"use client";

import { useRef, useEffect, useState } from "react";
import { Heart, Shield, Zap, ChevronDown } from "lucide-react";
import { useAddFollow, useIsFollowing, useRemoveFollow, useUpdateFollowMode } from "@/lib/hooks/useFollows";
import { useAuthStore } from "@/stores/authStore";
import { AuthModal } from "./AuthModal";
import { cn } from "@/lib/utils";

const MODES = {
  neutral: {
    label: "Following",
    icon: Heart,
    color: "bg-red-100 text-red-700 hover:bg-red-200 dark:bg-red-900/30 dark:text-red-400",
  },
  pocket_veto: {
    label: "Pocket Veto",
    icon: Shield,
    color: "bg-amber-100 text-amber-700 hover:bg-amber-200 dark:bg-amber-900/30 dark:text-amber-400",
  },
  pocket_boost: {
    label: "Pocket Boost",
    icon: Zap,
    color: "bg-green-100 text-green-700 hover:bg-green-200 dark:bg-green-900/30 dark:text-green-400",
  },
} as const;

type FollowMode = keyof typeof MODES;

interface FollowButtonProps {
  type: "bill" | "member" | "topic";
  value: string;
  label?: string;
  supportsModes?: boolean;
}

export function FollowButton({ type, value, label, supportsModes = false }: FollowButtonProps) {
  const existing = useIsFollowing(type, value);
  const add = useAddFollow();
  const remove = useRemoveFollow();
  const updateMode = useUpdateFollowMode();
  const token = useAuthStore((s) => s.token);
  const [open, setOpen] = useState(false);
  const [showAuthModal, setShowAuthModal] = useState(false);
  const dropdownRef = useRef<HTMLDivElement>(null);

  function requireAuth(action: () => void) {
    if (!token) { setShowAuthModal(true); return; }
    action();
  }

  const isFollowing = !!existing;
  const currentMode: FollowMode = (existing?.follow_mode as FollowMode) ?? "neutral";
  const isPending = add.isPending || remove.isPending || updateMode.isPending;

  // Close dropdown on outside click
  useEffect(() => {
    if (!open) return;
    const handler = (e: MouseEvent) => {
      if (dropdownRef.current && !dropdownRef.current.contains(e.target as Node)) {
        setOpen(false);
      }
    };
    document.addEventListener("mousedown", handler);
    return () => document.removeEventListener("mousedown", handler);
  }, [open]);

  // Simple toggle for non-bill follows
  if (!supportsModes) {
    const handleClick = () => {
      requireAuth(() => {
        if (isFollowing && existing) {
          remove.mutate(existing.id);
        } else {
          add.mutate({ type, value });
        }
      });
    };
    return (
      <>
        <button
          onClick={handleClick}
          disabled={isPending}
          className={cn(
            "flex items-center gap-1.5 px-3 py-1.5 rounded-md text-sm font-medium transition-colors",
            isFollowing
              ? "bg-red-100 text-red-700 hover:bg-red-200 dark:bg-red-900/30 dark:text-red-400"
              : "bg-muted text-muted-foreground hover:bg-accent hover:text-foreground"
          )}
        >
          <Heart className={cn("w-3.5 h-3.5", isFollowing && "fill-current")} />
          {isFollowing ? "Unfollow" : label || "Follow"}
        </button>
        <AuthModal open={showAuthModal} onClose={() => setShowAuthModal(false)} />
      </>
    );
  }

  // Mode-aware follow button for bills
  if (!isFollowing) {
    return (
      <>
        <button
          onClick={() => requireAuth(() => add.mutate({ type, value }))}
          disabled={isPending}
          className="flex items-center gap-1.5 px-3 py-1.5 rounded-md text-sm font-medium transition-colors bg-muted text-muted-foreground hover:bg-accent hover:text-foreground"
        >
          <Heart className="w-3.5 h-3.5" />
          {label || "Follow"}
        </button>
        <AuthModal open={showAuthModal} onClose={() => setShowAuthModal(false)} />
      </>
    );
  }

  const { label: modeLabel, icon: ModeIcon, color } = MODES[currentMode];
  const otherModes = (Object.keys(MODES) as FollowMode[]).filter((m) => m !== currentMode);

  const switchMode = (mode: FollowMode) => {
    requireAuth(() => {
      if (existing) updateMode.mutate({ id: existing.id, mode });
      setOpen(false);
    });
  };

  const handleUnfollow = () => {
    requireAuth(() => {
      if (existing) remove.mutate(existing.id);
      setOpen(false);
    });
  };

  const modeDescriptions: Record<FollowMode, string> = {
    neutral: "Alert me on all material changes",
    pocket_veto: "Alert me only if this bill advances toward passage",
    pocket_boost: "Alert me on all changes + remind me to contact my rep",
  };

  return (
    <>
      <div className="relative" ref={dropdownRef}>
        <button
          onClick={() => setOpen((v) => !v)}
          disabled={isPending}
          className={cn(
            "flex items-center gap-1.5 px-3 py-1.5 rounded-md text-sm font-medium transition-colors",
            color
          )}
        >
          <ModeIcon className={cn("w-3.5 h-3.5", currentMode === "neutral" && "fill-current")} />
          {modeLabel}
          <ChevronDown className="w-3 h-3 ml-0.5 opacity-70" />
        </button>

        {open && (
          <div className="absolute right-0 mt-1 w-64 bg-popover border border-border rounded-md shadow-lg z-50 py-1">
            {otherModes.map((mode) => {
              const { label: optLabel, icon: OptIcon } = MODES[mode];
              return (
                <button
                  key={mode}
                  onClick={() => switchMode(mode)}
                  title={modeDescriptions[mode]}
                  className="w-full text-left px-3 py-2 text-sm hover:bg-accent transition-colors flex flex-col gap-0.5"
                >
                  <span className="flex items-center gap-1.5 font-medium">
                    <OptIcon className="w-3.5 h-3.5" />
                    Switch to {optLabel}
                  </span>
                  <span className="text-xs text-muted-foreground pl-5">{modeDescriptions[mode]}</span>
                </button>
              );
            })}
            <div className="border-t border-border mt-1 pt-1">
              <button
                onClick={handleUnfollow}
                className="w-full text-left px-3 py-2 text-sm text-destructive hover:bg-accent transition-colors"
              >
                Unfollow
              </button>
            </div>
          </div>
        )}
      </div>
      <AuthModal open={showAuthModal} onClose={() => setShowAuthModal(false)} />
    </>
  );
}