#include <errno.h>
#include <string.h>

#include <parse.hpp>
#include <problem.hpp>
#include <list.hpp>
#include <refcounted.hpp>
#include <print.hpp>

refcounted<list<refcounted<problem>>> parse(const char* path)
{
    refcounted<list<refcounted<problem>>> problems = new list<refcounted<problem>>();
    
    FILE* stream = fopen(path, "r");
    
    char *line = NULL;
    size_t len = 0;
    ssize_t nread;
    
    while ((nread = getline(&line, &len, stream)) > 0)
    {
        line[--nread] = 0;
        
        if (line[0] == '\0') continue;
        if (line[0] == 'c') continue;
        
        if (line[0] != 'p')
        {
            assert(!"TODO");
            exit(1);
        }
        
        unsigned number_of_variables;
        unsigned number_of_clauses;
        
        int r = sscanf(line, " p %u %u ", &number_of_variables, &number_of_clauses);
        
        if (r < 2)
        {
            puts("syntax error");
            exit(1);
        }
        
        refcounted<problem> p = new problem(number_of_variables);
        
        for (unsigned i = 0; i < number_of_clauses; i++)
        {
            nread = getline(&line, &len, stream);
            
            if (nread < 0)
            {
                puts("syntax error");
                exit(1);
            }
            
            line[--nread] = 0;
            
            refcounted<clause> c = new clause();
            
            char *moving = line;
            
            for (char* word; (word = strtok_r(NULL, " ", &moving)); )
            {
                errno = 0;
                
                char* m;
                
                signed variable = strtol(word, &m, 10);
                
                if (errno || *m)
                {
                    puts("syntax error");
                    exit(1);
                }
                
                bool value = true;
                
                if (variable < 0)
                {
                    variable = -variable;
                    value = !value;
                }
                
                assert(variable > 0);
                
                c->bundles.append(
                    (clause::bundle) {(unsigned) variable, value});
            }
            
            p->clauses.append(c);
        }
        
        problems->append(p);
    }
    
    free(line);
    
    fclose(stream);
    
    return problems;
}