/* voronoi.c
 *
 * Created by Rory Healy (healyr@student.unimelb.edu.au)
 * Created on 11th September 2021
 * Last modified 14th September 2021
 *
 * Contains functions for reading a CSV of watchtower information into an 
 * array of towers.
 * 
 */

#ifndef TOWERS_HEADER
#include "towers.h"
#endif

#define BASE_10 10
#define MAX_CSV_ENTRY_LEN 512
#define MAX_FIELD_LEN 128
#define NUM_CSV_FIELDS 6

void readATower(char *lineBuffer, tower_t *tower) {
    /* Stores the current CSV field for the current line */
    char *token = strtok(lineBuffer, ",");
    size_t tokenLength;

    for (int i = 0; i < NUM_CSV_FIELDS; i++) {
        tokenLength = strlen(token);
        switch(i) {
            /* Cases represent each field in the CSV, and as such are handled
             * differently.
             */
            case 0:
                tower->id = malloc(sizeof(char) * tokenLength + 1);
                checkNullPointer(tower->id);
                strcpy(tower->id, token);
                tower->id[tokenLength] = '\0';
                break;
            case 1:
                tower->postcode = malloc(sizeof(char) * tokenLength + 1);
                checkNullPointer(tower->postcode);
                strcpy(tower->postcode, token);
                tower->postcode[tokenLength] = '\0';
                break;
            case 2:
                tower->population = strtol(token, NULL, BASE_10);
                break;
            case 3:
                tower->manager = malloc(sizeof(char) * tokenLength + 1);
                checkNullPointer(tower->manager);
                strcpy(tower->manager, token);
                tower->manager[tokenLength] = '\0';
                break;
            case 4:
                tower->x = strtod(token, NULL);
                break;
            case 5:
                tower->y = strtod(token, NULL);
                break;
        }
        token = strtok(NULL, ",");
    }
}

tower_t **readTowers(tower_t **towers, FILE *datasetFile, int *numTowers) {
    /* Maximum length of a single CSV line (+1 for null char in string) */
    size_t lineBufferSize = MAX_CSV_ENTRY_LEN + 1;

    /* Stores the current line from the CSV */
    char *lineBuffer = malloc(lineBufferSize * sizeof(*lineBuffer));
    checkNullPointer(lineBuffer);

    int maxSizetowers = 1;

    /* Discard the header line, then read the rest of the CSV */
    getline(&lineBuffer, &lineBufferSize, datasetFile);
    while (getline(&lineBuffer, &lineBufferSize, datasetFile) > 0) {
        /* Ensure there is enough space in the towers array */
        if (*numTowers == maxSizetowers) {
            maxSizetowers *= 2;
            tower_t **temp = realloc(towers, maxSizetowers * sizeof(*towers));
            checkNullPointer(temp);
            towers = temp;
        }

        /* The current tower being filled in with information */
        towers[*numTowers] = malloc(sizeof(*towers[*numTowers]));

        readATower(lineBuffer, towers[*numTowers]);
        *numTowers += 1;
    }
    free(lineBuffer);
    return towers;
}

void freeTowers(tower_t **towers, int numTowers) {
    if (!towers) {
        return;
    }

    for (int i = 0; i < numTowers; i++) {
        if (towers[i]->id) {
            free(towers[i]->id);
        }
        if (towers[i]->manager) {
            free(towers[i]->manager);
        }
        if (towers[i]->postcode) {
            free(towers[i]->postcode);
        }
        if (towers[i]) {
            free(towers[i]);
        }
    }
    free(towers);
}