#include "platform.h"

#include <string.h>

#include <stdio.h>

#include <stdlib.h>

#include <assert.h>

#include <ctype.h>

#include "pEp_internal.h"

#include "keymanagement.h"

#ifndef EMPTYSTR

#define EMPTYSTR(STR) ((STR) == NULL || (STR)[0] == '\0')

#endif

#define KEY_EXPIRE_DELTA (60 * 60 * 24 * 365)

// Space tolerant and case insensitive fingerprint string compare

static int _same_fpr(

        const char* fpra,

        size_t fpras,

        const char* fprb,

        size_t fprbs

    )

{

    size_t ai = 0;

    size_t bi = 0;

    do

    {

        if(fpra[ai] == 0 || fprb[bi] == 0)

        {

            return 0;

        }

        else if(fpra[ai] == ' ')

        {

            ai++;

        }

        else if(fprb[bi] == ' ')

        {

            bi++;

        }

        else if(toupper(fpra[ai]) == toupper(fprb[bi]))

        {

            ai++;

            bi++;

        }

        else

        {

            return 0;

        }

    }

    while(ai < fpras && bi < fprbs);

    return ai == fpras && bi == fprbs;

}

DYNAMIC_API PEP_STATUS update_identity(

        PEP_SESSION session, pEp_identity * identity

    )

{

    pEp_identity *stored_identity;

    PEP_STATUS status;

    assert(session);

    assert(identity);

    assert(!EMPTYSTR(identity->address));

    if (!(session && identity && !EMPTYSTR(identity->address)))

        return PEP_ILLEGAL_VALUE;

    int _no_user_id = EMPTYSTR(identity->user_id);

    if (_no_user_id)

    {

        free(identity->user_id);

        identity->user_id = calloc(1, identity->address_size + 6);

        if (!identity->user_id)

        {

            return PEP_OUT_OF_MEMORY;

        }

        snprintf(identity->user_id, identity->address_size + 5,

                 "TOFU_%s", identity->address);

        if(identity->user_id)

        {

            identity->user_id_size = strlen(identity->user_id);

        }

    }

    status = get_identity(session,

                          identity->address,

                          identity->user_id,

                          &stored_identity);

    assert(status != PEP_OUT_OF_MEMORY);

    if (status == PEP_OUT_OF_MEMORY)

        return PEP_OUT_OF_MEMORY;

    if (stored_identity) {

        PEP_comm_type _comm_type_key;

        status = get_key_rating(session, stored_identity->fpr, &_comm_type_key);

        assert(status != PEP_OUT_OF_MEMORY);

        if (status == PEP_OUT_OF_MEMORY)

            return PEP_OUT_OF_MEMORY;

        if (EMPTYSTR(identity->username)) {

            free(identity->username);

            identity->username = strndup(stored_identity->username, stored_identity->username_size);

            assert(identity->username);

            if (identity->username == NULL)

                return PEP_OUT_OF_MEMORY;

            identity->username_size = stored_identity->username_size;

        }

        if (EMPTYSTR(identity->fpr)) {

            identity->fpr = strndup(stored_identity->fpr, stored_identity->fpr_size);

            assert(identity->fpr);

            if (identity->fpr == NULL)

                return PEP_OUT_OF_MEMORY;

            identity->fpr_size = stored_identity->fpr_size;

            if (_comm_type_key < PEP_ct_unconfirmed_encryption) {

                identity->comm_type = _comm_type_key;

            }

            else {

                identity->comm_type = stored_identity->comm_type;

            }

        }

        else /* !EMPTYSTR(identity->fpr) */ {

            if (_same_fpr(identity->fpr,

                          identity->fpr_size,

                          stored_identity->fpr,

                          stored_identity->fpr_size)) {

                if (_comm_type_key < PEP_ct_unconfirmed_encryption) {

                    identity->comm_type = _comm_type_key;

                }else{

                    identity->comm_type = stored_identity->comm_type;

                    if (identity->comm_type == PEP_ct_unknown) {

                        identity->comm_type = _comm_type_key;

