/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2009 John Fitzgibbons and others
Copyright (C) 2010-2014 QuakeSpasm developers

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// sv_user.c -- server code for moving users

#include "quakedef.hpp"

edict_t *sv_player;

extern convar sv_friction;
convar sv_edgefriction{"edgefriction", "2"};
extern convar sv_stopspeed;

static vec3_t forward, right, up;

// world
float *angles;
float *origin;
float *velocity;

bool onground;

usercmd_t cmd;

convar sv_idealpitchscale{"sv_idealpitchscale", "0.8"};
convar sv_altnoclip{"sv_altnoclip", "1", {.archive = true}}; //johnfitz

/*
===============
SV_SetIdealPitch
===============
*/
#define	MAX_FORWARD	6

void SV_SetIdealPitch(void) {
    float angleval, sinval, cosval;
    trace_t tr;
    vec3_t top, bottom;
    float z[MAX_FORWARD];
    int i, j;
    int step, dir, steps;

    if (!((int) sv_player->v.flags & FL_ONGROUND))
        return;

    angleval = sv_player->v.angles[YAW] * M_PI * 2 / 360;
    sinval = sin(angleval);
    cosval = cos(angleval);

    for (i = 0; i < MAX_FORWARD; i++) {
        top[0] = sv_player->v.origin[0] + cosval * (i + 3) * 12;
        top[1] = sv_player->v.origin[1] + sinval * (i + 3) * 12;
        top[2] = sv_player->v.origin[2] + sv_player->v.view_ofs[2];

        bottom[0] = top[0];
        bottom[1] = top[1];
        bottom[2] = top[2] - 160;

        tr = SV_Move(top, vec3_origin, vec3_origin, bottom, 1, sv_player);
        if (tr.allsolid)
            return; // looking at a wall, leave ideal the way is was

        if (tr.fraction == 1)
            return; // near a dropoff

        z[i] = top[2] + tr.fraction * (bottom[2] - top[2]);
    }

    dir = 0;
    steps = 0;
    for (j = 1; j < i; j++) {
        step = z[j] - z[j - 1];
        if (step > -ON_EPSILON && step < ON_EPSILON)
            continue;

        if (dir && (step - dir > ON_EPSILON || step - dir < -ON_EPSILON))
            return; // mixed changes

        steps++;
        dir = step;
    }

    if (!dir) {
        sv_player->v.idealpitch = 0;
        return;
    }

    if (steps < 2)
        return;
    sv_player->v.idealpitch = -dir * sv_idealpitchscale.value;
}


/*
==================
SV_UserFriction

==================
*/
void SV_UserFriction(void) {
    float *vel;
    float speed, newspeed, control;
    vec3_t start, stop;
    float friction;
    trace_t trace;

    vel = velocity;

    speed = sqrt(vel[0] * vel[0] + vel[1] * vel[1]);
    if (!speed)
        return;

    // if the leading edge is over a dropoff, increase friction
    start[0] = stop[0] = origin[0] + vel[0] / speed * 16;
    start[1] = stop[1] = origin[1] + vel[1] / speed * 16;
    start[2] = origin[2] + sv_player->v.mins[2];
    stop[2] = start[2] - 34;

    trace = SV_Move(start, vec3_origin, vec3_origin, stop, true, sv_player);

    if (trace.fraction == 1.0)
        friction = sv_friction.value * sv_edgefriction.value;
    else
        friction = sv_friction.value;

    // apply friction
    control = speed < sv_stopspeed.value ? sv_stopspeed.value : speed;
    newspeed = speed - host_frametime * control * friction;

    if (newspeed < 0)
        newspeed = 0;
    newspeed /= speed;

    vel[0] = vel[0] * newspeed;
    vel[1] = vel[1] * newspeed;
    vel[2] = vel[2] * newspeed;
}

