// This Source Code Form is subject to the terms of the Mozilla PublicAA
// License, version 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <time.h>
#include <rnp/rnp.h>

#include "plugin.h"
#include "pgp.h"

#define RNP_SUCCESS 0

#define PGP_MESSAGE_HEADER "-----BEGIN PGP MESSAGE-----\r\n\r\n"
#define PGP_MESSAGE_FOOTER "\r\n-----END PGP MESSAGE-----\r\n"
#define PGP_SIGNATURE_HEADER "-----BEGIN PGP SIGNATURE-----\r\n\r\n"
#define PGP_SIGNATURE_FOOTER "\r\n-----END PGP SIGNATURE-----\r\n"

const char *PGP_ADVICE = "[PGP encrypted message (XEP-0027)]";

void pgp__init(struct t_pgp **pgp, const char *pub, const char *sec)
{
    struct t_pgp *new_pgp;
    rnp_input_t keyring;

    new_pgp = calloc(1, sizeof(**pgp));

    if (rnp_ffi_create(&new_pgp->context,
                       RNP_KEYSTORE_GPG, RNP_KEYSTORE_GPG) != RNP_SUCCESS) {
        return;
    }

    if (rnp_input_from_path(&keyring, pub) == RNP_SUCCESS) {
        if (rnp_load_keys(new_pgp->context, RNP_KEYSTORE_GPG,
                          keyring, RNP_LOAD_SAVE_PUBLIC_KEYS) == RNP_SUCCESS) {
            rnp_input_destroy(keyring);
        }
    }

    if (rnp_input_from_path(&keyring, sec) == RNP_SUCCESS) {
        if (rnp_load_keys(new_pgp->context, RNP_KEYSTORE_GPG,
                          keyring, RNP_LOAD_SAVE_SECRET_KEYS) == RNP_SUCCESS) {
            rnp_input_destroy(keyring);
        }
    }

    *pgp = new_pgp;
}

void pgp__free(struct t_pgp *pgp)
{
    if (pgp)
    {
        if (pgp->context)
            free(pgp->context);
        free(pgp);
    }
}

char *pgp__encrypt(struct t_gui_buffer *buffer, struct t_pgp *pgp, const char *source, const char *target, const char *message)
{
    rnp_op_encrypt_t encrypt = NULL;
    rnp_key_handle_t key = NULL;
    rnp_input_t      keyfile = NULL;
    rnp_input_t      input = NULL;
    rnp_output_t     output = NULL;
    char *           result = NULL;

    rnp_result_t ret;

    /* create memory input and file output objects for the message and encrypted message */
    if ((ret = rnp_input_from_memory(&input, (uint8_t *)message, strlen(message), false)) !=
        RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to create input object: %s\n", weechat_prefix("error"), reason);
        goto encrypt_finish;
    }

    if ((ret = rnp_output_to_memory(&output, 0)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to create output object: %s\n", weechat_prefix("error"), reason);
        goto encrypt_finish;
    }

    /* create encryption operation */
    if ((ret = rnp_op_encrypt_create(&encrypt, pgp->context, input, output)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to create encrypt operation: %s\n", weechat_prefix("error"), reason);
        goto encrypt_finish;
    }

    /* setup encryption parameters */
    rnp_op_encrypt_set_armor(encrypt, true);
    rnp_op_encrypt_set_file_name(encrypt, "message.txt");
    rnp_op_encrypt_set_file_mtime(encrypt, time(NULL));
    rnp_op_encrypt_set_compression(encrypt, "ZIP", 6);
    rnp_op_encrypt_set_cipher(encrypt, RNP_ALGNAME_AES_256);
    rnp_op_encrypt_set_aead(encrypt, "None");

