#include "fpga_cell.h"
#include "fpga_global.h"
#include "fpga_cell_lut34.h"
#include "fpga_cell_none.h"
#include "fpga_cell_wire.h"
#include <stdlib.h>

static struct fpga_cell_type fpga_cell_list[] = {
{
	.identifier = ' ',
	.cell_new = fpga_cell_none_new,
	.get_next_isp = fpga_cell_none_get_next_isp,
	.isp_length = 0
},
{
	.identifier = '[',
	.cell_new = fpga_cell_wire_new,
	.get_next_isp = fpga_cell_wire_get_next_isp,
	.isp_length = 0
},
{
	.identifier = ']',
	.cell_new = fpga_cell_wire_new,
	.get_next_isp = fpga_cell_wire_get_next_isp,
	.isp_length = 0
},
{
	.identifier = 'P',
	.cell_new = fpga_cell_wire_new,
	.get_next_isp = fpga_cell_wire_get_next_isp,
	.isp_length = 0
},
{
	.identifier = 'L',
	.cell_new = fpga_cell_lut34_new,
	.get_next_isp = fpga_cell_lut34_get_next_isp,
	.isp_length = 1 // TODO:TBD
},
{
	.identifier = '\0',
	.cell_new = NULL,
	.get_next_isp = NULL,
	.isp_length = 0
}
};

void fpga_cell_init(struct fpga_cell *cell,
		    struct fpga_cell_type *cell_type)
{
	int i;

	for (i = 0; i < FPGA_CELL_CONNECTION_COUNT; ++i) {
		cell->cell_connections[i] = NULL;
	}

	cell->type = cell_type;
	//fpga_cell->get_next_isp = fpga_cell_get_next_isp_dummy;

	report(LL_DEBUG,
	       "Initialized cell of type %d at %p.",
	       cell_type, cell);
}

enum fpga_cell_position fpga_cell_connection_opposing(enum fpga_cell_position position)
{
	switch (position) {
	case LEFT:
		return RIGHT;
	case RIGHT:
		return LEFT;
	case TOP:
		return BOTTOM;
	case BOTTOM:
		return TOP;
	default:
		report(LL_ERROR,
		       "Internal error: Requested opposite of invalid position %d.",
		       position);
		return LEFT;
	}
}

/**
 * @brief fpga_cell_connect Connect <fpga_cell> to the <position> of <target_cell>
 * @param fpga_cell
 * @param target_cell
 * @param position
 * @return 0 on success, -1 on failure
 */
int fpga_cell_connect(struct fpga_cell *fpga_cell,
		      struct fpga_cell *target_cell,
		      enum fpga_cell_position position)
{
	if (target_cell->cell_connections[position] ||
			fpga_cell->cell_connections[fpga_cell_connection_opposing(position)]) {
		report(LL_WARNING,
		       "Tried to connect cell %p to pos %d of %p, even though a connection already exists for a least one of them.",
		       fpga_cell, target_cell, position);
		errno = -ECONN;
		return -1;
	}

	target_cell->cell_connections[position] = fpga_cell;
	fpga_cell->cell_connections[fpga_cell_connection_opposing(position)] = target_cell;

	report(LL_DEBUG,
	       "Connected cell %p to port %d of %p.",
	       fpga_cell, position, target_cell);

	return 0;
}

/**
 * @brief fpga_cell_get_far Get cell on the far <position> of <cell>
 * @param cell
 * @param position
 * @return
 */
struct fpga_cell *fpga_cell_get_far(struct fpga_cell *cell,
				    enum fpga_cell_position position)
{
	struct fpga_cell *next = cell;

	while (next->cell_connections[position]) {
		next = next->cell_connections[position];
	}

	return next;
}

/**
 * @brief fpga_cell_get_next_isp Get the next cell in the ISP chain
 * @param fpga_cell the current cell in the ISP chain
 * @param isp_channel the current channel. This will be updated when calling this function!
 * @return the next ISP cell
 */
struct fpga_cell *fpga_cell_get_next_isp_dummy(struct fpga_cell *cell,
					       enum fpga_isp_channel *isp_channel)
{
	report(LL_CRITICAL,
	       "Internal error. Cell type %c does not implement get_next_isp!",
	       cell->type->identifier);
	*isp_channel = FPGA_ISP_CHANNEL_ERROR;
	return NULL;
}

/**
 * @brief fpga_cell_new Create a new instance of type <identifier>
 * @param identifier
 * @return
 */
struct fpga_cell *fpga_cell_new(char identifier)
{
	struct fpga_cell_type *cell_type = fpga_cell_list;
	struct fpga_cell *cell = NULL;

	while (cell_type->identifier) {
		if (identifier == cell_type->identifier) {
			cell = cell_type->cell_new();
			if (!cell) {
				report(LL_CRITICAL,
				       "Out of memory when creating cell.");
				return NULL;
			}
			cell->type = cell_type;
			report(LL_DEBUG,
			       "Created cell %p of type %c.",
			       cell, identifier);
			return cell;
		}
		cell_type++;
	}

	report(LL_ERROR,
	       "Invalid cell type %c found in FDEF.",
	       identifier);
	return NULL;
}

/**
 * @brief fpga_isp_chain_new
 * @param entry
 * @return
 */
struct fpga_chain *fpga_isp_chain_new(struct fpga_cell *entry)
{
	struct fpga_cell *current_cell = entry;
	enum fpga_isp_channel current_channel = FPGA_ISP_CHANNEL_NORMAL;
	struct fpga_chain *chain;

	report(LL_INFO,
	       "Generating ISP chain...");

	chain = calloc(sizeof (struct fpga_chain), 1);
	if (!chain) {
		report (LL_CRITICAL,
			"Out of memory during ISP chain generation.");
		return NULL;
	}

	while (current_cell) {
		if (current_channel == FPGA_ISP_CHANNEL_NORMAL &&
				current_cell->type->isp_length > 0) {
			report(LL_DEBUG,
			       "Adding %p (%c) to ISP chain.",
			       current_cell, current_cell->type->identifier);

			if (!chain->head) {
				chain->head = malloc(sizeof(chain->head));
				*(chain->head) = current_cell;
				chain->length = 1;
			} else {
				chain->length++;
				chain->head = realloc(chain->head,
						      sizeof(chain->head) * chain->length);
				*(chain->head + chain->length - 1) = current_cell;
			}

		} else {
			report(LL_DEBUG,
			       "Using %p (%c) for ISP routing.",
			       current_cell, current_cell->type->identifier);
		}

		current_cell = current_cell->type->get_next_isp(current_cell,
								&current_channel);
		if (current_channel == FPGA_ISP_CHANNEL_ERROR) {
			/* TODO: Clean up memory */
			return NULL;
		}
	}

	report(LL_INFO,
	       "Added %d cells to ISP chain.",
	       chain->length);

	for (int i = 0; i < chain->length; ++i) {
		report(LL_DEBUG,
		       "  %4d = %p",
		       i, chain->head[i]);
	}

	report(LL_INFO,
	       "ISP chain generated finished.");

	return chain;
}