/*
==============
SV_Accelerate
==============
*/
convar sv_maxspeed{"sv_maxspeed", "320", {.notify = true, . server_info = true}};
convar sv_accelerate{"sv_accelerate", "10"};

void SV_Accelerate(float wishspeed, const vec3_t wishdir) {
    int i;
    float addspeed, accelspeed, currentspeed;

    currentspeed = DotProduct(velocity, wishdir);
    addspeed = wishspeed - currentspeed;
    if (addspeed <= 0)
        return;
    accelspeed = sv_accelerate.value * host_frametime * wishspeed;
    if (accelspeed > addspeed)
        accelspeed = addspeed;

    for (i = 0; i < 3; i++)
        velocity[i] += accelspeed * wishdir[i];
}

void SV_AirAccelerate(float wishspeed, vec3_t wishveloc) {
    int i;
    float addspeed, wishspd, accelspeed, currentspeed;

    wishspd = VectorNormalize(wishveloc);
    if (wishspd > 30)
        wishspd = 30;
    currentspeed = DotProduct(velocity, wishveloc);
    addspeed = wishspd - currentspeed;
    if (addspeed <= 0)
        return;
    //	accelspeed = sv_accelerate.value * host_frametime;
    accelspeed = sv_accelerate.value * wishspeed * host_frametime;
    if (accelspeed > addspeed)
        accelspeed = addspeed;

    for (i = 0; i < 3; i++)
        velocity[i] += accelspeed * wishveloc[i];
}


void DropPunchAngle(void) {
    float len;

    len = VectorNormalize(sv_player->v.punchangle);

    len -= 10 * host_frametime;
    if (len < 0)
        len = 0;
    VectorScale(sv_player->v.punchangle, len, sv_player->v.punchangle);
}

/*
===================
SV_WaterMove

===================
*/
void SV_WaterMove(void) {
    int i;
    vec3_t wishvel;
    float speed, newspeed, wishspeed, addspeed, accelspeed;

    //
    // user intentions
    //
    AngleVectors(sv_player->v.v_angle, forward, right, up);

    for (i = 0; i < 3; i++)
        wishvel[i] = forward[i] * cmd.forwardmove + right[i] * cmd.sidemove;

    if (!cmd.forwardmove && !cmd.sidemove && !cmd.upmove)
        wishvel[2] -= 60; // drift towards bottom
    else
        wishvel[2] += cmd.upmove;

    wishspeed = VectorLength(wishvel);
    if (wishspeed > sv_maxspeed.value) {
        VectorScale(wishvel, sv_maxspeed.value / wishspeed, wishvel);
        wishspeed = sv_maxspeed.value;
    }
    wishspeed *= 0.7;

    //
    // water friction
    //
    speed = VectorLength(velocity);
    if (speed) {
        newspeed = speed - host_frametime * speed * sv_friction.value;
        if (newspeed < 0)
            newspeed = 0;
        VectorScale(velocity, newspeed / speed, velocity);
    } else
        newspeed = 0;

    //
    // water acceleration
    //
    if (!wishspeed)
        return;

    addspeed = wishspeed - newspeed;
    if (addspeed <= 0)
        return;

    VectorNormalize(wishvel);
    accelspeed = sv_accelerate.value * wishspeed * host_frametime;
    if (accelspeed > addspeed)
        accelspeed = addspeed;

    for (i = 0; i < 3; i++)
        velocity[i] += accelspeed * wishvel[i];
}

void SV_WaterJump(void) {
    if (sv.time > sv_player->v.teleport_time
        || !sv_player->v.waterlevel) {
        sv_player->v.flags = (int) sv_player->v.flags & ~FL_WATERJUMP;
        sv_player->v.teleport_time = 0;
    }
    sv_player->v.velocity[0] = sv_player->v.movedir[0];
    sv_player->v.velocity[1] = sv_player->v.movedir[1];
}