    /* locate recipient's key and add it to the operation context. */
    if ((ret = rnp_locate_key(pgp->context, "keyid", target, &key)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to locate recipient key: %s\n", weechat_prefix("error"), reason);
        goto encrypt_finish;
    }

    if ((ret = rnp_op_encrypt_add_recipient(encrypt, key)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to add recipient: %s\n", weechat_prefix("error"), reason);
        goto encrypt_finish;
    }
    rnp_key_handle_destroy(key);
    key = NULL;

    /* locate carbon-copy key and add it to the operation context. */
    if ((ret = rnp_locate_key(pgp->context, "keyid", source, &key)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to locate recipient key: %s\n", weechat_prefix("error"), reason);
        goto encrypt_finish;
    }

    if ((ret = rnp_op_encrypt_add_recipient(encrypt, key)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to add recipient: %s\n", weechat_prefix("error"), reason);
        goto encrypt_finish;
    }
    rnp_key_handle_destroy(key);
    key = NULL;

    /* execute encryption operation */
    if ((ret = rnp_op_encrypt_execute(encrypt)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: encryption failed: %s\n", weechat_prefix("error"), reason);
        goto encrypt_finish;
    }

    uint8_t *buf;
    size_t buf_len;

    rnp_output_memory_get_buf(output, &buf, &buf_len, false);
    result = strndup((char *)buf + strlen(PGP_MESSAGE_HEADER),
                     buf_len - strlen(PGP_MESSAGE_HEADER) - strlen(PGP_MESSAGE_FOOTER));
encrypt_finish:
    rnp_op_encrypt_destroy(encrypt);
    rnp_input_destroy(keyfile);
    rnp_input_destroy(input);
    rnp_output_destroy(output);
    rnp_key_handle_destroy(key);
    return result;
}

//"hQIMAzlgcSFDGLKEAQ//cGG3DFughC5xBF7xeXz1RdayOfhBAPfoZIq62MVuSnfS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\npw==\n=euIB"
char *pgp__decrypt(struct t_gui_buffer *buffer, struct t_pgp *pgp, const char *ciphertext)
{
    rnp_input_t  input = NULL;
    rnp_output_t output = NULL;
    uint8_t *    buf = NULL;
    size_t       buf_len = 0;
    char *       result = NULL;

    rnp_result_t ret;

    buf_len = strlen(PGP_MESSAGE_HEADER) + strlen(ciphertext) + strlen(PGP_MESSAGE_FOOTER) + 1;
    buf = malloc(sizeof(char) * buf_len);
    buf_len = snprintf((char *)buf, buf_len, PGP_MESSAGE_HEADER "%s" PGP_MESSAGE_FOOTER, ciphertext);

    /* create file input and memory output objects for the encrypted message and decrypted
     * message */
    if ((ret = rnp_input_from_memory(&input, buf, buf_len, false)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to create input object: %s\n", weechat_prefix("error"), reason);
        goto decrypt_finish;
    }

    if ((ret = rnp_output_to_memory(&output, 0)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to create output object: %s\n", weechat_prefix("error"), reason);
        goto decrypt_finish;
    }

    if ((ret = rnp_decrypt(pgp->context, input, output)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: public-key decryption failed: %s\n", weechat_prefix("error"), reason);
        goto decrypt_finish;
    }
    free(buf);

    /* get the decrypted message from the output structure */
    if (rnp_output_memory_get_buf(output, &buf, &buf_len, false) != RNP_SUCCESS) {
        goto decrypt_finish;
    }

    result = strndup((const char *)buf, (int)buf_len);
decrypt_finish:
    rnp_input_destroy(input);
    rnp_output_destroy(output);
    return result;
}

char *pgp__verify(struct t_gui_buffer *buffer, struct t_pgp *pgp, const char *certificate)
{
    rnp_op_verify_t verify = NULL;
    rnp_input_t     input = NULL;
    rnp_input_t     signature = NULL;
    uint8_t *       buf = NULL;
    size_t          buf_len = 0;
    size_t          sigcount = 0;
    char *          result = NULL;

    rnp_result_t ret;

    buf_len = strlen(PGP_SIGNATURE_HEADER) + strlen(certificate) + strlen(PGP_SIGNATURE_FOOTER) + 1;
    buf = malloc(sizeof(char) * buf_len);
    buf_len = snprintf((char *)buf, buf_len, PGP_SIGNATURE_HEADER "%s" PGP_SIGNATURE_FOOTER, certificate);

