/* **************************************
 *  Includes                            *
 * **************************************/

#include "Unit.h"

/* Units sprite data */
#include "PeasantSpr.i"
#include "SoldierSpr.i"

/* Buildings sprite data */
#include "BarracksSpr.i"
#include "TownCentre.i"

/* **************************************
 *  Defines                             *
 * **************************************/

/* **************************************
*   Structs and enums                   *
* **************************************/

struct t_coordinates
{
    int8_t x;
    int8_t y;
};

/* **************************************
*   Local prototypes                    *
* **************************************/

/* **************************************
 *  Local variables                     *
 * **************************************/

/* Tables */
static uint8_t const UnitHPTable[MAX_UNITS_BUILDINGS] = {   [PEASANT] = 25,
                                                            [SOLDIER] = 80,
                                                            [BARRACKS] = 100,
                                                            [TOWN_CENTER] = 200    };

static TYPE_RESOURCES const UnitResourcesTable[MAX_UNITS_BUILDINGS] = { [PEASANT] =     {.Wood = 0,     .Gold = 0,  .Food = 50},
                                                                        [SOLDIER] =     {.Wood = 25,    .Gold = 10, .Food = 50},
                                                                        [BARRACKS] =    {.Wood = 100,   .Gold = 0,  .Food = 0},
                                                                        [TOWN_CENTER] = {.Wood = 200,   .Gold = 0,  .Food = 0}  };

static uint8_t const UnitSpeedTable[MAX_UNITS_BUILDINGS] = {    [PEASANT] = 1,
                                                                [SOLDIER] = 1,
                                                                [BARRACKS] = 0,
                                                                [TOWN_CENTER] = 0  };

static const char* const UnitActionsTable_Level[MAX_ACTIONS] = {    [ACTION_BUILD_BARRACKS] =       "B.BARR",
                                                                    [ACTION_CREATE_PEASANT] =       "C.PEAS.",
                                                                    [ACTION_CREATE_SOLDIER] =       "C.SLDR.",
                                                                    [ACTION_BUILD_TOWER_CENTER] =   "C.TWNC."};

static uint8_t const UnitActionsTable[MAX_UNITS_BUILDINGS] =    {   [PEASANT] = ((1 << ACTION_BUILD_BARRACKS) | (1 << ACTION_BUILD_TOWER_CENTER)),
                                                                    [SOLDIER] = 0,
                                                                    [BARRACKS] = (1 << ACTION_CREATE_SOLDIER),
                                                                    [TOWN_CENTER] = (1 << ACTION_CREATE_PEASANT)             };

/* **************. */
/* Sprite tables. */
/* **************. */
static TYPE_SPRITE UnitSprTable[MAX_UNITS_BUILDINGS];
static TYPE_SPRITE UnitWalkingShadowSprTable[MAX_UNITS_BUILDINGS];
static const struct t_coordinates UnitShadowOffsetTable[MAX_BUILDING_ID - FIRST_BUILDING_ID] = {    [BARRACKS - FIRST_BUILDING_ID] = {.x = -6,      .y = 0},
                                                                                                    [TOWN_CENTER - FIRST_BUILDING_ID] = {.x = -3,   .y = 0} };

void UnitInit(void)
{
    /* ***********************************
     * Unit sprite data init
     * ***********************************/

    UnitSprTable[PEASANT].Data = Peasant_SprData;
    UnitSprTable[PEASANT].w = GfxGetWidthFromSpriteData(Peasant_SprData);
    UnitSprTable[PEASANT].h = GfxGetHeightFromSpriteData(Peasant_SprData);
    UnitSprTable[PEASANT].flip = 0;
    UnitSprTable[PEASANT].rotation = 0;
    UnitSprTable[PEASANT].color = GFX_BLACK;

    UnitSprTable[SOLDIER].Data = SoldierSprData;
    UnitSprTable[SOLDIER].w = GfxGetWidthFromSpriteData(SoldierSprData);
    UnitSprTable[SOLDIER].h = GfxGetHeightFromSpriteData(SoldierSprData);
    UnitSprTable[SOLDIER].flip = 0;
    UnitSprTable[SOLDIER].rotation = 0;
    UnitSprTable[SOLDIER].color = GFX_BLACK;

    UnitWalkingShadowSprTable[PEASANT].Data = Peasant_Walking_SprData;
    UnitWalkingShadowSprTable[PEASANT].w = GfxGetWidthFromSpriteData(Peasant_Walking_SprData);
    UnitWalkingShadowSprTable[PEASANT].h = GfxGetHeightFromSpriteData(Peasant_Walking_SprData);
    UnitWalkingShadowSprTable[PEASANT].flip = 0;
    UnitWalkingShadowSprTable[PEASANT].rotation = 0;
    UnitWalkingShadowSprTable[PEASANT].color = GFX_BLACK;

