use crate::bibliography::bibliography_dict::BibliographyDictionary;
use crate::bibliography::bibliography_entry::{BibliographyEntry, BibliographyEntryReference};
use crate::bibliography::keys::K_KEY;
use crate::bibliography::FromHashMap;
use crate::references::anchor::BibListAnchor;
use parking_lot::Mutex;
use std::collections::HashMap;
use std::io;
use std::io::BufRead;
use std::iter::FromIterator;
use std::sync::Arc;
use toml::Value;

/// The root manager for that should be used for further reference operations that
/// go beyond insertion.
#[derive(Clone, Debug)]
pub struct BibManager {
    root_ref_anchor: Arc<Mutex<BibListAnchor>>,
    entry_dictionary: Arc<Mutex<BibliographyDictionary>>,
}

impl BibManager {
    /// Creates a new BibRefManager with an empty root anchor
    pub fn new() -> Self {
        Self {
            root_ref_anchor: Arc::new(Mutex::new(BibListAnchor::new())),
            entry_dictionary: Arc::new(Mutex::new(BibliographyDictionary::new())),
        }
    }

    /// Returns the BibRefManagers root anchor that.
    pub fn root_ref_anchor(&self) -> Arc<Mutex<BibListAnchor>> {
        Arc::clone(&self.root_ref_anchor)
    }

    /// Creates a new child BibManager with a child anchor and the parents entry dict
    pub fn create_child(&self) -> BibManager {
        let anchor = self.root_ref_anchor.lock().create_anchor();
        let entry_dict = Arc::clone(&self.entry_dictionary);

        Self {
            entry_dictionary: entry_dict,
            root_ref_anchor: anchor,
        }
    }

    /// Returns the reference to the entry dictionary
    pub fn entry_dictionary(&self) -> Arc<Mutex<BibliographyDictionary>> {
        Arc::clone(&self.entry_dictionary)
    }

    /// Assigns the corresponding bib entry to each bib reference
    pub fn assign_entries_to_references(&self) {
        let entry_dict = self.entry_dictionary.lock();
        let mut root_anchor = self.root_ref_anchor.lock();
        root_anchor.flatten();
        let entries = root_anchor.references();
        entries.iter().for_each(|e| {
            if let Some(bib) = entry_dict.get(e.key()) {
                e.anchor().lock().entry = Some(bib)
            }
        })
    }

    /// Returns the list of bibliography entries ordered by first referenced
    pub fn get_entry_list_by_occurrence(&self) -> Vec<BibliographyEntryReference> {
        let mut entries = Vec::new();
        let mut inserted_keys = Vec::new();
        let entry_dict = self.entry_dictionary.lock();

        for bib_ref in self.root_ref_anchor.lock().references() {
            if let Some(bib_entry) = entry_dict.get(bib_ref.key()) {
                if !inserted_keys.contains(bib_ref.key()) {
                    entries.push(bib_entry);
                    inserted_keys.push(bib_ref.key().clone())
                }
            }
        }

        entries
    }

    /// Reads a toml bibliography file and inserts each entry into the dictionary
    pub fn read_bib_file(&self, reader: &mut impl BufRead) -> io::Result<()> {
        let mut contents = String::new();
        reader.read_to_string(&mut contents)?;
        let bib_content = contents.parse::<Value>()?;
        let mut entry_dict = self.entry_dictionary.lock();

        if let Some(table) = bib_content.as_table() {
            let mut entries = table
                .iter()
                .filter_map(|(k, v)| {
                    let entry_iter = v
                        .as_table()?
                        .iter()
                        .filter_map(|(k, v)| Some((k.clone(), v.as_str()?.to_string())));

                    let mut entry_map: HashMap<String, String> = HashMap::from_iter(entry_iter);

                    entry_map.insert(K_KEY.to_string(), k.clone());

                    Some(*BibliographyEntry::from_hash_map(&entry_map).ok()?)
                })
                .collect::<Vec<BibliographyEntry>>();

            while let Some(entry) = entries.pop() {
                entry_dict.insert(entry)
            }
        }

        Ok(())
    }
}