"use client";

import { useState, useRef, useEffect } from "react";
import { useReviewStore } from "@/hooks/use-review-player";
import { ScrollArea } from "@/components/ui/scroll-area";
import { Button } from "@/components/ui/button";
import { Textarea } from "@/components/ui/textarea";
import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar";
import { Badge } from "@/components/ui/badge";
import { cn } from "@/lib/utils";
import { getInitials, formatRelativeDate } from "@/lib/utils";
import { frameToTimecode } from "@/lib/frame-utils";
import {
  CheckCircle2,
  Circle,
  MessageSquare,
  Send,
  ChevronDown,
  ChevronUp,
  Filter,
} from "lucide-react";
import { addComment, addReply, resolveComment } from "@/actions/comments";
import { useToast } from "@/components/ui/use-toast";
import type { CommentWithReplies } from "@/types";

interface CommentPanelProps {
  versionId: string;
  fps: number;
  comments: CommentWithReplies[];
  onCommentsChange?: () => void;
  pendingFrame?: number | null;
  onPendingFrameCleared?: () => void;
  onSeekToFrame?: (frame: number) => void;
}

export function CommentPanel({
  versionId,
  fps,
  comments,
  onCommentsChange,
  pendingFrame,
  onPendingFrameCleared,
  onSeekToFrame,
}: CommentPanelProps) {
  const { currentFrame, setCurrentFrame } = useReviewStore();
  const [filterResolved, setFilterResolved] = useState<"all" | "unresolved" | "resolved">("all");
  const [isSubmitting, setIsSubmitting] = useState(false);
  const [commentText, setCommentText] = useState("");
  const [activeCommentFrame, setActiveCommentFrame] = useState<number | null>(null);
  const { toast } = useToast();
  const inputRef = useRef<HTMLTextAreaElement>(null);

  // Handle pending frame from "Add Comment" button click
  useEffect(() => {
    if (pendingFrame !== null && pendingFrame !== undefined) {
      setActiveCommentFrame(pendingFrame);
      setTimeout(() => inputRef.current?.focus(), 50);
      onPendingFrameCleared?.();
    }
  }, [pendingFrame, onPendingFrameCleared]);

  const filteredComments = comments.filter((c) => {
    if (filterResolved === "unresolved") return !c.isResolved;
    if (filterResolved === "resolved") return c.isResolved;
    return true;
  });

  const handleSubmitComment = async () => {
    if (!commentText.trim() || activeCommentFrame === null) return;
    setIsSubmitting(true);
    try {
      const timestamp = activeCommentFrame / fps;
      await addComment({
        versionId,
        frameNumber: activeCommentFrame,
        timestamp,
        text: commentText.trim(),
      });
      setCommentText("");
      setActiveCommentFrame(null);
      onCommentsChange?.();
      toast({ title: "Comment added", variant: "default" });
    } catch (err) {
      toast({ title: "Failed to add comment", variant: "destructive" });
    } finally {
      setIsSubmitting(false);
    }
  };

  const handleKeyDown = (e: React.KeyboardEvent<HTMLTextAreaElement>) => {
    if (e.key === "Enter" && (e.ctrlKey || e.metaKey)) {
      e.preventDefault();
      handleSubmitComment();
    }
    if (e.key === "Escape") {
      setActiveCommentFrame(null);
      setCommentText("");
    }
  };

  return (
    <div className="flex flex-col h-full bg-card border-l border-border">
      {/* Header */}
      <div className="flex items-center justify-between px-4 py-3 border-b border-border shrink-0">
        <div className="flex items-center gap-2">
          <MessageSquare className="h-4 w-4 text-muted-foreground" />
          <span className="text-sm font-medium">
            Comments
            {comments.length > 0 && (
              <span className="ml-1.5 text-xs text-muted-foreground">
                ({comments.length})
              </span>
            )}
          </span>
        </div>
        <div className="flex gap-1">
          {(["all", "unresolved", "resolved"] as const).map((f) => (
            <button
              key={f}
              onClick={() => setFilterResolved(f)}
              className={cn(
                "px-2 py-0.5 rounded text-xs transition-colors",
                filterResolved === f
                  ? "bg-primary/20 text-primary"
                  : "text-muted-foreground hover:text-foreground"
              )}
            >
              {f === "all" ? "All" : f === "unresolved" ? "Open" : "Resolved"}
            </button>
          ))}
        </div>
      </div>

