//
// imag - the personal information management suite for the commandline
// Copyright (C) 2015, 2016 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
//

use std::fmt::{Debug, Formatter, Error as FmtError};
use std::result::Result as RResult;

use libimagstore::store::Store;
use libimagstore::store::FileLockEntry;
use libimagstore::storeid::StoreIdIterator;
use libimagerror::trace::trace_error;

use diaryid::DiaryId;
use diaryid::FromStoreId;
use is_in_diary::IsInDiary;
use error::DiaryErrorKind as DEK;
use error::DiaryError as DE;
use error::ResultExt;
use error::Result;

/// A iterator for iterating over diary entries
pub struct DiaryEntryIterator<'a> {
    store: &'a Store,
    name: String,
    iter: StoreIdIterator,

    year: Option<i32>,
    month: Option<u32>,
    day: Option<u32>,
}

impl<'a> Debug for DiaryEntryIterator<'a> {

    fn fmt(&self, fmt: &mut Formatter) -> RResult<(), FmtError> {
        write!(fmt, "DiaryEntryIterator<name = {}, year = {:?}, month = {:?}, day = {:?}>",
               self.name, self.year, self.month, self.day)
    }

}

impl<'a> DiaryEntryIterator<'a> {

    pub fn new(store: &'a Store, diaryname: String, iter: StoreIdIterator) -> DiaryEntryIterator<'a> {
        DiaryEntryIterator {
            store: store,
            name: diaryname,
            iter: iter,

            year: None,
            month: None,
            day: None,
        }
    }

    // Filter by year, get all diary entries for this year
    pub fn year(mut self, year: i32) -> DiaryEntryIterator<'a> {
        self.year = Some(year);
        self
    }

    // Filter by month, get all diary entries for this month (every year)
    pub fn month(mut self, month: u32) -> DiaryEntryIterator<'a> {
        self.month = Some(month);
        self
    }

    // Filter by day, get all diary entries for this day (every year, every year)
    pub fn day(mut self, day: u32) -> DiaryEntryIterator<'a> {
        self.day = Some(day);
        self
    }

}

impl<'a> Iterator for DiaryEntryIterator<'a> {
    type Item = Result<FileLockEntry<'a>>;

    fn next(&mut self) -> Option<Self::Item> {
        loop {
            let next = match self.iter.next() {
                Some(s) => s,
                None => return None,
            };
            debug!("Next element: {:?}", next);

            if next.is_in_diary(&self.name) {
                debug!("Seems to be in diary: {:?}", next);
                let id = match DiaryId::from_storeid(&next) {
                    Ok(i) => i,
                    Err(e) => {
                        trace_error(&e);
                        debug!("Couldn't parse {:?} into DiaryId: {:?}", next, e);
                        continue;
                    }
                };
                debug!("Success parsing id = {:?}", id);

                let y = match self.year  { None => true, Some(y) => y == id.year() };
                let m = match self.month { None => true, Some(m) => m == id.month() };
                let d = match self.day   { None => true, Some(d) => d == id.day() };

                if y && m && d {
                    debug!("Return = {:?}", id);
                    return Some(self
                                .store
                                .retrieve(next)
                                .chain_err(|| DEK::StoreReadError));
                }
            } else {
                debug!("Not in the requested diary ({}): {:?}", self.name, next);
            }
        }
    }

}


/// Get diary names.
///
/// # Warning
///
/// Does _not_ run a `unique` on the iterator!
pub struct DiaryNameIterator(StoreIdIterator);

impl DiaryNameIterator {
    pub fn new(s: StoreIdIterator) -> DiaryNameIterator {
        DiaryNameIterator(s)
    }
}

impl Iterator for DiaryNameIterator {
    type Item = Result<String>;

    fn next(&mut self) -> Option<Self::Item> {
        self.0
            .next()
            .map(|s| {
                s.to_str()
                    .chain_err(|| DEK::DiaryNameFindingError)
                    .and_then(|s| {
                        s.split("diary/")
                            .nth(1)
                            .and_then(|n| n.split("/").nth(0).map(String::from))
                            .ok_or(DE::from_kind(DEK::DiaryNameFindingError))
                    })
            })
    }

}