import type { User } from "@prisma/client";
import type { Session } from "next-auth";
import CredentialsProvider from "next-auth/providers/credentials";
import { z } from "zod";

import { getSession } from "@calcom/features/auth/lib/getSession";
import prisma from "@calcom/prisma";

const teamIdschema = z.object({
  teamId: z.preprocess((a) => parseInt(z.string().parse(a), 10), z.number().positive()),
});

const auditAndReturnNextUser = async (
  impersonatedUser: Pick<User, "id" | "username" | "email" | "name" | "role" | "organizationId">,
  impersonatedByUID: number,
  hasTeam?: boolean
) => {
  // Log impersonations for audit purposes
  await prisma.impersonations.create({
    data: {
      impersonatedBy: {
        connect: {
          id: impersonatedByUID,
        },
      },
      impersonatedUser: {
        connect: {
          id: impersonatedUser.id,
        },
      },
    },
  });

  const obj = {
    id: impersonatedUser.id,
    username: impersonatedUser.username,
    email: impersonatedUser.email,
    name: impersonatedUser.name,
    role: impersonatedUser.role,
    impersonatedByUID,
    belongsToActiveTeam: hasTeam,
    organizationId: impersonatedUser.organizationId,
  };

  return obj;
};

type Credentials = Record<"username" | "teamId", string> | undefined;

export function parseTeamId(creds: Partial<Credentials>) {
  return creds?.teamId ? teamIdschema.parse({ teamId: creds.teamId }).teamId : undefined;
}

export function checkSelfImpersonation(session: Session | null, creds: Partial<Credentials>) {
  if (session?.user.username === creds?.username || session?.user.email === creds?.username) {
    throw new Error("You cannot impersonate yourself.");
  }
}

export function checkUserIdentifier(creds: Partial<Credentials>) {
  if (!creds?.username) throw new Error("User identifier must be present");
}

export function checkPermission(session: Session | null) {
  if (session?.user.role !== "ADMIN" && process.env.NEXT_PUBLIC_TEAM_IMPERSONATION === "false") {
    throw new Error("You do not have permission to do this.");
  }
}

const ImpersonationProvider = CredentialsProvider({
  id: "impersonation-auth",
  name: "Impersonation",
  type: "credentials",
  credentials: {
    username: { type: "text" },
    teamId: { type: "text" },
  },
  async authorize(creds, req) {
    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
    // @ts-ignore need to figure out how to correctly type this
    const session = await getSession({ req });
    const teamId = parseTeamId(creds);
    checkSelfImpersonation(session, creds);
    checkUserIdentifier(creds);
    checkPermission(session);

    // Get user who is being impersonated
    const impersonatedUser = await prisma.user.findFirst({
      where: {
        OR: [{ username: creds?.username }, { email: creds?.username }],
      },
      select: {
        id: true,
        username: true,
        role: true,
        name: true,
        email: true,
        organizationId: true,
        disableImpersonation: true,
        teams: {
          where: {
            disableImpersonation: false, // Ensure they have impersonation enabled
            accepted: true, // Ensure they are apart of the team and not just invited.
            team: {
              id: teamId, // Bring back only the right team
            },
          },
          select: {
            teamId: true,
            disableImpersonation: true,
            role: true,
          },
        },
      },
    });

    // Check if impersonating is allowed for this user
    if (!impersonatedUser) {
      throw new Error("This user does not exist");
    }

    if (session?.user.role === "ADMIN") {
      if (impersonatedUser.disableImpersonation) {
        throw new Error("This user has disabled Impersonation.");
      }
      return auditAndReturnNextUser(
        impersonatedUser,
        session?.user.id as number,
        impersonatedUser.teams.length > 0 // If the user has any teams, they belong to an active team and we can set the hasActiveTeam ctx to true
      );
    }

    if (!teamId) throw new Error("You do not have permission to do this.");

    // Check session
    const sessionUserFromDb = await prisma.user.findUnique({
      where: {
        id: session?.user.id,
      },
      include: {
        teams: {
          where: {
            AND: [
              {
                role: {
                  in: ["ADMIN", "OWNER"],
                },
              },
              {
                team: {
                  id: teamId,
                },
              },
            ],
          },
          select: {
            role: true,
          },
        },
      },
    });

    if (sessionUserFromDb?.teams.length === 0 || impersonatedUser.teams.length === 0) {
      throw new Error("You do not have permission to do this.");
    }

    // We find team by ID so we know there is only one team in the array
    if (sessionUserFromDb?.teams[0].role === "ADMIN" && impersonatedUser.teams[0].role === "OWNER") {
      throw new Error("You do not have permission to do this.");
    }

    return auditAndReturnNextUser(
      impersonatedUser,
      session?.user.id as number,
      impersonatedUser.teams.length > 0 // If the user has any teams, they belong to an active team and we can set the hasActiveTeam ctx to true
    );
  },
});

export default ImpersonationProvider;