<?php
/**
 * includes/build_slides.php
 *
 * build_slides(array $session): array
 *
 * Assembles the full slide sequence for a rosary session.
 * Applies variable substitution for {name}, {pronoun}, {pronoun_obj}, {pronoun_poss}.
 */

require_once __DIR__ . '/../data/prayers.php';

/**
 * Fetch ordered builder steps (with prayer text) for a custom session.
 */
function get_builder_steps(PDO $pdo, int $session_id): array {
    $st = $pdo->prepare("
        SELECT bs.step_type, bs.bead_type, bs.attribution,
               cp.name, cp.leader_text, cp.all_text
        FROM   builder_steps bs
        LEFT   JOIN custom_prayers cp ON cp.id = bs.prayer_id
        WHERE  bs.session_id = ?
        ORDER  BY bs.step_order ASC
    ");
    $st->execute([$session_id]);
    return $st->fetchAll();
}

/**
 * Returns the slide array for one decade of the Chaplet of Divine Mercy.
 *
 * Large bead : "Eternal Father…"
 * Small beads: "For the sake of His sorrowful Passion…" × 10
 * No mystery announcement; no Glory Be between decades.
 *
 * @param int $decade_num     1–5
 * @param int $of_bead_index  bead_index for the large (Our Father) bead
 * @param int $hm_bead_start  bead_index for the first small bead of this decade
 */
function build_chaplet_decade_slides(int $decade_num, int $of_bead_index, int $hm_bead_start): array {
    $slides = [];

    $slides[] = [
        'id'         => 'dm_eternal_father_d' . $decade_num,
        'type'       => 'prayer',
        'section'    => 'dm_chaplet_decade_' . $decade_num,
        'title'      => 'Eternal Father',
        'leader'     => "Eternal Father, I offer You the Body and Blood,\nSoul and Divinity of Your dearly beloved Son,\nOur Lord Jesus Christ,",
        'all'        => "in atonement for our sins and those of the whole world.",
        'bead'       => 'large',
        'bead_index' => $of_bead_index,
    ];

    for ($i = 0; $i < 10; $i++) {
        $slides[] = [
            'id'         => 'dm_for_sake_d' . $decade_num . '_' . ($i + 1),
            'type'       => 'prayer',
            'section'    => 'dm_chaplet_decade_' . $decade_num,
            'title'      => 'For the Sake of His Sorrowful Passion',
            'leader'     => 'For the sake of His sorrowful Passion,',
            'all'        => 'have mercy on us and on the whole world.',
            'bead'       => 'small',
            'bead_index' => $hm_bead_start + $i,
        ];
    }

    return $slides;
}

/**
 * Build the complete slide array for a session.
 *
 * @param array $session  Row from the sessions table (keys match column names)
 * @return array          Flat array of slide arrays
 */
function build_slides(array $session): array {
    global $opening, $mysteries, $hail_holy_queen, $rosary_closing_prayer,
           $litany_passion, $novena_prayers, $litany_departed, $closing,
           $divine_mercy_opening, $divine_mercy_novena_prayers,
           $divine_mercy_chaplet_opening, $divine_mercy_chaplet_close;

    $slides = [];

    // -----------------------------------------------------------------------
    // Custom builder session — build directly from builder_steps
    // -----------------------------------------------------------------------
    if ($session['occasion'] === 'custom') {
        $pdo   = get_pdo();
        $steps = get_builder_steps($pdo, (int)$session['id']);

        // Cover slide
        $cover_all = '';
        if (!empty($session['subject_name'])) {
            $cover_all = "For {$session['subject_name']}";
        }
        $slides[] = [
            'id'         => 'cover',
            'type'       => 'cover',
            'section'    => 'cover',
            'title'      => $session['name'],
            'leader'     => '',
            'all'        => $cover_all,
            'bead'       => null,
            'bead_index' => null,
            'photo_path' => $session['photo_path'] ?? null,
        ];

        $bead_idx = 0; // increments for each bead separator step
        foreach ($steps as $i => $step) {
            $type = $step['step_type'] ?? 'prayer';

            if ($type === 'bead') {
                $slides[] = [
                    'id'         => 'bead_' . $i,
                    'type'       => 'prayer',
                    'section'    => 'bead',
                    'title'      => '',
                    'leader'     => '',
                    'all'        => '',
                    'bead'       => $step['bead_type'] ?? 'small',
                    'bead_index' => $bead_idx++,
                ];
                continue;
            }

            $attr   = $step['attribution'] ?? 'leader_all';
            $leader = '';
            $all    = '';

            if ($attr === 'leader_all' || $attr === 'leader_only') {
                $leader = $step['leader_text'] ?? '';
            }
            if ($attr === 'leader_all' || $attr === 'all_only') {
                $all = $step['all_text'] ?? '';
            }
            if ($attr === 'none') {
                $leader = ($step['leader_text'] ?: $step['all_text']) ?? '';
            }

            $bead_type = $step['bead_type'] ?? null;
            $slides[] = [
                'id'         => 'custom_' . $i,
                'type'       => 'prayer',
                'section'    => $step['name'],
                'title'      => $step['name'],
                'leader'     => $leader,
                'all'        => $all,
                'bead'       => $bead_type,
                'bead_index' => $bead_type ? $bead_idx++ : null,
            ];
        }

