/*
 Itay Marom
 Cisco Systems, Inc.
*/

/*
Copyright (c) 2015-2015 Cisco Systems, Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

#include <string>
#include <sstream>
#include <trex_streams_compiler.h>
#include <trex_stream.h>
#include <assert.h>
#include <trex_stateless.h>
#include <iostream>

/**
 * describes a graph node in the pre compile check
 * 
 * @author imarom (16-Nov-15)
 */
class GraphNode {
public:
    GraphNode(TrexStream *stream, GraphNode *next) : m_stream(stream), m_next(next) {
        marked   = false;
        m_compressed_stream_id=-1;
    }

    uint32_t get_stream_id() const {
        return m_stream->m_stream_id;
    }

    const TrexStream *m_stream;
    GraphNode *m_next;
    std::vector<const GraphNode *> m_parents;
    bool marked;
    int m_compressed_stream_id;
};

/**
 * node map
 * 
 */
class GraphNodeMap {
public:

    GraphNodeMap() : m_dead_end(NULL, NULL) {

    }

    bool add(GraphNode *node) {
        if (has(node->get_stream_id())) {
            return false;
        }

        m_nodes[node->get_stream_id()] = node;

        if (node->m_stream->m_self_start) {
            m_roots.push_back(node);
        }

        return true;
    }

    bool has(uint32_t stream_id) {

        return (get(stream_id) != NULL);
    }

    GraphNode * get(uint32_t stream_id) {

        if (stream_id == -1) {
            return &m_dead_end;
        }

        auto search = m_nodes.find(stream_id);

        if (search != m_nodes.end()) {
            return search->second;
        } else {
            return NULL;
        }
    }

    void clear_marks() {
        for (auto node : m_nodes) {
            node.second->marked = false;
        }
    }

    void get_unmarked(std::vector <GraphNode *> &unmarked) {
        for (auto node : m_nodes) {
            if (!node.second->marked) {
                unmarked.push_back(node.second);
            }
        }
    }


    ~GraphNodeMap() {
        for (auto node : m_nodes) {
            delete node.second;
        }
        m_nodes.clear();
    }

    std::vector <GraphNode *> & get_roots() {
        return m_roots;
    }


    std::unordered_map<uint32_t, GraphNode *> get_nodes() {
        return m_nodes;
    }

private:
    std::unordered_map<uint32_t, GraphNode *> m_nodes;
    std::vector <GraphNode *> m_roots;
    GraphNode m_dead_end;
};

/**************************************
 * stream compiled object
 *************************************/
TrexStreamsCompiledObj::TrexStreamsCompiledObj(uint8_t port_id, double mul) : m_port_id(port_id), m_mul(mul) {
}

TrexStreamsCompiledObj::~TrexStreamsCompiledObj() {
    for (auto obj : m_objs) {
        delete obj.m_stream;
    }
    m_objs.clear();
}


void 
TrexStreamsCompiledObj::add_compiled_stream(TrexStream * stream){

    obj_st obj;

    obj.m_stream = stream->clone_as_dp();

    m_objs.push_back(obj);
}

void 
TrexStreamsCompiledObj::add_compiled_stream(TrexStream * stream,
                                            uint32_t my_dp_id, int next_dp_id) {
    obj_st obj;

    obj.m_stream = stream->clone_as_dp();
    /* compress the id's*/
    obj.m_stream->fix_dp_stream_id(my_dp_id,next_dp_id);

    m_objs.push_back(obj);
}

void TrexStreamsCompiledObj::Dump(FILE *fd){
    for (auto obj : m_objs) {
        obj.m_stream->Dump(fd);
    }
}



TrexStreamsCompiledObj *
TrexStreamsCompiledObj::clone() {

    /* use multiplier of 1 to avoid double mult */
    TrexStreamsCompiledObj *new_compiled_obj = new TrexStreamsCompiledObj(m_port_id, 1);

    /**
     * clone each element
     */
    for (auto obj : m_objs) {
        new_compiled_obj->add_compiled_stream(obj.m_stream);
    }

    new_compiled_obj->m_mul = m_mul;

    return new_compiled_obj;
}

void
TrexStreamsCompiler::add_warning(const std::string &warning) {
    m_warnings.push_back("*** warning: " + warning);
}

void
TrexStreamsCompiler::err(const std::string &err) {
    throw TrexException("*** error: " + err);
}

void
TrexStreamsCompiler::check_stream(const TrexStream *stream) {
    std::stringstream ss;

    /* cont. stream can point only on itself */
    if (stream->get_type() == TrexStream::stCONTINUOUS) {
        if (stream->m_next_stream_id != -1) {
            ss << "continous stream '" << stream->m_stream_id << "' cannot point on another stream";
            err(ss.str());
        }
    }
}

void
TrexStreamsCompiler::allocate_pass(const std::vector<TrexStream *> &streams,
                                   GraphNodeMap *nodes) {
    std::stringstream ss;
    uint32_t compressed_stream_id=0;


