"use client";

import { useRef, useState } from "react";
import { useRouter } from "next/navigation";
import Image from "next/image";
import { useAuth } from "@/components/auth/auth-provider";
import { auth, AuthError, type User } from "@/lib/auth";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";

/**
 * Profile edit form. Two responsibilities:
 *
 *   1. Inline name edit (debounced save on form submit).
 *   2. Avatar upload via R2 presigned PUT:
 *        click [Change] → presign → PUT to R2 → PATCH /users/me with new URL.
 *
 * The new avatar URL appended with a `?v=<random>` cache-buster forces the
 * browser to fetch the new image even if the key happened to collide
 * (extremely unlikely given our random suffix, but cheap insurance).
 */
export function ProfileForm({ user }: { user: User }) {
  const router = useRouter();
  const { logOut, setUser } = useAuth();
  const fileInput = useRef<HTMLInputElement>(null);

  const [name, setName] = useState(user.name);
  const [avatarUrl, setAvatarUrl] = useState<string | null>(user.avatar_url);
  const [saving, setSaving] = useState(false);
  const [uploading, setUploading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [success, setSuccess] = useState<string | null>(null);

  async function onSave(e: React.SyntheticEvent) {
    e.preventDefault();
    setError(null);
    setSuccess(null);
    setSaving(true);
    try {
      const updated = await auth.updateProfile(name);
      setUser(updated);
      setSuccess("Profile saved.");
    } catch (err) {
      setError(err instanceof AuthError ? err.message : "Could not save.");
    } finally {
      setSaving(false);
    }
  }

  async function onAvatarChange(e: React.ChangeEvent<HTMLInputElement>) {
    const file = e.target.files?.[0];
    if (!file) return;
    setError(null);
    setSuccess(null);
    setUploading(true);
    try {
      const publicURL = await auth.uploadAvatar(file);
      const updated = await auth.updateProfile(undefined, publicURL);
      setUser(updated);
      setAvatarUrl(updated.avatar_url);
      setSuccess("Avatar updated.");
    } catch (err) {
      setError(err instanceof AuthError ? err.message : "Upload failed.");
    } finally {
      setUploading(false);
      if (fileInput.current) fileInput.current.value = "";
    }
  }

  async function onRemoveAvatar() {
    setError(null);
    setUploading(true);
    try {
      const updated = await auth.updateProfile(undefined, "");
      setUser(updated);
      setAvatarUrl(null);
    } catch (err) {
      setError(err instanceof AuthError ? err.message : "Could not remove avatar.");
    } finally {
      setUploading(false);
    }
  }

  async function onLogout() {
    await logOut();
    router.push("/");
    router.refresh();
  }

  return (
    <div className="space-y-8">
      <section className="space-y-4">
        <h2 className="font-heading text-lg font-medium">Avatar</h2>
        <div className="flex items-center gap-4">
          <AvatarPreview src={avatarUrl} name={user.name} />
          <div className="flex flex-col gap-2">
            <input
              ref={fileInput}
              type="file"
              accept="image/png,image/jpeg,image/webp,image/gif"
              hidden
              onChange={onAvatarChange}
            />
            <Button
              variant="outline"
              type="button"
              onClick={() => fileInput.current?.click()}
              disabled={uploading}
              className="h-11 px-5 text-base"
            >
              {uploading ? "Uploading…" : avatarUrl ? "Change avatar" : "Upload avatar"}
            </Button>
            {avatarUrl ? (
              <Button
                variant="ghost"
                type="button"
                onClick={onRemoveAvatar}
                disabled={uploading}
                className="h-11 px-5 text-base"
              >
                Remove
              </Button>
            ) : null}
          </div>
        </div>
      </section>

      <form onSubmit={onSave} className="space-y-4">
        <h2 className="font-heading text-lg font-medium">Details</h2>
        <div className="space-y-1.5">
          <Label htmlFor="email">Email</Label>
          <Input id="email" value={user.email} disabled />
          <p className="text-xs text-muted-foreground">
            Email changes aren&apos;t supported yet — drop us a note if you need this.
          </p>
        </div>
        <div className="space-y-1.5">
          <Label htmlFor="name">Display name</Label>
          <Input
            id="name"
            value={name}
            onChange={(e) => setName(e.target.value)}
            maxLength={120}
            required
          />
        </div>
        {error ? <p className="text-sm text-destructive">{error}</p> : null}
        {success ? <p className="text-sm text-emerald-600">{success}</p> : null}
        <div className="flex justify-between items-center pt-2">
          <Button
            type="submit"
            disabled={saving || name === user.name}
            className="h-11 px-6 text-base"
          >
            {saving ? "Saving…" : "Save changes"}
          </Button>
          <Button
            type="button"
            variant="ghost"
            onClick={onLogout}
            className="h-11 px-5 text-base"
          >
            Log out
          </Button>
        </div>
      </form>
    </div>
  );
}

function AvatarPreview({ src, name }: { src: string | null; name: string }) {
  if (src) {
    return (
      <Image
        src={src}
        alt={name}
        width={80}
        height={80}
        className="size-20 rounded-full object-cover ring-1 ring-foreground/10"
        unoptimized
      />
    );
  }
  const initials =
    name
      .split(/\s+/)
      .map((p) => p[0])
      .slice(0, 2)
      .join("")
      .toUpperCase() || "?";
  return (
    <div className="size-20 rounded-full bg-muted flex items-center justify-center text-2xl font-medium text-muted-foreground ring-1 ring-foreground/10">
      {initials}
    </div>
  );
}