// This file is part of Moonfire NVR, a security camera digital video recorder.
// Copyright (C) 2018 Scott Lamb <slamb@slamb.org>
//
// 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.
//
// In addition, as a special exception, the copyright holders give
// permission to link the code of portions of this program with the
// OpenSSL library under certain conditions as described in each
// individual source file, and distribute linked combinations including
// the two.
//
// You must obey the GNU General Public License in all respects for all
// of the code used other than OpenSSL. If you modify file(s) with this
// exception, you may extend this exception to your version of the
// file(s), but you are not obligated to do so. If you do not wish to do
// so, delete this exception statement from your version. If you delete
// this exception statement from all source files in the program, then
// also delete it here.
//
// 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 <http://www.gnu.org/licenses/>.

/// Upgrades a version 1 schema to a version 2 schema.

use db::schema::DirMeta;
use db::dir;
use failure::Error;
use std::fs;
use rusqlite;
use uuid::Uuid;

pub struct U<'a> {
    sample_file_path: &'a str,
    dir_meta: Option<DirMeta>,
}

pub fn new<'a>(args: &'a super::Args) -> Result<Box<super::Upgrader + 'a>, Error> {
    let sample_file_path =
        args.flag_sample_file_dir
            .as_ref()
            .ok_or_else(|| format_err!("--sample-file-dir required when upgrading from \
                                        schema version 1 to 2."))?;
    Ok(Box::new(U { sample_file_path, dir_meta: None }))
}

impl<'a> U<'a> {
    /// Ensures there are sample files in the directory for all listed recordings.
    /// Among other problems, this catches a fat-fingered `--sample-file-dir`.
    fn verify_sample_files(&self, tx: &rusqlite::Transaction) -> Result<(), Error> {
        // Build a hash of the uuids found in sample_file_path. Ignore other files.
        let n: i64 = tx.query_row("select count(*) from recording", &[], |r| r.get_checked(0))??;
        let mut files = ::fnv::FnvHashSet::with_capacity_and_hasher(n as usize, Default::default());
        for e in fs::read_dir(self.sample_file_path)? {
            let e = e?;
            let f = e.file_name();
            let s = match f.to_str() {
                Some(s) => s,
                None => continue,
            };
            let uuid = match Uuid::parse_str(s) {
                Ok(u) => u,
                Err(_) => continue,
            };
            if s != uuid.hyphenated().to_string() {  // non-canonical form.
                continue;
            }
            files.insert(uuid);
        }

        // Iterate through the database and check that everything has a matching file.
        let mut stmt = tx.prepare(r"select sample_file_uuid from recording_playback")?;
        let mut rows = stmt.query(&[])?;
        while let Some(row) = rows.next() {
            let row = row?;
            let uuid: ::db::FromSqlUuid = row.get_checked(0)?;
            if !files.contains(&uuid.0) {
                bail!("{} is missing from dir {}!", uuid.0, self.sample_file_path);
            }
        }
        Ok(())
    }
}

impl<'a> super::Upgrader for U<'a> {
    fn in_tx(&mut self, tx: &rusqlite::Transaction) -> Result<(), Error> {
        self.verify_sample_files(tx)?;

        // These create statements match the schema.sql when version 2 was the latest.
        tx.execute_batch(r#"
            create table meta (
              uuid blob not null check (length(uuid) = 16)
            );
            create table open (
              id integer primary key,
              uuid blob unique not null check (length(uuid) = 16)
            );
            create table sample_file_dir (
              id integer primary key,
              path text unique not null,
              uuid blob unique not null check (length(uuid) = 16),
              last_complete_open_id integer references open (id)
            );
        "#)?;
        let db_uuid = ::uuid::Uuid::new_v4();
        let db_uuid_bytes = &db_uuid.as_bytes()[..];
        tx.execute("insert into meta (uuid) values (?)", &[&db_uuid_bytes])?;
        let open_uuid = ::uuid::Uuid::new_v4();
        let open_uuid_bytes = &open_uuid.as_bytes()[..];
        tx.execute("insert into open (uuid) values (?)", &[&open_uuid_bytes])?;
        let open_id = tx.last_insert_rowid() as u32;
        let dir_uuid = ::uuid::Uuid::new_v4();
        let dir_uuid_bytes = &dir_uuid.as_bytes()[..];

        let mut meta = DirMeta::default();
        {
            meta.db_uuid.extend_from_slice(db_uuid_bytes);
            meta.dir_uuid.extend_from_slice(dir_uuid_bytes);
            let open = meta.mut_in_progress_open();
            open.id = open_id;
            open.uuid.extend_from_slice(&open_uuid_bytes);
        }

        tx.execute(r#"
            insert into sample_file_dir (path,  uuid, last_complete_open_id)
                                 values (?,     ?,    ?)
        "#, &[&self.sample_file_path, &dir_uuid_bytes, &open_id])?;
        self.dir_meta = Some(meta);

        tx.execute_batch(r#"
            drop table reserved_sample_files;
            alter table camera rename to old_camera;
            alter table recording rename to old_recording;
            alter table video_sample_entry rename to old_video_sample_entry;
            drop index recording_cover;

            create table camera (
              id integer primary key,
              uuid blob unique not null check (length(uuid) = 16),
              short_name text not null,
              description text,
              host text,
              username text,
              password text
            );