                    }

                }

            } else {

                status = get_trust(session, identity);

                assert(status != PEP_OUT_OF_MEMORY);

                if (status == PEP_OUT_OF_MEMORY)

                    return PEP_OUT_OF_MEMORY;

                if (identity->comm_type < stored_identity->comm_type)

                    identity->comm_type = PEP_ct_unknown;

            }

        }

        if (identity->lang[0] == 0) {

            identity->lang[0] = stored_identity->lang[0];

            identity->lang[1] = stored_identity->lang[1];

            identity->lang[2] = 0;

        }

    }

    else /* stored_identity == NULL */ {

        if (!EMPTYSTR(identity->fpr)) {

            PEP_comm_type _comm_type_key;

            status = get_key_rating(session, identity->fpr, &_comm_type_key);

            assert(status != PEP_OUT_OF_MEMORY);

            if (status == PEP_OUT_OF_MEMORY)

                return PEP_OUT_OF_MEMORY;

            identity->comm_type = _comm_type_key;

        }

        else /* EMPTYSTR(identity->fpr) */ {

            PEP_STATUS status;

            stringlist_t *keylist;

            char *_fpr = NULL;

            identity->comm_type = PEP_ct_unknown;

            status = find_keys(session, identity->address, &keylist);

            assert(status != PEP_OUT_OF_MEMORY);

            if (status == PEP_OUT_OF_MEMORY)

                return PEP_OUT_OF_MEMORY;

            stringlist_t *_keylist;

            for (_keylist = keylist; _keylist && _keylist->value; _keylist = _keylist->next) {

                PEP_comm_type _comm_type_key;

                status = get_key_rating(session, _keylist->value, &_comm_type_key);

                assert(status != PEP_OUT_OF_MEMORY);

                if (status == PEP_OUT_OF_MEMORY) {

                    free_stringlist(keylist);

                    return PEP_OUT_OF_MEMORY;

                }

                if (identity->comm_type == PEP_ct_unknown) {

                    if (_comm_type_key != PEP_ct_compromized && _comm_type_key != PEP_ct_unknown) {

                        identity->comm_type = _comm_type_key;

                        _fpr = _keylist->value;

                    }

                }

                else {

                    if (_comm_type_key != PEP_ct_compromized && _comm_type_key != PEP_ct_unknown) {

                        if (_comm_type_key > identity->comm_type) {

                            identity->comm_type = _comm_type_key;

                            _fpr = _keylist->value;

                        }

                    }

                }

            }

            if (_fpr) {

                free(identity->fpr);

                identity->fpr = strdup(_fpr);

                if (identity->fpr == NULL) {

                    free_stringlist(keylist);

                    return PEP_OUT_OF_MEMORY;

                }

                identity->fpr_size = strlen(identity->fpr);

            }

            free_stringlist(keylist);

        }

    }

    status = PEP_STATUS_OK;

    if (identity->comm_type != PEP_ct_unknown && !EMPTYSTR(identity->user_id)) {

        assert(!EMPTYSTR(identity->username)); // this should not happen

        if (EMPTYSTR(identity->username)) { // mitigate

            free(identity->username);

            identity->username = strdup("anonymous");

            if (identity->username == NULL)

                return PEP_OUT_OF_MEMORY;

            identity->username_size = 9;

        }

        // Identity doesn't get stored if is was just about checking existing

        // user by address (i.e. no user id but already stored)

        if (!(_no_user_id && stored_identity))

        {

            status = set_identity(session, identity);

            assert(status == PEP_STATUS_OK);

            if (status != PEP_STATUS_OK) {

                return status;

            }

        }

    }

    if (identity->comm_type != PEP_ct_compromized &&

            identity->comm_type < PEP_ct_strong_but_unconfirmed)

        if (session->examine_identity)

            session->examine_identity(identity, session->examine_management);

    return status;

}

DYNAMIC_API PEP_STATUS myself(PEP_SESSION session, pEp_identity * identity)

{

    pEp_identity *stored_identity;

