civdos barbarian units ai (fix 4)

#define IM_CITY       1
#define IM_IRRIGATION 2
#define IM_MINE       4

#define SQ_OCEAN     10

#define UR_DEFENCE    2 //land defence: only musketeers. In theory also militia, phalanx, riflemen and mech. inf.
#define UR_TRANSPORT  5 //sail or frigate (in theory also trireme and transport)

#define UD_LAND       0 //land unit
#define UD_FLEET      2 //unit is a boat

#define U_DIPLOMAT 0x2A

change_x[9] = {0,0,1,1,1,0,-1,-1,-1};
change_y[9] = {0,-1,-1,0,1,1,1,0,-1};

check_ZOC(civ,x,y)
{
    res = 0;
    impr = get_improvements(x,y);
    if ((impr & IM_CITY) == 0)
        res = check_ZOC_B(civ,x,y); //check blocking unit. If civ == player_civ - draw it and draw terrain and city in its square.
    else
        res = 0; //unit can always go from and to the city
    return res;
}

get_city_area_civ(x,y)
{
    return (current_terrain_value[x][y]&7);
    //returns 0..7 (city civ) for 21 squares of city area
    //but what about other squares?
    //if it's similar to save file (see current terrain value in JCivED), then...
    //8 for +1 radius line around a city area -> returns 0 - it's ok...
    //but if there's no city nearby then current land value can be 0 or 9..15
    //problem here: what about 9..15 land value outside city areas?
    //it will return current_terrain_value[x][y]-8 instead of civ number. But m.b. this is ok...
}

barbarian_unit_ai_func(civ, unit_id) //civ == 0
{
    unit = get_unit_type(civ,unit_id); //legion, cavalry, diplomat etc.
    x = get_unit_x(civ,unit_id);
    y = get_unit_y(civ,unit_id);
    if (y < 2 || y > 47)
    {
        unkn_var = disband_unit(param_civ,unit_id); //it returns void! it never returns anything anywhere but here!
        return unkn_var; //?
    }

    zoc_here = check_ZOC(civ,x,y); //1 if any adjacent enemy units (not in ocean...). If city - then always 0 (you can always go in and from a city ignoring ZoC...)
    //zone of control in current square. If zoc_here == 1 && zoc_next == 1 -> no go

    if (get_unit_role(unit) == UR_TRANSPORT)
    {
        if (next_unit_in_stack != -1) //has passengers
        {
            city = find_closest_city(x,y); //return city id and set global var: gl_distance
            dist_closest_city = gl_distance;
            for (dir = 1; dir < 9; dir++)
            {
                x2 = normalize(x+change_x[dir]); //the world is round. For example, x = -1 -> x = 79
                y2 = y+change_y[dir];
                terr = get_terrain(x2,y2);
                impr = get_improvements(x2,y2);
                if (dist_closest_city < 9 && terr != SQ_OCEAN
                && (impr&IM_CITY) == 0 //there's no city in this square
                && civ_id_of_unit_in_xy(x2,y2) == -1 //no units by any civ in this square
                && y2 > 1 && y2 < 48)
                {
                    if (map_of_explored_terrain[x][y] & (1<<player_civ)) != 0 //square is explored by player civ
                    && get_city_civ(city) == player_civ)
                    {
                        cont1 = get_continent(city_x[city],city_y[city]);
                        cont2 = get_continent(x2,y2);
                        if (cont1 == cont2)
                        {
                            unit_visibility |= (1<<player_civ); //set visibility bit of player civ to 1

