use std::fs;
use std::fs::File;
use std::io::prelude::*;
use std::io::BufWriter;
use std::path::PathBuf;
use std::time::SystemTime;

use crossbeam_channel::Receiver;

use crate::common::Common;
use crate::common_dir_traversal::{Collect, DirTraversalBuilder, DirTraversalResult, ErrorType, FileEntry, ProgressData};
use crate::common_directory::Directories;
use crate::common_extensions::Extensions;
use crate::common_items::ExcludedItems;
use crate::common_messages::Messages;
use crate::common_traits::*;

#[derive(Eq, PartialEq, Clone, Debug)]
pub enum DeleteMethod {
    None,
    Delete,
}

/// Info struck with helpful information's about results
#[derive(Default)]
pub struct Info {
    pub number_of_invalid_symlinks: usize,
}

impl Info {
    pub fn new() -> Self {
        Default::default()
    }
}

/// Struct with required information's to work
pub struct InvalidSymlinks {
    text_messages: Messages,
    information: Info,
    invalid_symlinks: Vec<FileEntry>,
    directories: Directories,
    allowed_extensions: Extensions,
    excluded_items: ExcludedItems,
    recursive_search: bool,
    delete_method: DeleteMethod,
    stopped_search: bool,
}

impl InvalidSymlinks {
    pub fn new() -> Self {
        Self {
            text_messages: Messages::new(),
            information: Info::new(),
            recursive_search: true,
            allowed_extensions: Extensions::new(),
            directories: Directories::new(),
            excluded_items: ExcludedItems::new(),
            invalid_symlinks: vec![],
            delete_method: DeleteMethod::None,
            stopped_search: false,
        }
    }

    pub fn find_invalid_links(&mut self, stop_receiver: Option<&Receiver<()>>, progress_sender: Option<&futures::channel::mpsc::UnboundedSender<ProgressData>>) {
        self.directories.optimize_directories(self.recursive_search, &mut self.text_messages);
        if !self.check_files(stop_receiver, progress_sender) {
            self.stopped_search = true;
            return;
        }
        self.delete_files();
        self.debug_print();
    }

    pub fn get_stopped_search(&self) -> bool {
        self.stopped_search
    }

    pub const fn get_invalid_symlinks(&self) -> &Vec<FileEntry> {
        &self.invalid_symlinks
    }

    pub const fn get_text_messages(&self) -> &Messages {
        &self.text_messages
    }

    pub const fn get_information(&self) -> &Info {
        &self.information
    }

    pub fn set_delete_method(&mut self, delete_method: DeleteMethod) {
        self.delete_method = delete_method;
    }

    pub fn set_recursive_search(&mut self, recursive_search: bool) {
        self.recursive_search = recursive_search;
    }

    #[cfg(target_family = "unix")]
    pub fn set_exclude_other_filesystems(&mut self, exclude_other_filesystems: bool) {
        self.directories.set_exclude_other_filesystems(exclude_other_filesystems);
    }

    pub fn set_included_directory(&mut self, included_directory: Vec<PathBuf>) -> bool {
        self.directories.set_included_directory(included_directory, &mut self.text_messages)
    }

    pub fn set_excluded_directory(&mut self, excluded_directory: Vec<PathBuf>) {
        self.directories.set_excluded_directory(excluded_directory, &mut self.text_messages);
    }
    pub fn set_allowed_extensions(&mut self, allowed_extensions: String) {
        self.allowed_extensions.set_allowed_extensions(allowed_extensions, &mut self.text_messages);
    }

    pub fn set_excluded_items(&mut self, excluded_items: Vec<String>) {
        self.excluded_items.set_excluded_items(excluded_items, &mut self.text_messages);
    }

    /// Check files for any with size == 0
    fn check_files(&mut self, stop_receiver: Option<&Receiver<()>>, progress_sender: Option<&futures::channel::mpsc::UnboundedSender<ProgressData>>) -> bool {
        let result = DirTraversalBuilder::new()
            .root_dirs(self.directories.included_directories.clone())
            .group_by(|_fe| ())
            .stop_receiver(stop_receiver)
            .progress_sender(progress_sender)
            .collect(Collect::InvalidSymlinks)
            .directories(self.directories.clone())
            .allowed_extensions(self.allowed_extensions.clone())
            .excluded_items(self.excluded_items.clone())
            .recursive_search(self.recursive_search)
            .build()
            .run();
        match result {
            DirTraversalResult::SuccessFiles {
                start_time,
                grouped_file_entries,
                warnings,
            } => {
                if let Some(((), invalid_symlinks)) = grouped_file_entries.into_iter().next() {
                    self.invalid_symlinks = invalid_symlinks;
                }
                self.information.number_of_invalid_symlinks = self.invalid_symlinks.len();
                self.text_messages.warnings.extend(warnings);
                Common::print_time(start_time, SystemTime::now(), "check_files_name".to_string());
                true
            }
            DirTraversalResult::SuccessFolders { .. } => unreachable!(),
            DirTraversalResult::Stopped => false,
        }
    }

