#include "transmission.h"
#include "program.h"
#include "buffer.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#define NUM_COLUMNS 10

int transmission_is_daemon_running(void) {
    const char *args[] = { "transmission-remote", "-si", NULL };
    return program_exec(args, NULL, NULL);
}

int transmission_start_daemon(const char *download_dir) {
    /* TODO: Make seed ratio configurable */
    const char *args[] = { "transmission-daemon", "--global-seedratio", "2.0", "--download-dir", download_dir, NULL };
    int res = program_exec(args, NULL, NULL);
    if(res != 0)
        return res;

    fprintf(stderr, "Waiting for the transmission daemon to startup...\n");
    int num_tries = 0;
    const int max_tries = 7; /* 7 seconds */

    while(transmission_is_daemon_running() != 0 && num_tries < max_tries) {
        sleep(1);
        ++num_tries;
    }
    
    if(num_tries == max_tries) {
        fprintf(stderr, "Failed to launch transmission daemon in 7 seconds\n");
        return -1;
    }

    fprintf(stderr, "The transmission daemon is now running!\n");
    return 0;
}

int transmission_add_torrent(const char *url) {
    const char *args[] = { "transmission-remote", "-a", "--", url, NULL };
    return program_exec(args, NULL, NULL);
}

int transmission_get_all_torrents(TorrentListCallback callback, void *userdata) {
    int result = 0;

    Buffer buffer;
    buffer_init(&buffer);

    const char *args[] = { "transmission-remote", "--list", NULL };
    int exec_res = program_exec(args, program_buffer_write_callback, &buffer);
    if(exec_res != 0) {
        result = exec_res;
        goto cleanup;
    }
    buffer_append(&buffer, "\0", 1);

    char id[6];
    char done[6];
    char have[13];
    char format[7];
    char eta[33];
    char eta2[13];
    char up[11];
    char down[11];
    char ratio[11];
    char status[33];
    char name[256];

    char *end_of_first_line = strchr(buffer.data, '\n');
    if(!end_of_first_line)
        goto cleanup;

    int num_bytes_read = 0;
    size_t offset = end_of_first_line - (char*)buffer.data;
    while(offset < buffer.size) {
        /* ID, Done, Have (size, format), ETA, Up, Down, Ratio, Status, Name */
        int res = sscanf(buffer.data + offset, "%5s %5s %12s %6s %32s %12s %10s %10s %10s %32s %[^\n] %n", id, done, have, format, eta, eta2, up, down, ratio, status, name, &num_bytes_read);
        if(res == EOF || res != NUM_COLUMNS + 1) {
            int res = sscanf(buffer.data + offset, "%5s %5s %12s %6s %32s %10s %10s %10s %32s %[^\n] %n", id, done, have, format, eta, up, down, ratio, status, name, &num_bytes_read);
            if(res == EOF || res != NUM_COLUMNS)
                break;
        }
        callback(atoi(id), atof(done), name, userdata);
        offset += num_bytes_read;
    }

    cleanup:
    buffer_deinit(&buffer);
    return result;
}

static int find_start_of_line(const char *str, int offset) {
    for(int i = offset; i >= 0; --i) {
        if(*str == '\n')
            return i + 1;
    }
    return 0;
}

static int find_end_of_previous_line(const char *str, int offset) {
    for(int i = offset; i >= 0; --i) {
        if(*str == '\n')
            return i - 1;
    }
    return 0;
}

int transmission_get_last_added_torrent(int *id_result, float *percentage_finished_result, char *title_result) {
    int result = 0;

    Buffer buffer;
    buffer_init(&buffer);

    const char *args[] = { "transmission-remote", "--list", NULL };
    int exec_res = program_exec(args, program_buffer_write_callback, &buffer);
    if(exec_res != 0) {
        result = exec_res;
        goto cleanup;
    }

    char id[6];
    char done[6];
    char have[13];
    char format[7];
    char eta[33];
    char eta2[13];
    char up[11];
    char down[11];
    char ratio[11];
    char status[33];
    char name[256];

    int end_of_second_last_line = find_end_of_previous_line(buffer.data, (int)buffer.size - 1);
    int start_of_second_last_line = find_start_of_line(buffer.data, end_of_second_last_line);

    /* ID, Done, Have (size, format), ETA, Up, Down, Ratio, Status, Name */
    int res = sscanf(buffer.data + start_of_second_last_line, "%5s %5s %12s %6s %32s %12s %10s %10s %10s %32s %[^\n]", id, done, have, format, eta, eta2, up, down, ratio, status, name);
    if(res == EOF || res != NUM_COLUMNS + 1) {
        int res = sscanf(buffer.data + start_of_second_last_line, "%5s %5s %12s %6s %32s %10s %10s %10s %32s %[^\n]", id, done, have, format, eta, up, down, ratio, status, name);
        if(res == EOF || res != NUM_COLUMNS) {
            result = -1;
            goto cleanup;
        }
    }

    *id_result = atoi(id);
    *percentage_finished_result = atof(done);
    strcpy(title_result, name);

    cleanup:
    buffer_deinit(&buffer);
    return result;
}