package Dakkar::TweetArchive::Store;
use 5.024;
use Moo;
use experimental 'signatures';
use DBI;
use Types::Standard qw(Str InstanceOf);
use DateTime::Format::Strptime;
use DateTime::Format::Pg;
use JSON::MaybeXS;
use namespace::clean;

use Data::Printer;

has [qw(dsn user pass)] => (
    is => 'ro',
    required => 1,
    isa => Str,
);

has dbh => (
    is => 'lazy',
    isa => InstanceOf['DBI::db'],
);

sub _build_dbh($self) {
    my $dbh = DBI->connect(
        $self->dsn, $self->user, $self->pass,
        {
            PrintError => 0,
            AutoCommit => 1,
            RaiseError => 1,
        },
    );
    $self->_ensure_schema($dbh);
    return $dbh;
}

my $dt_parser = DateTime::Format::Strptime->new(pattern => '%a %b %d %T %z %Y');
my $dt_printer = DateTime::Format::Pg->new();

my $json_printer = JSON::MaybeXS->new(
    ascii => 1,
    pretty => 0,
    allow_nonref => 1,
    allow_unknown => 1,
    allow_blessed => 1,
    convert_blessed => 1,
);

sub latest_tweet_id($self) {
    return $self->dbh->selectall_arrayref(
        q{SELECT MAX(id) FROM tweets},
    )->[0][0];
}

sub store_tweet($self,$tweet) {
    # yes, the source most probably decoded this from a string, we
    # have to serialise it again, so that PostgreSQL can parse it
    # *again*
    my $tweet_str = $json_printer->encode($tweet);
    my $created_at = $dt_parser->parse_datetime($tweet->{created_at});

    $self->dbh->do(<<'SQL', {},
INSERT INTO tweets(id,created_at,data) VALUES(?,?,?)
 ON CONFLICT (id) DO UPDATE SET
   created_at = EXCLUDED.created_at,
   data = EXCLUDED.data
SQL
                   $tweet->{id_str},
                   $dt_printer->format_datetime($created_at),
                   $tweet_str,
               );
}

sub store_friends($self,$friends) {
    my $friends_str = $json_printer->encode($friends);

    $self->dbh->do(<<'SQL', {}, $friends_str);
INSERT INTO friends(users) VALUES(?)
SQL
}

sub store_followers($self,$followers) {
    my $followers_str = $json_printer->encode($followers);

    $self->dbh->do(<<'SQL', {}, $followers_str);
INSERT INTO followers(users) VALUES(?)
SQL
}

sub _schema_deploy($self,$dbh,$next_version) {
    my $method_name = "_schema_deploy_${next_version}";
    if (my $method = $self->can($method_name)) {
        $self->$method($dbh);
        $dbh->do(<<'SQL', {}, $next_version);
INSERT INTO meta(version) VALUES (?)
SQL
        return 1;
    }
    else {
        return 0;
    }
}

sub _ensure_schema($self,$dbh) {
    # simple-minded schema version management
    {
        # silence the 'NOTICE:  relation "meta" already exists, skipping'
        local $dbh->{PrintWarn} = 0;
        $dbh->do(<<'SQL');
CREATE TABLE IF NOT EXISTS meta (
  version INTEGER PRIMARY KEY,
  created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
)
SQL
    }
    my $current_version = $dbh->selectall_arrayref(
        q{SELECT max(version) FROM meta}
    )->[0][0];
    $current_version //= 0;

    my $next_version = $current_version + 1;
    while ($self->_schema_deploy($dbh,$next_version)) {
        ++$next_version;
    }
}

sub _schema_deploy_1($self,$dbh) {
    $dbh->do(<<'SQL');
CREATE TABLE tweets (
  id VARCHAR(255) PRIMARY KEY,
  created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
  data JSONB NOT NULL
)
SQL
}

sub _schema_deploy_2($self,$dbh) {
    $dbh->do(<<'SQL');
CREATE TABLE followers (
  taken_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP PRIMARY KEY,
  users JSONB NOT NULL
)
SQL
    $dbh->do(<<'SQL');
CREATE TABLE friends (
  taken_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP PRIMARY KEY,
  users JSONB NOT NULL
)
SQL
}

1;