    UnitWalkingShadowSprTable[SOLDIER].Data = SoldierSprData_Walking;
    UnitWalkingShadowSprTable[SOLDIER].w = GfxGetWidthFromSpriteData(SoldierSprData_Walking);
    UnitWalkingShadowSprTable[SOLDIER].h = GfxGetHeightFromSpriteData(SoldierSprData_Walking);
    UnitWalkingShadowSprTable[SOLDIER].flip = 0;
    UnitWalkingShadowSprTable[SOLDIER].rotation = 0;
    UnitWalkingShadowSprTable[SOLDIER].color = GFX_BLACK;

    /* ***********************************
     * Buildings sprite data init
     * ***********************************/

    UnitSprTable[BARRACKS].Data = BarracksSpr_Data;
    UnitSprTable[BARRACKS].w = GfxGetWidthFromSpriteData(BarracksSpr_Data);
    UnitSprTable[BARRACKS].h = GfxGetHeightFromSpriteData(BarracksSpr_Data);
    UnitSprTable[BARRACKS].flip = 0;
    UnitSprTable[BARRACKS].rotation = 0;
    UnitSprTable[BARRACKS].color = GFX_BLACK;

    UnitSprTable[TOWN_CENTER].Data = TownCentreSprData;
    UnitSprTable[TOWN_CENTER].w = GfxGetWidthFromSpriteData(TownCentreSprData);
    UnitSprTable[TOWN_CENTER].h = GfxGetHeightFromSpriteData(TownCentreSprData);
    UnitSprTable[TOWN_CENTER].flip = 0;
    UnitSprTable[TOWN_CENTER].rotation = 0;
    UnitSprTable[TOWN_CENTER].color = GFX_BLACK;

    UnitWalkingShadowSprTable[BARRACKS].Data = BarracksShadowSpr_Data;
    UnitWalkingShadowSprTable[BARRACKS].w = GfxGetWidthFromSpriteData(BarracksShadowSpr_Data);
    UnitWalkingShadowSprTable[BARRACKS].h = GfxGetHeightFromSpriteData(BarracksShadowSpr_Data);
    UnitWalkingShadowSprTable[BARRACKS].flip = 0;
    UnitWalkingShadowSprTable[BARRACKS].rotation = 0;
    UnitWalkingShadowSprTable[BARRACKS].color = GFX_GRAY;

    UnitWalkingShadowSprTable[TOWN_CENTER].Data = TownCentreShadowSprData;
    UnitWalkingShadowSprTable[TOWN_CENTER].w = GfxGetWidthFromSpriteData(TownCentreShadowSprData);
    UnitWalkingShadowSprTable[TOWN_CENTER].h = GfxGetHeightFromSpriteData(TownCentreShadowSprData);
    UnitWalkingShadowSprTable[TOWN_CENTER].flip = 0;
    UnitWalkingShadowSprTable[TOWN_CENTER].rotation = 0;
    UnitWalkingShadowSprTable[TOWN_CENTER].color = GFX_GRAY;
}

void UnitDrawShadow(TYPE_UNIT *ptrUnit, TYPE_CAMERA *ptrCamera)
{
    uint8_t id = ptrUnit->id;

    CameraApplyCoordinatesToSprite( ptrCamera,
                                    &UnitWalkingShadowSprTable[id],
                                    ptrUnit->x + UnitShadowOffsetTable[id - FIRST_BUILDING_ID].x,
                                    ptrUnit->y + UnitShadowOffsetTable[id - FIRST_BUILDING_ID].y  );

    GfxDrawSprite(&UnitWalkingShadowSprTable[id]);
}

void UnitDraw(TYPE_UNIT *ptrUnit, TYPE_CAMERA* ptrCamera, bool bHighlighted)
{
    uint8_t id = ptrUnit->id;
    TYPE_SPRITE* ptrSpr;

    if (ptrUnit->alive == false)
    {
        return;
    }

    if (ptrUnit->building == false)
    {
        enum
        {
            WALK_FRAMES = 4
        };

