#include "internal.h"

bool file_exists(cstr path){
    if(path[0]=='.'){
        if(path[1]==0 || (path[1]==path_sep && path[2]==0))
            return false; // . or ./ is not a file
        // else if(path[1]=='.' && path[2]==path_sep)
        //TODO path_resolve because windows doesnt recognize .\ pattern
    }

#if TLIBC_FS_USE_WINDOWS_H
    DWORD dwAttrib = GetFileAttributes(path);
    return (bool)(
        (dwAttrib != INVALID_FILE_ATTRIBUTES) && // file exists
        !(dwAttrib & FILE_ATTRIBUTE_DIRECTORY)); // file is not directory
#else
    struct stat stats;
    i32 rez=stat(path, &stats);
    return (bool)(
        (rez!=-1) && // file exists
        !(S_ISDIR(stats.st_mode))); // file is not directory
#endif
}

Result(FILE*) file_open(cstr file_name, cstr fopen_mode){
    FILE* f = fopen(file_name, fopen_mode);
    if(f == NULL){
        char* errno_s = strerror_malloc(errno);
        ResultVar(void) err = RESULT_ERROR_FMT(
            "Can't open (%s) file '%s': %s",
            fopen_mode, file_name, errno_s);
        free(errno_s);
        return err;
    }
    return RESULT_VALUE(p, f);
}

Result(FILE*) file_openOrCreateReadWrite(cstr file_name){
    cstr fopen_mode = "rb+";
    FILE* f = fopen(file_name, fopen_mode);
    if(f == NULL){
        fopen_mode = "wb+";
        f = fopen(file_name, fopen_mode);
        if(f == NULL){
            char* errno_s = strerror_malloc(errno);
            ResultVar(void) err = RESULT_ERROR_FMT(
                "Can't open (%s) file '%s': %s",
                fopen_mode, file_name, errno_s);
            free(errno_s);
            return err;
        }
    }
    return RESULT_VALUE(p, f);
}



Result(i64) file_tellPos(FILE* f){
    i64 r = IFWIN(_ftelli64, ftello64)(f);
    if(r < 0){
        return RESULT_ERROR_ERRNO();
    }
    return RESULT_VALUE(i, r);
}

Result(void) file_seek(FILE* f, i64 offset, SeekOrigin origin){
    if(IFWIN(_fseeki64, fseeko64)(f, offset, (int)origin) != 0){
        char* errno_s = strerror_malloc(errno);
        ResultVar(void) err = RESULT_ERROR_FMT(
            "Can't seek (offset: "FMT_i64", origin: %i) in file: %s",
            offset, origin, errno_s);
        free(errno_s);
        return err;
    }
    return RESULT_VOID;
}

Result(i64) file_getSize(FILE* f){
    Deferral(4);
    // get current position
    try(i64 original_pos, i, file_tellPos(f));
    // seek to end
    try_void(file_seek(f, 0, SeekOrigin_End));
    try(i64 size, i, file_tellPos(f));
    // restore original position
    try_void(file_seek(f, original_pos, SeekOrigin_Start));
    Return RESULT_VALUE(i, size);
}


Result(void) file_writeStructs(FILE* f, const void* src, u64 struct_size, u64 count){
    u64 r = fwrite(src, struct_size, count, f);
    if(r != count){
        return RESULT_ERROR_ERRNO();
    }
    return RESULT_VOID;
}

Result(void) file_writeByte(FILE* f, u8 b){
    if(fputc(b, f) != 0){
        return RESULT_ERROR_ERRNO();
    }
    return RESULT_VOID;
}

Result(bool) file_readByte(FILE* f, u8* out_byte){
    int r = fgetc(f);
    if(ferror(f)){
        return RESULT_ERROR_ERRNO();
    }
    if(feof(f)){
        return RESULT_VALUE(u, false);
    }
    *out_byte = r;
    return RESULT_VALUE(u, true);
}

Result(u64) file_readStructs(FILE* f, void* dst, u64 struct_size, u64 max_count){
    u64 r = fread(dst, struct_size, max_count, f);
    if(ferror(f)){
        return RESULT_ERROR_ERRNO();
    }
    return RESULT_VALUE(u, r);
}

Result(void) file_readStructsExactly(FILE* f, void* dst, u64 struct_size, u64 exact_count){
    u64 r = fread(dst, struct_size, exact_count, f);
    if(ferror(f)){
        return RESULT_ERROR_ERRNO();
    }
    if(r != exact_count){
        return RESULT_ERROR_FMT(
            "read "FMT_u64" structures out of "FMT_u64,
            r, exact_count);
    }
    return RESULT_VOID;
}

Result(void) file_readWhole(FILE* f, Array(u8)* out_buf){
    Deferral(1);
    bool success = false;
    
    try(i64 f_size, i, file_getSize(f));
    Array(u8) buf = Array_u8_alloc(f_size);
    Defer(if(!success) Array_u8_destroy(&buf));

    try_void(file_readBytesArrayExactly(f, buf));

    *out_buf = buf;
    success = true;
    Return RESULT_VOID;
}

Result(void) file_readWholeText(FILE* f, str* out_str){
    Deferral(1);
    bool success = false;
    
    try(i64 f_size, i, file_getSize(f));
    Array(u8) buf = Array_u8_alloc(f_size + 1);
    Defer(if(!success) Array_u8_destroy(&buf));
    buf.len--;
    
    try_void(file_readBytesArrayExactly(f, buf));
    buf.data[buf.len] = '\0';

    *out_str = Array_u8_castTo_str(buf, true);
    success = true;
    Return RESULT_VOID;
}