#include "hashmap.h"
#include "bitwriter.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
    if (argc != 2)
    {
        printf("Usage: %s <input file>\n", argv[0]);
        exit(1);
    }

    char *input_file_name = argv[1];
    char *output_file_name = malloc(sizeof(char) * 
        (strlen(input_file_name) + strlen(".deflate") + 1));
    sprintf(output_file_name, "%s.deflate", input_file_name);

    FILE *input_file = fopen(input_file_name, "r");
    FILE *output_file = fopen(output_file_name, "w");
    free(output_file_name);
    BitWriter *bitWriter = BitWriter_init(output_file);
    Hashmap *hashMap = Hashmap_init();


    BitWriter_write_bit(bitWriter, 1); /* BFINAL */
    
    BitWriter_write_bit(bitWriter, 1); /* BTYPE */
    BitWriter_write_bit(bitWriter, 0);



    fseek(input_file, 0, SEEK_END);
    size_t input_file_length = ftell(input_file);
    fseek(input_file, 0, SEEK_SET);

    size_t cursor = 0;

    while (cursor < input_file_length)
    {
        printf("Compressed %ld/%ld\n", cursor, input_file_length);
        uint32_t best_length = 0;
        size_t best_length_start = 0;
        size_t scan_start = 0;
        if (cursor > 32768) scan_start = cursor - 32768;
        for (size_t start = scan_start; start < cursor; start++)
        {
            uint32_t length = 0;
            while (start + length < cursor && cursor + length < input_file_length && length < 258)
            {
                uint8_t back, cur;
                fseek(input_file, start + length, SEEK_SET);
                fread(&back, 1, 1, input_file);
                fseek(input_file, cursor + length, SEEK_SET);
                fread(&cur, 1, 1, input_file);
                if (back == cur) length += 1;
                else break;
            }

            if (length > best_length)
            {
                best_length = length;
                best_length_start = start;
            }
        }

        if (best_length > 2)
        {
            uint32_t backtrack = cursor - best_length_start;
            BitWriter_write_length(bitWriter, best_length);
            BitWriter_write_distance(bitWriter, backtrack);
            cursor += best_length;
        }
        else
        {
            fseek(input_file, cursor, SEEK_SET);
            uint8_t b;
            fread(&b, 1, 1, input_file);
            BitWriter_write_alpha(bitWriter, b);
            cursor += 1;
        }




    }

    

    BitWriter_write_bin(bitWriter, 0, 7); /* EOB */

    BitWriter_flush(bitWriter);

    Hashmap_free(hashMap);
    BitWriter_free(bitWriter);
    fclose(input_file);
    fclose(output_file);
}