>
                        <SelectItem value="home">Home</SelectItem>
                        <SelectItem value="work">Work</SelectItem>
                        <SelectItem value="other">Other</SelectItem>
                      </SelectContent>
                    </Select>
                  )}
                />
              </EditField>
              <EditField label="Country Code" error={errors.phone_number?.[i]?.country_code?.message} required>
                <Input {...register(`phone_number.${i}.country_code`)} placeholder="e.g. 63" />
              </EditField>
              <EditField label="Number" error={errors.phone_number?.[i]?.number?.message} required>
                <Input {...register(`phone_number.${i}.number`)} placeholder="e.g. 9123456789" />
              </EditField>
            </div>
          </div>
        ))}
      </div>

    </form>
  );
}

// ─── Reusable EditSection ─────────────────────────────────────────────────────
function EditSection({ title, children }) {
  return (
    <div className="bg-card border rounded-lg p-6 flex flex-col gap-4">
      <h2 className="text-sm font-semibold text-muted-foreground uppercase tracking-wide">
        {title}
      </h2>
      <div className="grid xs:grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-4">
        {children}
      </div>
    </div>
  );
}

// ─── Reusable EditField ───────────────────────────────────────────────────────
function EditField({ label, error, required, children }) {
  return (
    <div className="flex flex-col gap-1.5">
      <Label className="text-xs text-muted-foreground">
        {label}
        {required && <span className="text-destructive ml-1">*</span>}
      </Label>
      {children}
      {error && <p className="text-xs text-destructive">{error}</p>}
    </div>
  );
}