import Link from "next/link";
import { createPortal } from "react-dom";
import type { CSSProperties } from "react";
import { useState } from "react";

import TaskReadOnlyPreviewModal from "@/components/tasks/TaskReadOnlyPreviewModal";
import type { MessageLinkedTask, TaskPriority } from "@/types/api";

type TaskLinkPillTask = Pick<
  MessageLinkedTask,
  | "id"
  | "title"
  | "board_id"
  | "board_name"
  | "column_color"
  | "priority"
  | "priority_display"
  | "can_open"
> & { link_id?: number };

type TaskLinkPillProps = {
  task: TaskLinkPillTask;
  tone?: "default" | "onAccent";
  maxTitleClassName?: string;
  className?: string;
};

const fallbackColumnColor = "#38bdf8";

const priorityColors: Record<TaskPriority, string> = {
  low: "#22c55e",
  medium: "#38bdf8",
  high: "#f59e0b",
  critical: "#ef4444",
};

const priorityLabels: Record<TaskPriority, string> = {
  low: "Низкий",
  medium: "Средний",
  high: "Высокий",
  critical: "Критический",
};

const priorityTitleShiftClasses: Record<TaskPriority, string> = {
  low: "group-hover/task-pill:translate-x-10 group-focus-visible/task-pill:translate-x-10",
  medium: "group-hover/task-pill:translate-x-12 group-focus-visible/task-pill:translate-x-12",
  high: "group-hover/task-pill:translate-x-12 group-focus-visible/task-pill:translate-x-12",
  critical: "group-hover/task-pill:translate-x-16 group-focus-visible/task-pill:translate-x-16",
};

function normalizeHexColor(value?: string | null): string {
  const color = String(value || "").trim();
  if (/^#[0-9a-f]{6}$/i.test(color)) return color;
  if (/^#[0-9a-f]{3}$/i.test(color)) {
    const [, r, g, b] = color;
    return `#${r}${r}${g}${g}${b}${b}`;
  }
  return fallbackColumnColor;
}

function hexToRgb(color: string): { red: number; green: number; blue: number } {
  const normalized = normalizeHexColor(color).slice(1);
  return {
    red: parseInt(normalized.slice(0, 2), 16),
    green: parseInt(normalized.slice(2, 4), 16),
    blue: parseInt(normalized.slice(4, 6), 16),
  };
}

function getReadableTextColor(color: string): string {
  const { red, green, blue } = hexToRgb(color);
  const luminance = (0.299 * red + 0.587 * green + 0.114 * blue) / 255;
  return luminance > 0.62 ? "#07111f" : "#ffffff";
}

export default function TaskLinkPill({
  task,
  tone = "default",
  maxTitleClassName = "max-w-44",
  className = "",
}: TaskLinkPillProps) {
  const [previewOpen, setPreviewOpen] = useState(false);
  const columnColor = normalizeHexColor(task.column_color);
  const priority = task.priority || "medium";
  const priorityColor = priorityColors[priority];
  const priorityLabel = task.priority_display || priorityLabels[priority];
  const priorityTitleShiftClass = priorityTitleShiftClasses[priority];
  const textColor = getReadableTextColor(columnColor);
  const isOnAccent = tone === "onAccent";
  const title = `${task.board_name ? `${task.board_name}: ` : ""}${task.title}, ${priorityLabel}`;
  const style: CSSProperties = {
    backgroundColor: columnColor,
    boxShadow: isOnAccent ? "inset 0 1px 0 rgba(255, 255, 255, 0.18)" : undefined,
    color: textColor,
  };
  const href = `/tasks?board=${task.board_id}&task=${task.id}`;
  const canOpen = task.can_open !== false;
  const pillClassName = `group/task-pill inline-flex min-w-0 max-w-full items-center gap-1.5 overflow-hidden rounded-full px-2 py-1 text-[11px] font-medium shadow-sm transition ${
    canOpen
      ? "hover:brightness-110 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-white/45"
      : "cursor-pointer hover:brightness-105 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-white/45"
  } ${className}`;
  const content = (
    <>
      <span className="relative h-4 w-2.5 shrink-0" aria-hidden="true">
        <span
          className="absolute left-0 top-1/2 z-10 inline-flex h-2.5 min-w-2.5 max-w-2.5 -translate-y-1/2 items-center justify-center overflow-hidden rounded-full border transition-[height,max-width,padding] duration-200 ease-out group-hover/task-pill:h-4 group-hover/task-pill:max-w-24 group-hover/task-pill:px-1.5 group-focus-visible/task-pill:h-4 group-focus-visible/task-pill:max-w-24 group-focus-visible/task-pill:px-1.5"
          style={{
            backgroundColor: priorityColor,
            borderColor: textColor,
          }}
        >
          <span className="max-w-0 whitespace-nowrap text-[9px] font-semibold leading-none text-white opacity-0 transition-[max-width,opacity] duration-200 ease-out group-hover/task-pill:max-w-20 group-hover/task-pill:opacity-100 group-focus-visible/task-pill:max-w-20 group-focus-visible/task-pill:opacity-100">
            {priorityLabel}
          </span>
        </span>
      </span>
      <span className={`${maxTitleClassName} min-w-0 truncate transition-transform duration-200 ease-out ${priorityTitleShiftClass}`}>
        {task.title}
      </span>
    </>
  );

  if (!canOpen) {
    return (
      <>
        <button
          type="button"
          className={pillClassName}
          style={style}
          title={`${title}. Открыть только для чтения`}
          aria-haspopup="dialog"
          onClick={() => setPreviewOpen(true)}
          disabled={!task.link_id}
        >
          {content}
        </button>
        {task.link_id && previewOpen && typeof document !== "undefined"
          ? createPortal(
              <TaskReadOnlyPreviewModal
                isOpen={previewOpen}
                linkId={task.link_id}
                taskId={task.id}
                onClose={() => setPreviewOpen(false)}
              />,
              document.body,
            )
          : null}
      </>
    );
  }

  return (
    <Link
      href={href}
      className={pillClassName}
      style={style}
      title={title}
    >
      {content}
    </Link>
  );
}