use crate::common::Common;
use crate::common_directory::Directories;
use crate::common_extensions::Extensions;
use crate::common_items::ExcludedItems;
use crate::common_messages::Messages;
use crate::common_traits::{DebugPrint, PrintResults, SaveResults};
use crossbeam_channel::Receiver;
use humansize::{file_size_opts as options, FileSize};
use std::collections::BTreeMap;
use std::ffi::OsStr;
use std::fs;
use std::fs::{File, Metadata};
use std::io::Write;
use std::path::PathBuf;
use std::time::{SystemTime, UNIX_EPOCH};

#[derive(Clone)]
pub struct FileEntry {
    pub path: PathBuf,
    pub size: u64,
    pub modified_date: u64,
}

/// Info struck with helpful information's about results
#[derive(Default)]
pub struct Info {
    pub number_of_checked_files: usize,
    pub number_of_checked_folders: usize,
    pub number_of_ignored_files: usize,
    pub number_of_ignored_things: usize,
    pub taken_space: u64,
    pub number_of_real_files: usize,
}

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

/// Struct with required information's to work
pub struct BigFile {
    text_messages: Messages,
    information: Info,
    big_files: BTreeMap<u64, Vec<FileEntry>>,
    excluded_items: ExcludedItems,
    directories: Directories,
    allowed_extensions: Extensions,
    recursive_search: bool,
    number_of_files_to_check: usize,
    stopped_search: bool,
}

impl BigFile {
    pub fn new() -> Self {
        Self {
            text_messages: Default::default(),
            information: Info::new(),
            big_files: Default::default(),
            excluded_items: ExcludedItems::new(),
            directories: Directories::new(),
            allowed_extensions: Extensions::new(),
            recursive_search: true,
            number_of_files_to_check: 50,
            stopped_search: false,
        }
    }

    pub fn find_big_files(&mut self, rx: Option<&Receiver<()>>) {
        self.optimize_directories();
        if !self.look_for_big_files(rx) {
            self.stopped_search = true;
            return;
        }
        self.debug_print();
    }
    pub fn get_stopped_search(&self) -> bool {
        self.stopped_search
    }

    pub const fn get_big_files(&self) -> &BTreeMap<u64, Vec<FileEntry>> {
        &self.big_files
    }

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

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

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

    /// List of allowed extensions, only files with this extensions will be checking if are duplicates
    pub fn set_allowed_extensions(&mut self, allowed_extensions: String) {
        self.allowed_extensions.set_allowed_extensions(allowed_extensions, &mut self.text_messages);
    }

    fn look_for_big_files(&mut self, rx: Option<&Receiver<()>>) -> bool {
        let start_time: SystemTime = SystemTime::now();
        let mut folders_to_check: Vec<PathBuf> = Vec::with_capacity(1024 * 2); // This should be small enough too not see to big difference and big enough to store most of paths without needing to resize vector

        // Add root folders for finding
        for id in &self.directories.included_directories {
            folders_to_check.push(id.clone());
        }
        self.information.number_of_checked_folders += folders_to_check.len();

        while !folders_to_check.is_empty() {
            if rx.is_some() && rx.unwrap().try_recv().is_ok() {
                return false;
            }
            let current_folder = folders_to_check.pop().unwrap();
            let read_dir = match fs::read_dir(&current_folder) {
                Ok(t) => t,
                Err(_) => {
                    self.text_messages.warnings.push(format!("Cannot open dir {}", current_folder.display()));
                    continue;
                } // Permissions denied
            };
            'dir: for entry in read_dir {
                let entry_data = match entry {
                    Ok(t) => t,
                    Err(_) => {
                        self.text_messages.warnings.push(format!("Cannot read entry in dir {}", current_folder.display()));
                        continue;
                    } //Permissions denied
                };
                let metadata: Metadata = match entry_data.metadata() {
                    Ok(t) => t,
                    Err(_) => {
                        self.text_messages.warnings.push(format!("Cannot read metadata in dir {}", current_folder.display()));
                        continue;
                    } //Permissions denied
                };
                if metadata.is_dir() {
                    self.information.number_of_checked_folders += 1;

                    if !self.recursive_search {
                        continue;
                    }

                    let next_folder = current_folder.join(entry_data.file_name());
                    if self.directories.is_excluded(&next_folder) || self.excluded_items.is_excluded(&next_folder) {
                        continue 'dir;
                    }

                    folders_to_check.push(next_folder);
                } else if metadata.is_file() {
                    // Extracting file extension
                    let file_extension = entry_data.path().extension().and_then(OsStr::to_str).map(str::to_lowercase);

                    // Checking allowed extensions
                    if !self.allowed_extensions.file_extensions.is_empty() {
                        let allowed = self.allowed_extensions.file_extensions.iter().map(|e| e.to_lowercase()).any(|e| file_extension == Some(e));
                        if !allowed {
                            // Not an allowed extension, ignore it.
                            self.information.number_of_ignored_files += 1;
                            continue 'dir;
                        }
                    }