        /* ***************. */
        /* Units. */
        /* ***************. */

        ptrSpr = ptrUnit->walking ? &UnitWalkingShadowSprTable[id] : &UnitSprTable[id];

        ptrSpr->rotation = GFX_NOROT;
        ptrSpr->flip = GFX_NOFLIP;

        if (ptrUnit->walking != false)
        {
            if (++ptrUnit->walk_counter > WALK_FRAMES)
            {
                ptrUnit->walk_counter = 0;
                ptrUnit->mirror = ptrUnit->mirror ? false : true;
            }
        }

        switch (ptrUnit->dir)
        {
            case DIRECTION_UP:
                ptrSpr->flip |= GFX_FLIPV;

                if (ptrUnit->mirror != false)
                {
                    ptrSpr->flip |= GFX_FLIPH;
                }
            break;

            case DIRECTION_DOWN:
                if (ptrUnit->mirror != false)
                {
                    ptrSpr->flip |= GFX_FLIPH;
                }
            break;

            case DIRECTION_LEFT:
                ptrSpr->rotation = GFX_ROTCCW;
                ptrSpr->flip |= GFX_FLIPH;

                if (ptrUnit->mirror != false)
                {
                    ptrSpr->flip |= GFX_FLIPV;
                }
            break;

            case DIRECTION_RIGHT:
                ptrSpr->rotation = GFX_ROTCCW;

                if (ptrUnit->mirror != false)
                {
                    ptrSpr->flip |= GFX_FLIPV;
                }
            break;
        }
    }
    else
    {
        /* *******************. */
        /* Buildings. */
        /* *******************. */
        ptrSpr = &UnitSprTable[id];
    }

    CameraApplyCoordinatesToSprite( ptrCamera,
                                    ptrSpr,
                                    ptrUnit->x,
                                    ptrUnit->y );

    GfxDrawSprite(ptrSpr);

    if ( (bHighlighted != false) || (ptrUnit->selected != false) )
    {
        TYPE_COLLISION_BLOCK cb = CameraApplyCoordinatesToCoordinates(ptrCamera, ptrUnit->x, ptrUnit->y);
        int8_t colour = ptrUnit->selected? GFX_BLACK : GFX_GRAY;
        uint8_t w = UnitGetWidthFromID(id);
        uint8_t h = UnitGetHeightFromID(id);

        if (ptrUnit->building != false)
        {
            GfxDrawRectangle(cb.x - (w >> 3), cb.y - (h >> 3), w + (w >> 2), h + (h >> 2), colour);
        }
        else
        {
            GfxDrawCircle(cb.x + (w >> 1), cb.y + (h >> 1), w, colour);
        }
    }
}

uint8_t UnitGetWidthFromID(TYPE_UNIT_ID id)
{
    return GfxGetWidthFromSpriteData(UnitSprTable[id].Data);
}

uint8_t UnitGetHeightFromID(TYPE_UNIT_ID id)
{
    return GfxGetHeightFromSpriteData(UnitSprTable[id].Data);
}

uint8_t UnitGetHpFromID(TYPE_UNIT_ID id)
{
    return UnitHPTable[id];
}

TYPE_RESOURCES UnitNeededResourcesFromID(TYPE_UNIT_ID id)
{
    return UnitResourcesTable[id];
}

void UnitMoveTo(TYPE_UNIT *ptrUnit, uint16_t x, uint16_t y)
{
    ptrUnit->target_x = x;
    ptrUnit->target_y = y;
    ptrUnit->walking = true;
}

void UnitAttackAccepted(TYPE_UNIT *ptrUnit)
{
    ptrUnit->selecting_attack = true;
}

bool UnitCheckCollisionAgainstOtherUnits(TYPE_COLLISION_BLOCK* cb, TYPE_UNIT *ptrUnitArray, TYPE_UNIT* ptrCurrentUnit)
{
    for (uint8_t i = 0; i < PLAYER_MAX_UNITS_BUILDINGS; i++)
    {
        TYPE_UNIT *ptrOtherUnit = &ptrUnitArray[i];
        TYPE_COLLISION_BLOCK ocb = {.x = ptrOtherUnit->x,
                                    .y = ptrOtherUnit->y,
                                    .w = UnitGetWidthFromID(ptrOtherUnit->id),
                                    .h = UnitGetHeightFromID(ptrOtherUnit->id)};

        if (ptrOtherUnit->alive == false)
        {
            continue;
        }

        if (ptrOtherUnit == ptrCurrentUnit)
        {
            /* We are referring to the same TYPE_UNIT instance. Discard. */
            continue;
        }

        if (SystemCollisionCheck(cb, &ocb) != false)
        {
            return true;
        }
    }

    return false;
}

void UnitHandler(TYPE_UNIT* unitArray, size_t sz)
{
    size_t i;

    for (i = 0; i < sz; i++)
    {
        TYPE_UNIT *ptrUnit = &unitArray[i];

        if (ptrUnit->alive == false)
        {
            continue;
        }

        bool bMoving = true;