    /// Function to delete files, from filed Vector
    fn delete_files(&mut self) {
        let start_time: SystemTime = SystemTime::now();

        match self.delete_method {
            DeleteMethod::Delete => {
                for file_entry in &self.invalid_symlinks {
                    if fs::remove_file(file_entry.path.clone()).is_err() {
                        self.text_messages.warnings.push(file_entry.path.display().to_string());
                    }
                }
            }
            DeleteMethod::None => {
                //Just do nothing
            }
        }

        Common::print_time(start_time, SystemTime::now(), "delete_files".to_string());
    }
}

impl Default for InvalidSymlinks {
    fn default() -> Self {
        Self::new()
    }
}

impl DebugPrint for InvalidSymlinks {
    #[allow(dead_code)]
    #[allow(unreachable_code)]
    /// Debugging printing - only available on debug build
    fn debug_print(&self) {
        #[cfg(not(debug_assertions))]
        {
            return;
        }
        println!("---------------DEBUG PRINT---------------");
        println!("### Information's");

        println!("Errors size - {}", self.text_messages.errors.len());
        println!("Warnings size - {}", self.text_messages.warnings.len());
        println!("Messages size - {}", self.text_messages.messages.len());

        println!("### Other");

        println!("Invalid symlinks list size - {}", self.invalid_symlinks.len());
        println!("Excluded items - {:?}", self.excluded_items.items);
        println!("Included directories - {:?}", self.directories.included_directories);
        println!("Excluded directories - {:?}", self.directories.excluded_directories);
        println!("Recursive search - {}", self.recursive_search);
        #[cfg(target_family = "unix")]
        println!("Skip other filesystems - {}", self.directories.exclude_other_filesystems());
        println!("Delete Method - {:?}", self.delete_method);
        println!("-----------------------------------------");
    }
}

impl SaveResults for InvalidSymlinks {
    fn save_results_to_file(&mut self, file_name: &str) -> bool {
        let start_time: SystemTime = SystemTime::now();
        let file_name: String = match file_name {
            "" => "results.txt".to_string(),
            k => k.to_string(),
        };

        let file_handler = match File::create(&file_name) {
            Ok(t) => t,
            Err(e) => {
                self.text_messages.errors.push(format!("Failed to create file {}, reason {}", file_name, e));
                return false;
            }
        };
        let mut writer = BufWriter::new(file_handler);

        if let Err(e) = writeln!(
            writer,
            "Results of searching {:?} with excluded directories {:?} and excluded items {:?}",
            self.directories.included_directories, self.directories.excluded_directories, self.excluded_items.items
        ) {
            self.text_messages.errors.push(format!("Failed to save results to file {}, reason {}", file_name, e));
            return false;
        }

        if !self.invalid_symlinks.is_empty() {
            writeln!(writer, "Found {} invalid symlinks.", self.information.number_of_invalid_symlinks).unwrap();
            for file_entry in self.invalid_symlinks.iter() {
                writeln!(
                    writer,
                    "{}\t\t{}\t\t{}",
                    file_entry.path.display(),
                    file_entry.symlink_info.clone().expect("invalid traversal result").destination_path.display(),
                    match file_entry.symlink_info.clone().expect("invalid traversal result").type_of_error {
                        ErrorType::InfiniteRecursion => "Infinite Recursion",
                        ErrorType::NonExistentFile => "Non Existent File",
                    }
                )
                .unwrap();
            }
        } else {
            write!(writer, "Not found any invalid symlinks.").unwrap();
        }
        Common::print_time(start_time, SystemTime::now(), "save_results_to_file".to_string());
        true
    }
}

impl PrintResults for InvalidSymlinks {
    /// Print information's about duplicated entries
    /// Only needed for CLI
    fn print_results(&self) {
        let start_time: SystemTime = SystemTime::now();
        println!("Found {} invalid symlinks.\n", self.information.number_of_invalid_symlinks);
        for file_entry in self.invalid_symlinks.iter() {
            println!(
                "{}\t\t{}\t\t{}",
                file_entry.path.display(),
                file_entry.symlink_info.clone().expect("invalid traversal result").destination_path.display(),
                match file_entry.symlink_info.clone().expect("invalid traversal result").type_of_error {
                    ErrorType::InfiniteRecursion => "Infinite Recursion",
                    ErrorType::NonExistentFile => "Non Existent File",
                }
            );
        }

        Common::print_time(start_time, SystemTime::now(), "print_entries".to_string());
    }
}