import { HttpService } from "@nestjs/axios";
import { ConfigService } from "@nestjs/config";
import { JwtPayload, Signer } from "@sd-jwt/types";
import { exportJWK, importSPKI, JWK, JWTHeaderParameters } from "jose";
import { firstValueFrom } from "rxjs";
import { Repository } from "typeorm/repository/Repository";
import { v4 } from "uuid";
import {
    CryptoImplementationService,
    CryptoType,
} from "../crypto-implementation/crypto-implementation.service";
import { KeyImportDto } from "../dto/key-import.dto";
import { KeyObj } from "../dto/key-object.dto";
import { CertEntity } from "../entities/cert.entity";
import { KeyService } from "../key.service";

export class VaultKeyService extends KeyService {
    // url to the vault instance
    private vaultUrl: string;
    // headers for the vault api
    private headers: { headers: { "X-Vault-Token": string } };

    constructor(
        private httpService: HttpService,
        configService: ConfigService,
        private cryptoService: CryptoImplementationService,
        certRepository: Repository<CertEntity>,
    ) {
        super(configService, certRepository);

        this.vaultUrl = this.configService.get<string>("VAULT_URL") as string;
        this.headers = {
            headers: {
                "X-Vault-Token": this.configService.get<string>(
                    "VAULT_TOKEN",
                ) as string,
            },
        };
    }

    /**
     * Create a new transit for the tenant.
     * @param tenantId
     */
    async init(tenantId: string) {
        //TODO: what to do when it throws an error e.g. when the transit already exists
        await firstValueFrom(
            this.httpService.post(
                `${this.vaultUrl}/v1/sys/mounts/${tenantId}`,
                {
                    type: "transit",
                },
                this.headers,
            ),
        ).catch((err) => {
            console.error(JSON.stringify(err.response.data, null, 2));
        });
        return this.create(tenantId);
    }

    // eslint-disable-next-line @typescript-eslint/no-unused-vars
    import(tenantId: string, body: KeyImportDto): Promise<string> {
        throw new Error("Importing not supported by VaultKeyService");
    }

    getKeys(tenantId: string): Promise<KeyObj[]> {
        return firstValueFrom(
            this.httpService.get<any>(
                `${this.vaultUrl}/v1/${tenantId}/keys?list=true`,
                this.headers,
            ),
        ).then((res) => {
            //TODO: get all the public keys from the vault
            return Promise.all(
                res.data.data.keys.map(async (id: string) => {
                    const publicKey = await this.getPublicKey(
                        "jwk",
                        tenantId,
                        id,
                    );
                    const crt = await this.getCertificate(tenantId, id);
                    return {
                        id,
                        publicKey,
                        crt,
                    } as KeyObj;
                }),
            );
        });
    }

    /**
     * Get the signer for the key service
     */
    signer(tenantId: string): Promise<Signer> {
        //TODO: validate if this is correct.
        return Promise.resolve((input: string) => this.sign(input, tenantId));
    }

    /**
     * Creates a new keypair in the vault
     * @param createKeyDto
     * @param user
     * @returns
     */
    async create(tenantId: string) {
        const types: Map<CryptoType, string> = new Map();
        types.set("ES256", "ecdsa-p256");
        const id = v4();
        await firstValueFrom(
            this.httpService.post(
                `${this.vaultUrl}/v1/${tenantId}/keys/${id}`,
                {
                    exportable: false,
                    type: types.get(this.cryptoService.getAlg()),
                },
                this.headers,
            ),
        );
        return id;
    }

    /**
     * Get all keys and take the first one.
     * @param tenantId
     * @returns
     */
    getKid(tenantId: string): Promise<string> {
        return firstValueFrom(
            this.httpService.get<any>(
                `${this.vaultUrl}/v1/${tenantId}/keys?list=true`,
                this.headers,
            ),
        ).then(
            (res) => {
                if (
                    !res.data.data.keys ||
                    (res.data.data.keys as string[]).length === 0
                ) {
                    throw new Error("No keys found");
                }
                return (res.data.data.keys as string[])[0];
            },
            (err) => {
                throw new Error(
                    `Error getting keys for tenant ${tenantId}: ${err.message}`,
                );
            },
        );
    }

    /**
     * Gets the public key and converts it to a KeyLike object.
     * @param id
     * @returns
     */
    async getPublicKey(
        type: "pem",
        tenantId: string,
        keyId?: string,
    ): Promise<string>;
    async getPublicKey(
        type: "jwk",
        tenantId: string,
        keyId: string,
    ): Promise<JWK>;
    async getPublicKey(
        type: "jwk" | "pem",
        tenantId: string,
        keyId?: string,
    ): Promise<JWK | string> {
        if (!keyId) {
            keyId = await this.getKid(tenantId);
        }

        return firstValueFrom(
            this.httpService.get<any>(
                `${this.vaultUrl}/v1/${tenantId}/keys/${keyId}`,
                this.headers,
            ),
        ).then(async (res) => {
            return type === "pem"
                ? (res.data.data.keys["1"].public_key as string)
                : await this.getJWK(
                      res.data.data.keys["1"].public_key,
                      tenantId,
                  );
        });
    }

    private getJWK(key: string, tenantId: string): Promise<JWK> {
        return importSPKI(key, this.cryptoService.getAlg())
            .then((cryptoKey) => exportJWK(cryptoKey))
            .then(async (jwk) => {
                jwk.kid = await this.getKid(tenantId);
                return jwk;
            });
    }

    /**
     * Signs a value with a key in the vault.
     * @param id
     * @param user
     * @param value
     * @returns
     */
    async sign(
        value: string,
        tenantId: string,
        keyId?: string,
    ): Promise<string> {
        if (!keyId) {
            keyId = await this.getKid(tenantId);
        }
        return firstValueFrom(
            this.httpService.post(
                `${this.vaultUrl}/v1/${tenantId}/sign/${keyId}`,
                {
                    input: Buffer.from(value).toString("base64"),
                    marshaling_algorithm: "jws",
                },
                this.headers,
            ),
        ).then((res) => res.data.data.signature.split(":")[2]);
    }

    /**
     * Creates a proof of possession jwt.
     * @param user
     * @param value
     */
    async signJWT(
        payload: JwtPayload,
        header: JWTHeaderParameters,
        tenantId: string,
        keyId?: string,
    ): Promise<string> {
        // Convert header and payload to Base64 to prepare for Vault
        const encodedHeader = Buffer.from(JSON.stringify(header)).toString(
            "base64url",
        );
        const encodedPayload = Buffer.from(JSON.stringify(payload)).toString(
            "base64url",
        );
        const signingInput = `${encodedHeader}.${encodedPayload}`;

        // Request to Vault for signing
        try {
            const signature = await this.sign(signingInput, tenantId, keyId);
            return `${encodedHeader}.${encodedPayload}.${signature}`;
        } catch (error) {
            console.error("Error signing JWT with Vault:", error);
            throw error;
        }
    }
}