// bibiman - a TUI for managing BibLaTeX databases
// Copyright (C) 2024  lukeflo
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
/////

use super::app::App;
use super::tui::Tui;
use crate::backend::{bib::BibiData, search::BibiSearch};
use color_eyre::eyre::{Context, Ok, Result};
use core::panic;
use editor_command::EditorBuilder;
use ratatui::widgets::{ScrollbarState, TableState};
use std::process::{Command, Stdio};

#[derive(Debug)]
pub enum EntryTableColumn {
    Authors,
    Title,
    Year,
    Pubtype,
}

// Define list containing entries as table
#[derive(Debug)]
pub struct EntryTable {
    pub entry_table_items: Vec<EntryTableItem>,
    pub entry_table_at_search_start: Vec<EntryTableItem>,
    pub entry_table_selected_column: EntryTableColumn,
    pub entry_table_reversed_sort: bool,
    pub entry_table_state: TableState,
    pub entry_scroll_state: ScrollbarState,
    pub entry_info_scroll: u16,
    pub entry_info_scroll_state: ScrollbarState,
}

impl EntryTable {
    pub fn new(entry_list: Vec<BibiData>) -> Self {
        let entry_table_items = Self::set_entry_table(entry_list);
        let entry_table_state = TableState::default().with_selected(0);
        let entry_scroll_state = ScrollbarState::new(entry_table_items.len());
        let entry_info_scroll_state = ScrollbarState::default();
        Self {
            entry_table_items,
            entry_table_at_search_start: Vec::new(),
            entry_table_selected_column: EntryTableColumn::Authors,
            entry_table_reversed_sort: false,
            entry_table_state,
            entry_scroll_state,
            entry_info_scroll: 0,
            entry_info_scroll_state,
        }
    }

    pub fn set_entry_table(entry_list: Vec<BibiData>) -> Vec<EntryTableItem> {
        let mut entry_table: Vec<EntryTableItem> = entry_list
            .into_iter()
            .map(|e| EntryTableItem {
                authors: e.authors,
                short_author: String::new(),
                title: e.title,
                year: e.year,
                pubtype: e.pubtype,
                keywords: e.keywords,
                citekey: e.citekey,
                abstract_text: e.abstract_text,
                doi_url: e.doi_url,
                filepath: e.filepath,
            })
            .collect();

        entry_table.sort_by(|a, b| a.authors.to_lowercase().cmp(&b.authors.to_lowercase()));
        entry_table
    }

    // Sort entry table by specific column.
    // Toggle sorting by hitting same key again
    pub fn sort_entry_table(&mut self, toggle: bool) {
        if toggle {
            self.entry_table_reversed_sort = !self.entry_table_reversed_sort;
        }
        if self.entry_table_reversed_sort {
            match self.entry_table_selected_column {
                EntryTableColumn::Authors => self
                    .entry_table_items
                    .sort_by(|a, b| b.authors.to_lowercase().cmp(&a.authors.to_lowercase())),
                EntryTableColumn::Title => self
                    .entry_table_items
                    .sort_by(|a, b| b.title.to_lowercase().cmp(&a.title.to_lowercase())),
                EntryTableColumn::Year => self
                    .entry_table_items
                    .sort_by(|a, b| b.year.to_lowercase().cmp(&a.year.to_lowercase())),
                EntryTableColumn::Pubtype => self
                    .entry_table_items
                    .sort_by(|a, b| b.pubtype.to_lowercase().cmp(&a.pubtype.to_lowercase())),
            }
        } else if !self.entry_table_reversed_sort {
            match self.entry_table_selected_column {
                EntryTableColumn::Authors => self
                    .entry_table_items
                    .sort_by(|a, b| a.authors.to_lowercase().cmp(&b.authors.to_lowercase())),
                EntryTableColumn::Title => self
                    .entry_table_items
                    .sort_by(|a, b| a.title.to_lowercase().cmp(&b.title.to_lowercase())),
                EntryTableColumn::Year => self
                    .entry_table_items
                    .sort_by(|a, b| a.year.to_lowercase().cmp(&b.year.to_lowercase())),
                EntryTableColumn::Pubtype => self
                    .entry_table_items
                    .sort_by(|a, b| a.pubtype.to_lowercase().cmp(&b.pubtype.to_lowercase())),
            }
        }
    }
}

