/// dynamic array class
/// written by: Harry Irving

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

typedef struct {
    int size;
    int capacity;
    char* data;
} String;

String str_with_capacity(int capacity) {
    String s;

    /// allocate memory for 'capacity' chars
    s.data = (char*)calloc(capacity, sizeof(char));

    s.size = 0;
    s.capacity = capacity;

    return s;
}

String str_from_chars(char* string) {
    String s;

    s.data = (char*)calloc(strlen(string), sizeof(char));
    strcpy(s.data, string);
    s.size = strlen(string);
    s.capacity = strlen(string);
    return s;
}

String str_from_slice(char* string, int len) {
    String s;

    s.data = (char*)calloc(len, sizeof(char));
    strncpy(s.data, string, len);
    s.size = len;
    s.capacity = len;
    return s;
}


String str_new() {
    return str_with_capacity(1);
}

int str_dealloc(String* self) {
    free(self->data);
    return 0;
}

void str_push(String* self, char c) {
    // check size < capacity
    if (self->size < self->capacity) {
        self->data[self->size] = c;
        self->size++;
        return;
    }

    // reallocate to add capacity for an extra char
    int newcap = self->capacity + sizeof(char);
    self->data = (char*)realloc(self->data, newcap);
    self->data[self->size] = c;
    self->size++;
    self->capacity = newcap;
    return;
}

char str_pop(String* self) {
    if (self->size == 0) {
        return '\0';
    }
    self->size--;
    char c = self->data[self->size];
    return c;
}

void str_insert(String* self, int index, char c) {
    if (index > self->size) {
        return;
    }
    self->size++;
    for (int i = self->size - 1; i > index; i--) {
        self->data[i] = self->data[i - 1];
    }
    self->data[index] = c;
}

void str_remove(String* self, int index) {
    if (index >= self->size) {
        return;
    }
    self->size--;
    for (int i = index; i < self->size; i++) {
        self->data[i] = self->data[i + 1];
    }
}

String* str_lines(String* self, int* numlines) {

    char* string = self->data;
    String* lines = NULL;
    
    // find the number of lines in the file
    *numlines = 0;
    for (int i = 0; i < strlen(string); i++) {
        if (string[i] == '\n') {
            (*numlines)++;
        }
    }

    // add one if the last char is not a newline
    // in this case there is one more line than newline symbols
    if (self->data[strlen(self->data) - 1] != '\n') {
        (*numlines)++;
    }

    // allocate memory for an array of pointers to each line
    lines = (String*)malloc((*numlines + 1) * sizeof(String));

    int i = 0;
    char* start = string;
    char* end = string;

    while (*end != '\0') {
        if (*end == '\n') {
            lines[i] = str_from_slice(start, end - start);

            end++;
            start = end;

            i++;
        } else {
            end++;
        }
    }
    // returns an array of String
    return lines;
}

/// splits a string into an array of strings based on a delimiter
String* str_split(String* self, int* res_len, char c) {

    char* string = self->data;
    String* elements = NULL;
    
    // find the number of lines in the file

    bool flag = false;
    *res_len = 0;
    for (int i = 0; i < strlen(string); i++) {
        if (string[i] == c) {
            if (flag) {
                (*res_len)++;
                flag = false;
            }
        } else {
            flag = true;
        }
    }
    if (flag) {
        (*res_len)++;
    }

    // allocate memory for an array of pointers to each line
    elements = (String*)malloc((*res_len) * sizeof(String));

    int i = 0;
    flag = false;
    char* start = string;
    char* end = string;

    while (*end != '\0') {
        if (*end == c) {
            if (flag) {
                elements[i] = str_from_slice(start, end - start);
                i++;
            }
            end++;
            start = end;
            flag = false;
        } else {
            end++;
            flag = true;
        }
    } if (flag) {
        elements[i] = str_from_slice(start, end - start);
    }


    // returns an array of String
    return elements;
}

int str_len(String* s) {
    return s->size;
}

char* to_chars(String* s) {
    return s->data;
}

// int main() {
//     String s = str_from_chars("hello\nworld\neeeee\notherline\n\0");

//     int numlines = 0;
//     String* lns = str_lines(&s, &numlines);
//     str_dealloc(&s);

//     for (int i = 0; i < numlines; i++) {
//         printf("%s\n", lns[i].data);
//         str_dealloc(&lns[i]);
//     }

//     String s2 = str_from_chars("$this$needs$to$be$split");

//     int elements = 0;
//     String* split = str_split(&s2, &elements, '$');
//     str_dealloc(&s2);

//     printf("%d elements\n", elements);
//     for (int i = 0; i < elements; i++) {
//         printf("%s\n", split[i].data);
//         str_dealloc(&split[i]);
//         printf("(dealloced)\n");
//     }   
// }