#include "lib.h"
#include "log.h"
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

ImplList(Buffer)

Buffer ListBuffer_serialize(ListBuffer list) {
	Buffer out = {0};
	for (ListBuffer lptr = list; lptr != NULL; lptr = lptr->rest) {
		Buffer buf = lptr->head;
		out = concat(out, Buffer_serialize(buf));
	}
	return out;
}

ListBuffer ListBuffer_deserialize(Buffer buf) {
	ListBuffer out = NULL;
	for (size_t len = 0; len < buf.len;) {
		Buffer mbuf = Buffer_deserialize((Buffer) {
				.buf = buf.len + (Byte*)len,
				.len = 0,
			});
		len += mbuf.len + sizeof(size_t);
		out = ListBuffer_cons(mbuf, out);
	}

	return out;
}

bool mkdir_p(SafeStr fpath, mode_t mode) {
	char* tmp = calloc(fpath.len + 1, sizeof(char));
	size_t len = 0;
	for (size_t i = 0; i < fpath.len; ++i) {
		char c = fpath.str[i];
		if (c == '/') {
			if (len != 0) {
				if (mkdir(tmp, mode) != 0) {
					if (errno != EEXIST)
						try(-1);
				}
			}
		}
		tmp[len++] = c;
	}
	// INFO: This needs to get done one more time in case there isn't a '/' at
	// the end of the fpath
	if (mkdir(tmp, mode) != 0) {
		if (errno != EEXIST)
			try(-1);
	}
	return true;
}

void Buffer_deinit(Buffer kod) {
	free(kod.buf);
}

void Buffer_write(Buffer buf, FILE* f) {
	exists(f);
	fwrite(buf.buf, sizeof(Byte), buf.len, f);
}

Buffer Buffer_read(FILE* f) {
	exists(f);
	fseek(f, 0, SEEK_END);
	size_t len = (size_t)ftell(f);
	fseek(f, 0, SEEK_SET);
	Buffer buf = {
		.buf = calloc(len, sizeof(Byte)),
		.len = len,
	};
	exists(buf.buf);

	size_t count = fread(buf.buf, sizeof(Byte), len, f);

	if (count != len) {
		log(FATAL, "Error reading file\n");
		exit(EXIT_FAILURE);
	}

	return buf;
}

Byte* copy(Byte* src, size_t nbytes) {
	exists(src);
	Byte* out = (Byte*)malloc(nbytes * sizeof(Byte));
	exists(out);
	memcpy(out, src, nbytes);
	return out;
}

/// Allocates new memory from src and returns a buffer to that memory. The user
/// must free that memory.
Buffer bufcpy(Buffer src) {
	Byte* buf = (Byte*)malloc(src.len * sizeof(Byte));
	exists(buf);
	memcpy(buf, src.buf, src.len);
	return (Buffer){
		.buf = buf,
		.len = src.len,
	};
}

/// Checks whether the buffer contains a valid string and that the size provided
/// matches the size of that string.
Buffer validate_str(Buffer str, size_t max_len) {
	size_t calculated_len = safe_strlen((const char*)str.buf, max_len);
	if (str.len != calculated_len) {
		log(ERROR, "%s:%d String's length (%zu) is not equal to given length (%zu).", __FILE__, __LINE__, calculated_len, str.len);

		printf("\nBuffer contains: ");
		for (size_t i = 0; i < max_len; ++i) printf("[%d] ", str.buf[i]);
		printf("\n");

		exit(1);
	}
	if (str.len > max_len) {
		log(ERROR, "%s:%d String's length (%zu) is larger than the buffer that contains it (%zu)\n", str.len, calculated_len);

		printf("\nBuffer contains: ");
		for (size_t i = 0; i < max_len; ++i) printf("[%d] ", str.buf[i]);
		printf("\n");

		exit(1);
	}
	return str;
}

// uses memchr to calculate strlen.
size_t safe_strlen(Str str, size_t max_len) {
	char* last = memchr(str, '\0', max_len);
	return last != NULL ? (size_t)last - (size_t)str : max_len;
}

// Esta funcion convierte un string a un buffer.
Buffer atob(const char* str) {
	return (Buffer){
		.buf = (Byte*)str,
		.len = strlen(str),
	};
}

Buffer SafeStr_serialize(SafeStr str) {
	return concat(size_t_serialize(str.len), to_buffer(str.str, str.len));
}