    PEP_STATUS status;

    stringlist_t *keylist = NULL;

    assert(session);

    assert(identity);

    assert(identity->address);

    assert(identity->username);

    assert(identity->user_id);

    if (!(session && identity && identity->address && identity->username &&

                identity->user_id))

        return PEP_ILLEGAL_VALUE;

    identity->comm_type = PEP_ct_pEp;

    identity->me = true;

    DEBUG_LOG("myself", "debug", identity->address);

    status = get_identity(session,

                          identity->address,

                          identity->user_id,

                          &stored_identity);

    assert(status != PEP_OUT_OF_MEMORY);

    if (status == PEP_OUT_OF_MEMORY)

        return PEP_OUT_OF_MEMORY;

    if (stored_identity)

    {

        if (EMPTYSTR(identity->fpr)) {

            identity->fpr = strndup(stored_identity->fpr, stored_identity->fpr_size);

            assert(identity->fpr);

            if (identity->fpr == NULL)

            {

                return PEP_OUT_OF_MEMORY;

            }

            identity->fpr_size = stored_identity->fpr_size;

        }

    }

    else

    {

        free(identity->fpr);

        identity->fpr_size = 0;

        status = find_keys(session, identity->address, &keylist);

        assert(status != PEP_OUT_OF_MEMORY);

        if (status == PEP_OUT_OF_MEMORY)

            return PEP_OUT_OF_MEMORY;

        if (keylist != NULL && keylist->value != NULL)

        {

            // BUG : Vulnerable to auto-key-import poisoning.

            //       Attacker's key with forged userId could have been

            //       auto imported from already received email and be used here

            // TODO : iterate over list to elect best key

            // TODO : discard keys which aren't private

            // TODO : discard keys which aren't either

            //             - own generated key

            //             - own from synchronized device group

            //             - already fully trusted as a public key of known

            //               identity, for that same address

            //               (case of imported key for mailing lists)

            identity->fpr = strdup(keylist->value);

            assert(identity->fpr);

            if (identity->fpr == NULL)

            {

                return PEP_OUT_OF_MEMORY;

            }

            identity->fpr_size = strlen(identity->fpr);

        }

    }

    // TODO : Check key for revoked state

    if (EMPTYSTR(identity->fpr) /* or revoked */)

    {

        DEBUG_LOG("generating key pair", "debug", identity->address);

        status = generate_keypair(session, identity);

        assert(status != PEP_OUT_OF_MEMORY);

        if (status != PEP_STATUS_OK) {

            char buf[11];

            snprintf(buf, 11, "%d", status);

            DEBUG_LOG("generating key pair failed", "debug", buf);

            return status;

        }

        status = find_keys(session, identity->address, &keylist);

        assert(status != PEP_OUT_OF_MEMORY);

        if (status == PEP_OUT_OF_MEMORY)

            return PEP_OUT_OF_MEMORY;

        assert(keylist && keylist->value);

        if (keylist == NULL || keylist->value == NULL) {

            return PEP_UNKNOWN_ERROR;

        }

    }

    else

    {

        bool expired;

        status = key_expired(session, identity->fpr, &expired);

        assert(status == PEP_STATUS_OK);

        if (status != PEP_STATUS_OK) {

            goto free_keylist;

        }

        if (status == PEP_STATUS_OK && expired) {

            timestamp *ts = new_timestamp(time(NULL) + KEY_EXPIRE_DELTA);

            renew_key(session, identity->fpr, ts);

            free_timestamp(ts);

        }

    }

    status = set_identity(session, identity);

    assert(status == PEP_STATUS_OK);

    if (status != PEP_STATUS_OK) {

        goto free_keylist;

    }

    return PEP_STATUS_OK;

free_keylist:

    free_stringlist(keylist);

    return status;

}

DYNAMIC_API PEP_STATUS register_examine_function(

        PEP_SESSION session, 

        examine_identity_t examine_identity,

        void *management

    )

{

    assert(session);

    if (!session)

        return PEP_ILLEGAL_VALUE;

    session->examine_management = management;

    session->examine_identity = examine_identity;

    return PEP_STATUS_OK;