                    // Checking expressions
                    let current_file_name = current_folder.join(entry_data.file_name());
                    if self.excluded_items.is_excluded(&current_file_name) {
                        continue 'dir;
                    }

                    // Creating new file entry
                    let fe: FileEntry = FileEntry {
                        path: current_file_name.clone(),
                        size: metadata.len(),
                        modified_date: match metadata.modified() {
                            Ok(t) => match t.duration_since(UNIX_EPOCH) {
                                Ok(d) => d.as_secs(),
                                Err(_) => {
                                    self.text_messages.warnings.push(format!("File {} seems to be modified before Unix Epoch.", current_file_name.display()));
                                    0
                                }
                            },
                            Err(_) => {
                                self.text_messages.warnings.push(format!("Unable to get modification date from file {}", current_file_name.display()));
                                continue;
                            } // Permissions Denied
                        },
                    };

                    self.big_files.entry(metadata.len()).or_insert_with(Vec::new);
                    self.big_files.get_mut(&metadata.len()).unwrap().push(fe);

                    self.information.number_of_checked_files += 1;
                } else {
                    // Probably this is symbolic links so we are free to ignore this
                    self.information.number_of_ignored_things += 1;
                }
            }
        }

        // Extract n biggest files to new TreeMap
        let mut new_map: BTreeMap<u64, Vec<FileEntry>> = Default::default();

        for (size, vector) in self.big_files.iter().rev() {
            if self.information.number_of_real_files < self.number_of_files_to_check {
                for file in vector {
                    if self.information.number_of_real_files < self.number_of_files_to_check {
                        new_map.entry(*size).or_insert_with(Vec::new);
                        new_map.get_mut(size).unwrap().push(file.clone());
                        self.information.taken_space += size;
                        self.information.number_of_real_files += 1;
                    } else {
                        break;
                    }
                }
            } else {
                break;
            }
        }
        self.big_files = new_map;

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

    pub fn set_number_of_files_to_check(&mut self, number_of_files_to_check: usize) {
        self.number_of_files_to_check = number_of_files_to_check;
    }

    /// Setting excluded items which needs to contains * wildcard
    /// Are a lot of slower than absolute path, so it should be used to heavy
    pub fn set_excluded_items(&mut self, excluded_items: String) {
        self.excluded_items.set_excluded_items(excluded_items, &mut self.text_messages);
    }

    /// Remove unused entries when included or excluded overlaps with each other or are duplicated etc.
    fn optimize_directories(&mut self) {
        self.directories.optimize_directories(self.recursive_search, &mut self.text_messages);
    }

    /// Setting included directories, at least one must be provided
    pub fn set_included_directory(&mut self, included_directory: String) {
        self.directories.set_included_directory(included_directory, &mut self.text_messages);
    }

    /// Setting absolute path to exclude
    pub fn set_excluded_directory(&mut self, excluded_directory: String) {
        self.directories.set_excluded_directory(excluded_directory, &mut self.text_messages);
    }
}

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

impl DebugPrint for BigFile {
    #[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!("Number of checked files - {}", self.information.number_of_checked_files);
        println!("Number of checked folders - {}", self.information.number_of_checked_folders);
        println!("Number of ignored files - {}", self.information.number_of_ignored_files);
        println!("Number of ignored things(like symbolic links) - {}", self.information.number_of_ignored_things);

        println!("### Other");
        println!("Big files size {} in {} groups", self.information.number_of_real_files, self.big_files.len());
        println!("Allowed extensions - {:?}", self.allowed_extensions.file_extensions);
        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.to_string());
        println!("Number of files to check - {:?}", self.number_of_files_to_check);
        println!("-----------------------------------------");
    }
}

impl SaveResults for BigFile {
    /// Saving results to provided file
    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 mut file = match File::create(&file_name) {
            Ok(t) => t,
            Err(_) => {
                self.text_messages.errors.push("Failed to create file ".to_string() + file_name.as_str());
                return false;
            }
        };

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

        if self.information.number_of_real_files != 0 {
            write!(file, "{} the biggest files.\n\n", self.information.number_of_real_files).unwrap();

            for (size, files) in self.big_files.iter().rev() {
                for file_entry in files {
                    writeln!(file, "{} ({}) - {}", size.file_size(options::BINARY).unwrap(), size, file_entry.path.display()).unwrap();
                }
            }
        } else {
            write!(file, "Not found any empty folders.").unwrap();
        }
        Common::print_time(start_time, SystemTime::now(), "save_results_to_file".to_string());
        true
    }
}

impl PrintResults for BigFile {
    fn print_results(&self) {
        let start_time: SystemTime = SystemTime::now();
        println!("Found {} files which take {}:", self.information.number_of_real_files, self.information.taken_space.file_size(options::BINARY).unwrap());
        for (size, vector) in self.big_files.iter().rev() {
            // TODO Align all to same width
            for entry in vector {
                println!("{} ({} bytes) - {}", size.file_size(options::BINARY).unwrap(), size, entry.path.display());
            }
        }
        Common::print_time(start_time, SystemTime::now(), "print_entries".to_string());
    }
}