#include "buffer.h"
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static int file_read(
    char** text, size_t* text_capacity, size_t* text_length, const char* path)
{
    FILE* file = fopen(path, "r");
    if (!file) {
        fprintf(stderr, "error: could not open file '%s'\n", path);
        return -1;
    }

    fseek(file, 0, SEEK_END);
    size_t file_size = (size_t)ftell(file);
    rewind(file);

    size_t initial_capacity = 8;
    while (initial_capacity < file_size + 1)
        initial_capacity *= 2;

    *text = calloc(initial_capacity, sizeof(char));
    *text_capacity = initial_capacity;
    *text_length = file_size;

    size_t bytes_read = fread(*text, sizeof(char), file_size, file);
    if (bytes_read != file_size) {
        fprintf(stderr, "error: could not read file '%s'\n", path);
        return -1;
    }

    return 0;
}

void buffer_init(Buffer* buffer)
{
    const size_t text_initial_capacity = 8;

    *buffer = (Buffer) {
        .path = nullptr,
        .text = calloc(1, text_initial_capacity),
        .text_capacity = text_initial_capacity,
        .text_length = 0,
        .changed = false,
    };
}

int buffer_from_file(Buffer* buffer, const char* path)
{
    *buffer = (Buffer) {
        .path = strdup(path),
        .text = nullptr,
        .text_capacity = 0,
        .text_length = 0,
        .changed = false,
    };
    int status = file_read(
        &buffer->text, &buffer->text_capacity, &buffer->text_length, path);
    return status;
}

void buffer_deinit(Buffer* buffer)
{
    if (buffer->path)
        free(buffer->path);
    free(buffer->text);
}