// Define contents of each entry table row
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub struct EntryTableItem {
    pub authors: String,
    pub short_author: String,
    pub title: String,
    pub year: String,
    pub pubtype: String,
    pub keywords: String,
    pub citekey: String,
    pub abstract_text: String,
    pub doi_url: String,
    pub filepath: String,
}

impl EntryTableItem {
    // This functions decides which fields are rendered in the entry table
    // Fields which should be usable but not visible can be left out
    pub fn ref_vec(&mut self) -> Vec<&str> {
        self.short_author = match self.authors.split_once(",") {
            Some((first, _rest)) => {
                if self.authors.contains("(ed.)") {
                    let first_author = format!("{} et al. (ed.)", first);
                    first_author
                } else {
                    let first_author = format!("{} et al.", first);
                    first_author
                }
            }
            None => String::from(""),
        };

        vec![
            {
                if self.short_author.is_empty() {
                    &self.authors
                } else {
                    &self.short_author
                }
            },
            &self.title,
            &self.year,
            &self.pubtype,
        ]
    }

    pub fn authors(&self) -> &str {
        &self.authors
    }

    pub fn title(&self) -> &str {
        &self.title
    }

    pub fn year(&self) -> &str {
        &self.year
    }

    pub fn pubtype(&self) -> &str {
        &self.pubtype
    }

    pub fn citekey(&self) -> &str {
        &self.citekey
    }

    pub fn doi_url(&self) -> &str {
        &self.doi_url
    }

    pub fn filepath(&self) -> &str {
        &self.filepath
    }
}

impl App {
    // Entry Table commands

    // Movement
    pub fn select_next_entry(&mut self, entries: u16) {
        self.entry_table.entry_info_scroll = 0;
        self.entry_table.entry_info_scroll_state =
            self.entry_table.entry_info_scroll_state.position(0);
        self.entry_table.entry_table_state.scroll_down_by(entries);
        self.entry_table.entry_scroll_state = self
            .entry_table
            .entry_scroll_state
            .position(self.entry_table.entry_table_state.selected().unwrap());
    }

    pub fn select_previous_entry(&mut self, entries: u16) {
        self.entry_table.entry_info_scroll = 0;
        self.entry_table.entry_info_scroll_state =
            self.entry_table.entry_info_scroll_state.position(0);
        self.entry_table.entry_table_state.scroll_up_by(entries);
        self.entry_table.entry_scroll_state = self
            .entry_table
            .entry_scroll_state
            .position(self.entry_table.entry_table_state.selected().unwrap());
    }

    pub fn select_first_entry(&mut self) {
        self.entry_table.entry_info_scroll = 0;
        self.entry_table.entry_info_scroll_state =
            self.entry_table.entry_info_scroll_state.position(0);
        self.entry_table.entry_table_state.select_first();
        self.entry_table.entry_scroll_state = self.entry_table.entry_scroll_state.position(0);
    }

    pub fn select_last_entry(&mut self) {
        self.entry_table.entry_info_scroll = 0;
        self.entry_table.entry_info_scroll_state =
            self.entry_table.entry_info_scroll_state.position(0);
        self.entry_table.entry_table_state.select_last();
        self.entry_table.entry_scroll_state = self
            .entry_table
            .entry_scroll_state
            .position(self.entry_table.entry_table_items.len());
    }

    pub fn select_next_column(&mut self) {
        match self.entry_table.entry_table_selected_column {
            EntryTableColumn::Authors => {
                self.entry_table.entry_table_selected_column = EntryTableColumn::Title;
                self.entry_table.sort_entry_table(false);
            }
            EntryTableColumn::Title => {
                self.entry_table.entry_table_selected_column = EntryTableColumn::Year;
                self.entry_table.sort_entry_table(false);
            }
            EntryTableColumn::Year => {
                self.entry_table.entry_table_selected_column = EntryTableColumn::Pubtype;
                self.entry_table.sort_entry_table(false);
            }
            EntryTableColumn::Pubtype => {
                self.entry_table.entry_table_selected_column = EntryTableColumn::Authors;
                self.entry_table.sort_entry_table(false);
            }
        }
    }