                            //fix view position? (if incorrect??) and change view position to x-8,y-6

                            gl_message_type = 3; //Military Advisor:
                            //message about landing...
                        }
                    }
                    unit_visibility |= get_terrain_visibility(x,y);
                    unit_remaining_moves = 0;
                    return 0x75; //'u'->unload
                }
                if (civ_id_of_unit_in_xy(x2,y2) > 0) //somebody is next to us and it's not a barbarian
                    return dir; //direction of movement/attack
            } //for: all 8 directions
            if (goto_x != -1) //boat is already in GoTo state
                return 0;
        } //transport has passengers
        best_city = 0;
        cit_count = 0;
        best_val; //best_val value was undefined?
        do
        {
            if (city_flags[cit_count] != -1) //city exists
            {
                distance = find_distance(x,y,city_x[cit_count],city_y[cit_count]);
                city_val = get_city_gold_loot(cit_count); // city_population*civ_treasure/(civ_population+1)
                city_val = (city_val+50)/(distance+1); //formula for target city
                if (city_val > best_val)
                {
                    best_city = cit_count;
                    best_val = city_val;
                }
            }
            cit_count++;
        }
        while (cit_count < 128);
        if (best_city != 0)
        {
            goto_x = city_x[cit_count];
            goto_y = city_y[cit_count];
            return 0;
        }
        goto LABEL_DISBAND;
    } //unit role: transport

    city = find_closest_city(x,y); //it sets global var: gl_distance
    dist_closest_city = gl_distance;
    cit_civ = get_city_civ(city);
    if (dist_closest_city == 0 && (next_unit_in_stack == -1 || get_unit_role(unit) == UR_DEFENCE))
        return 0x66; //'f' -> fortify

    x_direction_to_city = -2;
    y_direction_to_city = -2;
    if (game_turn&3 == 0) //every 4th turn
    {
        cont1 = get_continent(x,y);
        cont2 = get_continent(city_x[city], city_y[city]);
        if ((cont1 != cont2) || dist_closest_city > 8)
        {
            goto LABEL_DISBAND;
        }
    }
    if (city != -1) //at least 1 city exists in the world
    {
        cont1 = get_continent(x,y);
        cont2 = get_continent(city_x[city], city_y[city]);
        if (cont1 == cont2
        && (human_civ_bits & (1<<cit_civ)) != 0) //this is a human player's city... human_civ_bits and player_civ are different variables. Human civ bits are bit flags.
        {
            x_direction_to_city = get_sign(city_x[city] - x); //-1 if < 0 0 if 0 +1 if > 0
            y_direction_to_city = get_sign(city_y[city] - y);
        }
    }
    if (cit_civ == civ //barbarian city
    || (civ_cities_total[cit_civ] < 2 && gold[cit_civ] < 100)) //or city owner has only 1 city and less than 100$
    {
        x_direction_to_city = -2;
        y_direction_to_city = -2;
    }
    if (x_direction_to_city != -2)
    {
        //go straight to the city!
        goto_x = city_x[city];
        goto_y = city_y[city];
        goto_dir = moveUnitGoto(civ,unit_id); //returns direction of next move: 1..9 //Unknown9 field in JCivED.
        //moveUnitGoto was disassembled by darkpanda. You can find it somewhere on the forums...
    }
    goto_x = -1; //GoTo off. Barbarian units don't check it anywhere anyway and boat routine never go here, so it's kinda pointless?..
    if (unit == U_DIPLOMAT)
    {
        terr = get_terrain(x,y);
        if (next_unit_in_stack != -1 && terr != SQ_OCEAN && get_unit_type(civ,next_unit_in_stack) != U_DIPLOMAT) //if our diplomat's on land and some other barbarian unit's here and it's not an another diplomat
        {
            return 0x20; //space -> skip turn
        }

        if (terr == SQ_OCEAN)
        {
            if (dist_closest_city > 2)
                goto LABEL_NOT_DIPLOMAT;
        }
        else
        {
            unit_id2 = find_my_closest_unit_id(civ,unit_id,x,y); //set gl_distance
            dist_closest_unit = gl_distance;
            if (dist_closest_unit < 4 && get_unit_type(civ,unit_id2) != U_DIPLOMAT)
            {
                goto_x = get_unit_x(civ,unit_id2);
                goto_y = get_unit_y(civ,unit_id2);
                return 0; //do nothing?
            }
            if ((game_turn&7)+4 > dist_closest_city) //if remainder of dividing game_turn by 8 +4 > dist_closest_city
                goto LABEL_NOT_DIPLOMAT;
        }
        LABEL_DISBAND:
        disband_unit(civ,unit_id);
    }
    else
    {
        LABEL_NOT_DIPLOMAT:
        best_direction = 0;
        best_val = -999;
        dir = 1;
        while (dir < 9)
        {
            x2 = normalize(x+change_x[dir]);
            y2 = y+change_y[dir];
            terr = get_terrain(x2,y2);

