"use server";

import { create } from "@zitadel/client";
import { ChecksSchema } from "@zitadel/proto/zitadel/session/v2/session_service_pb";
import { AuthenticationMethodType } from "@zitadel/proto/zitadel/user/v2/user_service_pb";
import { getTranslations } from "next-intl/server";
import { headers } from "next/headers";
import { idpTypeToIdentityProviderType, idpTypeToSlug } from "../idp";

import { PasskeysType } from "@zitadel/proto/zitadel/settings/v2/login_settings_pb";
import { UserState } from "@zitadel/proto/zitadel/user/v2/user_pb";
import { getServiceUrlFromHeaders } from "../service-url";
import {
  getActiveIdentityProviders,
  getIDPByID,
  getLoginSettings,
  getOrgsByDomain,
  listAuthenticationMethodTypes,
  listIDPLinks,
  searchUsers,
  SearchUsersCommand,
  startIdentityProviderFlow,
} from "../zitadel";
import { createSessionAndUpdateCookie } from "./cookie";
import { getOriginalHost } from "./host";
import { IDPLink } from "@zitadel/proto/zitadel/user/v2/idp_pb";

export type SendLoginnameCommand = {
  loginName: string;
  requestId?: string;
  organization?: string;
  suffix?: string;
};

const ORG_SUFFIX_REGEX = /(?<=@)(.+)/;

export async function sendLoginname(command: SendLoginnameCommand) {
  const _headers = await headers();
  const { serviceUrl } = getServiceUrlFromHeaders(_headers);

  const t = await getTranslations("loginname");

  const loginSettingsByContext = await getLoginSettings({
    serviceUrl,
    organization: command.organization,
  });

  if (!loginSettingsByContext) {
    return { error: t("errors.couldNotGetLoginSettings") };
  }

  let searchUsersRequest: SearchUsersCommand = {
    serviceUrl,
    searchValue: command.loginName,
    organizationId: command.organization,
    loginSettings: loginSettingsByContext,
    suffix: command.suffix,
  };

  const searchResult = await searchUsers(searchUsersRequest);

  if ("error" in searchResult && searchResult.error) {
    return searchResult;
  }

  if (!("result" in searchResult)) {
    return { error: t("errors.couldNotSearchUsers") };
  }

  const { result: potentialUsers } = searchResult;

  const redirectUserToIDP = async (userId?: string, organization?: string) => {
    // If userId is provided, check for user-specific IDP links first
    let identityProviders: IDPLink[] = [];
    if (userId) {
      identityProviders = await listIDPLinks({
        serviceUrl,
        userId,
      }).then((resp) => {
        return resp.result;
      });
    }

    // If no IDP links exist for the user (or no userId provided), try to get active IDPs from the organization
    if (identityProviders.length === 0) {
      const activeIdps = await getActiveIdentityProviders({
        serviceUrl,
        orgId: organization,
      }).then((resp) => {
        return resp.identityProviders;
      });

      // If exactly one active IDP exists in the organization, redirect to it
      if (activeIdps.length === 1) {
        const _headers = await headers();
        const { serviceUrl } = getServiceUrlFromHeaders(_headers);
        const host = await getOriginalHost();

        const identityProviderType = activeIdps[0].type;
        const provider = idpTypeToSlug(identityProviderType);

        const params = new URLSearchParams();

        if (userId) {
          params.set("userId", userId);
        }

        if (command.requestId) {
          params.set("requestId", command.requestId);
        }

        if (organization) {
          params.set("organization", organization);
        }

        const basePath = process.env.NEXT_PUBLIC_BASE_PATH ?? "";

        const url = await startIdentityProviderFlow({
          serviceUrl,
          idpId: activeIdps[0].id,
          urls: {
            successUrl:
              `${host.includes("localhost") ? "http://" : "https://"}${host}${basePath}/idp/${provider}/success?` +
              new URLSearchParams(params),
            failureUrl:
              `${host.includes("localhost") ? "http://" : "https://"}${host}${basePath}/idp/${provider}/failure?` +
              new URLSearchParams(params),
          },
        });

        if (!url) {
          return { error: t("errors.couldNotStartIDPFlow") };
        }

        return { redirect: url };
      }
    }

    if (identityProviders.length === 1) {
      const _headers = await headers();
      const { serviceUrl } = getServiceUrlFromHeaders(_headers);
      const host = await getOriginalHost();

      const identityProviderId = identityProviders[0].idpId;

      const idp = await getIDPByID({
        serviceUrl,
        id: identityProviderId,
      });

      const idpType = idp?.type;

      if (!idp || !idpType) {
        throw new Error(t("errors.couldNotFindIdentityProvider"));
      }

      const identityProviderType = idpTypeToIdentityProviderType(idpType);
      const provider = idpTypeToSlug(identityProviderType);

