#[macro_use]
extern crate log;
extern crate chrono;
extern crate env_logger;
extern crate image;
extern crate rexif;
extern crate rustc_serialize;
extern crate dotenv;
extern crate diesel;
extern crate rphotos;

use chrono::format::ParseError;
use chrono::naive::datetime::NaiveDateTime;
use rexif::{ExifData, ExifEntry, ExifTag, TagValue};
use std::path::Path;
use dotenv::dotenv;
use diesel::pg::PgConnection;
use self::diesel::prelude::*;
use rphotos::models::{Modification, Photo};

mod env;
use env::{dburl, photos_dir};
mod photosdir;
use photosdir::PhotosDir;


fn main() {
    dotenv().ok();
    env_logger::init().unwrap();
    let db = PgConnection::establish(&dburl())
                 .expect("Error connecting to database");
    let photos = PhotosDir::new(photos_dir());

    let args = std::env::args().skip(1);
    if args.len() > 0 {
        for a in args {
            do_find(&db, &photos, Path::new(&a));
        }
    } else {
        println!("No args");
    }
}

fn do_find(db: &PgConnection, photos: &PhotosDir, only_in: &Path) {
    photos.find_files(only_in,
                      &|path, exif| {
                          match save_photo(&db, path, &exif) {
                              Ok(()) => debug!("Saved photo {}", path),
                              Err(e) => {
                                  warn!("Failed to save photo {}: {:?}",
                                        path,
                                        e)
                              }
                          }
                      })
          .unwrap();
}

fn save_photo(db: &PgConnection,
              file_path: &str,
              exif: &ExifData)
              -> FindPhotoResult<()> {
    let photo = match try!(Photo::create_or_set_basics(db, file_path,
                                               Some(try!(find_date(&exif))),
                                               try!(find_rotation(&exif)))) {
        Modification::Created(photo) => {
            info!("Created {:?}", photo);
            photo
        }
        Modification::Updated(photo) => {
            info!("Modified {:?}", photo);
            photo
        }
        Modification::Unchanged(photo) => {
            debug!("No change for {:?}", photo);
            photo
        }
    };
    if let Some((lat, long)) = try!(find_position(&exif)) {
        debug!("Position for {} is {} {}", file_path, lat, long);
        use rphotos::schema::positions::dsl::*;
        if let Ok((pos, clat, clong)) =
               positions.filter(photo_id.eq(photo.id))
                        .select((id, latitude, longitude))
                        .first::<(i32, i32, i32)>(db) {
            if (clat != (lat * 1e6) as i32) || (clong != (long * 1e6) as i32) {
                panic!("TODO Should update position #{} from {} {} to {} {}",
                       pos, clat, clong, lat, long)
            }
        } else {
            info!("Position for {} is {} {}", file_path, lat, long);
            use rphotos::models::NewPosition;
            diesel::insert(&NewPosition {
                photo_id: photo.id,
                latitude: (lat * 1e6) as i32,
                longitude: (long * 1e6) as i32,
            })
                .into(positions)
                .execute(db)
                .expect("Insert image position");
        }
    }
    Ok(())
}

type FindPhotoResult<T> = Result<T, FindPhotoError>;

#[derive(Debug)]
enum FindPhotoError {
    DatabaseError(diesel::result::Error),
    ExifOfUnexpectedType(TagValue),
    ExifTagMissing(ExifTag),
    TimeFormat(ParseError),
    UnknownOrientation(u16),
    BadLatLong(TagValue),
}
impl From<diesel::result::Error> for FindPhotoError {
    fn from(err: diesel::result::Error) -> FindPhotoError {
        FindPhotoError::DatabaseError(err)
    }
}
impl From<ParseError> for FindPhotoError {
    fn from(err: ParseError) -> FindPhotoError {
        FindPhotoError::TimeFormat(err)
    }
}

fn find_rotation(exif: &ExifData) -> FindPhotoResult<i16> {
    if let Some(ref value) = find_entry(exif, &ExifTag::Orientation) {
        if let TagValue::U16(ref v) = value.value {
            let n = v[0];
            debug!("Raw orientation is {}", n);
            match n {
                1 => Ok(0),
                3 => Ok(180),
                6 => Ok(90),
                8 => Ok(270),
                x => Err(FindPhotoError::UnknownOrientation(x)),
            }
        } else {
            Err(FindPhotoError::ExifOfUnexpectedType(value.value.clone()))
        }
    } else {
        info!("Orientation tag missing, default to 0 degrees");
        Ok(0)
    }
}

fn find_date(exif: &ExifData) -> FindPhotoResult<NaiveDateTime> {
    find_entry(exif, &ExifTag::DateTimeOriginal)
        .or_else(|| find_entry(exif, &ExifTag::DateTime))
        .or_else(|| find_entry(exif, &ExifTag::DateTimeDigitized))
        .map(|value| {
            debug!("Found {:?}", value);
            if let TagValue::Ascii(ref str) = value.value {
                debug!("Try to parse {:?} (from {:?}) as datetime",
                       str, value.tag);
                Ok(try!(NaiveDateTime::parse_from_str(str, "%Y:%m:%d %T")))
            } else {
                Err(FindPhotoError::ExifOfUnexpectedType(value.value.clone()))
            }
        })
        .unwrap_or_else(|| {
            Err(FindPhotoError::ExifTagMissing(ExifTag::DateTimeOriginal))
        })
}

fn find_position(exif: &ExifData) -> FindPhotoResult<Option<(f64, f64)>> {
    if let Some(lat) = find_entry(exif, &ExifTag::GPSLatitude) {
        if let Some(long) = find_entry(exif, &ExifTag::GPSLongitude) {
            return Ok(Some((try!(rat2float(&lat.value)),
                            try!(rat2float(&long.value)))));
        }
    }
    Ok(None)
}

fn rat2float(val: &rexif::TagValue) -> FindPhotoResult<f64> {
    if let rexif::TagValue::URational(ref v) = *val {
        if v.len() == 3 {
            return Ok(v[0].value() +
                      (v[1].value() + v[2].value() / 60.0) / 60.0);
        }
    }
    Err(FindPhotoError::BadLatLong(val.clone()))
}

fn find_entry<'a>(exif: &'a ExifData, tag: &ExifTag) -> Option<&'a ExifEntry> {
    for entry in &exif.entries {
        if entry.tag == *tag {
            return Some(entry);
        }
    }
    None
}