import NextAuth, { NextAuthOptions } from "next-auth";
import KeycloakProvider from "next-auth/providers/keycloak";
import { jwtDecode } from "jwt-decode";

interface KeycloakProfile {
  sub: string;
  email?: string;
  name?: string;
  roles?: string[];
  preferred_username?: string;
  given_name?: string;
  family_name?: string;
  realm_access?: {
    roles: string[];
  };
}

interface DecodedToken {
  realm_access?: {
    roles: string[];
  };
  [key: string]: any;
}

declare module "next-auth" {
  interface Session {
    user: {
      id: string;
      name?: string | null;
      email?: string | null;
      image?: string | null;
      username: string;
      first_name: string;
      last_name: string;
      role: string[];
    };
    accessToken: string;
    nextcloudToken: string;
  }

  interface JWT {
    sub?: string;
    accessToken: string;
    refreshToken: string;
    accessTokenExpires: number;
    role: string[];
    username: string;
    first_name: string;
    last_name: string;
    error?: string;
  }
}

function getRequiredEnvVar(name: string): string {
  const value = process.env[name];
  if (!value) {
    throw new Error(`Missing required environment variable: ${name}`);
  }
  return value;
}

async function refreshAccessToken(token: JWT) {
  try {
    const response = await fetch(`${process.env.KEYCLOAK_ISSUER}/protocol/openid-connect/token`, {
      headers: { "Content-Type": "application/x-www-form-urlencoded" },
      body: new URLSearchParams({
        client_id: process.env.KEYCLOAK_CLIENT_ID!,
        client_secret: process.env.KEYCLOAK_CLIENT_SECRET!,
        grant_type: "refresh_token",
        refresh_token: token.refreshToken,
      }),
      method: "POST",
    });

    const refreshedTokens = await response.json();

    if (!response.ok) {
      throw refreshedTokens;
    }

    return {
      ...token,
      accessToken: refreshedTokens.access_token,
      refreshToken: refreshedTokens.refresh_token ?? token.refreshToken,
      accessTokenExpires: Date.now() + refreshedTokens.expires_in * 1000,
    };
  } catch (error) {
    console.error("Error refreshing access token:", error);
    return {
      ...token,
      error: "RefreshAccessTokenError",
    };
  }
}

// Add NextCloud token exchange logic
async function exchangeKeycloakTokenForNextCloud(token: string): Promise<string> {
  const response = await fetch(`${process.env.NEXTCLOUD_URL}/apps/oauth2/api/v1/token`, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded',
    },
    body: new URLSearchParams({
      grant_type: 'urn:ietf:params:oauth:grant-type:token-exchange',
      subject_token: token,
      subject_token_type: 'urn:ietf:params:oauth:token-type:access_token',
      requested_token_type: 'urn:ietf:params:oauth:token-type:access_token'
    })
  });

  if (!response.ok) {
    throw new Error('Failed to exchange token with NextCloud');
  }

  const data = await response.json();
  return data.access_token;
}

export const authOptions: NextAuthOptions = {
  providers: [
    KeycloakProvider({
      clientId: getRequiredEnvVar("KEYCLOAK_CLIENT_ID"),
      clientSecret: getRequiredEnvVar("KEYCLOAK_CLIENT_SECRET"),
      issuer: getRequiredEnvVar("KEYCLOAK_ISSUER"),
      authorization: {
        params: {
          scope: "openid profile email roles"
        }
      },
      profile(profile) {
        console.log('Keycloak profile callback:', {
          rawProfile: profile,
          rawRoles: profile.roles,
          realmAccess: profile.realm_access,
          groups: profile.groups
        });

        // Get roles from realm_access
        const roles = profile.realm_access?.roles || [];
        console.log('Profile callback raw roles:', roles);

        // Clean up roles by removing ROLE_ prefix and converting to lowercase
        const cleanRoles = roles.map((role: string) => 
          role.replace(/^ROLE_/, '').toLowerCase()
        );

        console.log('Profile callback cleaned roles:', cleanRoles);

        return {
          id: profile.sub,
          name: profile.name ?? profile.preferred_username,
          email: profile.email,
          first_name: profile.given_name ?? '',
          last_name: profile.family_name ?? '',
          username: profile.preferred_username ?? profile.email?.split('@')[0] ?? '',
          role: cleanRoles,
        }
      },
    }),
  ],
  session: {
    strategy: "jwt",
    maxAge: 30 * 24 * 60 * 60, // 30 days
  },
  callbacks: {
    async jwt({ token, account }) {
      if (account?.access_token) {
        token.accessToken = account.access_token;
        // Only set refresh token if it exists
        if (account.refresh_token) {
          token.refreshToken = account.refresh_token;
        }
        // Set expiry if it exists, otherwise set a default
        token.accessTokenExpires = account.expires_at ? account.expires_at * 1000 : Date.now() + 3600 * 1000;
      }
      return token;
    },
    async session({ session, token }) {
      if (token) {
        session.accessToken = token.accessToken;
        // We'll handle Nextcloud authentication separately using app passwords
        session.user = {
          ...session.user,
          id: token.sub || '',
          role: token.role || [],
          username: token.username || '',
          first_name: token.first_name || '',
          last_name: token.last_name || '',
        };
      }
      return session;
    }
  },
  pages: {
    signIn: '/signin',
    error: '/signin',
  },
  debug: process.env.NODE_ENV === 'development',
};

const handler = NextAuth(authOptions);
export { handler as GET, handler as POST };

interface JWT {
  accessToken: string;
  refreshToken: string;
  accessTokenExpires: number;
}

interface Profile {
  sub?: string;
  email?: string;
  name?: string;
  roles?: string[];
}