      const params = new URLSearchParams();

      if (userId) {
        params.set("userId", userId);
      }

      if (command.requestId) {
        params.set("requestId", command.requestId);
      }

      if (organization) {
        params.set("organization", organization);
      }

      const basePath = process.env.NEXT_PUBLIC_BASE_PATH ?? "";

      const url = await startIdentityProviderFlow({
        serviceUrl,
        idpId: idp.id,
        urls: {
          successUrl:
            `${host.includes("localhost") ? "http://" : "https://"}${host}${basePath}/idp/${provider}/success?` +
            new URLSearchParams(params),
          failureUrl:
            `${host.includes("localhost") ? "http://" : "https://"}${host}${basePath}/idp/${provider}/failure?` +
            new URLSearchParams(params),
        },
      });

      if (!url) {
        return { error: t("errors.couldNotStartIDPFlow") };
      }

      return { redirect: url };
    }
  };

  if (potentialUsers.length > 1) {
    return { error: t("errors.moreThanOneUserFound") };
  } else if (potentialUsers.length == 1 && potentialUsers[0].userId) {
    const user = potentialUsers[0];
    const userId = potentialUsers[0].userId;

    const userLoginSettings = await getLoginSettings({
      serviceUrl,
      organization: user.details?.resourceOwner,
    });

    // compare with the concatenated suffix when set
    const concatLoginname = command.suffix ? `${command.loginName}@${command.suffix}` : command.loginName;

    const humanUser = potentialUsers[0].type.case === "human" ? potentialUsers[0].type.value : undefined;

    // recheck login settings after user discovery, as the search might have been done without org scope
    if (userLoginSettings?.disableLoginWithEmail && userLoginSettings?.disableLoginWithPhone) {
      if (user.preferredLoginName !== concatLoginname) {
        return { error: t("errors.userNotFound") };
      }
    } else if (userLoginSettings?.disableLoginWithEmail) {
      if (user.preferredLoginName !== concatLoginname || humanUser?.phone?.phone !== command.loginName) {
        return { error: t("errors.userNotFound") };
      }
    } else if (userLoginSettings?.disableLoginWithPhone) {
      if (user.preferredLoginName !== concatLoginname || humanUser?.email?.email !== command.loginName) {
        return { error: t("errors.userNotFound") };
      }
    }

    const checks = create(ChecksSchema, {
      user: { search: { case: "userId", value: userId } },
    });

    const sessionOrError = await createSessionAndUpdateCookie({
      checks,
      requestId: command.requestId,
    }).catch((error) => {
      if (error?.rawMessage === "Errors.User.NotActive (SESSION-Gj4ko)") {
        return { error: t("errors.userNotActive") };
      }
      throw error;
    });

    if ("error" in sessionOrError) {
      return sessionOrError;
    }

    const session = sessionOrError;

    if (!session.factors?.user?.id) {
      return { error: t("errors.couldNotCreateSession") };
    }

    // TODO: check if handling of userstate INITIAL is needed
    if (user.state === UserState.INITIAL) {
      return { error: t("errors.initialUserNotSupported") };
    }

    // Resolve organization from command or session
    const organization = command.organization ?? session.factors?.user?.organizationId;

    const methods = await listAuthenticationMethodTypes({
      serviceUrl,
      userId: session.factors?.user?.id,
    });

    // always resend invite if user has no auth method set
    if (!methods.authMethodTypes || !methods.authMethodTypes.length) {
      const params = new URLSearchParams({
        loginName: session.factors?.user?.loginName as string,
        send: "true", // set this to true to request a new code immediately
        invite: humanUser?.email?.isVerified ? "false" : "true", // sendInviteEmailCode results in an error if user is already initialized
      });

      if (command.requestId) {
        params.append("requestId", command.requestId);
      }

      if (organization) {
        params.append("organization", organization);
      }

      return { redirect: `/verify?` + params };
    }

    if (methods.authMethodTypes.length == 1) {
      const method = methods.authMethodTypes[0];
      switch (method) {
        case AuthenticationMethodType.PASSWORD: // user has only password as auth method
          if (!userLoginSettings?.allowUsernamePassword) {
            // Check if user has IDPs available as alternative, that could eventually be used to register/link.
            const idpResp = await redirectUserToIDP(userId, organization);
            if (idpResp?.redirect) {
              return idpResp;
            }

            return {
              error: t("errors.usernamePasswordNotAllowed"),
            };
          }

          const paramsPassword = new URLSearchParams({
            loginName: session.factors?.user?.loginName,
          });

