#include "private.h"

#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "../tools.h"
#include "../renderer.h"
#include "../system.h"

#define MAX_SKYDOME_LIGHTS 100

static int _inited = 0;

/******************** Definition ********************/
static void _validateDefinition(AtmosphereDefinition* definition)
{
    if (definition->hour < 0)
    {
        definition->hour = 0;
    }
    if (definition->hour > 23)
    {
        definition->hour = 23;
    }
    if (definition->minute < 0)
    {
        definition->minute = 0;
    }
    if (definition->minute > 59)
    {
        definition->minute = 59;
    }

    definition->_daytime = (double)definition->hour / 24.0 + (double)definition->minute / 1440.0;
}

static AtmosphereDefinition* _createDefinition()
{
    AtmosphereDefinition* result;

    /* TODO Find a better place for this */
    if (!_inited)
    {
        _inited = 1;
        brunetonInit();
    }

    result = malloc(sizeof(AtmosphereDefinition));

    atmosphereAutoPreset(result, ATMOSPHERE_PRESET_CLEAR_DAY);

    return result;
}

static void _deleteDefinition(AtmosphereDefinition* definition)
{
    free(definition);
}

static void _copyDefinition(AtmosphereDefinition* source, AtmosphereDefinition* destination)
{
    destination->model = source->model;
    destination->hour = source->hour;
    destination->minute = source->minute;
    destination->sun_color = source->sun_color;
    destination->sun_radius = source->sun_radius;
    destination->dome_lighting = source->dome_lighting;
    destination->humidity = source->humidity;

    _validateDefinition(destination);
}

static void _saveDefinition(PackStream* stream, AtmosphereDefinition* definition)
{
    packWriteInt(stream, (int*)&definition->model);
    packWriteInt(stream, &definition->hour);
    packWriteInt(stream, &definition->minute);
    colorSave(stream, &definition->sun_color);
    packWriteDouble(stream, &definition->sun_radius);
    packWriteDouble(stream, &definition->dome_lighting);
    packWriteDouble(stream, &definition->humidity);
}

static void _loadDefinition(PackStream* stream, AtmosphereDefinition* definition)
{
    packReadInt(stream, (int*)&definition->model);
    packReadInt(stream, &definition->hour);
    packReadInt(stream, &definition->minute);
    colorLoad(stream, &definition->sun_color);
    packReadDouble(stream, &definition->sun_radius);
    packReadDouble(stream, &definition->dome_lighting);
    packReadDouble(stream, &definition->humidity);

    _validateDefinition(definition);
}

StandardDefinition AtmosphereDefinitionClass = {
    (FuncObjectCreate)_createDefinition,
    (FuncObjectDelete)_deleteDefinition,
    (FuncObjectCopy)_copyDefinition,
    (FuncObjectValidate)_validateDefinition,
    (FuncObjectSave)_saveDefinition,
    (FuncObjectLoad)_loadDefinition
};

/******************** Binding ********************/
static Color _fakeApplyAerialPerspective(Renderer* renderer, Vector3 location, Color base)
{
    UNUSED(renderer);
    UNUSED(location);
    return base;
}
static Color _fakeGetSkyColor(Renderer* renderer, Vector3 direction)
{
    UNUSED(renderer);
    UNUSED(direction);
    return COLOR_WHITE;
}

static Color _getSkyColor(Renderer* renderer, Vector3 direction)
{
    AtmosphereDefinition* definition;
    Vector3 sun_direction, sun_position;
    Color sky_color, sun_color;

    definition = renderer->atmosphere->definition;

    sun_direction = renderer->atmosphere->getSunDirection(renderer);
    direction = v3Normalize(direction);
    sun_position = v3Scale(sun_direction, SUN_DISTANCE_SCALED);

