import { parseProxy } from "./parseProxy";
import {
  itemTypeLabel,
  normalizeItemValue,
  type DraftItemType,
} from "./profileItems";

export type RouteMode = "external" | "local-singbox";

export interface ConfigSnapshotItem {
  type: DraftItemType;
  value: string;
}

export interface ConfigSnapshot {
  routeMode: RouteMode;
  proxy: string;
  selectedServerId: string;
  selectedServerTag: string;
  items: ConfigSnapshotItem[];
}

export interface PendingChangeRow {
  id: string;
  label: string;
  before?: string;
  after: string;
  tone?: "added" | "removed" | "changed";
}

export function configSnapshotFromUi(
  routeMode: RouteMode,
  proxyInput: string,
  items: Array<{ type: DraftItemType; value: string }>,
  selectedServerId?: string,
  selectedServerTag?: string,
): ConfigSnapshot {
  return {
    routeMode,
    proxy: routeMode === "external" ? normalizeProxySnapshot(proxyInput) : "",
    selectedServerId:
      routeMode === "local-singbox" ? (selectedServerId?.trim() ?? "") : "",
    selectedServerTag:
      routeMode === "local-singbox" ? (selectedServerTag?.trim() ?? "") : "",
    items: normalizeSnapshotItems(items),
  };
}

export function configChangeRows(
  applied: ConfigSnapshot,
  current: ConfigSnapshot,
): PendingChangeRow[] {
  if (sameConfigSnapshot(applied, current)) return [];

  const rows: PendingChangeRow[] = [];
  if (applied.routeMode !== current.routeMode) {
    rows.push({
      id: "route-mode",
      label: "Маршрут",
      before: routeModeLabel(applied.routeMode),
      after: routeModeLabel(current.routeMode),
    });
  }
  if (
    applied.proxy !== current.proxy &&
    (applied.routeMode === "external" || current.routeMode === "external")
  ) {
    rows.push({
      id: "external-proxy",
      label: "SOCKS5",
      before: snapshotProxyChangeText(applied),
      after: snapshotProxyChangeText(current),
    });
  }
  if (
    applied.selectedServerId !== current.selectedServerId &&
    (applied.routeMode === "local-singbox" ||
      current.routeMode === "local-singbox")
  ) {
    rows.push({
      id: "vpn-server",
      label: "VPN сервер",
      before: snapshotServerChangeText(applied),
      after: snapshotServerChangeText(current),
    });
  }
  rows.push(...snapshotItemChangeRows(applied.items, current.items));
  return rows;
}

export function sameConfigSnapshot(
  left: ConfigSnapshot,
  right: ConfigSnapshot,
) {
  return (
    left.routeMode === right.routeMode &&
    left.proxy === right.proxy &&
    left.selectedServerId === right.selectedServerId &&
    left.selectedServerTag === right.selectedServerTag &&
    left.items.length === right.items.length &&
    left.items.every((item, index) => {
      const other = right.items[index];
      return item.type === other.type && item.value === other.value;
    })
  );
}

export function routeModeLabel(routeMode: RouteMode) {
  return routeMode === "local-singbox" ? "Локальный прокси" : "Внешний прокси";
}

export function displaySnapshotProxy(proxy: string) {
  return proxy.replace(/^socks5:\/\//, "") || "не указан";
}

export function displayServerTag(tag: string) {
  const withoutFlags = tag
    .replace(/[\u{1f1e6}-\u{1f1ff}]/gu, "")
    .replace(/\s*->\s*/g, " -> ")
    .replace(/\s*->\s*$/g, "")
    .replace(/^\s*->\s*/g, "")
    .replace(/\s{2,}/g, " ")
    .trim();

  return withoutFlags || tag;
}

function normalizeProxySnapshot(value: string) {
  try {
    const parsed = parseProxy(value);
    return `${parsed.protocol}://${parsed.host.trim().toLowerCase()}:${parsed.port}`;
  } catch {
    return value.trim().toLowerCase();
  }
}

function normalizeSnapshotItems(
  items: Array<{ type: DraftItemType; value: string }>,
): ConfigSnapshotItem[] {
  return items
    .map((item) => ({
      type: item.type,
      value: normalizeItemValue(item.value, item.type).toLowerCase(),
    }))
    .filter((item) => item.value)
    .sort((left, right) =>
      `${left.type}:${left.value}`.localeCompare(
        `${right.type}:${right.value}`,
      ),
    );
}

function snapshotProxyChangeText(snapshot: ConfigSnapshot) {
  return snapshot.routeMode === "external"
    ? displaySnapshotProxy(snapshot.proxy)
    : "не используется";
}

function snapshotServerChangeText(snapshot: ConfigSnapshot) {
  if (snapshot.routeMode !== "local-singbox") return "не используется";
  return snapshot.selectedServerTag
    ? displayServerTag(snapshot.selectedServerTag)
    : "сервер не выбран";
}

function snapshotItemChangeRows(
  appliedItems: ConfigSnapshotItem[],
  currentItems: ConfigSnapshotItem[],
): PendingChangeRow[] {
  const appliedKeys = new Set(appliedItems.map(snapshotItemKey));
  const currentKeys = new Set(currentItems.map(snapshotItemKey));
  const added = currentItems.filter(
    (item) => !appliedKeys.has(snapshotItemKey(item)),
  );
  const removed = appliedItems.filter(
    (item) => !currentKeys.has(snapshotItemKey(item)),
  );

  return [
    ...added.map((item) => ({
      id: `app-add-${snapshotItemKey(item)}`,
      label: "Добавлено",
      after: `+ ${formatSnapshotItem(item)}`,
      tone: "added" as const,
    })),
    ...removed.map((item) => ({
      id: `app-remove-${snapshotItemKey(item)}`,
      label: "Удалено",
      after: `- ${formatSnapshotItem(item)}`,
      tone: "removed" as const,
    })),
  ];
}

function snapshotItemKey(item: ConfigSnapshotItem) {
  return `${item.type}:${item.value}`;
}

function formatSnapshotItem(item: ConfigSnapshotItem) {
  return `${itemTypeLabel(item.type)} ${item.value}`;
}