import type { ChannelDirectoryEntry } from "clawdbot/plugin-sdk";

import { GRAPH_ROOT } from "./attachments/shared.js";
import { loadMSTeamsSdkWithAuth } from "./sdk.js";
import { resolveMSTeamsCredentials } from "./token.js";

type GraphUser = {
  id?: string;
  displayName?: string;
  userPrincipalName?: string;
  mail?: string;
};

type GraphGroup = {
  id?: string;
  displayName?: string;
};

type GraphChannel = {
  id?: string;
  displayName?: string;
};

type GraphResponse<T> = { value?: T[] };

function readAccessToken(value: unknown): string | null {
  if (typeof value === "string") return value;
  if (value && typeof value === "object") {
    const token =
      (value as { accessToken?: unknown }).accessToken ?? (value as { token?: unknown }).token;
    return typeof token === "string" ? token : null;
  }
  return null;
}

function normalizeQuery(value?: string | null): string {
  return value?.trim() ?? "";
}

function escapeOData(value: string): string {
  return value.replace(/'/g, "''");
}

async function fetchGraphJson<T>(params: {
  token: string;
  path: string;
  headers?: Record<string, string>;
}): Promise<T> {
  const res = await fetch(`${GRAPH_ROOT}${params.path}`, {
    headers: {
      Authorization: `Bearer ${params.token}`,
      ...(params.headers ?? {}),
    },
  });
  if (!res.ok) {
    const text = await res.text().catch(() => "");
    throw new Error(`Graph ${params.path} failed (${res.status}): ${text || "unknown error"}`);
  }
  return (await res.json()) as T;
}

async function resolveGraphToken(cfg: unknown): Promise<string> {
  const creds = resolveMSTeamsCredentials((cfg as { channels?: { msteams?: unknown } })?.channels?.msteams);
  if (!creds) throw new Error("MS Teams credentials missing");
  const { sdk, authConfig } = await loadMSTeamsSdkWithAuth(creds);
  const tokenProvider = new sdk.MsalTokenProvider(authConfig);
  const token = await tokenProvider.getAccessToken("https://graph.microsoft.com/.default");
  const accessToken = readAccessToken(token);
  if (!accessToken) throw new Error("MS Teams graph token unavailable");
  return accessToken;
}

async function listTeamsByName(token: string, query: string): Promise<GraphGroup[]> {
  const escaped = escapeOData(query);
  const filter = `resourceProvisioningOptions/Any(x:x eq 'Team') and startsWith(displayName,'${escaped}')`;
  const path = `/groups?$filter=${encodeURIComponent(filter)}&$select=id,displayName`;
  const res = await fetchGraphJson<GraphResponse<GraphGroup>>({ token, path });
  return res.value ?? [];
}

async function listChannelsForTeam(token: string, teamId: string): Promise<GraphChannel[]> {
  const path = `/teams/${encodeURIComponent(teamId)}/channels?$select=id,displayName`;
  const res = await fetchGraphJson<GraphResponse<GraphChannel>>({ token, path });
  return res.value ?? [];
}

export async function listMSTeamsDirectoryPeersLive(params: {
  cfg: unknown;
  query?: string | null;
  limit?: number | null;
}): Promise<ChannelDirectoryEntry[]> {
  const query = normalizeQuery(params.query);
  if (!query) return [];
  const token = await resolveGraphToken(params.cfg);
  const limit = typeof params.limit === "number" && params.limit > 0 ? params.limit : 20;

  let users: GraphUser[] = [];
  if (query.includes("@")) {
    const escaped = escapeOData(query);
    const filter = `(mail eq '${escaped}' or userPrincipalName eq '${escaped}')`;
    const path = `/users?$filter=${encodeURIComponent(filter)}&$select=id,displayName,mail,userPrincipalName`;
    const res = await fetchGraphJson<GraphResponse<GraphUser>>({ token, path });
    users = res.value ?? [];
  } else {
    const path = `/users?$search=${encodeURIComponent(`"displayName:${query}"`)}&$select=id,displayName,mail,userPrincipalName&$top=${limit}`;
    const res = await fetchGraphJson<GraphResponse<GraphUser>>({
      token,
      path,
      headers: { ConsistencyLevel: "eventual" },
    });
    users = res.value ?? [];
  }

  return users
    .map((user) => {
      const id = user.id?.trim();
      if (!id) return null;
      const name = user.displayName?.trim();
      const handle = user.userPrincipalName?.trim() || user.mail?.trim();
      return {
        kind: "user",
        id: `user:${id}`,
        name: name || undefined,
        handle: handle ? `@${handle}` : undefined,
        raw: user,
      } satisfies ChannelDirectoryEntry;
    })
    .filter(Boolean) as ChannelDirectoryEntry[];
}

export async function listMSTeamsDirectoryGroupsLive(params: {
  cfg: unknown;
  query?: string | null;
  limit?: number | null;
}): Promise<ChannelDirectoryEntry[]> {
  const rawQuery = normalizeQuery(params.query);
  if (!rawQuery) return [];
  const token = await resolveGraphToken(params.cfg);
  const limit = typeof params.limit === "number" && params.limit > 0 ? params.limit : 20;
  const [teamQuery, channelQuery] = rawQuery.includes("/")
    ? rawQuery.split("/", 2).map((part) => part.trim()).filter(Boolean)
    : [rawQuery, null];

  const teams = await listTeamsByName(token, teamQuery);
  const results: ChannelDirectoryEntry[] = [];

  for (const team of teams) {
    const teamId = team.id?.trim();
    if (!teamId) continue;
    const teamName = team.displayName?.trim() || teamQuery;
    if (!channelQuery) {
      results.push({
        kind: "group",
        id: `team:${teamId}`,
        name: teamName,
        handle: teamName ? `#${teamName}` : undefined,
        raw: team,
      });
      if (results.length >= limit) return results;
      continue;
    }
    const channels = await listChannelsForTeam(token, teamId);
    for (const channel of channels) {
      const name = channel.displayName?.trim();
      if (!name) continue;
      if (!name.toLowerCase().includes(channelQuery.toLowerCase())) continue;
      results.push({
        kind: "group",
        id: `conversation:${channel.id}`,
        name: `${teamName}/${name}`,
        handle: `#${name}`,
        raw: channel,
      });
      if (results.length >= limit) return results;
    }
  }

  return results;
}