      {/* Comment Input */}
      {activeCommentFrame !== null ? (
        <div className="shrink-0 border-b border-border p-3 bg-primary/5">
          <div className="flex items-center gap-2 mb-2">
            <Badge variant="pending" className="text-xs font-mono">
              Frame {activeCommentFrame}
            </Badge>
            <span className="text-xs text-muted-foreground">
              {frameToTimecode(activeCommentFrame, fps)}
            </span>
          </div>
          <Textarea
            ref={inputRef}
            value={commentText}
            onChange={(e) => setCommentText(e.target.value)}
            onKeyDown={handleKeyDown}
            placeholder="Add your feedback... (Ctrl+Enter to submit)"
            className="min-h-[80px] text-sm bg-background/50"
            autoFocus
          />
          <div className="flex items-center justify-between mt-2">
            <button
              className="text-xs text-muted-foreground hover:text-foreground"
              onClick={() => { setActiveCommentFrame(null); setCommentText(""); }}
            >
              Cancel (Esc)
            </button>
            <Button
              size="sm"
              onClick={handleSubmitComment}
              disabled={isSubmitting || !commentText.trim()}
            >
              <Send className="h-3 w-3 mr-1" />
              {isSubmitting ? "Posting..." : "Post"}
            </Button>
          </div>
        </div>
      ) : (
        <div className="shrink-0 px-3 py-2 border-b border-border">
          <Button
            variant="outline"
            size="sm"
            className="w-full text-xs"
            onClick={() => setActiveCommentFrame(currentFrame)}
          >
            <MessageSquare className="h-3 w-3 mr-2" />
            Comment at frame {currentFrame}
          </Button>
        </div>
      )}

      {/* Comment List */}
      <ScrollArea className="flex-1">
        <div className="p-3 space-y-3">
          {filteredComments.length === 0 ? (
            <div className="flex flex-col items-center justify-center py-12 text-muted-foreground">
              <MessageSquare className="h-8 w-8 mb-3 opacity-30" />
              <p className="text-sm">No comments yet</p>
              <p className="text-xs mt-1">
                Pause the video and click &quot;Add Comment&quot;
              </p>
            </div>
          ) : (
            filteredComments.map((comment) => (
              <CommentThread
                key={comment.id}
                comment={comment}
                fps={fps}
                isActive={comment.frameNumber === currentFrame}
                onJumpToFrame={(frame) => {
                  setCurrentFrame(frame);
                  onSeekToFrame?.(frame);
                }}
                onResolved={onCommentsChange}
              />
            ))
          )}
        </div>
      </ScrollArea>
    </div>
  );
}

// ── Individual Comment Thread ─────────────────────────────────────────────────

interface CommentThreadProps {
  comment: CommentWithReplies;
  fps: number;
  isActive: boolean;
  onJumpToFrame: (frame: number) => void;
  onResolved?: () => void;
}

function CommentThread({
  comment,
  fps,
  isActive,
  onJumpToFrame,
  onResolved,
}: CommentThreadProps) {
  const [showReplies, setShowReplies] = useState(false);
  const [replyText, setReplyText] = useState("");
  const [isSubmittingReply, setIsSubmittingReply] = useState(false);
  const { toast } = useToast();

  const handleReply = async () => {
    if (!replyText.trim()) return;
    setIsSubmittingReply(true);
    try {
      await addReply(comment.id, replyText.trim());
      setReplyText("");
      onResolved?.();
    } catch {
      toast({ title: "Failed to post reply", variant: "destructive" });
    } finally {
      setIsSubmittingReply(false);
    }
  };

  const handleToggleResolve = async () => {
    try {
      await resolveComment(comment.id, !comment.isResolved);
      onResolved?.();
    } catch {
      toast({ title: "Failed to update comment", variant: "destructive" });
    }
  };