            if (((get_unit_domain(unit) == UD_FLEET) == (terr == SQ_OCEAN)) //if boat and in ocean OR not a boat and on land
            && check_if_xy_within_the_map(x2,y2)) //X:0-79,Y:0-49 returns 0 if not
            {
                unit_id2 = get_unit_id_in_xy(x2,y2); //returns -1 if no units here. Sets gl_unit_civ if some unit is here.
                if (get_unit_type(civ, unit_id) == U_DIPLOMAT)
                {
                    curr_val = 0;
                    if (unit_id2 != -1)
                    {
                        if (civ == gl_unit_civ) //it's a barbarian unit
                        {
                            curr_val = 99;
                        }
                        else //it's an enemy unit
                        {
                            curr_val = -99;
                        }
                    }
                    find_closest_city(x2,y2); //set gl_distance
                    dist_closest_city = gl_distance;
                    rand = random(4); //0..3
                    curr_val += dist_closest_city*4+rand+get_terrain_movement_cost(terr); //1 for grassland etc, 2 for hills etc, 3 for mountains
                    LABEL_SET_BEST_VALUE:
                    if (curr_val > best_val)
                    {
                        best_val = curr_val;
                        best_direction = dir;
                    }
                } //if diplomat
                else
                {
                    impr = get_improvements(x2,y2);
                    if ((impr&IM_CITY) == 0) //no city in square
                    || get_city_area_civ(x2,y2) == 0) //or it's a barbarian city
                    {
                        impr = get_improvements(x2,y2); //yep, again...
                        if ((impr&IM_IRRIGATION)==0 && (impr&IM_MINE)==0) //no irrigation and no mines here
                            var_C = 0;
                        else
                            var_C = 6; //do want!

                        if (get_city_area_civ(x2,y2) == 0)
                            var_D = 0;
                        else
                            var_D = 4;  //city area or good terrain - do want!
                            //not too sure if it actually returns non-zero value for good terrain outside of city area...

                        curr_val = var_C+var_D+random(6);
                        if (unit_id2 == -1) //no units in this direction
                        {
                            LABEL_REPEATED_PART:
                            if (zoc_here == 0 //this square is free from enemy adjacent units (not in ocean) or there's a city here
                            || get_unit_domain(unit) != UD_LAND //sea and air units ignore zones of control
                            || unit_id2 != -1 //you can always move to square with other unit of your civ. Or you can attack enemy unit?..
                            || check_ZOC(civ,x2,y2) == 0) //the next square is free from enemy adjacent units
                            {
                                if (goto_dir == dir) //we are already going in this direction
                                    curr_val += 6;
                                if (change_x[dir] == x_direction_to_city)
                                    curr_val += 2;
                                if (change_y[dir] == y_direction_to_city)
                                    curr_val += 2;
                            }
                            goto LABEL_SET_BEST_VALUE;
                        }
                        else //some units in this direciton
                        {
                            if (civ == gl_unit_civ) //it's a barbarian unit
                            {
                                terr = get_terrain(x,y);
                                if (terr == SQ_OCEAN)
                                {
                                    curr_val -= 20;
                                    goto LABEL_REPEATED_PART;
                                }
                            }
                            else //it's an enemy
                            {
                                terr = get_terrain(x,y);
                                if (terr != SQ_OCEAN)
                                {
                                    if (get_unit_type(gl_unit2) != U_DIPLOMAT)
                                        curr_val += 99;
                                    goto LABEL_REPEATED_PART;
                                }
                            }
                        }
                    } //no city in x2,y2 or it's a barbarian city
                    else //there's a city in the next square
                    {
                        terr = get_terrain(x,y);
                        if (terr != SQ_OCEAN)
                            return dir; //direction of movement/attack
                    }
                }
            }
            dir++;
        } //while - check 8 adj. squares...
        impr = get_improvements(x,y);
        if ((impr&IM_CITY) == 0 || next_unit_in_stack != -1 || best_val >= 99)
        {
            goto_dir = best_direction;
            return best_direction; //direction of movement/attack
        }
    } //not diplomat
    return 0x20; //space->skip turn
}