#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void mul(int **a, int **b, int **c, int m, int k, int n) {
    int i, j, l;
    for (i = 0; i < m; i++) {
        for (j = 0; j < n; j++) {
            c[i][j] = 0;
            for (l = 0; l < k; l++) {
                c[i][j] += a[i][l] * b[l][j];
            }
        }
    }
}

void read_matrix(FILE *file, int **a, int rows, int cols) {
    char line[1000];
    char *token;
    int i, j;
    for (i = 0; i < rows; i++) {
        fgets(line, sizeof(line), file);
        token = strtok(line, " \n");
        for (j = 0; j < cols; j++) {
            a[i][j] = atoi(token);
            token = strtok(NULL, " \n");
        }
    }
}

int get_matrix_dimensions(FILE *file, int *m, int *k, int *n) {
    char line[1000];
    int rows1 = 0, cols1 = 0, rows2 = 0, cols2 = 0;
    int first_matrix = 1;
    int cols;
    char *token;

    while (fgets(line, sizeof(line), file)) {
        if (strlen(line) <= 1) {
            first_matrix = 0;
            continue;
        }

        token = strtok(line, " \n");
        cols = 0;
        while (token != NULL) {
            cols++;
            token = strtok(NULL, " \n");
        }

        if (first_matrix) {
            cols1 = cols;
            rows1++;
        } else {
            cols2 = cols;
            rows2++;
        }
    }

    *m = rows1;
    *k = cols1;
    *n = cols2;

    if (cols1 != rows2) {
        printf("錯誤!矩陣無法相乘\n");
        printf("k1=%d, k2=%d\n",cols1,rows2);
        return 1;
    }

    return 0;
}

int main() {
    FILE *file;
    int m, k, n, i, j;

    if ((file = fopen("matrix_input.txt", "r")) == NULL) {
        printf("錯誤!無法打開文件\n");
        return 1;
    }

    if (get_matrix_dimensions(file, &m, &k, &n)) {
        fclose(file);
        return 1;
    }

    printf("第一個矩陣：%d 行 %d 列\n", m, k);
    printf("第二個矩陣：%d 行 %d 列\n", k, n);

    int **arr_a = (int**)malloc(m * sizeof(int*));
    int **arr_b = (int**)malloc(k * sizeof(int*));
    int **arr_c = (int**)malloc(m * sizeof(int*));

    for (i = 0; i < m; i++) {
        arr_a[i] = (int*)malloc(k * sizeof(int));
        arr_c[i] = (int*)malloc(n * sizeof(int));
    }
    for (i = 0; i < k; i++) {
        arr_b[i] = (int*)malloc(n * sizeof(int));
    }
    
	//回到文件的開始
    rewind(file);
    
    read_matrix(file, arr_a, m, k);

    /* 跳過矩陣之間的空行 */
    char line[1000];
    fgets(line, sizeof(line), file);

    read_matrix(file, arr_b, k, n);

    mul(arr_a, arr_b, arr_c, m, k, n);

    printf("結果矩陣：\n");
    for (i = 0; i < m; i++) {
        for (j = 0; j < n; j++) {
            printf("%d ", arr_c[i][j]);
        }
        printf("\n");
    }

    fclose(file);

    free(arr_a);
    free(arr_b);
    free(arr_c);
    for (i = 0; i < m; i++) {
        free(arr_a[i]);
        free(arr_c[i]);
    }
    for (i = 0; i < k; i++) {
        free(arr_b[i]);
    }
    
    return 0;
}