"use client";

import { useRef, useState } from "react";
import Image from "next/image";
import Link from "next/link";
import { useTranslations } from "next-intl";
import { toast } from "sonner";
import { ExternalLink, Paperclip, X, FileText, MessageSquare } from "lucide-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 { Badge } from "@/components/ui/badge";
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select";
import { uploadToPresignedPost } from "@/lib/upload-client";

type TicketType = "bug" | "suggestion" | "question";
type TicketStatus = "open" | "triaged" | "closed";

type Attachment = { id: string; contentType: string; url: string };

type Comment = { id: string; authorType: "user" | "admin" | "gitea"; body: string; createdAt: string };

type Ticket = {
  id: string;
  type: TicketType;
  title: string;
  description: string;
  status: TicketStatus;
  giteaIssueUrl: string | null;
  createdAt: string;
  attachments: Attachment[];
};

type PendingAttachment = {
  key: string;
  contentType: string;
  sizeBytes: number;
  preview: string | null;
  name: string;
};

const MAX_ATTACHMENTS = 5;
const MAX_FILE_SIZE = 10 * 1024 * 1024;
const ACCEPT = "image/jpeg,image/png,image/webp,image/avif,image/gif,application/pdf,text/plain,application/json,application/zip";

function formatDate(iso: string) {
  return new Date(iso).toLocaleDateString(undefined, {
    year: "numeric",
    month: "short",
    day: "numeric",
  });
}

function isImage(contentType: string) {
  return contentType.startsWith("image/");
}

export function SupportManager({
  initialTickets,
  prefill,
}: {
  initialTickets: Ticket[];
  prefill?: { type: TicketType; title: string };
}) {
  const t = useTranslations("support");
  const [tickets, setTickets] = useState<Ticket[]>(initialTickets);
  const [type, setType] = useState<TicketType>(prefill?.type ?? "bug");
  const [title, setTitle] = useState(prefill?.title ?? "");
  const [description, setDescription] = useState("");
  const [submitting, setSubmitting] = useState(false);
  const [pendingAttachments, setPendingAttachments] = useState<PendingAttachment[]>([]);
  const [uploadingCount, setUploadingCount] = useState(0);
  const inputRef = useRef<HTMLInputElement>(null);
  const [expandedId, setExpandedId] = useState<string | null>(null);
  const [comments, setComments] = useState<Record<string, Comment[]>>({});
  const [commentDraft, setCommentDraft] = useState("");
  const [sendingComment, setSendingComment] = useState(false);

  async function toggleConversation(ticketId: string) {
    if (expandedId === ticketId) {
      setExpandedId(null);
      return;
    }
    setExpandedId(ticketId);
    setCommentDraft("");
    if (!comments[ticketId]) {
      try {
        const res = await fetch(`/api/v1/support/${ticketId}/comments`);
        if (res.ok) {
          const data = (await res.json()) as Comment[];
          setComments((prev) => ({ ...prev, [ticketId]: data }));
        }
      } catch {
        // leave the section empty — the send box below still works
      }
    }
  }

  async function sendComment(ticketId: string) {
    const body = commentDraft.trim();
    if (!body) return;
    setSendingComment(true);
    try {
      const res = await fetch(`/api/v1/support/${ticketId}/comments`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ body }),
      });
      if (!res.ok) throw new Error();
      const comment = (await res.json()) as Comment;
      setComments((prev) => ({ ...prev, [ticketId]: [...(prev[ticketId] ?? []), comment] }));
      setCommentDraft("");
    } catch {
      toast.error(t("commentSendFailed"));
    } finally {
      setSendingComment(false);
    }
  }

  async function handleFiles(files: FileList) {
    const room = MAX_ATTACHMENTS - pendingAttachments.length;
    const toUpload = Array.from(files).slice(0, Math.max(0, room));
    if (files.length > toUpload.length) {
      toast.error(t("attachmentLimitReached", { count: MAX_ATTACHMENTS }));
    }
    setUploadingCount((c) => c + toUpload.length);
    for (const file of toUpload) {
      if (file.size > MAX_FILE_SIZE) {
        toast.error(t("attachmentTooLarge", { name: file.name }));
        setUploadingCount((c) => c - 1);
        continue;
      }
      try {
        const res = await fetch("/api/v1/support/attachments/presign", {
          method: "POST",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify({ contentType: file.type, fileSize: file.size }),
        });
        if (!res.ok) throw new Error();
        const { url, fields, key } = (await res.json()) as { url: string; fields: Record<string, string>; key: string };
        const uploaded = await uploadToPresignedPost(url, fields, file);
        if (!uploaded) throw new Error();
        setPendingAttachments((prev) => [
          ...prev,
          {
            key,
            contentType: file.type,
            sizeBytes: file.size,
            preview: isImage(file.type) ? URL.createObjectURL(file) : null,
            name: file.name,
          },
        ]);
      } catch {
        toast.error(t("attachmentUploadFailed", { name: file.name }));
      } finally {
        setUploadingCount((c) => c - 1);
      }
    }
  }

  function removePending(key: string) {
    setPendingAttachments((prev) => prev.filter((a) => a.key !== key));
  }