          // TODO: does this have to be checked in loginSettings.allowDomainDiscovery

          if (organization) {
            paramsPassword.append("organization", organization);
          }

          if (command.requestId) {
            paramsPassword.append("requestId", command.requestId);
          }

          return {
            redirect: "/password?" + paramsPassword,
          };

        case AuthenticationMethodType.PASSKEY: // AuthenticationMethodType.AUTHENTICATION_METHOD_TYPE_PASSKEY
          if (userLoginSettings?.passkeysType === PasskeysType.NOT_ALLOWED) {
            return {
              error: t("errors.passkeysNotAllowed"),
            };
          }

          const paramsPasskey = new URLSearchParams({
            loginName: session.factors?.user?.loginName,
          });
          if (command.requestId) {
            paramsPasskey.append("requestId", command.requestId);
          }

          if (organization) {
            paramsPasskey.append("organization", organization);
          }

          return { redirect: "/passkey?" + paramsPasskey };

        case AuthenticationMethodType.IDP:
          const resp = await redirectUserToIDP(userId, organization);

          if (resp?.error) {
            return { error: resp.error };
          }

          return resp;
      }
    } else {
      // prefer passkey in favor of other methods
      if (methods.authMethodTypes.includes(AuthenticationMethodType.PASSKEY)) {
        const passkeyParams = new URLSearchParams({
          loginName: session.factors?.user?.loginName,
          altPassword: `${methods.authMethodTypes.includes(AuthenticationMethodType.PASSWORD) && userLoginSettings?.allowUsernamePassword}`, // show alternative password option only if allowed
        });

        if (command.requestId) {
          passkeyParams.append("requestId", command.requestId);
        }

        if (organization) {
          passkeyParams.append("organization", organization);
        }

        return { redirect: "/passkey?" + passkeyParams };
      } else if (methods.authMethodTypes.includes(AuthenticationMethodType.IDP)) {
        return redirectUserToIDP(userId, organization);
      } else if (methods.authMethodTypes.includes(AuthenticationMethodType.PASSWORD)) {
        // Check if password authentication is allowed
        if (!userLoginSettings?.allowUsernamePassword) {
          return {
            error: "Username Password not allowed! Contact your administrator for more information.",
          };
        }

        // user has no passkey setup and login settings allow passwords
        const paramsPasswordDefault = new URLSearchParams({
          loginName: session.factors?.user?.loginName,
        });

        if (command.requestId) {
          paramsPasswordDefault.append("requestId", command.requestId);
        }

        if (organization) {
          paramsPasswordDefault.append("organization", organization);
        }

        return {
          redirect: "/password?" + paramsPasswordDefault,
        };
      }
    }
  }

  // user not found, check if register is enabled on instance / organization context
  if (loginSettingsByContext?.allowRegister && !loginSettingsByContext?.allowUsernamePassword) {
    const resp = await redirectUserToIDP(undefined, command.organization);
    if (resp) {
      return resp;
    }
    return { error: t("errors.userNotFound") };
  } else if (loginSettingsByContext?.allowRegister && loginSettingsByContext?.allowUsernamePassword) {
    let orgToRegisterOn: string | undefined = command.organization;

    if (
      !loginSettingsByContext?.ignoreUnknownUsernames &&
      !orgToRegisterOn &&
      command.loginName &&
      ORG_SUFFIX_REGEX.test(command.loginName)
    ) {
      const matched = ORG_SUFFIX_REGEX.exec(command.loginName);
      const suffix = matched?.[1] ?? "";

      // this just returns orgs where the suffix is set as primary domain
      const orgs = await getOrgsByDomain({
        serviceUrl,
        domain: suffix,
      });
      const orgToCheckForDiscovery = orgs.result && orgs.result.length === 1 ? orgs.result[0].id : undefined;

      const orgLoginSettings = await getLoginSettings({
        serviceUrl,
        organization: orgToCheckForDiscovery,
      });
      if (orgLoginSettings?.allowDomainDiscovery) {
        orgToRegisterOn = orgToCheckForDiscovery;
      }
    }

    // do not register user if ignoreUnknownUsernames is set
    if (orgToRegisterOn && !loginSettingsByContext?.ignoreUnknownUsernames) {
      const params = new URLSearchParams({ organization: orgToRegisterOn });

      if (command.requestId) {
        params.set("requestId", command.requestId);
      }

      if (command.loginName) {
        params.set("email", command.loginName);
      }

      return { redirect: "/register?" + params };
    }
  }

  if (loginSettingsByContext?.ignoreUnknownUsernames) {
    const paramsPasswordDefault = new URLSearchParams({
      loginName: command.loginName,
    });

    if (command.requestId) {
      paramsPasswordDefault.append("requestId", command.requestId);
    }

    if (command.organization) {
      paramsPasswordDefault.append("organization", command.organization);
    }

    return { redirect: "/password?" + paramsPasswordDefault };
  }

  // fallbackToPassword

  return { error: t("errors.userNotFound") };
}