    /* create file input memory objects for the signed message and verified message */
    if ((ret = rnp_input_from_memory(&input, buf, buf_len, false)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to create input object: %s\n", weechat_prefix("error"), reason);
        goto verify_finish;
    }

    if ((ret = rnp_input_from_memory(&signature, buf, buf_len, false)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to create input object: %s\n", weechat_prefix("error"), reason);
        goto verify_finish;
    }

    if ((ret = rnp_op_verify_detached_create(&verify, pgp->context, input, signature)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to create verification context: %s\n", weechat_prefix("error"), reason);
        goto verify_finish;
    }

  //if ((
            ret = rnp_op_verify_execute(verify)
                ;
  //        ) != RNP_ERROR_SIGNATURE_INVALID)
  //    if (ret != RNP_ERROR_SIGNATURE_INVALID) {
  //        const char *reason = rnp_result_to_string(ret);
  //        weechat_printf(buffer, "%spgp: failed to execute verification operation: %s\n", weechat_prefix("error"), reason);
  //        goto verify_finish;
  //    }

    /* now check signatures and get some info about them */
    if ((ret = rnp_op_verify_get_signature_count(verify, &sigcount)) != RNP_SUCCESS) {
        const char *reason = rnp_result_to_string(ret);
        weechat_printf(buffer, "%spgp: failed to get signature count: %s\n", weechat_prefix("error"), reason);
        goto verify_finish;
    }

    for (size_t i = 0; i < sigcount; i++) {
        rnp_op_verify_signature_t sig = NULL;
        rnp_key_handle_t          key = NULL;
        rnp_signature_handle_t    signature = NULL;
        char *                    keyid = NULL;

        if ((ret = rnp_op_verify_get_signature_at(verify, i, &sig)) != RNP_SUCCESS) {
            const char *reason = rnp_result_to_string(ret);
            weechat_printf(buffer, "%spgp: failed to get signature %d: %s\n", weechat_prefix("error"), (int)i, reason);
            goto verify_finish;
        }

        if ((ret = rnp_op_verify_signature_get_key(sig, &key)) == RNP_SUCCESS) {
            if ((ret = rnp_key_get_keyid(key, &keyid)) != RNP_SUCCESS) {
                const char *reason = rnp_result_to_string(ret);
                weechat_printf(buffer, "%spgp: failed to get key id %d: %s\n", weechat_prefix("error"), (int)i, reason);
                rnp_key_handle_destroy(key);
                goto verify_finish;
            }

            if ((ret = rnp_key_get_signature_at(key, 0, &signature)) == RNP_SUCCESS) {
                if ((ret = rnp_signature_get_keyid(signature, &keyid)) != RNP_SUCCESS) {
                    const char *reason = rnp_result_to_string(ret);
                    weechat_printf(buffer, "%spgp: failed to get key id: %s\n", weechat_prefix("error"), reason);
                    rnp_key_handle_destroy(key);
                    goto verify_finish;
                }
                rnp_signature_handle_destroy(signature);
            }
        } else {
            if ((ret = rnp_op_verify_signature_get_handle(sig, &signature)) != RNP_SUCCESS) {
                const char *reason = rnp_result_to_string(ret);
                weechat_printf(buffer, "%spgp: failed to get signature's %d handle: %s\n", weechat_prefix("error"), (int)i, reason);
                goto verify_finish;
            }

            if ((ret = rnp_signature_get_keyid(signature, &keyid)) != RNP_SUCCESS) {
                const char *reason = rnp_result_to_string(ret);
                weechat_printf(buffer, "%spgp: failed to get key id: %s\n", weechat_prefix("error"), reason);
                rnp_key_handle_destroy(key);
                goto verify_finish;
            }
        }

