import { useState } from "react";
import type { Message } from "@/types/Message";
import { cn } from "@/lib/utils";
import { Avatar, AvatarFallback } from "@/components/ui/avatar";
import { Badge } from "@/components/ui/badge";
import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from "@/components/ui/tooltip";

interface Props {
  message: Message;
  compact?: boolean;
  lastInGroup?: boolean;
  replyTarget?: Message;
  onSelect: (id: string) => void;
  onDelete: (channelId: string, msgId: string) => void;
  onRestore: (channelId: string, msgId: string) => void;
  currentUsername: string;
  selected: boolean;
}

const TYPE_CONFIG: Record<string, { border: string; label: string; labelBg: string }> = {
  text: { border: "border-l-transparent", label: "", labelBg: "" },
  code: { border: "border-l-[var(--color-msg-code)]", label: "CODE", labelBg: "bg-[var(--color-msg-code)]/15 text-[var(--color-msg-code)]" },
  result: { border: "border-l-[var(--color-msg-result)]", label: "RESULT", labelBg: "bg-[var(--color-msg-result)]/15 text-[var(--color-msg-result)]" },
  error: { border: "border-l-[var(--color-msg-error)]", label: "ERROR", labelBg: "bg-[var(--color-msg-error)]/15 text-[var(--color-msg-error)]" },
  plan: { border: "border-l-[var(--color-msg-plan)]", label: "PLAN", labelBg: "bg-[var(--color-msg-plan)]/15 text-[var(--color-msg-plan)]" },
};

function timeAgo(dateStr: string): string {
  const diff = Date.now() - new Date(dateStr).getTime();
  const mins = Math.floor(diff / 60000);
  if (mins < 1) return "now";
  if (mins < 60) return `${mins}m`;
  const hrs = Math.floor(mins / 60);
  if (hrs < 24) return `${hrs}h`;
  return `${Math.floor(hrs / 24)}d`;
}

function renderContent(text: string) {
  // Split on @mentions and URLs
  // URL regex: stop before trailing punctuation like ),. etc
  const parts = text.split(/((?:https?:\/\/)[^\s),.\]}>]+|@[\w-]+)/g);
  return parts.map((part, i) => {
    if (part.startsWith("@")) {
      return (
        <span key={i} className="text-primary font-bold cursor-default">
          {part}
        </span>
      );
    }
    if (part.startsWith("http://") || part.startsWith("https://")) {
      return (
        <a
          key={i}
          href={part}
          target="_blank"
          rel="noopener noreferrer"
          onClick={(e) => e.stopPropagation()}
          className="text-primary underline underline-offset-2 hover:text-primary/80"
        >
          {part}
        </a>
      );
    }
    return part;
  });
}

// Stable OKLCH hue from username — same user always gets same color
function userHue(username: string): number {
  let hash = 0;
  for (let i = 0; i < username.length; i++) {
    hash = username.charCodeAt(i) + ((hash << 5) - hash);
  }
  return Math.abs(hash) % 360;
}

export function MessageItem({ message, compact, lastInGroup, replyTarget, onSelect, onDelete, onRestore, currentUsername, selected }: Props) {
  const [metaOpen, setMetaOpen] = useState(false);
  const isAgent = message.user.role === "agent";
  const isDeleted = !!message.deleted_at;
  const cfg = TYPE_CONFIG[message.type] || TYPE_CONFIG.text;
  const meta = message.metadata as Record<string, string> | null;

  function scrollToMessage(id: string) {
    const el = document.getElementById(`msg-${id}`);
    if (el) {
      el.scrollIntoView({ behavior: "smooth", block: "center" });
      el.classList.add("!bg-primary/10");
      setTimeout(() => el.classList.remove("!bg-primary/10"), 1500);
    }
  }

  return (
    <div
      id={`msg-${message.id}`}
      onClick={() => onSelect(message.id)}
      className={cn(
        "group relative border-l-4 transition-all duration-300 cursor-pointer",
        lastInGroup ? "border-b border-border/50" : "",
        cfg.border,
        selected ? "!border-l-primary bg-primary/5" : isAgent ? "bg-card" : "bg-background",
        "hover:bg-muted/30",
      )}
    >
      {/* Reply context — click to scroll to quoted message */}
      {replyTarget && (
        <button
          type="button"
          onClick={() => scrollToMessage(replyTarget.id)}
          className="w-full text-left px-4 pt-2 pb-0.5 text-[11px] text-muted-foreground flex items-center gap-1.5 hover:text-foreground transition-colors"
        >
          <span className="text-primary font-bold">^</span>
          <span className="font-bold">{replyTarget.user.display_name}</span>
          <span className="truncate max-w-48 md:max-w-96 opacity-60">{replyTarget.content}</span>
        </button>
      )}

      <div className={cn("px-4 md:px-5", compact ? (lastInGroup ? "pt-0.5 pb-3 md:pb-4" : "py-0.5") : "py-3 md:py-4")}>
        {/* Header — hidden in compact mode */}
        {!compact && <div className="flex items-center gap-2.5 text-[11px] flex-wrap">
          {/* Avatar — ape emoji with OKLCH color, agents get first letter */}
          <Avatar size="sm" className="rounded-none">
            <AvatarFallback
              className="rounded-none text-[12px]"
              style={isAgent
                ? { backgroundColor: 'oklch(0.25 0.08 250)', color: 'oklch(0.7 0.15 250)' }
                : { backgroundColor: `oklch(0.25 0.08 ${userHue(message.user.username)})` }
              }
            >
              {isAgent ? message.user.display_name[0] : "🐒"}
            </AvatarFallback>
          </Avatar>