    pub fn select_prev_column(&mut self) {
        match self.entry_table.entry_table_selected_column {
            EntryTableColumn::Authors => {
                self.entry_table.entry_table_selected_column = EntryTableColumn::Pubtype;
                self.entry_table.sort_entry_table(false);
            }
            EntryTableColumn::Title => {
                self.entry_table.entry_table_selected_column = EntryTableColumn::Authors;
                self.entry_table.sort_entry_table(false);
            }
            EntryTableColumn::Year => {
                self.entry_table.entry_table_selected_column = EntryTableColumn::Title;
                self.entry_table.sort_entry_table(false);
            }
            EntryTableColumn::Pubtype => {
                self.entry_table.entry_table_selected_column = EntryTableColumn::Year;
                self.entry_table.sort_entry_table(false);
            }
        }
    }

    // Get the citekey of the selected entry
    pub fn get_selected_citekey(&self) -> &str {
        let idx = self.entry_table.entry_table_state.selected().unwrap();
        let citekey = &self.entry_table.entry_table_items[idx].citekey;
        citekey
    }

    pub fn run_editor(&mut self, tui: &mut Tui) -> Result<()> {
        // get filecontent and citekey for calculating line number
        let citekey = self.get_selected_citekey();
        // create independent copy of citekey for finding entry after updating list
        let saved_key = citekey.to_owned();
        let filepath = self.main_biblio.bibfile.display().to_string();
        let filecontent = self.main_biblio.bibfilestring.clone();
        let mut line_count = 0;

        for line in filecontent.lines() {
            line_count = line_count + 1;
            // if reaching the citekey break the loop
            // if reaching end of lines without match, reset to 0
            if line.contains(&citekey) {
                break;
            } else if line_count == filecontent.len() {
                eprintln!(
                    "Citekey {} not found, opening file {} at line 1",
                    &citekey, &filepath
                );
                line_count = 0;
                break;
            }
        }

        // Exit TUI to enter editor
        tui.exit()?;
        // Use VISUAL or EDITOR. Set "vi" as last fallback
        let mut cmd: Command = EditorBuilder::new()
            .environment()
            .source(Some("vi"))
            .build()
            .unwrap();
        // Prepare arguments to open file at specific line
        let args: Vec<String> = vec![format!("+{}", line_count), filepath];
        let status = cmd.args(&args).status()?;
        if !status.success() {
            eprintln!("Spawning editor failed with status {}", status);
        }

        // Enter TUI again
        tui.enter()?;
        tui.terminal.clear()?;

        // Update the database and the lists to show changes
        self.update_lists();

        // Search for entry, selected before editing, by matching citekeys
        // Use earlier saved copy of citekey to match
        let mut idx_count = 0;
        loop {
            if self.entry_table.entry_table_items[idx_count]
                .citekey
                .contains(&saved_key)
            {
                break;
            }
            idx_count = idx_count + 1
        }

        // Set selected entry to vec-index of match
        self.entry_table.entry_table_state.select(Some(idx_count));

        Ok(())
    }

    // Search entry list
    pub fn search_entries(&mut self) {
        // Use snapshot of entry list saved when starting the search
        // so deleting a char, will show former entries too
        let orig_list = self.entry_table.entry_table_at_search_start.clone();
        let filtered_list =
            BibiSearch::search_entry_list(&mut self.search_struct.search_string, orig_list.clone());
        self.entry_table.entry_table_items = filtered_list;
        if self.entry_table.entry_table_reversed_sort {
            self.entry_table.sort_entry_table(false);
        }
        self.entry_table.entry_scroll_state = ScrollbarState::content_length(
            self.entry_table.entry_scroll_state,
            self.entry_table.entry_table_items.len(),
        );
    }