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    if (title.trim().length < 3 || description.trim().length < 10) return;
    setSubmitting(true);
    try {
      const res = await fetch("/api/v1/support", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          type,
          title: title.trim(),
          description: description.trim(),
          attachments: pendingAttachments.map((a) => ({
            key: a.key,
            contentType: a.contentType,
            sizeBytes: a.sizeBytes,
          })),
        }),
      });
      if (!res.ok) {
        const data = (await res.json()) as { error?: string };
        throw new Error(data.error ?? t("submitFailed"));
      }
      const ticket = (await res.json()) as Ticket;
      setTickets((prev) => [ticket, ...prev]);
      setTitle("");
      setDescription("");
      setType("bug");
      setPendingAttachments([]);
      toast.success(t("submitSuccess"));
    } catch (err) {
      toast.error(err instanceof Error ? err.message : t("submitFailed"));
    } finally {
      setSubmitting(false);
    }
  }

  const statusVariant: Record<TicketStatus, "default" | "secondary" | "outline"> = {
    open: "default",
    triaged: "secondary",
    closed: "outline",
  };

  return (
    <div className="space-y-8">
      <form onSubmit={handleSubmit} className="space-y-4">
        <div className="space-y-2">
          <Label htmlFor="support-type">{t("typeLabel")}</Label>
          <Select value={type} onValueChange={(v) => setType(v as TicketType)}>
            <SelectTrigger id="support-type" className="w-full sm:w-64">
              <SelectValue />
            </SelectTrigger>
            <SelectContent>
              <SelectItem value="bug">{t("typeBug")}</SelectItem>
              <SelectItem value="suggestion">{t("typeSuggestion")}</SelectItem>
              <SelectItem value="question">{t("typeQuestion")}</SelectItem>
            </SelectContent>
          </Select>
        </div>

        <div className="space-y-2">
          <Label htmlFor="support-title">{t("titleLabel")}</Label>
          <Input
            id="support-title"
            value={title}
            onChange={(e) => setTitle(e.target.value)}
            placeholder={t("titlePlaceholder")}
            maxLength={200}
            required
          />
        </div>

        <div className="space-y-2">
          <Label htmlFor="support-description">{t("descriptionLabel")}</Label>
          <Textarea
            id="support-description"
            value={description}
            onChange={(e) => setDescription(e.target.value)}
            placeholder={t("descriptionPlaceholder")}
            maxLength={5000}
            rows={6}
            required
          />
        </div>

        <div className="space-y-2">
          <Label>{t("attachmentsLabel")}</Label>
          <div className="flex flex-wrap gap-3">
            {pendingAttachments.map((a) => (
              <div key={a.key} className="relative group h-16 w-16">
                {a.preview ? (
                  <Image
                    src={a.preview}
                    unoptimized
                    alt={a.name}
                    fill
                    className="rounded-lg object-cover border"
                  />
                ) : (
                  <div className="h-full w-full rounded-lg border flex flex-col items-center justify-center gap-0.5 bg-muted/40 px-1">
                    <FileText className="h-4 w-4 text-muted-foreground" />
                    <span className="text-[9px] text-muted-foreground truncate w-full text-center">{a.name}</span>
                  </div>
                )}
                <button
                  type="button"
                  onClick={() => removePending(a.key)}
                  className="absolute -top-1.5 -right-1.5 rounded-full bg-destructive text-destructive-foreground p-0.5 opacity-0 group-hover:opacity-100 transition-opacity"
                  title={t("removeAttachment")}
                >
                  <X className="h-3 w-3" />
                </button>
              </div>
            ))}