SafeStr SafeStr_deserialize(Buffer buf) {
	size_t len = size_t_deserialize((Buffer) {
			.buf = buf.buf,
			.len = sizeof(size_t)
		});
	Str str = calloc(len + 1, sizeof(char));

	memcpy((void*)str, (void*)(buf.buf + sizeof(size_t)), len);

	return (SafeStr){
		.str = str,
		.len = len,
	};
}

Buffer size_t_serialize(size_t a) {
	Buffer out = {
		.len = sizeof(size_t),
		.buf = (Byte*)calloc(1, sizeof(size_t)),
	};

	memcpy(out.buf, &a, sizeof(size_t));

	return out;
}

size_t size_t_deserialize(Buffer buf) {
	size_t out = 0;

	if (buf.len != sizeof(size_t)) {
		log(FATAL, "size_t has incorrect size\n");
		exit(EXIT_FAILURE);
	}

	memcpy(&out, buf.buf, sizeof(size_t));

	return out;
}

Buffer concat(Buffer l, Buffer r) {
	// INFO: Notice that whenever either is null, the other is returned.
	if (l.buf == NULL) {
		return r;
	} else if (r.buf == NULL) {
		return l;
	}
	Buffer out = {
		.len = l.len + r.len,
		.buf = (Byte*)calloc(l.len + r.len, sizeof(Byte)),
	};
	exists(out.buf);

	memcpy(out.buf, l.buf, l.len);
	memcpy(out.buf + l.len, r.buf, r.len);
	free(l.buf);
	free(r.buf);

	return out;
}

bool Str_eq(Str l, Str r) {
	return strcmp(l, r) == 0;
}

Buffer Buffer_serialize(Buffer buf) {
	Buffer size = size_t_serialize(buf.len);
	exists(size.buf);
	return concat(size, buf);
}

Buffer Buffer_deserialize(Buffer buf) {
	size_t size = size_t_deserialize((Buffer){ .buf = buf.buf, .len = sizeof(size_t) });

	if (buf.len < size + sizeof(size_t)) {
		log(FATAL, "Error deserializing buffer. Incorrect size. Got: %zu. Expected greater than: %zu\n", buf.len, size + sizeof(size_t)); 
		exit(EXIT_FAILURE);
	}

	Buffer out = {
		.buf = (Byte*)calloc(size, sizeof(Byte)),
		.len = size,
	};
	exists(out.buf);

	memcpy(out.buf, buf.buf + sizeof(size_t), size);
	return out;
}

Buffer to_buffer(const void* thing, size_t nbytes) {
	Buffer out = {
		.buf = (Byte*)calloc(1, nbytes),
		.len = nbytes,
	};
	exists(out.buf);

	memcpy(out.buf, thing, nbytes);
	return out;
}


Buffer uint8_t_serialize(uint8_t n) {
	return to_buffer(&n, sizeof(uint8_t));
}

uint8_t uint8_t_deserialize(Buffer buf) {
	exists(buf.buf);

	if (buf.len != sizeof(uint8_t)) {
		log(FATAL, "Could not deserialize uint8_t. Buffer length incorrect: %zu\n", buf.len);
		exit(EXIT_FAILURE);
	}

	uint8_t x;
	memcpy(&x, buf.buf, sizeof x);
	return x;
}


Buffer uint16_t_serialize(uint16_t n) {
	return to_buffer(&n, sizeof(uint16_t));
}

uint16_t uint16_t_deserialize(Buffer buf) {
	exists(buf.buf);

	if (buf.len != sizeof(uint16_t)) {
		log(FATAL, "Could not deserialize uint16_t. Buffer length incorrect: %zu\n", buf.len);
		exit(EXIT_FAILURE);
	}

	uint16_t x;
	memcpy(&x, buf.buf, sizeof x);
	return x;
}

Buffer uint32_t_serialize(uint32_t n) {
	return to_buffer(&n, sizeof(uint32_t));
}

uint32_t uint32_t_deserialize(Buffer buf) {
	exists(buf.buf);

	if (buf.len != sizeof(uint32_t)) {
		log(FATAL, "Could not deserialize uint32_t. Buffer length incorrect: %zu\n", buf.len);
		exit(EXIT_FAILURE);
	}

	uint32_t x;
	memcpy(&x, buf.buf, sizeof x);
	return x;
}

SafeStr atoss(Str str) {
	return (SafeStr) {
		.str = str,
		.len = strlen(str),
	};
}

size_t min(size_t l, size_t r) {
	return l < r ? l : r;
}


LazyBuffer open(Str fpath) {
	FILE* f = fopen(fpath, "r");
	exists(f);
	fseek(f, 0, SEEK_END);
	size_t size = (size_t)ftell(f);
	fseek(f, 0, SEEK_SET);
	return (LazyBuffer){
		.fptr = f,
		.buf = {0},
		.len = 0,
		.position = 0,
		.size = size,
	};
}

LazyBuffer next_chunk(LazyBuffer b) {
	exists(b.fptr);

	size_t read_len = min(b.size - b.position, CHUNK_SIZE);
	if (read_len == 0) {
		b.len = 0;
		return b;
	}
	size_t count = fread(b.buf, sizeof(Byte), read_len, b.fptr);

	if (count != read_len) {
		log(FATAL, "Error reading file. Expected to read %zu bytes, got %zu\n", read_len, count);
		exit(EXIT_FAILURE);
	}

	b.position += read_len;
	b.len = read_len;
	return b;
}