    /* Get base scattering*/
    switch (definition->model)
    {
    case ATMOSPHERE_MODEL_BRUNETON:
        sky_color = brunetonGetSkyColor(definition, renderer->camera_location, direction, sun_position);
        break;
    case ATMOSPHERE_MODEL_PREETHAM:
        sky_color = preethamGetSkyColor(definition, renderer->camera_location, direction, sun_position);
        break;
    default:
        sky_color = COLOR_BLUE;
    }

    /* Get sun shape */
    double sun_radius = definition->sun_radius * SUN_RADIUS_SCALED;
    Vector3 hit1, hit2;
    int hits = euclidRayIntersectSphere(renderer->camera_location, direction, sun_position, sun_radius, &hit1, &hit2);
    if (hits > 1)
    {
        double dist = v3Norm(v3Sub(hit2, hit1)) / sun_radius; /* distance between intersection points (relative to radius) */

        sun_color = definition->sun_color;
        sun_color.r *= 100.0;
        sun_color.g *= 100.0;
        sun_color.b *= 100.0;

        if (dist > 0.05)
        {
            return sun_color;
        }
        else
        {
            sun_color.a = 1.0 - dist / 0.05;
            colorMask(&sky_color, &sun_color);
            return sky_color;
        }
    }
    else
    {
        return sky_color;
    }
}

static Vector3 _getSunDirection(Renderer* renderer)
{
    Vector3 result;
    double sun_angle = (renderer->atmosphere->definition->_daytime + 0.75) * M_PI * 2.0;
    result.x = cos(sun_angle);
    result.y = sin(sun_angle);
    result.z = 0.0;
    return result;
}

static void _fakeGetLightingStatus(Renderer* renderer, LightStatus* status, Vector3 normal, int opaque)
{
    LightDefinition light;

    UNUSED(renderer);
    UNUSED(normal);
    UNUSED(opaque);

    light.color.r = 0.8;
    light.color.g = 0.8;
    light.color.b = 0.8;
    light.direction.x = -0.7;
    light.direction.y = -0.7;
    light.direction.z = 0.7;
    light.altered = 0;
    light.reflection = 0.0;
    lightingPushLight(status, &light);
    light.color.r = 0.3;
    light.color.g = 0.31;
    light.color.b = 0.34;
    light.direction.x = 0.7;
    light.direction.y = -0.7;
    light.direction.z = -0.7;
    light.altered = 0;
    light.reflection = 0.0;
    lightingPushLight(status, &light);
}

/******************** Renderer ********************/
static AtmosphereRenderer* _createRenderer()
{
    AtmosphereRenderer* result;

    result = malloc(sizeof(AtmosphereRenderer));
    result->definition = AtmosphereDefinitionClass.create();

    result->getLightingStatus = _fakeGetLightingStatus;
    result->getSunDirection = _getSunDirection;
    result->applyAerialPerspective = _fakeApplyAerialPerspective;
    result->getSkyColor = _fakeGetSkyColor;

    return result;
}

static void _deleteRenderer(AtmosphereRenderer* renderer)
{
    AtmosphereDefinitionClass.destroy(renderer->definition);
    free(renderer);
}

static void _bindRenderer(Renderer* renderer, AtmosphereDefinition* definition)
{
    AtmosphereDefinitionClass.copy(definition, renderer->atmosphere->definition);

    renderer->atmosphere->getSkyColor = _getSkyColor;

    switch (definition->model)
    {
        case ATMOSPHERE_MODEL_BRUNETON:
            renderer->atmosphere->applyAerialPerspective = brunetonApplyAerialPerspective;
            renderer->atmosphere->getLightingStatus = brunetonGetLightingStatus;
            break;
        default:
            renderer->atmosphere->applyAerialPerspective = basicApplyAerialPerspective;
            renderer->atmosphere->getLightingStatus = basicGetLightingStatus;
    }
}

StandardRenderer AtmosphereRendererClass = {
    (FuncObjectCreate)_createRenderer,
    (FuncObjectDelete)_deleteRenderer,
    (FuncObjectBind)_bindRenderer
};