//
// imag - the personal information management suite for the commandline
// Copyright (C) 2015-2020 Matthias Beyer <mail@beyermatthias.de> and contributors
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; version
// 2.1 of the License.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//

#![forbid(unsafe_code)]

#![deny(
    non_camel_case_types,
    non_snake_case,
    path_statements,
    trivial_numeric_casts,
    unstable_features,
    unused_allocation,
    unused_import_braces,
    unused_imports,
    unused_must_use,
    unused_mut,
    unused_qualifications,
    while_true,
)]

extern crate clap;
#[macro_use] extern crate log;
#[macro_use] extern crate failure;
extern crate toml_query;
extern crate resiter;
extern crate handlebars;

extern crate libimagrt;
extern crate libimagmail;
extern crate libimagerror;
extern crate libimagstore;
extern crate libimagutil;
extern crate libimagentryref;
extern crate libimaginteraction;

use std::io::Write;

use failure::Fallible as Result;
use failure::err_msg;
use clap::App;
use resiter::AndThen;
use resiter::IterInnerOkOrElse;
use resiter::Filter;
use resiter::Map;
use handlebars::Handlebars;

use libimagmail::store::MailStore;
use libimagmail::store::Sorting;
use libimagmail::mail::Mail;
use libimagmail::store::MailStoreWithConnection;
use libimagmail::mailtree::Mailtree;
use libimagmail::notmuch::connection::NotmuchConnection;
use libimagrt::runtime::Runtime;
use libimagrt::application::ImagApplication;
use libimagstore::iter::get::StoreIdGetIteratorExtension;
use libimagstore::store::FileLockEntry;

mod ui;
mod util;

/// Marker enum for implementing ImagApplication on
///
/// This is used by binaries crates to execute business logic
/// or to build a CLI completion.
pub enum ImagMail {}
impl ImagApplication for ImagMail {
    fn run(rt: Runtime) -> Result<()> {
        match rt.cli().subcommand_name().ok_or_else(|| err_msg("No subcommand called"))? {
            "import"   => import(&rt),
            "list"     => list(&rt),
            "print-id" => print_id(&rt),
            other      => {
                debug!("Unknown command");
                if rt.handle_unknown_subcommand("imag-mail", other, rt.cli())?.success() {
                    Ok(())
                } else {
                    Err(err_msg("Failed to handle unknown subcommand"))
                }
            },
        }
    }

    fn build_cli<'a>(app: App<'a, 'a>) -> App<'a, 'a> {
        ui::build_ui(app)
    }

    fn name() -> &'static str {
        env!("CARGO_PKG_NAME")
    }

    fn description() -> &'static str {
        "Mail collection tool"
    }

    fn version() -> &'static str {
        env!("CARGO_PKG_VERSION")
    }
}

fn import(rt: &Runtime) -> Result<()> {
    let scmd               = rt.cli().subcommand_matches("import").unwrap();
    let query              = scmd.value_of("query").unwrap();
    let store              = rt.store();
    let notmuch_path       = crate::util::get_notmuch_database_path(rt)?;
    let notmuch_connection = NotmuchConnection::open(notmuch_path)?;

    debug!("Importing mail with query = '{}'", query);

    let r = store
        .with_connection(&notmuch_connection)
        .import_with_query(query)?
        .into_iter()
        .map(|fle| rt.report_touched(fle.get_location()))
        .collect::<Result<Vec<_>>>()
        .map(|_| ());

    r
}

fn list(rt: &Runtime) -> Result<()> {
    debug!("Listing mail");
    let scmd               = rt.cli().subcommand_matches("list").unwrap();
    let store              = rt.store();
    let list_format        = util::get_mail_print_format("mail.list_format", rt, &scmd)?;
    debug!("List-format:  {:?}", list_format);

    let notmuch_path       = crate::util::get_notmuch_database_path(rt)?;
    debug!("notmuch path: {:?}", notmuch_path);

    let notmuch_connection = NotmuchConnection::open(notmuch_path)?;

    let tree               = scmd.is_present("tree");
    debug!("tree:         {}", tree);

    let find_root          = scmd.is_present("find-root");
    debug!("find_root:    {}", find_root);

    let mut out            = rt.stdout();
    let mut i              = 0;

    /// Helper function for processing a tree
    ///
    /// This function implements the normal-style printing functionality (without "--tree").
    fn process_nontree<'a, I>(iter: I,
                              i: &mut usize,
                              conn: &NotmuchConnection,
                              list_format: &Handlebars,
                              rt: &Runtime,
                              out: &mut dyn Write)
        -> Result<()>
        where I: Iterator<Item = Result<FileLockEntry<'a>>>
    {
        debug!("Processing non-tree");
        iter.and_then_ok(|fle| {
            trace!("Loading: {}", fle.get_location());
            let loaded = fle.load(&conn)?
                .ok_or_else(|| format_err!("Mail not found: {}", fle.get_location()))?;
            trace!("Loaded: {}", fle.get_location());

            let parsed = loaded.parsed()?;
            trace!("Parsed: {}", fle.get_location());

            let r = crate::util::list_mail(&parsed, *i, 0, list_format, out); // indentation hard coded to zero
            trace!("Listed: {}", fle.get_location());
            *i += 1; // poor mans enumerate()
            r.map(|_| fle)
        })
        .and_then_ok(|fle| rt.report_touched(fle.get_location()))
        .collect::<Result<Vec<_>>>()
        .map(|_| ())
    };