        if (ptrUnit->walking != false)
        {
            int16_t x_dist = ptrUnit->target_x - (ptrUnit->x + (UnitGetWidthFromID(ptrUnit->id) >> 1));
            int16_t y_dist = ptrUnit->target_y - (ptrUnit->y + (UnitGetHeightFromID(ptrUnit->id) >> 1));
            uint8_t unit_speed = UnitSpeedTable[ptrUnit->id];

            int8_t x_d = 0;
            int8_t y_d = 0;

            if ( (uint16_t)abs(x_dist) > (uint16_t)(abs(y_dist) << 2) ) /* Add some hysteresis so unit does not change constantly its direction */
            {
                if (x_dist >= (int16_t)unit_speed)
                {
                    x_d = unit_speed;
                    ptrUnit->dir = DIRECTION_RIGHT;
                }
                else if (x_dist <= (int16_t)-unit_speed)
                {
                    x_d = (int8_t)-unit_speed;
                    ptrUnit->dir = DIRECTION_LEFT;
                }
                else
                {
                    bMoving = false;
                }
            }
            else
            {
                if (y_dist >= (int16_t)unit_speed)
                {
                    y_d = unit_speed;
                    ptrUnit->dir = DIRECTION_DOWN;
                }
                else if (y_dist <= (int16_t)-unit_speed)
                {
                    y_d = (int8_t)-unit_speed;
                    ptrUnit->dir = DIRECTION_UP;
                }
                else
                {
                    bMoving = false;
                }
            }

            /* ~ if ( (ptrUnit->x - UnitSpeedTable[ptrUnit->id]) > ptrUnit->target_x). */
            /* ~ {. */
                /* ~ ptrUnit->dir = DIRECTION_LEFT;. */
                /* ~ x_d = (int8_t)-UnitSpeedTable[ptrUnit->id];. */
            /* ~ }. */
            /* ~ else if ( (ptrUnit->x + UnitSpeedTable[ptrUnit->id]) < ptrUnit->target_x). */
            /* ~ {. */
                /* ~ ptrUnit->dir = DIRECTION_RIGHT;. */
                /* ~ x_d = (int8_t)UnitSpeedTable[ptrUnit->id];. */
            /* ~ }. */
            /* ~ else if ( (ptrUnit->y - UnitSpeedTable[ptrUnit->id]) > ptrUnit->target_y). */
            /* ~ {. */
                /* ~ ptrUnit->dir = DIRECTION_UP;. */
                /* ~ y_d = (int8_t)-UnitSpeedTable[ptrUnit->id];. */
            /* ~ }. */
            /* ~ else if ( (ptrUnit->y + UnitSpeedTable[ptrUnit->id]) < ptrUnit->target_y). */
            /* ~ {. */
                /* ~ ptrUnit->dir = DIRECTION_DOWN;. */
                /* ~ y_d = (int8_t)UnitSpeedTable[ptrUnit->id];. */
            /* ~ }. */
            /* ~ else. */
            /* ~ {. */
                /* ~ bMoving = false;. */
            /* ~ }. */

            if (ptrUnit->walking != false)
            {
                TYPE_COLLISION_BLOCK cu = { .x = ptrUnit->x + x_d,
                                            .y = ptrUnit->y + y_d,
                                            .w = UnitGetWidthFromID(ptrUnit->id),
                                            .h = UnitGetHeightFromID(ptrUnit->id) };

                if (UnitCheckCollisionAgainstOtherUnits(&cu, unitArray, ptrUnit) == true)
                {
                    switch (ptrUnit->dir)
                    {
                        case DIRECTION_LEFT:
                            /* Fall through. */
                        case DIRECTION_RIGHT:
                            y_d = -x_d;
                            x_d = 0;
                            ptrUnit->dir = y_d > 0? DIRECTION_DOWN: DIRECTION_UP;
                        break;

                        case DIRECTION_UP:
                            /* Fall through. */
                        case DIRECTION_DOWN:
                            x_d = y_d;
                            y_d = 0;
                            ptrUnit->dir = x_d > 0? DIRECTION_RIGHT: DIRECTION_LEFT;
                        break;
                    }
                }
            }

            ptrUnit->walking = bMoving;

            if (ptrUnit->walking != false)
            {
                /* If no collision is detected, keep moving to the new position */
                ptrUnit->x += x_d;
                ptrUnit->y += y_d;
            }
        }
    }
}

uint8_t UnitGetAvailableActions(TYPE_UNIT *ptrUnit)
{
    return UnitActionsTable[ptrUnit->id];
}

const char* UnitGetActionString(UNIT_ACTION action)
{
    return UnitActionsTable_Level[action];
}