/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version. 
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2007 Blender Foundation.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): Nathan Letwory.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/nodes/intern/node_exec.c
 *  \ingroup nodes
 */


#include "DNA_node_types.h"

#include "BLI_listbase.h"
#include "BLI_utildefines.h"

#include "BKE_global.h"
#include "BKE_node.h"

#include "MEM_guardedalloc.h"

#include "node_exec.h"
#include "node_util.h"


/* supported socket types in old nodes */
int node_exec_socket_use_stack(bNodeSocket *sock)
{
	return ELEM(sock->type, SOCK_FLOAT, SOCK_VECTOR, SOCK_RGBA, SOCK_SHADER);
}

/* for a given socket, find the actual stack entry */
bNodeStack *node_get_socket_stack(bNodeStack *stack, bNodeSocket *sock)
{
	if (stack && sock && sock->stack_index >= 0)
		return stack + sock->stack_index;
	return NULL;
}

void node_get_stack(bNode *node, bNodeStack *stack, bNodeStack **in, bNodeStack **out)
{
	bNodeSocket *sock;
	
	/* build pointer stack */
	if (in) {
		for (sock = node->inputs.first; sock; sock = sock->next) {
			*(in++) = node_get_socket_stack(stack, sock);
		}
	}
	
	if (out) {
		for (sock = node->outputs.first; sock; sock = sock->next) {
			*(out++) = node_get_socket_stack(stack, sock);
		}
	}
}

static void node_init_input_index(bNodeSocket *sock, int *index)
{
	/* Only consider existing link if from socket is valid! */
	if (sock->link && sock->link->fromsock && sock->link->fromsock->stack_index >= 0) {
		sock->stack_index = sock->link->fromsock->stack_index;
	}
	else {
		if (node_exec_socket_use_stack(sock))
			sock->stack_index = (*index)++;
		else
			sock->stack_index = -1;
	}
}

static void node_init_output_index(bNodeSocket *sock, int *index, ListBase *internal_links)
{
	if (internal_links) {
		bNodeLink *link;
		/* copy the stack index from internally connected input to skip the node */
		for (link = internal_links->first; link; link = link->next) {
			if (link->tosock == sock) {
				sock->stack_index = link->fromsock->stack_index;
				/* set the link pointer to indicate that this socket
				 * should not overwrite the stack value!
				 */
				sock->link = link;
				break;
			}
		}
		/* if not internally connected, assign a new stack index anyway to avoid bad stack access */
		if (!link) {
			if (node_exec_socket_use_stack(sock))
				sock->stack_index = (*index)++;
			else
				sock->stack_index = -1;
		}
	}
	else {
		if (node_exec_socket_use_stack(sock))
			sock->stack_index = (*index)++;
		else
			sock->stack_index = -1;
	}
}

/* basic preparation of socket stacks */
static struct bNodeStack *setup_stack(bNodeStack *stack, bNodeTree *ntree, bNode *node, bNodeSocket *sock)
{
	bNodeStack *ns = node_get_socket_stack(stack, sock);
	if (!ns)
		return NULL;
	
	/* don't mess with remote socket stacks, these are initialized by other nodes! */
	if (sock->link)
		return ns;
	
	ns->sockettype = sock->type;
	
	switch (sock->type) {
		case SOCK_FLOAT:
			ns->vec[0] = node_socket_get_float(ntree, node, sock);
			break;
		case SOCK_VECTOR:
			node_socket_get_vector(ntree, node, sock, ns->vec);
			break;
		case SOCK_RGBA:
			node_socket_get_color(ntree, node, sock, ns->vec);
			break;
	}
	
	return ns;
}

bNodeTreeExec *ntree_exec_begin(bNodeExecContext *context, bNodeTree *ntree, bNodeInstanceKey parent_key)
{
	bNodeTreeExec *exec;
	bNode *node;
	bNodeExec *nodeexec;
	bNodeInstanceKey nodekey;
	bNodeSocket *sock;
	bNodeStack *ns;
	int index;
	bNode **nodelist;
	int totnodes, n;
	/* XXX texnodes have threading issues with muting, have to disable it there ... */
	
	/* ensure all sock->link pointers and node levels are correct */
	ntreeUpdateTree(G.main, ntree);
	
	/* get a dependency-sorted list of nodes */
	ntreeGetDependencyList(ntree, &nodelist, &totnodes);
	
	/* XXX could let callbacks do this for specialized data */
	exec = MEM_callocN(sizeof(bNodeTreeExec), "node tree execution data");
	/* backpointer to node tree */
	exec->nodetree = ntree;
	
	/* set stack indices */
	index = 0;
	for (n = 0; n < totnodes; ++n) {
		node = nodelist[n];
		
		node->stack_index = index;
		
