/*
 *  File:       losparam.h
 *  Summary:    Parameters for the LOS algorithm
 */

#ifndef LOSPARAM_H
#define LOSPARAM_H

// Note: find_ray relies on the fact that 2*OPC_HALF == OPC_OPAQUE.
// On the other hand, losight tracks this explicitly.
enum opacity_type
{
    OPC_CLEAR  = 0,
    OPC_HALF   = 1,    // for opaque clouds; two or more block
    OPC_OPAQUE = 2,

    NUM_OPACITIES
};

struct opacity_func
{
    virtual ~opacity_func() {}
    virtual opacity_type operator()(const coord_def& p) const = 0;

    // XXX: to be able to call from gdb.
    virtual opacity_type call(const coord_def& p) const
    {
        return (*this)(p);
    }
};

struct bounds_func
{
    virtual ~bounds_func() {}
    virtual bool operator()(const coord_def& p) const = 0;

    // XXX: to be able to call from gdb.
    virtual bool call(const coord_def& p) const
    {
        return (*this)(p);
    }
};

// Default LOS rules.
struct opacity_default : opacity_func
{
    opacity_type operator()(const coord_def& p) const;
};
static opacity_default opc_default;

// Default LOS rules, but only consider fully opaque features blocking.
// In particular, clouds don't affect the result.
struct opacity_fullyopaque : opacity_func
{
    opacity_type operator()(const coord_def& p) const;
};
static opacity_fullyopaque opc_fullyopaque;

// Make anything solid block in addition to normal LOS.
// XXX: Are trees, bushes solid?
struct opacity_solid : opacity_func
{
    opacity_type operator()(const coord_def& p) const;
};
static opacity_solid opc_solid;

// Opacity for monster movement, based on the late monster_los.
struct opacity_monmove : opacity_func
{
    const monsters& mon;

    opacity_monmove(const monsters& m)
        : mon(m)
    {
    }

    opacity_type operator()(const coord_def& p) const;
};

// LOS bounded by fixed presquared radius.
struct bounds_radius_sq : bounds_func
{
    int radius_sq;
    bounds_radius_sq(int r_sq)
        : radius_sq(r_sq) {}
    bool operator()(const coord_def& p) const;
};

// LOS bounded by fixed radius.
struct bounds_radius : bounds_radius_sq
{
    bounds_radius(int r)
        : bounds_radius_sq(r * r + 1)
    {
    }
};

static bounds_radius bds_deflos = bounds_radius(LOS_RADIUS);
static bounds_radius bds_maxlos = bounds_radius(LOS_MAX_RADIUS);

// LOS bounded by current global LOS radius.
struct bounds_cur_los_radius : bounds_func
{
    bool operator()(const coord_def& p) const;
};
static bounds_cur_los_radius bds_default;

// Subclasses of this are passed to losight() to modify the
// LOS calculation. Implementations will have to translate between
// relative coordinates (-8,-8)..(8,8) and real coordinates,
// specify how opaque the cells are and determine what values
// are written to the visible cells.
struct los_param
{
    virtual ~los_param() {}

    // Whether the translated coordinate lies within the map
    // (including boundary) and within the LOS area
    virtual bool los_bounds(const coord_def& p) const = 0;

    // appearance(p) will be copied to show(sh_o+p) for visible p.
    virtual unsigned appearance(const coord_def& p) const = 0;

    virtual opacity_type opacity(const coord_def& p) const = 0;
};

#endif