  return (
    <div
      className={cn(
        "rounded-lg border border-border/60 overflow-hidden transition-all",
        isActive && "border-primary/40 bg-primary/5",
        comment.isResolved && "opacity-60"
      )}
    >
      {/* Comment body */}
      <div className="p-3">
        <div className="flex items-start gap-2">
          <Avatar className="h-6 w-6 shrink-0 mt-0.5">
            {comment.author?.image && (
              <AvatarImage src={comment.author.image} alt={comment.author.name ?? ""} />
            )}
            <AvatarFallback className="text-[9px]">
              {getInitials(comment.author?.name ?? null)}
            </AvatarFallback>
          </Avatar>
          <div className="flex-1 min-w-0">
            <div className="flex items-center gap-2 flex-wrap">
              <span className="text-xs font-medium">
                {comment.author?.name ?? comment.author?.email ?? "Deleted User"}
              </span>
              <button
                className="font-mono text-xs text-primary/80 hover:text-primary hover:underline"
                onClick={() => onJumpToFrame(comment.frameNumber)}
              >
                F{String(comment.frameNumber).padStart(4, "0")}
              </button>
              <span className="text-xs text-muted-foreground ml-auto">
                {formatRelativeDate(comment.createdAt)}
              </span>
            </div>
            <p className="text-sm mt-1.5 leading-relaxed whitespace-pre-wrap">
              {comment.text}
            </p>
          </div>
        </div>

        {/* Actions */}
        <div className="flex items-center gap-3 mt-2 ml-8">
          <button
            className="flex items-center gap-1 text-xs text-muted-foreground hover:text-foreground transition-colors"
            onClick={handleToggleResolve}
          >
            {comment.isResolved ? (
              <>
                <CheckCircle2 className="h-3 w-3 text-emerald-500" />
                <span className="text-emerald-500">Resolved</span>
              </>
            ) : (
              <>
                <Circle className="h-3 w-3" />
                <span>Resolve</span>
              </>
            )}
          </button>

          <button
            className="flex items-center gap-1 text-xs text-muted-foreground hover:text-foreground transition-colors"
            onClick={() => setShowReplies(!showReplies)}
          >
            {comment.replies.length > 0 && (
              <>
                {showReplies ? <ChevronUp className="h-3 w-3" /> : <ChevronDown className="h-3 w-3" />}
                {comment.replies.length} {comment.replies.length === 1 ? "reply" : "replies"}
              </>
            )}
            {comment.replies.length === 0 && "Reply"}
          </button>
        </div>
      </div>

      {/* Replies */}
      {showReplies && (
        <div className="border-t border-border/50 bg-background/30">
          {comment.replies.map((reply) => (
            <div key={reply.id} className="flex gap-2 px-3 py-2.5 border-b border-border/30 last:border-0">
              <Avatar className="h-5 w-5 shrink-0 mt-0.5">
                {reply.author?.image && (
                  <AvatarImage src={reply.author.image} />
                )}
                <AvatarFallback className="text-[8px]">
                  {getInitials(reply.author?.name ?? null)}
                </AvatarFallback>
              </Avatar>
              <div className="flex-1 min-w-0">
                <div className="flex items-center gap-2">
                  <span className="text-xs font-medium">
                    {reply.author?.name ?? reply.author?.email ?? "Deleted User"}
                  </span>
                  <span className="text-xs text-muted-foreground">
                    {formatRelativeDate(reply.createdAt)}
                  </span>
                </div>
                <p className="text-xs mt-0.5 text-foreground/80 whitespace-pre-wrap">
                  {reply.text}
                </p>
              </div>
            </div>
          ))}

          {/* Reply input */}
          <div className="p-2">
            <div className="flex gap-2">
              <Textarea
                value={replyText}
                onChange={(e) => setReplyText(e.target.value)}
                onKeyDown={(e) => {
                  if (e.key === "Enter" && (e.ctrlKey || e.metaKey)) {
                    e.preventDefault();
                    handleReply();
                  }
                }}
                placeholder="Reply..."
                className="min-h-[48px] text-xs py-2 bg-background/50"
              />
              <Button
                size="icon-sm"
                onClick={handleReply}
                disabled={isSubmittingReply || !replyText.trim()}
                className="self-end"
              >
                <Send className="h-3 w-3" />
              </Button>
            </div>
          </div>
        </div>
      )}
    </div>
  );
}