package Mnemosyne::Telegram;
use strict;
use warnings;
use Mojo::UserAgent;
use Mojo::JSON qw(encode_json);
use Carp qw(croak);

use constant API_BASE      => 'https://api.telegram.org/bot';
use constant TITLE_TRUNCATE => 24;

# new($class, $token) — create client
sub new {
    my ($class, $token) = @_;
    croak "token required" unless $token;
    return bless {
        _token => $token,
        _ua    => Mojo::UserAgent->new,
    }, $class;
}

# -----------------------------------------------------------------------
# Core API calls
# -----------------------------------------------------------------------

# send_message($self, $chat_id, $text, %opts) → response hashref
# opts: parse_mode, reply_markup, disable_notification
sub send_message {
    my ($self, $chat_id, $text, %opts) = @_;
    return $self->_post('sendMessage', {
        chat_id    => $chat_id,
        text       => $text,
        parse_mode => $opts{parse_mode} // 'HTML',
        defined $opts{reply_markup}         ? (reply_markup         => $opts{reply_markup})         : (),
        defined $opts{disable_notification} ? (disable_notification => $opts{disable_notification}) : (),
    });
}

# edit_message($self, $chat_id, $message_id, $text, %opts) → response hashref
sub edit_message {
    my ($self, $chat_id, $message_id, $text, %opts) = @_;
    return $self->_post('editMessageText', {
        chat_id    => $chat_id,
        message_id => $message_id,
        text       => $text,
        parse_mode => $opts{parse_mode} // 'HTML',
        defined $opts{reply_markup} ? (reply_markup => $opts{reply_markup}) : (),
    });
}

# edit_reply_markup($self, $chat_id, $message_id, $reply_markup) → response hashref
# Pass undef to remove the keyboard entirely.
sub edit_reply_markup {
    my ($self, $chat_id, $message_id, $reply_markup) = @_;
    return $self->_post('editMessageReplyMarkup', {
        chat_id      => $chat_id,
        message_id   => $message_id,
        reply_markup => $reply_markup // {},
    });
}

# answer_callback_query($self, $callback_query_id, %opts)
# opts: text (notification text), show_alert (bool)
sub answer_callback_query {
    my ($self, $cbq_id, %opts) = @_;
    return $self->_post('answerCallbackQuery', {
        callback_query_id => $cbq_id,
        defined $opts{text}       ? (text       => $opts{text})                  : (),
        defined $opts{show_alert} ? (show_alert => $opts{show_alert} ? \1 : \0)  : (),
    });
}

# set_webhook($self, $url, $secret) → response hashref
sub set_webhook {
    my ($self, $url, $secret) = @_;
    croak "url required"    unless $url;
    croak "secret required" unless $secret;
    return $self->_post('setWebhook', {
        url             => $url,
        secret_token    => $secret,
        allowed_updates => ['message', 'callback_query'],
    });
}

# delete_webhook($self) → response hashref
sub delete_webhook {
    my ($self) = @_;
    return $self->_post('deleteWebhook', { drop_pending_updates => \1 });
}

# -----------------------------------------------------------------------
# Keyboard factories — all return inline_keyboard hashrefs
# -----------------------------------------------------------------------

# mark_done_keyboard(\@tasks) → reply_markup hashref
# Each $task: { id => ..., title => ... }
# One button per task: "✓ <truncated title>",  callback: done:<id>
sub mark_done_keyboard {
    my ($class, $tasks) = @_;
    my @rows = map {
        [{ text => "\x{2713} " . _trunc($_->{title}), callback_data => "done:$_->{id}" }]
    } @$tasks;
    return { inline_keyboard => \@rows };
}

# undo_keyboard($completion_id) → reply_markup hashref
sub undo_keyboard {
    my ($class, $cid) = @_;
    return { inline_keyboard => [[
        { text => "\x{21A9} Undo", callback_data => "undo:$cid" }
    ]]};
}

# confirm_delete_keyboard($task_id) → reply_markup hashref
sub confirm_delete_keyboard {
    my ($class, $task_id) = @_;
    return { inline_keyboard => [[
        { text => "\x{274C} Delete", callback_data => "confirm_delete:$task_id" },
        { text => "\x{2716} Cancel", callback_data => "cancel"                  },
    ]]};
}