    // Open file connected with entry through 'file' or 'pdf' field
    pub fn open_connected_file(&mut self) -> Result<()> {
        let idx = self.entry_table.entry_table_state.selected().unwrap();
        let filepath = &self.entry_table.entry_table_items[idx].filepath.clone();

        // Build command to execute pdf-reader. 'xdg-open' is Linux standard
        let cmd = {
            match std::env::consts::OS {
                "linux" => String::from("xdg-open"),
                "macos" => String::from("open"),
                "windows" => String::from("start"),
                _ => panic!("Couldn't detect OS for setting correct opener"),
            }
        };

        // Pass filepath as argument, pipe stdout and stderr to /dev/null
        // to keep the TUI clean (where is it piped on Windows???)
        let _ = Command::new(&cmd)
            .arg(&filepath)
            .stdout(Stdio::null())
            .stderr(Stdio::null())
            .spawn()
            .wrap_err("Opening file not possible");

        Ok(())
    }

    pub fn open_doi_url(&mut self) -> Result<()> {
        let idx = self.entry_table.entry_table_state.selected().unwrap();
        let web_adress = self.entry_table.entry_table_items[idx].doi_url.clone();

        // Resolve strings using the resolving function of dx.doi.org, so the
        // terminal is not blocked by the resolving process
        let url = if web_adress.starts_with("10.") {
            let prefix = "https://doi.org/".to_string();
            prefix + &web_adress
        } else if web_adress.starts_with("www.") {
            let prefix = "https://".to_string();
            prefix + &web_adress
        } else {
            web_adress
        };

        // Build command to execute browser. 'xdg-open' is Linux standard
        let cmd = {
            match std::env::consts::OS {
                "linux" => String::from("xdg-open"),
                "macos" => String::from("open"),
                "windows" => String::from("start"),
                _ => panic!("Couldn't detect OS for setting correct opener"),
            }
        };

        // Pass filepath as argument, pipe stdout and stderr to /dev/null
        // to keep the TUI clean (where is it piped on Windows???)
        let _ = Command::new(&cmd)
            .arg(url)
            .stdout(Stdio::null())
            .stderr(Stdio::null())
            .spawn()
            .wrap_err("Opening file not possible");

        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::EntryTableItem;

    #[test]
    fn check_os() {
        let os = std::env::consts::OS;
        assert_eq!(
            os,
            "linux",
            "You're not coding on linux, but on {}... Switch to linux, now!",
            std::env::consts::OS
        )
    }

    #[test]
    fn shorten_authors() {
        let mut entry: EntryTableItem = EntryTableItem {
            authors: "Miller, Schmitz, Bernard".to_string(),
            short_author: "".to_string(),
            title: "A title".to_string(),
            year: "2000".to_string(),
            pubtype: "article".to_string(),
            keywords: "key1, key2".to_string(),
            citekey: "miller_2000".to_string(),
            abstract_text: "An abstract".to_string(),
            doi_url: "www.text.org".to_string(),
            filepath: "/home/test".to_string(),
        };

        let entry_vec = EntryTableItem::ref_vec(&mut entry);

        let mut entry_editors: EntryTableItem = EntryTableItem {
            authors: "Miller, Schmitz, Bernard (ed.)".to_string(),
            short_author: "".to_string(),
            title: "A title".to_string(),
            year: "2000".to_string(),
            pubtype: "article".to_string(),
            keywords: "key1, key2".to_string(),
            citekey: "miller_2000".to_string(),
            abstract_text: "An abstract".to_string(),
            doi_url: "www.text.org".to_string(),
            filepath: "/home/test".to_string(),
        };

        let entry_vec_editors = EntryTableItem::ref_vec(&mut entry_editors);

        assert_eq!(
            entry_vec,
            vec!["Miller et al.", "A title", "2000", "article"]
        );
        assert_eq!(
            entry_vec_editors,
            vec!["Miller et al. (ed.)", "A title", "2000", "article"]
        )
    }
}