		/* init node socket stack indexes */
		for (sock = node->inputs.first; sock; sock = sock->next)
			node_init_input_index(sock, &index);
		
		if (node->flag & NODE_MUTED || node->type == NODE_REROUTE) {
			for (sock = node->outputs.first; sock; sock = sock->next)
				node_init_output_index(sock, &index, &node->internal_links);
		}
		else {
			for (sock = node->outputs.first; sock; sock = sock->next)
				node_init_output_index(sock, &index, NULL);
		}
	}
	
	/* allocated exec data pointers for nodes */
	exec->totnodes = totnodes;
	exec->nodeexec = MEM_callocN(exec->totnodes * sizeof(bNodeExec), "node execution data");
	/* allocate data pointer for node stack */
	exec->stacksize = index;
	exec->stack = MEM_callocN(exec->stacksize * sizeof(bNodeStack), "bNodeStack");
	
	/* all non-const results are considered inputs */
	for (n = 0; n < exec->stacksize; ++n)
		exec->stack[n].hasinput = 1;
	
	/* prepare all nodes for execution */
	for (n = 0, nodeexec = exec->nodeexec; n < totnodes; ++n, ++nodeexec) {
		node = nodeexec->node = nodelist[n];
		nodeexec->freeexecfunc = node->typeinfo->freeexecfunc;
		
		/* tag inputs */
		for (sock = node->inputs.first; sock; sock = sock->next) {
			/* disable the node if an input link is invalid */
			if (sock->link && !(sock->link->flag & NODE_LINK_VALID))
				node->need_exec = 0;
			
			ns = setup_stack(exec->stack, ntree, node, sock);
			if (ns)
				ns->hasoutput = 1;
		}
		
		/* tag all outputs */
		for (sock = node->outputs.first; sock; sock = sock->next) {
			/* ns = */ setup_stack(exec->stack, ntree, node, sock);
		}
		
		nodekey = BKE_node_instance_key(parent_key, ntree, node);
		nodeexec->data.preview = context->previews ? BKE_node_instance_hash_lookup(context->previews, nodekey) : NULL;
		if (node->typeinfo->initexecfunc)
			nodeexec->data.data = node->typeinfo->initexecfunc(context, node, nodekey);
	}
	
	if (nodelist)
		MEM_freeN(nodelist);
	
	return exec;
}

void ntree_exec_end(bNodeTreeExec *exec)
{
	bNodeExec *nodeexec;
	int n;
	
	if (exec->stack)
		MEM_freeN(exec->stack);
	
	for (n = 0, nodeexec = exec->nodeexec; n < exec->totnodes; ++n, ++nodeexec) {
		if (nodeexec->freeexecfunc)
			nodeexec->freeexecfunc(nodeexec->data.data);
	}
	
	if (exec->nodeexec)
		MEM_freeN(exec->nodeexec);
	
	MEM_freeN(exec);
}

/**** Material/Texture trees ****/

bNodeThreadStack *ntreeGetThreadStack(bNodeTreeExec *exec, int thread)
{
	ListBase *lb = &exec->threadstack[thread];
	bNodeThreadStack *nts;
	
	for (nts = lb->first; nts; nts = nts->next) {
		if (!nts->used) {
			nts->used = true;
			break;
		}
	}
	
	if (!nts) {
		nts = MEM_callocN(sizeof(bNodeThreadStack), "bNodeThreadStack");
		nts->stack = MEM_dupallocN(exec->stack);
		nts->used = true;
		BLI_addtail(lb, nts);
	}

	return nts;
}

void ntreeReleaseThreadStack(bNodeThreadStack *nts)
{
	nts->used = 0;
}

bool ntreeExecThreadNodes(bNodeTreeExec *exec, bNodeThreadStack *nts, void *callerdata, int thread)
{
	bNodeStack *nsin[MAX_SOCKET] = {NULL};   /* arbitrary... watch this */
	bNodeStack *nsout[MAX_SOCKET] = {NULL};  /* arbitrary... watch this */
	bNodeExec *nodeexec;
	bNode *node;
	int n;
	
	/* nodes are presorted, so exec is in order of list */
	
	for (n = 0, nodeexec = exec->nodeexec; n < exec->totnodes; ++n, ++nodeexec) {
		node = nodeexec->node;
		if (node->need_exec) {
			node_get_stack(node, nts->stack, nsin, nsout);
			/* Handle muted nodes...
			 * If the mute func is not set, assume the node should never be muted,
			 * and hence execute it!
			 */
//			if (node->typeinfo->compatibility == NODE_NEW_SHADING)
//				return false;
			if (node->typeinfo->execfunc && !(node->flag & NODE_MUTED))
				node->typeinfo->execfunc(callerdata, thread, node, &nodeexec->data, nsin, nsout);
		}
	}
	
	/* signal to that all went OK, for render */
	return true;
}