}

DYNAMIC_API PEP_STATUS do_keymanagement(

        retrieve_next_identity_t retrieve_next_identity,

        void *management

    )

{

    PEP_SESSION session;

    pEp_identity *identity;

    PEP_STATUS status;

    assert(retrieve_next_identity);

    assert(management);

    if (!retrieve_next_identity || !management)

        return PEP_ILLEGAL_VALUE;

    status = init(&session);

    assert(status == PEP_STATUS_OK);

    if (status != PEP_STATUS_OK)

        return status;

    log_event(session, "keymanagement thread started", "pEp engine", NULL, NULL);

    while ((identity = retrieve_next_identity(management))) 

    {

        assert(identity->address);

        if(identity->address)

        {

            DEBUG_LOG("do_keymanagement", "retrieve_next_identity", identity->address);

            if (identity->me) {

                status = myself(session, identity);

            } else {

                status = recv_key(session, identity->address);

            }

            assert(status != PEP_OUT_OF_MEMORY);

            if(status == PEP_OUT_OF_MEMORY)

                return PEP_OUT_OF_MEMORY;

        }

        free_identity(identity);

    }

    log_event(session, "keymanagement thread shutdown", "pEp engine", NULL, NULL);

    release(session);

    return PEP_STATUS_OK;

}

DYNAMIC_API PEP_STATUS key_compromized(

        PEP_SESSION session,

        pEp_identity *ident

    )

{

    PEP_STATUS status = PEP_STATUS_OK;

    assert(session);

    assert(ident);

    assert(!EMPTYSTR(ident->fpr));

    if (!(session && ident && ident->fpr))

        return PEP_ILLEGAL_VALUE;

    if (ident->me)

        revoke_key(session, ident->fpr, NULL);

    status = mark_as_compromized(session, ident->fpr);

    return status;

}

DYNAMIC_API PEP_STATUS key_reset_trust(

        PEP_SESSION session,

        pEp_identity *ident

    )

{

    PEP_STATUS status = PEP_STATUS_OK;

    assert(session);

    assert(ident);

    assert(!ident->me);

    assert(!EMPTYSTR(ident->fpr));

    assert(!EMPTYSTR(ident->address));

    assert(!EMPTYSTR(ident->user_id));

    if (!(session && ident && !ident->me && ident->fpr && ident->address &&

            ident->user_id))

        return PEP_ILLEGAL_VALUE;

    status = update_identity(session, ident);

    if (status != PEP_STATUS_OK)

        return status;

    if (ident->comm_type == PEP_ct_mistrusted)

        ident->comm_type = PEP_ct_unknown;

    else

        ident->comm_type &= ~PEP_ct_confirmed;

    status = set_identity(session, ident);

    if (status != PEP_STATUS_OK)

        return status;

    if (ident->comm_type == PEP_ct_unknown)

        status = update_identity(session, ident);

    return status;

}

DYNAMIC_API PEP_STATUS trust_personal_key(

        PEP_SESSION session,

        pEp_identity *ident

    )

{

    PEP_STATUS status = PEP_STATUS_OK;

    assert(session);

    assert(ident);

    assert(!EMPTYSTR(ident->address));

    assert(!EMPTYSTR(ident->user_id));

    assert(!EMPTYSTR(ident->fpr));

    assert(!ident->me);

    if (!ident || EMPTYSTR(ident->address) || EMPTYSTR(ident->user_id) ||

            EMPTYSTR(ident->fpr) || ident->me)

        return PEP_ILLEGAL_VALUE;

    status = update_identity(session, ident);

    if (status != PEP_STATUS_OK)

        return status;

    if (ident->comm_type > PEP_ct_strong_but_unconfirmed) {

        ident->comm_type |= PEP_ct_confirmed;

        status = set_identity(session, ident);

    }

    else {

        // MISSING: S/MIME has to be handled depending on trusted CAs

        status = PEP_CANNOT_SET_TRUST;

    }

    return status;

}