#include <malloc.h>

#include "logger.h"
#include "utils.h"
#include "sk6812.h"

#include "fader.h"

int fader_init(struct fader_ctx *ctx, uint32_t nMod, struct sk6812_ctx *ledCtx)
{
	ctx->num_modules = nMod;
	ctx->fadestep = 1;

	ctx->cur_colour = malloc(nMod * sizeof(struct fader_colour));
	if(!ctx->cur_colour) {
		LOG(LVL_ERR, "fader: could not allocate the array of current colours!");
		return -1;
	}

	ctx->target_colour = malloc(nMod * sizeof(struct fader_colour));
	if(!ctx->target_colour) {
		LOG(LVL_ERR, "fader: could not allocate the array of target colours!");
		return -1;
	}

	for(uint32_t i = 0; i < ctx->num_modules; i++) {
		ctx->cur_colour[i].red   = ctx->target_colour[i].red   = 0;
		ctx->cur_colour[i].green = ctx->target_colour[i].green = 0;
		ctx->cur_colour[i].blue  = ctx->target_colour[i].blue  = 0;
		ctx->cur_colour[i].white = ctx->target_colour[i].white = 0;
	}

	// store LED context (initalized externally)
	ctx->led_ctx = ledCtx;

	return 0;
}

void fader_shutdown(struct fader_ctx *ctx)
{
	free(ctx->cur_colour);
	free(ctx->target_colour);
}

void fader_set_colour(struct fader_ctx *ctx, uint32_t module, uint8_t r, uint8_t g, uint8_t b, uint8_t w)
{
	ctx->cur_colour[module].red   = ctx->target_colour[module].red   = r;
	ctx->cur_colour[module].green = ctx->target_colour[module].green = g;
	ctx->cur_colour[module].blue  = ctx->target_colour[module].blue  = b;
	ctx->cur_colour[module].white = ctx->target_colour[module].white = w;

	ctx->something_changed = 1;
}

void fader_fade_colour(struct fader_ctx *ctx, uint32_t module, uint8_t r, uint8_t g, uint8_t b, uint8_t w)
{
	ctx->target_colour[module].red   = r;
	ctx->target_colour[module].green = g;
	ctx->target_colour[module].blue  = b;
	ctx->target_colour[module].white = w;
}

void fader_add_colour(struct fader_ctx *ctx, uint32_t module, uint8_t r, uint8_t g, uint8_t b, uint8_t w)
{
	ctx->cur_colour[module].red   += r;
	ctx->cur_colour[module].green += g;
	ctx->cur_colour[module].blue  += b;
	ctx->cur_colour[module].white += w;

	if(ctx->cur_colour[module].red > 255) { ctx->cur_colour[module].red = 255; }
	if(ctx->cur_colour[module].green > 255) { ctx->cur_colour[module].green = 255; }
	if(ctx->cur_colour[module].blue > 255) { ctx->cur_colour[module].blue = 255; }
	if(ctx->cur_colour[module].white > 255) { ctx->cur_colour[module].white = 255; }

	ctx->target_colour[module] = ctx->cur_colour[module];

	ctx->something_changed = 1;
}

void fader_set_fadestep(struct fader_ctx *ctx, uint8_t newFadestep)
{
	ctx->fadestep = newFadestep;
}

/*!
 * Fade the colour value in cur towards target.
 *
 * \param cur      The colour value to update.
 * \param target   The target value that should be reached.
 * \param changed  Output value which is set to 1 if cur was changed.
 */
void fade_colour(struct fader_ctx *ctx, float *cur, const float *target, uint8_t *changed)
{
	float diff;
	if(*cur > *target) {
		diff = *cur - *target;
		if(diff < ctx->fadestep) {
			*cur = *target;
		} else {
			*cur -= ctx->fadestep;
		}

		*changed = 1;
	} else if(*cur < *target) {
		diff = *target - *cur;
		if(diff < ctx->fadestep) {
			*cur = *target;
		} else {
			*cur += ctx->fadestep;
		}

		*changed = 1;
	}
}

void fader_update(struct fader_ctx *ctx)
{
	for(uint32_t i = 0; i < ctx->num_modules; i++) {
		fade_colour(ctx, &(ctx->cur_colour[i].red), &(ctx->target_colour[i].red), &ctx->something_changed);
		fade_colour(ctx, &(ctx->cur_colour[i].green), &(ctx->target_colour[i].green), &ctx->something_changed);
		fade_colour(ctx, &(ctx->cur_colour[i].blue), &(ctx->target_colour[i].blue), &ctx->something_changed);
		fade_colour(ctx, &(ctx->cur_colour[i].white), &(ctx->target_colour[i].white), &ctx->something_changed);

		sk6812_set_colour(ctx->led_ctx, i,
				(uint8_t)ctx->cur_colour[i].red,
				(uint8_t)ctx->cur_colour[i].green,
				(uint8_t)ctx->cur_colour[i].blue,
				(uint8_t)ctx->cur_colour[i].white);
	}

	if(ctx->something_changed) {
		sk6812_send_update(ctx->led_ctx);
		ctx->something_changed = 0;
	}
}