#include "XMPPThread/internal.h"

#include <Cytoplasm/Memory.h>
#include <Cytoplasm/Str.h>
#include <Cytoplasm/Log.h>
#include <Cytoplasm/Sha.h>

#include <Parsee.h>

#include <string.h>

char *
ParseeGetBridgedRoom(ParseeData *data, XMLElement *stanza)
{
    char *to = ParseeDecodeMXID(HashMapGet(stanza->attrs, "to"));
    char *from = HashMapGet(stanza->attrs, "from");
    char *chat_id = ParseeGetFromMUCID(data, from);
    char *mroom_id = ParseeGetRoomID(data, chat_id);
    char *ret;

    Free(chat_id);
    if (mroom_id)
    {
        Free(to);
        return mroom_id;
    }

    /* Not a MUC, find the DMd room. */
    ret = ParseeFindDMRoom(data, to, from);
    Free(to);
    return ret;
}


char *
ParseeGetEventFromID(ParseeData *data, XMLElement *stanza, char *id)
{
    char *from = (HashMapGet(stanza->attrs, "from"));
    char *chat_id = ParseeGetFromMUCID(data, from);
    char *ret = ParseeEventFromSID(data, chat_id, id);
    char *mroom_id = ParseeGetBridgedRoom(data, stanza);

    if (!ret)
    {
        Free(ret);
        ret = ParseeEventFromID(data, chat_id, id);
    }

    Free(chat_id);
    if (ret)
    {
        Free(mroom_id);
        return ret;
    }
    ret = ParseeDMEventFromID(data, mroom_id, id);
    Free(mroom_id);

    return ret;
}
char *
ParseeGetReactedEvent(ParseeData *data, XMLElement *stanza)
{
    XMLElement *reactions = XMLookForTKV(stanza,
        "reactions", "xmlns", "urn:xmpp:reactions:0"
    );
    char *reacted_id = reactions ? HashMapGet(reactions->attrs, "id") : NULL;

    return ParseeGetEventFromID(data, stanza, reacted_id);
}



void
ParseePushAllStanza(ParseeData *args, XMLElement *stanza, char *event)
{
    char *xmpp_from = HashMapGet(stanza->attrs, "from");
    char *mroom_id  = ParseeGetBridgedRoom(args, stanza);
    char *chat_id   = ParseeGetFromMUCID(args, xmpp_from);

    char *id_str    = HashMapGet(stanza->attrs, "id");
    char *s_id_str  = XMPPGetStanzaID(stanza);

    if (!chat_id)
    {
        ParseePushDMStanza(
            args, mroom_id, s_id_str, 
            id_str, event, xmpp_from
        );
    }
    ParseePushStanza(args, chat_id, s_id_str, id_str, event, xmpp_from);
    Free(mroom_id);
    Free(chat_id);
}

bool
ParseeVerifyAllStanza(ParseeData *args, XMLElement *stanza)
{
    char *to, *room;
    char *from    = HashMapGet(stanza->attrs, "from");
    char *id      = HashMapGet(stanza->attrs, "id");
    char *chat_id = ParseeGetFromMUCID(args, from);
    bool ret;

    if (chat_id)
    {
        char *s_id_str  = XMPPGetStanzaID(stanza);
        ret = ParseeVerifyStanza(args, chat_id, s_id_str);

        Free(chat_id);
        return ret;
    }
    to = ParseeDecodeMXID(HashMapGet(stanza->attrs, "to"));
    room = ParseeFindDMRoom(args, to, from);
    ret = ParseeVerifyDMStanza(args, chat_id, id);

    Free(room);
    Free(to);

    return ret;
}

/* TODO: Cache this information. */
bool
ServerHasXEP421(ParseeData *data, char *from)
{
    char *server = NULL, *parsee;
    XMLElement *disco;
    bool ret;
    if (!data || !from)
    {
        return false;
    }

    server = strchr(from, '@');
    if (!server)
    {
        server = from;
    }
    else
    {
        server++;
    }
    server = StrDuplicate(server);

    if (strchr(server, '/'))
    {
        *(strchr(server, '/')) = '\0';
    }

    parsee = ParseeJID(data);
    disco = XMPPSendDisco(data->jabber, parsee, server);

    ret = XMPPDiscoAdvertises(disco, "urn:xmpp:occupant-id:0");

    XMLFreeElement(disco);
    Free(parsee);
    Free(server);
    return ret;
}

/* Scrambles an Occupant ID so that Matrix can use it for MXIDs.
 * Occupant IDs are to be treated as opaque, therefore, we hash them 
 * into a SHA-256 value
 * > "The recipient MUST consider the occupant identifier to be an opaque 
 * > string.". */
static char *
ScrambleOID(ParseeData *data, char *opaque_oid)
{
    unsigned char *raw;
    char *sha, *mxid;
    const ParseeConfig *c = data->config;
    if (!opaque_oid)
    {
        return NULL;
    }

    /* Turns this into a 128-byte long, Matrix-safe value. */
    raw = Sha256(opaque_oid);
    sha = ShaToHex(raw);
    Free(raw);

    /* TODO: Either mark this specially, or drop Parsee JID flags 
     * altogether before any 1.0.0 */
    mxid = StrConcat(
        6,
        "@", c->namespace_base, "_l_", sha, ":",
        c->server_base
    );
    Free(sha);
    return mxid;
}

/* TODO: Shove that function everywhere one can see fit. */
char *
ParseeGetBridgedUserI(ParseeData *data, XMLElement *stanza, char *force)
{
    char *user, *xmpp_from, *type;
    char *decode_from, *occ_id = NULL, *looked = NULL;
    bool is_chat, has_anon = false, is_anon = false;

    if (!data || !stanza)
    {
        return NULL;
    }

    xmpp_from = force ? force : HashMapGet(stanza->attrs, "from");
    type = HashMapGet(stanza->attrs, "type");
    decode_from = ParseeLookupJID(xmpp_from);

    is_chat = StrEquals(type, "chat");
    if (!is_chat)
    {
        has_anon = ServerHasXEP421(data, xmpp_from);
        is_anon = has_anon && StrEquals(xmpp_from, decode_from);
    }

    if (is_anon || force)
    {
        XMLElement *occupant;
        occupant = XMLookForTKV(
            stanza, "occupant-id", 
            "xmlns", "urn:xmpp:occupant-id:0"
        );
        occ_id = occupant ? HashMapGet(occupant->attrs, "id") : NULL;
        if (!occ_id)
        {
            occ_id = ParseeLookupOID(xmpp_from);
            looked = occ_id;
        }
        else
        {
            ParseePushOIDTable(xmpp_from, occ_id);
        }
    }

    if (!occ_id)
    {
        user = ParseeEncodeJID(
            data->config, 
            decode_from, 
            type ? is_chat : false
        );
        Free(decode_from);
        Free(looked);
        return user;
    }

    Free(decode_from);
    Free(looked);
    return ScrambleOID(data, occ_id);
}