/*
===================
SV_NoclipMove -- johnfitz

new, alternate noclip. old noclip is still handled in SV_AirMove
===================
*/
void SV_NoclipMove(void) {
    AngleVectors(sv_player->v.v_angle, forward, right, up);

    velocity[0] = forward[0] * cmd.forwardmove + right[0] * cmd.sidemove;
    velocity[1] = forward[1] * cmd.forwardmove + right[1] * cmd.sidemove;
    velocity[2] = forward[2] * cmd.forwardmove + right[2] * cmd.sidemove;
    velocity[2] += cmd.upmove * 2; //doubled to match running speed

    if (VectorLength(velocity) > sv_maxspeed.value) {
        VectorNormalize(velocity);
        VectorScale(velocity, sv_maxspeed.value, velocity);
    }
}

/*
===================
SV_AirMove
===================
*/
void SV_AirMove(void) {
    int i;
    vec3_t wishvel, wishdir;
    float wishspeed;
    float fmove, smove;

    AngleVectors(sv_player->v.angles, forward, right, up);

    fmove = cmd.forwardmove;
    smove = cmd.sidemove;

    // hack to not let you back into teleporter
    if (sv.time < sv_player->v.teleport_time && fmove < 0)
        fmove = 0;

    for (i = 0; i < 3; i++)
        wishvel[i] = forward[i] * fmove + right[i] * smove;

    if ((int) sv_player->v.movetype != MOVETYPE_WALK)
        wishvel[2] = cmd.upmove;
    else
        wishvel[2] = 0;

    VectorCopy(wishvel, wishdir);
    wishspeed = VectorNormalize(wishdir);
    if (wishspeed > sv_maxspeed.value) {
        VectorScale(wishvel, sv_maxspeed.value / wishspeed, wishvel);
        wishspeed = sv_maxspeed.value;
    }

    if (sv_player->v.movetype == MOVETYPE_NOCLIP) {
        // noclip
        VectorCopy(wishvel, velocity);
    } else if (onground) {
        SV_UserFriction();
        SV_Accelerate(wishspeed, wishdir);
    } else {
        // not on ground, so little effect on velocity
        SV_AirAccelerate(wishspeed, wishvel);
    }
}

/*
===================
SV_ClientThink

the move fields specify an intended velocity in pix/sec
the angle fields specify an exact angular motion in degrees
===================
*/
void SV_ClientThink(void) {
    vec3_t v_angle;

    if (sv_player->v.movetype == MOVETYPE_NONE)
        return;

    onground = (int) sv_player->v.flags & FL_ONGROUND;

    origin = sv_player->v.origin;
    velocity = sv_player->v.velocity;

    DropPunchAngle();

    //
    // if dead, behave differently
    //
    if (sv_player->v.health <= 0)
        return;

    //
    // angles
    // show 1/3 the pitch angle and all the roll angle
    cmd = host_client->cmd;
    angles = sv_player->v.angles;

    VectorAdd(sv_player->v.v_angle, sv_player->v.punchangle, v_angle);
    angles[ROLL] = V_CalcRoll(sv_player->v.angles, sv_player->v.velocity) * 4;
    if (!sv_player->v.fixangle) {
        angles[PITCH] = -v_angle[PITCH] / 3;
        angles[YAW] = v_angle[YAW];
    }

    if ((int) sv_player->v.flags & FL_WATERJUMP) {
        SV_WaterJump();
        return;
    }
    //
    // walk
    //
    //johnfitz -- alternate noclip
    if (sv_player->v.movetype == MOVETYPE_NOCLIP && sv_altnoclip.value)
        SV_NoclipMove();
    else if (sv_player->v.waterlevel >= 2 && sv_player->v.movetype != MOVETYPE_NOCLIP)
        SV_WaterMove();
    else
        SV_AirMove();
    //johnfitz
}


/*
===================
SV_ReadClientMove
===================
*/
void SV_ReadClientMove(usercmd_t *move) {
    int i;
    vec3_t angle;
    int bits;

    // read ping time
    host_client->ping_times[host_client->num_pings % NUM_PING_TIMES]
            = sv.time - net_message.read_float().value();
    host_client->num_pings++;