# class_keyboard() → reply_markup
sub class_keyboard {
    my ($class) = @_;
    return { inline_keyboard => [
        [{ text => 'Monthly date',             callback_data => 'add_class:monthly_date'    }],
        [{ text => 'Monthly weekday',          callback_data => 'add_class:monthly_weekday' }],
        [{ text => 'Every N period',           callback_data => 'add_class:every_n_period'  }],
        [{ text => 'Interval (reset on done)', callback_data => 'add_class:interval'        }],
        [{ text => 'Floating reminder',        callback_data => 'add_class:floating'        }],
        [{ text => "\x{2716} Cancel",          callback_data => 'add_cancel'                }],
    ]};
}

# weekday_keyboard() → reply_markup
sub weekday_keyboard {
    my ($class) = @_;
    my @days = (['Mon','1'],['Tue','2'],['Wed','3'],['Thu','4'],
                ['Fri','5'],['Sat','6'],['Sun','7']);
    my @row  = map { { text => $_->[0], callback_data => "add_weekday:$_->[1]" } } @days;
    return { inline_keyboard => [
        \@row,
        [{ text => "\x{2716} Cancel", callback_data => 'add_cancel' }],
    ]};
}

# ordinal_keyboard() → reply_markup
sub ordinal_keyboard {
    my ($class) = @_;
    return { inline_keyboard => [
        [map { { text => "${_}.", callback_data => "add_ordinal:$_" } } 1..4],
        [{ text => 'Last',           callback_data => 'add_ordinal:-1' },
         { text => "\x{2716} Cancel", callback_data => 'add_cancel'   }],
    ]};
}

# period_unit_keyboard() → reply_markup
sub period_unit_keyboard {
    my ($class) = @_;
    return { inline_keyboard => [[
        { text => 'Day',   callback_data => 'add_unit:day'   },
        { text => 'Week',  callback_data => 'add_unit:week'  },
        { text => 'Month', callback_data => 'add_unit:month' },
    ],[
        { text => "\x{2716} Cancel", callback_data => 'add_cancel' },
    ]]};
}

# priority_keyboard() → reply_markup
sub priority_keyboard {
    my ($class) = @_;
    return { inline_keyboard => [[
        { text => "\x{2605}\x{2605}\x{2605} High",   callback_data => 'add_priority:high'   },
        { text => "\x{2605}\x{2605} Medium",          callback_data => 'add_priority:medium' },
        { text => "\x{2605} Low",                     callback_data => 'add_priority:low'    },
    ],[
        { text => "\x{2716} Cancel", callback_data => 'add_cancel' },
    ]]};
}

# skip_keyboard() → reply_markup — "Skip" + "Cancel" for optional fields
sub skip_keyboard {
    my ($class) = @_;
    return { inline_keyboard => [[
        { text => 'Skip',            callback_data => 'add_skip'   },
        { text => "\x{2716} Cancel", callback_data => 'add_cancel' },
    ]]};
}

# save_cancel_keyboard() → reply_markup — final wizard confirmation
sub save_cancel_keyboard {
    my ($class) = @_;
    return { inline_keyboard => [[
        { text => "\x{2714} Save",   callback_data => 'add_save'   },
        { text => "\x{2716} Cancel", callback_data => 'add_cancel' },
    ]]};
}

# -----------------------------------------------------------------------
# Internal
# -----------------------------------------------------------------------

sub _post {
    my ($self, $method, $body) = @_;
    my $url = API_BASE . $self->{_token} . '/' . $method;
    my $tx  = $self->{_ua}->post(
        $url => { 'Content-Type' => 'application/json' } => encode_json($body)
    );
    my $res = eval { $tx->result };
    if ($@) {
        warn "Telegram connection error ($method): $@\n";
        return {};
    }
    unless ($res->is_success) {
        warn "Telegram API error ($method): " . $res->body . "\n";
    }
    return $res->json // {};
}

sub _trunc {
    my ($s) = @_;
    return length($s) <= TITLE_TRUNCATE
        ? $s
        : substr($s, 0, TITLE_TRUNCATE - 1) . "\x{2026}";
}

1;