    /* first pass - allocate all nodes and check for duplicates */
    for (auto stream : streams) {

        /* skip non enabled streams */
        if (!stream->m_enabled) {
            continue;
        }

        /* sanity check on the stream itself */
        check_stream(stream);

        /* duplicate stream id ? */
        if (nodes->has(stream->m_stream_id)) {
            ss << "duplicate instance of stream id " << stream->m_stream_id;
            err(ss.str());
        }

        GraphNode *node = new GraphNode(stream, NULL);
        /* allocate new compressed id */
        node->m_compressed_stream_id = compressed_stream_id;

        compressed_stream_id++;

        /* add to the map */
        assert(nodes->add(node));
    }

}

/**
 * on this pass we direct the graph to point to the right nodes
 * 
 */
void
TrexStreamsCompiler::direct_pass(GraphNodeMap *nodes) {
   
    /* second pass - direct the graph */
    for (auto p : nodes->get_nodes()) {

        GraphNode *node = p.second;
        const TrexStream *stream = node->m_stream;

        /* check the stream points on an existing stream */
        GraphNode *next_node = nodes->get(stream->m_next_stream_id);
        if (!next_node) {
            std::stringstream ss;
            ss << "stream " << node->get_stream_id() << " is pointing on non existent stream " << stream->m_next_stream_id;
            err(ss.str());
        }

        node->m_next = next_node;

        /* do we have more than one parent ? */
        next_node->m_parents.push_back(node);
    }


    /* check for multiple parents */
    for (auto p : nodes->get_nodes()) {
        GraphNode *node = p.second;

        if (node->m_parents.size() > 0 ) {
            std::stringstream ss;

            ss << "stream " << node->get_stream_id() << " is triggered by multiple streams: ";
            for (auto x : node->m_parents) {
                ss << x->get_stream_id() << " ";
            }

            add_warning(ss.str());
        }
    }
}

/**
 * mark sure all the streams are reachable
 * 
 */
void
TrexStreamsCompiler::check_for_unreachable_streams(GraphNodeMap *nodes) {
    /* start with the roots */
    std::vector <GraphNode *> next_nodes = nodes->get_roots();


    nodes->clear_marks();

    /* run BFS from all the roots */
    while (!next_nodes.empty()) {

        /* pull one */
        GraphNode *node = next_nodes.back();
        next_nodes.pop_back();
        if (node->marked) {
            continue;
        }

        node->marked = true;

        if (node->m_next != NULL) {
            next_nodes.push_back(node->m_next);
        }

    }

    std::vector <GraphNode *> unmarked;
    nodes->get_unmarked(unmarked);

    if (!unmarked.empty()) {
        std::stringstream ss;
        for (auto node : unmarked) {
            ss << "stream " << node->get_stream_id() << " is unreachable from any other stream\n";
        }
        err(ss.str());
    }


}

/**
 * check validation of streams for compile
 * 
 * @author imarom (16-Nov-15)
 * 
 * @param streams 
 * @param fail_msg 
 * 
 * @return bool 
 */
void
TrexStreamsCompiler::pre_compile_check(const std::vector<TrexStream *> &streams,
                                       GraphNodeMap & nodes) {

    m_warnings.clear();

    /* allocate nodes */
    allocate_pass(streams, &nodes);

    /* direct the graph */
    direct_pass(&nodes);

    /* check for non reachable streams inside the graph */
    check_for_unreachable_streams(&nodes);

}

/**************************************
 * stream compiler
 *************************************/
bool 
TrexStreamsCompiler::compile(const std::vector<TrexStream *> &streams,
                             TrexStreamsCompiledObj &obj,
                             std::string *fail_msg) {

#if 0
    fprintf(stdout,"------------pre compile \n");
    for (auto stream : streams) {
        stream->Dump(stdout);
    }
    fprintf(stdout,"------------pre compile \n");
#endif

    GraphNodeMap nodes;


    /* compile checks */
    try {
        pre_compile_check(streams,nodes);
    } catch (const TrexException &ex) {
        if (fail_msg) {
            *fail_msg = ex.what();
        } else {
            std::cout << ex.what();
        }
        return false;
    }


    /* for now we do something trivial, */
    for (auto stream : streams) {

        /* skip non-enabled streams */
        if (!stream->m_enabled) {
            continue;
        }

        int new_id= nodes.get(stream->m_stream_id)->m_compressed_stream_id;
        assert(new_id>=0);
        uint32_t my_stream_id = (uint32_t)new_id;
        int my_next_stream_id=-1;
        if (stream->m_next_stream_id>=0) {
            my_next_stream_id=nodes.get(stream->m_next_stream_id)->m_compressed_stream_id;
        }

        /* add it */
        obj.add_compiled_stream(stream,
                                my_stream_id,
                                my_next_stream_id
                                );
    }

    return true;
}