    // read current angles
    for (i = 0; i < 3; i++)
        //johnfitz -- 16-bit angles for PROTOCOL_FITZQUAKE
        if (sv.protocol == PROTOCOL_NETQUAKE)
            angle[i] = net_message.read_angle(static_cast<net::rmq_flags>(cl.protocolflags)).value();
        else
            angle[i] = net_message.read_angle_16(static_cast<net::rmq_flags>(cl.protocolflags)).value();
    //johnfitz

    VectorCopy(angle, host_client->edict->v.v_angle);

    // read movement
    move->forwardmove = net_message.read_short().value();
    move->sidemove = net_message.read_short().value();
    move->upmove = net_message.read_short().value();

    // read buttons
    bits = net_message.read_byte().value();
    host_client->edict->v.button0 = bits & 1;
    host_client->edict->v.button2 = (bits & 2) >> 1;

    if (const auto imp = net_message.read_byte(); imp.has_value())
        host_client->edict->v.impulse = imp.value();
}

/*
===================
SV_ReadClientMessage

Returns false if the client should be killed
===================
*/
bool SV_ReadClientMessage(void) {
    int ret;
    int ccmd;

    do {
    nextmsg:
        ret = NET_GetMessage(host_client->netconnection);
        if (ret == -1) {
            Sys_Printf("SV_ReadClientMessage: NET_GetMessage failed\n");
            return false;
        }
        if (!ret)
            return true;

        net_message.begin_reading();

        while (true) {
            if (!host_client->active)
                return false; // a command caused an error

            if (net_message.eos()) {
                Sys_Printf("SV_ReadClientMessage: badread\n");
                return false;
            }

            auto ccmdv = net_message.read_char();

            if (!ccmdv.has_value()) {
                goto nextmsg;
            }

            ccmd = ccmdv.value();

            switch (ccmd) {
                default:
                    Sys_Printf("SV_ReadClientMessage: unknown command char\n");
                    return false;

                case clc_nop:
                    //				Sys_Printf ("clc_nop\n");
                    break;

                case clc_stringcmd: {
                    auto s = net_message.read_string().value();
                    ret = 0;
                    if (q_strncasecmp(s.c_str(), "status", 6) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "god", 3) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "notarget", 8) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "fly", 3) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "name", 4) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "noclip", 6) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "setpos", 6) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "say", 3) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "say_team", 8) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "tell", 4) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "color", 5) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "kill", 4) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "pause", 5) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "spawn", 5) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "begin", 5) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "prespawn", 8) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "kick", 4) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "ping", 4) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "give", 4) == 0)
                        ret = 1;
                    else if (q_strncasecmp(s.c_str(), "ban", 3) == 0)
                        ret = 1;

                    if (ret == 1)
                        command::execute_string(s.c_str(), command::source::client);
                    else
                        console::debug("%s tried to %s\n", host_client->name, s.c_str());
                    break;
                }
                case clc_disconnect:
                    //	Sys_Printf ("SV_ReadClientMessage: client disconnected\n");
                    return false;

                case clc_move:
                    SV_ReadClientMove(&host_client->cmd);
                    break;
            }
        }
    } while (ret == 1);

    return true;
}


/*
==================
SV_RunClients
==================
*/
void SV_RunClients(void) {
    int i;

    for (i = 0, host_client = svs.clients; i < svs.maxclients; i++, host_client++) {
        if (!host_client->active)
            continue;

        sv_player = host_client->edict;

        if (!SV_ReadClientMessage()) {
            SV_DropClient(false); // client misbehaved...
            continue;
        }

        if (!host_client->spawned) {
            // clear client movement until a new packet is received
            memset(&host_client->cmd, 0, sizeof(host_client->cmd));
            continue;
        }

        // always pause in single player if in console or menus
        if (!sv.paused && (svs.maxclients > 1 || key_dest == key_game))
            SV_ClientThink();
    }
}