          {/* Name — apes don't deserve capitals */}
          <span className={cn(
            "font-sans font-bold text-xs",
            isAgent ? "text-primary uppercase" : "text-foreground lowercase"
          )}>
            {message.user.display_name}
          </span>

          {/* Agent badge */}
          {isAgent && (
            <Badge variant="outline" className="font-mono text-[11px] font-bold px-1.5 py-0 h-4 rounded-none border-primary/30 text-primary uppercase tracking-wider">
              AGT
            </Badge>
          )}

          {/* Type badge */}
          {cfg.label && (
            <Badge variant="secondary" className={cn("font-mono text-[11px] font-bold px-1.5 py-0 h-4 rounded-none uppercase tracking-wider", cfg.labelBg)}>
              {cfg.label}
            </Badge>
          )}

          {/* Time — tooltip shows full timestamp on mobile */}
          <TooltipProvider>
            <Tooltip>
              <TooltipTrigger className="text-muted-foreground font-mono tabular-nums text-[10px] cursor-default">
                  <span className="md:hidden">{timeAgo(message.created_at)}</span>
                  <span className="hidden md:inline">
                    {new Date(message.created_at).toLocaleTimeString("en-US", {
                      hour12: false, hour: "2-digit", minute: "2-digit", second: "2-digit",
                    })}
                  </span>
              </TooltipTrigger>
              <TooltipContent className="font-mono text-[10px] rounded-none">
                {new Date(message.created_at).toLocaleString()} · seq #{Number(message.seq)}
              </TooltipContent>
            </Tooltip>
          </TooltipProvider>

        </div>}

        {/* Floating action pill — top-right, appears on hover */}
        <div className="absolute -top-3 right-3 md:opacity-0 md:translate-y-1 md:group-hover:opacity-100 md:group-hover:translate-y-0 transition-all duration-150 flex border-2 border-border bg-card shadow-lg z-10">
          <button
            type="button"
            onClick={(e) => { e.stopPropagation(); onSelect(message.id); }}
            className={cn(
              "px-2.5 py-1.5 text-sm hover:bg-muted/50 transition-colors",
              selected ? "text-primary" : "text-muted-foreground hover:text-primary",
            )}
            title={selected ? "Deselect" : "Select for reply"}
          >
            {selected ? "✓" : "↩"}
          </button>
          {!isDeleted && message.user.username === currentUsername && (
            <button
              type="button"
              onClick={(e) => { e.stopPropagation(); onDelete(message.channel_id, message.id); }}
              className="px-2.5 py-1.5 text-sm text-muted-foreground hover:text-destructive hover:bg-destructive/10 transition-colors border-l-2 border-border"
              title="Delete"
            >
              ×
            </button>
          )}
          {isDeleted && (
            <button
              type="button"
              onClick={(e) => { e.stopPropagation(); onRestore(message.channel_id, message.id); }}
              className="px-2.5 py-1.5 text-[10px] font-mono text-muted-foreground hover:text-primary hover:bg-muted/50 transition-colors border-l-2 border-border"
              title="Restore deleted message"
            >
              undo
            </button>
          )}
        </div>

        {/* Content */}
        <div className={cn(
          "mt-1 text-sm leading-relaxed break-words font-mono",
          message.type === "code" && "bg-muted px-3 py-2 border-2 border-border whitespace-pre-wrap overflow-x-auto",
          message.type === "error" && "text-[var(--color-msg-error)]",
        )}>
          {isDeleted ? (
            <span className="italic text-muted-foreground/40">[deleted]</span>
          ) : (
            renderContent(message.content)
          )}
        </div>

        {/* Agent metadata */}
        {meta && isAgent && (
          <>
            <div className="hidden md:flex mt-1.5 gap-3 text-[10px] font-mono text-muted-foreground/50">
              {meta.model && <span>{meta.model}</span>}
              {meta.hostname && <span>{meta.hostname}</span>}
              {meta.cwd && <span className="text-muted-foreground/30">{meta.cwd}</span>}
              {meta.skill && <span className="text-primary/50">{meta.skill}</span>}
            </div>
            <button
              type="button"
              onClick={() => setMetaOpen(!metaOpen)}
              className="md:hidden mt-1 text-[11px] font-mono text-muted-foreground/40 min-h-[32px] flex items-center"
            >
              {metaOpen ? "[-] hide" : `[+] ${meta.model || "meta"}`}
            </button>
            {metaOpen && (
              <div className="md:hidden mt-0.5 text-[10px] font-mono text-muted-foreground/50 space-y-0.5 pl-2 border-l-2 border-border">
                {meta.model && <div>{meta.model}</div>}
                {meta.hostname && <div>{meta.hostname}</div>}
                {meta.cwd && <div>{meta.cwd}</div>}
                {meta.skill && <div className="text-primary/50">{meta.skill}</div>}
              </div>
            )}
          </>
        )}
      </div>
    </div>
  );
}