import DOMPurify from "dompurify";
import { Marked } from "marked";

import { initials } from "./context";

export interface Message {
  id: string;
  role: "user" | "assistant" | "tool";
  text: string;
  timestamp: string;
  partial: boolean;
  interrupted?: boolean;
  toolName?: string;
  toolArguments?: string;
}

function escapeHtml(text: string) {
  return text.replace(
    /[&<>"']/g,
    (character) => ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" })[character] ?? character,
  );
}
const markdown = new Marked({
  gfm: true,
  breaks: true,
  renderer: { html: ({ text }) => escapeHtml(text), checkbox: ({ checked }) => (checked ? "☑ " : "☐ ") },
});

/** Only passive, sanitized Markdown is allowed inside an assistant message. */
export function renderMarkdown(text: string): string {
  if (!DOMPurify.isSupported) {
    return escapeHtml(text);
  }
  try {
    const fragment = DOMPurify.sanitize(markdown.parse(text, { async: false }), {
      ALLOWED_TAGS: [
        "p",
        "br",
        "strong",
        "em",
        "del",
        "a",
        "img",
        "ul",
        "ol",
        "li",
        "h1",
        "h2",
        "h3",
        "h4",
        "h5",
        "h6",
        "blockquote",
        "pre",
        "code",
        "hr",
        "table",
        "thead",
        "tbody",
        "tr",
        "th",
        "td",
      ],
      ALLOWED_ATTR: ["href", "title", "src", "alt", "start", "align"],
      ALLOW_DATA_ATTR: false,
      ALLOW_ARIA_ATTR: false,
      RETURN_DOM_FRAGMENT: true,
    });
    for (const link of fragment.querySelectorAll("a")) {
      if (!link.hasAttribute("href")) {
        link.replaceWith(...link.childNodes);
      } else {
        link.target = "_blank";
        link.rel = "noopener noreferrer";
      }
    }
    for (const image of fragment.querySelectorAll("img")) {
      image.loading = "lazy";
    }
    for (const table of fragment.querySelectorAll("table")) {
      const wrapper = document.createElement("div");
      wrapper.className = "markdown-table";
      wrapper.tabIndex = 0;
      wrapper.setAttribute("role", "region");
      wrapper.setAttribute("aria-label", "Tabla de la respuesta");
      table.replaceWith(wrapper);
      wrapper.append(table);
    }
    for (const code of fragment.querySelectorAll("pre")) {
      code.tabIndex = 0;
    }
    const container = document.createElement("div");
    container.append(fragment);
    return container.innerHTML;
  } catch {
    return escapeHtml(text);
  }
}

export function displayTime(timestamp: string) {
  return new Intl.DateTimeFormat("es-CL", { timeZone: "America/Santiago", hour: "2-digit", minute: "2-digit" }).format(
    new Date(timestamp),
  );
}
export function serializeConversation(messages: Message[], userName: string) {
  return {
    exportedAt: new Date().toISOString(),
    messageCount: messages.length,
    messages: messages.map((message) =>
      message.role === "tool"
        ? {
            type: "tool" as const,
            timestamp: message.timestamp,
            name: message.toolName ?? "",
            args: message.toolArguments ?? "",
            output: message.text,
          }
        : {
            type: message.role,
            timestamp: message.timestamp,
            text: message.text,
            ...(message.role === "user"
              ? { name: userName || "Usuario", initials: initials(userName || "Usuario") }
              : {}),
            ...(message.interrupted ? { interrupted: true } : {}),
          },
    ),
  };
}
export function conversationText(conversation: ReturnType<typeof serializeConversation>) {
  const lines = [
    `Conversación Vocero — ${conversation.exportedAt}`,
    `Mensajes totales: ${String(conversation.messageCount)}`,
    "—".repeat(52),
    "",
  ];
  for (const message of conversation.messages) {
    if (message.type === "tool") {
      lines.push(
        `${message.timestamp}  HERRAMIENTA: ${message.name ?? ""}`,
        `Entrada:\n${message.args ?? ""}`,
        `Salida:\n${message.output ?? ""}`,
        "",
      );
    } else {
      lines.push(
        `${message.timestamp}  ${message.type === "user" ? (message.name ?? "Usuario") : "Vocero"}${message.interrupted ? " [interrumpida]" : ""}:`,
        message.text ?? "",
        "",
      );
    }
  }
  return lines.join("\n");
}
export function exportConversation(messages: Message[], userName: string) {
  const conversation = serializeConversation(messages, userName);
  const name = `vocero-conversacion-${conversation.exportedAt.replace(/[:.]/g, "-")}`;
  const downloads = [
    { content: JSON.stringify(conversation, null, 2), extension: "json", mime: "application/json" },
    { content: conversationText(conversation), extension: "txt", mime: "text/plain;charset=utf-8" },
  ];
  for (const { content, extension, mime } of downloads) {
    const url = URL.createObjectURL(new Blob([content], { type: mime }));
    const link = document.createElement("a");
    link.href = url;
    link.download = `${name}.${extension}`;
    document.body.append(link);
    link.click();
    link.remove();
    setTimeout(() => {
      URL.revokeObjectURL(url);
    }, 4000);
  }
}