            create table stream (
              id integer primary key,
              camera_id integer not null references camera (id),
              sample_file_dir_id integer references sample_file_dir (id),
              type text not null check (type in ('main', 'sub')),
              record integer not null check (record in (1, 0)),
              rtsp_path text not null,
              retain_bytes integer not null check (retain_bytes >= 0),
              flush_if_sec integer not null,
              next_recording_id integer not null check (next_recording_id >= 0),
              unique (camera_id, type)
            );

            create table recording (
              composite_id integer primary key,
              stream_id integer not null references stream (id),
              open_id integer not null,
              run_offset integer not null,
              flags integer not null,
              sample_file_bytes integer not null check (sample_file_bytes > 0),
              start_time_90k integer not null check (start_time_90k > 0),
              duration_90k integer not null
                  check (duration_90k >= 0 and duration_90k < 5*60*90000),
              local_time_delta_90k integer not null,
              video_samples integer not null check (video_samples > 0),
              video_sync_samples integer not null check (video_sync_samples > 0),
              video_sample_entry_id integer references video_sample_entry (id),
              check (composite_id >> 32 = stream_id)
            );

            create index recording_cover on recording (
              stream_id,
              start_time_90k,
              open_id,
              duration_90k,
              video_samples,
              video_sync_samples,
              video_sample_entry_id,
              sample_file_bytes,
              run_offset,
              flags
            );

            create table video_sample_entry (
              id integer primary key,
              sha1 blob unique not null check (length(sha1) = 20),
              width integer not null check (width > 0),
              height integer not null check (height > 0),
              rfc6381_codec text not null,
              data blob not null check (length(data) > 86)
            );

            create table garbage (
              sample_file_dir_id integer references sample_file_dir (id),
              composite_id integer,
              primary key (sample_file_dir_id, composite_id)
            ) without rowid;

            insert into camera
            select
              id,
              uuid,
              short_name,
              description,
              host,
              username,
              password
            from old_camera;

            -- Insert main streams using the same id as the camera, to ease changing recordings.
            insert into stream
            select
              old_camera.id,
              old_camera.id,
              sample_file_dir.id,
              'main',
              1,
              old_camera.main_rtsp_path,
              old_camera.retain_bytes,
              0,
              old_camera.next_recording_id
            from
              old_camera cross join sample_file_dir;

            -- Insert sub stream (if path is non-empty) using any id.
            insert into stream (camera_id, sample_file_dir_id, type, record, rtsp_path,
                                retain_bytes, flush_if_sec, next_recording_id)
            select
              old_camera.id,
              sample_file_dir.id,
              'sub',
              0,
              old_camera.sub_rtsp_path,
              0,
              90,
              1
            from
              old_camera cross join sample_file_dir
            where
              old_camera.sub_rtsp_path != '';

            insert into recording
            select
              r.composite_id,
              r.camera_id,
              o.open_id,
              r.run_offset,
              r.flags,
              r.sample_file_bytes,
              r.start_time_90k,
              r.duration_90k,
              r.local_time_delta_90k,
              r.video_samples,
              r.video_sync_samples,
              r.video_sample_entry_id
            from
              old_recording r cross join open o;
        "#)?;

        fix_video_sample_entry(tx)?;

        tx.execute_batch(r#"
            drop table old_camera;
            drop table old_recording;
            drop table old_video_sample_entry;
        "#)?;

        Ok(())
    }

    fn post_tx(&mut self) -> Result<(), Error> {
        let mut meta = self.dir_meta.take().unwrap();
        let d = dir::SampleFileDir::create(self.sample_file_path, &meta)?;
        ::std::mem::swap(&mut meta.last_complete_open, &mut meta.in_progress_open);
        d.write_meta(&meta)?;
        Ok(())
    }
}

fn fix_video_sample_entry(tx: &rusqlite::Transaction) -> Result<(), Error> {
    let mut select = tx.prepare(r#"
        select
          id,
          sha1,
          width,
          height,
          data
        from
          old_video_sample_entry
    "#)?;
    let mut insert = tx.prepare(r#"
        insert into video_sample_entry values (:id, :sha1, :width, :height, :rfc6381_codec, :data)
    "#)?;
    let mut rows = select.query(&[])?;
    while let Some(row) = rows.next() {
        let row = row?;
        let data: Vec<u8> = row.get_checked(4)?;
        insert.execute_named(&[
            (":id", &row.get_checked::<_, i32>(0)?),
            (":sha1", &row.get_checked::<_, Vec<u8>>(1)?),
            (":width", &row.get_checked::<_, i32>(2)?),
            (":height", &row.get_checked::<_, i32>(3)?),
            (":rfc6381_codec", &rfc6381_codec_from_sample_entry(&data)?),
            (":data", &data),
        ])?;
    }
    Ok(())
}

// This previously lived in h264.rs. As of version 1, H.264 is the only supported codec.
fn rfc6381_codec_from_sample_entry(sample_entry: &[u8]) -> Result<String, Error> {
    if sample_entry.len() < 99 || &sample_entry[4..8] != b"avc1" ||
       &sample_entry[90..94] != b"avcC" {
        bail!("not a valid AVCSampleEntry");
    }
    let profile_idc = sample_entry[103];
    let constraint_flags_byte = sample_entry[104];
    let level_idc = sample_entry[105];
    Ok(format!("avc1.{:02x}{:02x}{:02x}", profile_idc, constraint_flags_byte, level_idc))
}