    /// Helper function for processing a tree
    ///
    /// This function implements the tree-style printing functionality ("--tree").
    fn process_tree<'a, I>(iter: I,
                           mailstore: &'a MailStoreWithConnection<'a>,
                           i: &mut usize,
                           conn: &NotmuchConnection,
                           list_format: &Handlebars,
                           rt: &Runtime,
                           out: &mut dyn Write,
                           find_root: bool)
        -> Result<()>
        where I: Iterator<Item = Result<FileLockEntry<'a>>>
    {
        debug!("Processing tree");
        let iter = if find_root {
            let iter = iter.and_then_ok(|fle| {
                trace!("Loading: {}", fle.get_location());
                let id = fle
                    .load(conn)?
                    .ok_or_else(|| format_err!("Cannot load mail: {}", fle.get_location()))?
                    .parsed()?
                    .root_parent(&mailstore)?
                    .ok_or_else(|| format_err!("Failed to find root parent: {}", fle.get_location()))
                    .map(|p| p.get_id().clone());

                drop(fle);
                id
            });

            Box::new(iter) as Box<dyn Iterator<Item = Result<String>>>
        } else {
            let iter = iter.and_then_ok(|fle| fle.get_cached_id());
            Box::new(iter) as Box<dyn Iterator<Item = Result<String>>>
        };

        trace!("Printing mailtrees now!");

        // we have to collect here, so that all FLEs are drop()ed
        iter.collect::<Result<Vec<String>>>()?
            .into_iter()
            .map(|id: String| mailstore.get_mailtree(&id))
            .and_then_ok(|mt| print_traverse(&mailstore, mt, i, conn, list_format, rt, out))
            .collect::<Result<Vec<_>>>()
            .map(|_| ())
    }

    if let Some(query) = scmd.value_of("query") {
        // Use notmuch to find mails

        debug!("Importing mail with query = '{}'", query);

        let mailstore = store.with_connection(&notmuch_connection);
        let iter = mailstore
            .build_query(query)
            .sorted(Sorting::OldestFirst)
            .execute()?
            .into_iter()
            .map(Ok);

        if tree {
            process_tree(iter, &mailstore, &mut i, &notmuch_connection, &list_format, rt, &mut out, find_root)
        } else {
            process_nontree(iter, &mut i, &notmuch_connection, &list_format, rt, &mut out)
        }
    } else {
        // use StoreIds to find mails
        let iter = rt.ids::<crate::ui::PathProvider>()?
            .ok_or_else(|| err_msg("No ids supplied"))?
            .into_iter()
            .map(Ok)
            .into_get_iter(rt.store())
            .map_inner_ok_or_else(|| err_msg("Did not find one entry"))
            .and_then_ok(|m| m.is_mail().map(|b| (b, m)))
            .filter_ok(|tpl| tpl.0)
            .map_ok(|tpl| tpl.1);

        if tree {
            let mailstore = store.with_connection(&notmuch_connection);
            process_tree(iter, &mailstore, &mut i, &notmuch_connection, &list_format, rt, &mut out, find_root)
        } else {
            process_nontree(iter, &mut i, &notmuch_connection, &list_format, rt, &mut out)
        }
    }
}

fn print_id(rt: &Runtime) -> Result<()> {
    rt.ids::<crate::ui::PathProvider>()?
        .ok_or_else(|| err_msg("No ids supplied"))?
        .into_iter()
        .map(Ok)
        .into_get_iter(rt.store())
        .map_inner_ok_or_else(|| err_msg("Did not find one entry"))
        .and_then_ok(|fle| {
            let id = fle.get_cached_id()?;
            writeln!(rt.stdout(), "{}", id)?;
            Ok(fle)
        })
        .and_then_ok(|fle| rt.report_touched(fle.get_location()))
        .collect::<Result<Vec<_>>>()
        .map(|_| ())
}

fn print_traverse<'a>(store: &'a MailStoreWithConnection<'a>,
                      tree: Mailtree,
                      i: &mut usize,
                      conn: &NotmuchConnection,
                      list_format: &Handlebars,
                      rt: &Runtime,
                      out: &mut dyn Write) -> Result<()> {
    trace!("Print-Traversing starting with: {:?}", tree.root());
    for (indent, mid) in tree.traverse() {
        let fle    = store.get_mail_by_id(&mid)?.ok_or_else(|| format_err!("Cannot find mail with id = {}", mid))?;
        trace!("Printing: {}", fle.get_location());

        let loaded = fle.load(&conn)?
            .ok_or_else(|| format_err!("Mail not found: {}", fle.get_location()))?;
        trace!("Loaded: {}", fle.get_location());

        let parsed = loaded.parsed()?;
        trace!("Parsed: {}", fle.get_location());

        crate::util::list_mail(&parsed, *i, indent, list_format, out)?;
        trace!("Listed: {}", fle.get_location());
        rt.report_touched(fle.get_location())?;
        *i += 1; // poor mans enumerate()
    }

    Ok(())
}