mod args;
mod enumerations;
mod excel;
mod structures;

// https://crates.io/crates/cfg-if
cfg_if::cfg_if! {
    if #[cfg(feature = "walkdir")] {
        mod with_walkdir;
        pub use with_walkdir::get_all_files;
    } else {
        // default: use jwalk
        mod with_jwalk;
        pub use with_jwalk::get_all_files;
    }
}

pub use self::{
    args::Arguments,
    enumerations::algo::{Algorithm, PathBufExtension},
    structures::file_info::{FileExtension, FileInfo},
    structures::group_info::{GroupExtension, GroupInfo},
    structures::key_info::Key,
    structures::path_info::PathInfo,
    structures::total_info::TotalInfo,
};
pub use excel::write_xlsx;
use serde::Serializer;
use std::{
    fs::{self, File},
    path::{Path, PathBuf},
    process::Command,
    str,
};

pub type MyError = Box<dyn std::error::Error + Send + Sync>;
pub type MyResult<T> = Result<T, MyError>;

const STACK_SIZE: usize = 64 * 1024 * 1024;
const SEPARATOR: char = '.'; // thousands sep
pub const CSV_FILENAME: &str = "fdf.csv";
pub const XLSX_FILENAME: &str = "fdf.xlsx";

/**
If `thread '<unknown>' has overflowed its stack`, set the stack size to a new value.

The default rustc stack size for main thread is currently `8 * 1024 * 1024`.

Stack size can be changed during compile time.

<https://github.com/rust-lang/rust/blob/master/compiler/rustc_interface/src/util.rs#L132>

<https://github.com/rust-lang/rust/issues/111897>

<https://doc.rust-lang.org/stable/std/thread/index.html#stack-size>
*/
pub fn set_env_variables() {
    std::env::set_var("RUST_MIN_STACK", STACK_SIZE.to_string());
}

/// File is an object providing access to an open file on the filesystem.
pub fn open_file<P>(path: &P) -> MyResult<File>
where
    P: AsRef<Path> + std::fmt::Debug,
{
    let file: File = match fs::OpenOptions::new()
        .read(true)
        .write(false) // This option, when false, will indicate that the file should not be writable if opened.
        .create(false) // No files will be created
        .open(path)
    {
        Ok(file) => file,
        Err(error) => {
            eprintln!("Failed to open file {path:?}");
            eprintln!("Perhaps some temporary files no longer exist!");
            eprintln!("Or lack of permission to read this file!");
            panic!("{error}");
        }
    };

    Ok(file)
}

/// Get path from arguments or from default (current directory).
pub fn get_path(arguments: &Arguments) -> MyResult<PathBuf> {
    let path: PathBuf = match &arguments.input_dir {
        Some(path) => path.to_owned(),
        None => PathBuf::from("."),
    };

    if arguments.full_path {
        Ok(fs::canonicalize(path)?) // full path
    } else {
        Ok(path) // relative path
    }
}

/// Print buffer to stdout
pub fn my_print(buffer: &[u8]) -> MyResult<()> {
    // Converts a slice of bytes to a string slice
    let print_msg = match str::from_utf8(buffer) {
        Ok(valid_uft8) => valid_uft8,
        Err(error) => {
            eprintln!("fn my_print()");
            eprintln!("Invalid UTF-8 sequence!");
            panic!("{error}");
        }
    };

    // Print to stdout
    print!("{print_msg}");
    Ok(())
}

// https://stackoverflow.com/questions/34837011/how-to-clear-the-terminal-screen-in-rust-after-a-new-line-is-printed
// https://stackoverflow.com/questions/65497187/cant-run-a-system-command-in-windows
// https://askubuntu.com/questions/25077/how-to-really-clear-the-terminal
// https://www.redswitches.com/blog/how-to-clear-terminal-screen-in-linux
// Remove unwanted characters
// clear | cat -v ; echo
// ^[[H^[[2J^[[3J
/// Clear (wipe) the terminal screen
pub fn clear_terminal_screen() {
    if cfg!(target_os = "windows") {
        Command::new("cmd")
            .args(["/c", "cls"])
            .spawn()
            .expect("cls command failed to start")
            .wait()
            .expect("failed to wait");
    } else {
        Command::new("tput") // "clear" or "tput reset"
            .arg("reset")
            .spawn()
            .expect("tput command failed to start")
            .wait()
            .expect("failed to wait");
    };
}

/// Split integer and insert thousands separator
pub fn split_and_insert(integer: usize, insert: char) -> String {
    let group_size = 3;
    let integer_str = integer.to_string();

    if integer <= 999 {
        return integer_str;
    }

    let string_splitted: String = integer_str
        .chars()
        .enumerate()
        .flat_map(|(i, c)| {
            if (integer_str.len() - i) % group_size == 0 && i > 0 {
                Some(insert)
            } else {
                None
            }
            .into_iter()
            .chain(std::iter::once(c))
        })
        .collect::<String>();

    string_splitted
}

/// Serialize usize with fn split_and_insert().
pub fn add_thousands_separator<S>(size: &usize, serializer: S) -> Result<S::Ok, S::Error>
where
    S: Serializer,
{
    serializer.collect_str(&format!("{} bytes", &split_and_insert(*size, SEPARATOR)))
}

#[cfg(test)]
mod test_lib {
    use super::*;

    #[test]
    fn split_integer_into_groups() {
        // cargo test -- --show-output split_integer_into_groups

        let mut result: Vec<String> = Vec::new();

        for integer in [
            0, 1, 12, 999, 1000, 1001, 1234, 12345, 123456, 1234567, 12345678,
        ] {
            let integer_splitted: String = split_and_insert(integer, '_');
            println!("integer: {integer:<8} ; with thousands sep: {integer_splitted}");
            result.push(integer_splitted);
        }

        let valid = vec![
            "0",
            "1",
            "12",
            "999",
            "1_000",
            "1_001",
            "1_234",
            "12_345",
            "123_456",
            "1_234_567",
            "12_345_678",
        ];

        assert_eq!(valid, result);
    }
}