        result = strdup(keyid);
        rnp_buffer_destroy(keyid);
        rnp_key_handle_destroy(key);
        break;
    }

verify_finish:
    rnp_op_verify_destroy(verify);
    rnp_input_destroy(input);
    rnp_input_destroy(signature);
    return result;
}

char *pgp__sign(struct t_gui_buffer *buffer, struct t_pgp *pgp, const char *source, const char *message)
{
    rnp_input_t      keyfile = NULL;
    rnp_input_t      input = NULL;
    rnp_output_t     output = NULL;
    rnp_op_sign_t    sign = NULL;
    rnp_key_handle_t key = NULL;
    uint8_t *        buf = NULL;
    size_t           buf_len = 0;
    char *           result = NULL;

    /* create file input and memory output objects for the encrypted message and decrypted
     * message */
    if (rnp_input_from_memory(&input, (uint8_t *)message, strlen(message), false) !=
        RNP_SUCCESS) {
        weechat_printf(buffer, "%spgp: failed to create input object\n", weechat_prefix("error"));
        goto sign_finish;
    }

    if (rnp_output_to_memory(&output, 0) != RNP_SUCCESS) {
        weechat_printf(buffer, "%spgp: failed to create output object\n", weechat_prefix("error"));
        goto sign_finish;
    }

    /* initialize and configure sign operation */
    if (rnp_op_sign_detached_create(&sign, pgp->context, input, output) != RNP_SUCCESS) {
        weechat_printf(buffer, "%spgp: failed to create sign operation\n", weechat_prefix("error"));
        goto sign_finish;
    }

    /* armor, file name, compression */
    rnp_op_sign_set_armor(sign, true);
    rnp_op_sign_set_file_name(sign, "message.txt");
    rnp_op_sign_set_file_mtime(sign, time(NULL));
    rnp_op_sign_set_compression(sign, "ZIP", 6);
    /* signatures creation time - by default will be set to the current time as well */
    rnp_op_sign_set_creation_time(sign, time(NULL));
    /* signatures expiration time - by default will be 0, i.e. never expire */
    rnp_op_sign_set_expiration_time(sign, 365 * 24 * 60 * 60);
    /* set hash algorithm - should be compatible for all signatures */
    rnp_op_sign_set_hash(sign, RNP_ALGNAME_SHA256);

    /* now add signatures. First locate the signing key, then add and setup signature */
    if (rnp_locate_key(pgp->context, "keyid", source, &key) != RNP_SUCCESS) {
        weechat_printf(buffer, "%spgp: failed to locate signing key: %s\n", weechat_prefix("error"), source);
        goto sign_finish;
    }

    if (rnp_op_sign_add_signature(sign, key, NULL) != RNP_SUCCESS) {
        weechat_printf(buffer, "%spgp: failed to add signature for key: %s\n", weechat_prefix("error"), source);
        goto sign_finish;
    }

    rnp_key_handle_destroy(key);
    key = NULL;

    /* finally do signing */
    if (rnp_op_sign_execute(sign) != RNP_SUCCESS) {
        weechat_printf(buffer, "%spgp: failed to sign with key: %s\n", weechat_prefix("error"), source);
        goto sign_finish;
    }

    /* get the signature from the output structure */
    if (rnp_output_memory_get_buf(output, &buf, &buf_len, false) != RNP_SUCCESS) {
        goto sign_finish;
    }

    result = strndup((char *)buf + strlen(PGP_SIGNATURE_HEADER),
                     buf_len - strlen(PGP_SIGNATURE_HEADER) - strlen(PGP_SIGNATURE_FOOTER));
sign_finish:
    rnp_input_destroy(keyfile);
    rnp_key_handle_destroy(key);
    rnp_op_sign_destroy(sign);
    rnp_input_destroy(input);
    rnp_output_destroy(output);
    return result;
}