package PAGI::FastAPI::Context;

use v5.36;
use version;

our $VERSION   = qv('v0.0.1');
our $AUTHORITY = 'cpan:MANWAR';

=encoding utf-8

=head1 NAME

PAGI::FastAPI::Context - Request and Response Lifecycle Context for PAGI::FastAPI

=head1 VERSION

Version v0.0.1

=head1 SYNOPSIS

    # Inspecting Request Parameters
    my $user_id = $c->path_param('id');
    my $limit   = $c->query_param('limit');
    my $name    = $c->body('name');

    # Generic Parameter Fallback (Path -> Query -> Body)
    my $token   = $c->param('token');

    # Headers & Scope
    my $ua      = $c->header('User-Agent');
    my $scope   = $c->scope;

    # Stash Storage
    $c->stash->{user} = { id => 42, role => 'admin' };

    # Modifying Response State
    $c->status(201);
    $c->set_header('X-Custom-Header' => 'value');

=head1 DESCRIPTION

C<PAGI::FastAPI::Context> encapsulates the request environment, parsed parameters,
payload data, and response state for an individual HTTP exchange processed
by L<PAGI::FastAPI>.

An instance of this context is passed as the primary argument to route handlers,
middleware functions, and dependency blocks.

=head1 METHODS

=head2 C<new(%args)>

Constructor called internally by L<PAGI::FastAPI>. Accepts:

=over 4

=item * C<scope> - PAGI environment HashRef.

=item * C<query_params> - HashRef of validated query parameters.

=item * C<path_params> - HashRef of route path variables.

=item * C<body> - Decoded payload body (HashRef, ArrayRef, or Scalar).

=item * C<status> - Initial HTTP response code (default: C<200>).

=item * C<res_headers> - Initial response headers ArrayRef (default: C<[]>).

=item * C<stash> - Context-bound storage HashRef (default: C<{}>).

=back

=cut

sub new ($class, %args) {
    return bless {
        scope        => $args{scope}        // {},
        query_params => $args{query_params} // {},
        path_params  => $args{path_params}  // {},
        body         => $args{body},
        status       => $args{status}       // 200,
        res_headers  => $args{res_headers}  // [],
        stash        => $args{stash}        // {},
    }, $class;
}

=head2 C<scope()>

Returns the raw PAGI scope HashRef for the current request.

=cut

sub scope ($self) { $self->{scope} }

=head2 C<status([ $code ])>

Gets or sets the HTTP status code for the response.

    $c->status(403);
    my $code = $c->status; # 403

=cut

sub status ($self, $val = undef) {
    if (defined $val) {
        $self->{status} = $val;
    }
    return $self->{status};
}

=head2 C<res_headers()>

Returns the current list of outgoing response header pairs as an ArrayRef of
tuple pairs C<[ [$name, $val], ... ]>.

=cut

sub res_headers ($self) { $self->{res_headers} }

=head2 C<set_header($key, $val)>

Appends an outgoing HTTP header pair to the response headers list.

    $c->set_header('X-Frame-Options' => 'DENY');

=cut

sub set_header ($self, $key, $val) {
    push @{$self->{res_headers}}, [$key, $val];
}

=head2 C<header($name)>

Case-insensitively searches incoming request headers (from C<< $c->scope->{headers} >>)
and returns its scalar value, or C<undef> if missing.

    my $auth = $c->header('Authorization');

=cut

sub header ($self, $name) {
    my $headers = $self->{scope}{headers} // [];
    my $lc_name = lc($name);
    for my $h (@$headers) {
        return $h->[1] if lc($h->[0]) eq $lc_name;
    }
    return undef;
}

=head2 C<path_params()>

Returns the HashRef containing all parsed path parameters.

=cut

sub path_params ($self) { $self->{path_params} }

=head2 C<path_param($key)>

Returns a specific parsed path parameter by name, or C<undef> if absent.

=cut

sub path_param ($self, $name) {
    return $self->{path_params}{$name};
}

=head2 C<query_params()>

Returns the HashRef containing all parsed query parameters.

=cut

sub query_params ($self) { $self->{query_params} }

=head2 C<query_param($key)>

Returns a specific parsed query parameter by name, or C<undef> if absent.

=cut

sub query_param ($self, $name) {
    return $self->{query_params}{$name};
}

=head2 C<body([ $key ])>

If called without parameters, returns the full raw/decoded request body.

If called with a C<$key> parameter and the body is a HashRef, returns the
value for that key, or C<undef> if missing or if the body is not a HashRef.

    my $full_body = $c->body;
    my $user_name = $c->body('username');

=cut

sub body ($self, $key = undef) {
    if (defined $key) {
        return (ref $self->{body} eq 'HASH') ? $self->{body}{$key} : undef;
    }
    return $self->{body};
}

=head2 C<param($key)>

Convenience parameter accessor that checks parameter stores in priority order:

1. Path parameters (C<path_param>)
2. Query parameters (C<query_param>)
3. JSON/Body fields (C<body($key)>)

Returns the first matching non-undef value, or C<undef> if the key is not
present in any store.

=cut

# General parameter lookup (checks path -> query -> body in order)
sub param ($self, $key) {
    return $self->path_param($key)
        // $self->query_param($key)
        // $self->body($key);
}

=head2 C<stash()>

Returns a HashRef tied to the lifecycle of this context. Useful for sharing
data between middleware, dependency injection blocks, and final route
handlers.

    $c->stash->{db_session} = $db;

=cut

sub stash ($self) { $self->{stash} }

=head1 AUTHOR

Mohammad Sajid Anwar, C<< <mohammad.anwar at yahoo.com> >>

=head1 REPOSITORY

L<https://github.com/manwar/PAGI-FastAPI>

=head1 BUGS

Please report any bugs or feature requests through the web interface at L<https://github.com/manwar/PAGI-FastAPI/issues>.
I will be notified and then you'll automatically be notified of progress on your
bug as I make changes.

=head1 SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc PAGI::FastAPI::Context

You can also look for information at:

=over 4

=item * BUG Report

L<https://github.com/manwar/PAGI-FastAPI/issues>

=item * CPAN Ratings

L<http://cpanratings.perl.org/d/PAGI-FastAPI>

=item * Search MetaCPAN

L<https://metacpan.org/dist/PAGI-FastAPI/>

=back

=head1 LICENSE AND COPYRIGHT

Copyright (C) 2026 Mohammad Sajid Anwar.

This program is free software; you can redistribute it and/or modify it under
the terms of the Artistic License (2.0). You may obtain a copy of the full
license at:

L<http://www.perlfoundation.org/artistic_license_2_0>

Any use, modification, and distribution of the Standard or Modified Versions is
governed by this Artistic License. By using, modifying or distributing the Package,
you accept this license. Do not use, modify, or distribute the Package, if you do
not accept this license.

If your Modified Version has been derived from a Modified Version made by someone
other than you, you are nevertheless required to ensure that your Modified Version
complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark,
tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license
to make, have made, use, offer to sell, sell, import and otherwise transfer the
Package with respect to any patent claims licensable by the Copyright Holder that
are necessarily infringed by the Package. If you institute patent litigation
(including a cross-claim or counterclaim) against any party alleging that the
Package constitutes direct or contributory patent infringement, then this Artistic
License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND
CONTRIBUTORS "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS
REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE
OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=cut

1; # End of PAGI::FastAPI::Context