            {pendingAttachments.length < MAX_ATTACHMENTS && (
              <button
                type="button"
                onClick={() => inputRef.current?.click()}
                disabled={uploadingCount > 0}
                className="h-16 w-16 rounded-lg border-2 border-dashed border-muted-foreground/25 hover:border-muted-foreground/50 flex flex-col items-center justify-center gap-1 text-muted-foreground transition-colors disabled:opacity-50"
              >
                <Paperclip className="h-4 w-4" />
                <span className="text-[10px]">{uploadingCount > 0 ? t("attachmentUploading") : t("attachmentAdd")}</span>
              </button>
            )}
          </div>
          <p className="text-xs text-muted-foreground">{t("attachmentsHint", { count: MAX_ATTACHMENTS })}</p>
          <input
            ref={inputRef}
            type="file"
            accept={ACCEPT}
            multiple
            className="hidden"
            onChange={(e) => e.target.files && handleFiles(e.target.files)}
          />
        </div>

        <Button type="submit" disabled={submitting || uploadingCount > 0 || title.trim().length < 3 || description.trim().length < 10}>
          {submitting ? t("submitting") : t("submitButton")}
        </Button>
      </form>

      <div className="space-y-3">
        <h2 className="font-semibold text-lg">{t("historyTitle")}</h2>
        {tickets.length === 0 ? (
          <p className="text-sm text-muted-foreground">{t("noTickets")}</p>
        ) : (
          <div className="divide-y rounded-md border">
            {tickets.map((ticket) => (
              <div key={ticket.id} className="px-4 py-3 space-y-1.5">
                <div className="flex items-start justify-between gap-4">
                  <p className="text-sm font-medium">{ticket.title}</p>
                  <Badge variant={statusVariant[ticket.status]} className="text-xs shrink-0">
                    {t(`status.${ticket.status}`)}
                  </Badge>
                </div>
                <p className="text-sm text-muted-foreground whitespace-pre-wrap">{ticket.description}</p>
                {ticket.attachments.length > 0 && (
                  <div className="flex flex-wrap gap-2 pt-1">
                    {ticket.attachments.map((a) => (
                      <Link
                        key={a.id}
                        href={a.url}
                        target="_blank"
                        rel="noopener noreferrer"
                        className="relative h-12 w-12 rounded-md border overflow-hidden block"
                      >
                        {isImage(a.contentType) ? (
                          <Image src={a.url} unoptimized alt="Attachment" fill className="object-cover" />
                        ) : (
                          <div className="h-full w-full flex items-center justify-center bg-muted/40">
                            <FileText className="h-4 w-4 text-muted-foreground" />
                          </div>
                        )}
                      </Link>
                    ))}
                  </div>
                )}
                <div className="flex items-center gap-2 text-xs text-muted-foreground pt-1">
                  <Badge variant="outline" className="text-xs">{t(`type.${ticket.type}`)}</Badge>
                  <span>{formatDate(ticket.createdAt)}</span>
                  {ticket.giteaIssueUrl && (
                    <Link
                      href={ticket.giteaIssueUrl}
                      target="_blank"
                      rel="noopener noreferrer"
                      className="flex items-center gap-1 text-primary hover:underline"
                    >
                      {t("viewIssue")}
                      <ExternalLink className="h-3 w-3" />
                    </Link>
                  )}
                  <button
                    type="button"
                    onClick={() => { void toggleConversation(ticket.id); }}
                    className="flex items-center gap-1 hover:text-foreground"
                  >
                    <MessageSquare className="h-3 w-3" />
                    {t("conversation")}
                  </button>
                </div>

                {expandedId === ticket.id && (
                  <div className="mt-2 space-y-2 rounded-md border bg-muted/30 p-3">
                    {(comments[ticket.id] ?? []).length === 0 ? (
                      <p className="text-xs text-muted-foreground">{t("noComments")}</p>
                    ) : (
                      <div className="space-y-2">
                        {(comments[ticket.id] ?? []).map((c) => (
                          <div key={c.id} className="text-sm">
                            <span className="text-xs font-medium text-muted-foreground">
                              {t(`commentAuthor.${c.authorType}`)}
                            </span>
                            <p className="whitespace-pre-wrap">{c.body}</p>
                          </div>
                        ))}
                      </div>
                    )}
                    <div className="flex gap-2 pt-1">
                      <Textarea
                        value={commentDraft}
                        onChange={(e) => setCommentDraft(e.target.value)}
                        placeholder={t("commentPlaceholder")}
                        maxLength={3000}
                        rows={2}
                        className="text-sm"
                      />
                      <Button
                        type="button"
                        size="sm"
                        disabled={sendingComment || !commentDraft.trim()}
                        onClick={() => { void sendComment(ticket.id); }}
                      >
                        {t("commentSend")}
                      </Button>
                    </div>
                  </div>
                )}
              </div>
            ))}
          </div>
        )}
      </div>
    </div>
  );
}