        // Closing slide
        $slides[] = [
            'id'         => 'closing_custom',
            'type'       => 'closing',
            'section'    => 'closing',
            'title'      => '',
            'leader'     => '',
            'all'        => "May the souls of the faithful departed,\nthrough the mercy of God, rest in peace.",
            'bead'       => null,
            'bead_index' => null,
        ];

        // Apply variable substitution and return early
        $name    = $session['subject_name']    ?? '';
        $pronoun = $session['subject_pronoun'] ?? 'he';
        $dates   = $session['subject_dates']   ?? '';

        $pronoun_obj  = ($pronoun === 'she') ? 'her' : 'him';
        $pronoun_poss = ($pronoun === 'she') ? 'her' : 'his';

        $find    = ['{name}', '{pronoun}', '{pronoun_obj}', '{pronoun_poss}', '{subject_dates}'];
        $replace = [$name,    $pronoun,    $pronoun_obj,    $pronoun_poss,    $dates];

        foreach ($slides as &$slide) {
            $slide['title']  = str_replace($find, $replace, $slide['title']  ?? '');
            $slide['leader'] = str_replace($find, $replace, $slide['leader'] ?? '');
            $slide['all']    = str_replace($find, $replace, $slide['all']    ?? '');
        }
        unset($slide);

        return $slides;
    }

    // -----------------------------------------------------------------------
    // 1. Cover slide
    // -----------------------------------------------------------------------
    $cover_title = '';
    $cover_all   = '';

    switch ($session['occasion']) {
        case 'novena_deceased':
            $day = (int)($session['novena_day'] ?? 1);
            $cover_title = 'Nine-Day Novena Rosary';
            $cover_all   = "In Loving Memory of\n{name}\n{subject_dates}\n\nDay {$day} of 9";
            break;
        case 'memorial':
            $cover_title = 'Memorial Rosary';
            $cover_all   = "In Loving Memory of\n{name}\n{subject_dates}";
            break;
        case 'divine_mercy_novena':
            $day = (int)($session['novena_day'] ?? 1);
            $cover_title = 'Divine Mercy Novena';
            $cover_all   = "Chaplet of Divine Mercy\n\nDay {$day} of 9";
            break;
        case 'general_rosary':
        default:
            $cover_title = 'The Holy Rosary';
            $cover_all   = ucfirst($session['mystery_set']) . ' Mysteries';
            break;
    }

    $slides[] = [
        'id'         => 'cover',
        'type'       => 'cover',
        'section'    => 'cover',
        'title'      => $cover_title,
        'leader'     => '',
        'all'        => $cover_all,
        'bead'       => null,
        'bead_index' => null,
        'photo_path' => $session['photo_path'] ?? null,
    ];

    // -----------------------------------------------------------------------
    // 2. Opening prayers
    // -----------------------------------------------------------------------
    if ($session['occasion'] === 'divine_mercy_novena') {
        // Pre-chaplet devotion: opening prayer + O Blood and Water × 3
        foreach ($divine_mercy_opening as $slide) {
            $slides[] = $slide;
        }
        // Day-specific intention and prayer
        $day = (int)($session['novena_day'] ?? 1);
        if (isset($divine_mercy_novena_prayers[$day])) {
            foreach ($divine_mercy_novena_prayers[$day] as $slide) {
                $slides[] = $slide;
            }
        }
        // Chaplet opening on stem beads (Sign of Cross, Our Father, Hail Mary, Creed)
        foreach ($divine_mercy_chaplet_opening as $slide) {
            $slides[] = $slide;
        }
    } else {
        foreach ($opening as $slide) {
            $slides[] = $slide;
        }
    }

    // -----------------------------------------------------------------------
    // 3. Five decades
    //
    // Bead layout:
    //   Bead 0:      Crucifix  (Sign of Cross / Creed)
    //   Bead 1:      large     (Our Father, stem)
    //   Beads 2–4:   small     (3 Hail Marys / Creed for chaplet, stem)
    //   Bead 5:      large     (Our Father, Decade 1)
    //   Beads 6–15:  small     (Decade 1, 10 HMs / For the sake…)
    //   Bead 16:     large     (Our Father, Decade 2)
    //   Beads 17–26: small     (Decade 2)
    //   Bead 27:     large     (Our Father, Decade 3)
    //   Beads 28–37: small     (Decade 3)
    //   Bead 38:     large     (Our Father, Decade 4)
    //   Beads 39–48: small     (Decade 4)
    //   Bead 49:     large     (Our Father, Decade 5)
    //   Beads 50–59: small     (Decade 5)
    // -----------------------------------------------------------------------

    $decade_bead_map = [
        //  decade => [our_father_index, first_hm_index]
        1 => [5,  6],
        2 => [16, 17],
        3 => [27, 28],
        4 => [38, 39],
        5 => [49, 50],
    ];

    if ($session['occasion'] === 'divine_mercy_novena') {
        for ($d = 1; $d <= 5; $d++) {
            [$of_idx, $hm_idx] = $decade_bead_map[$d];
            foreach (build_chaplet_decade_slides($d, $of_idx, $hm_idx) as $slide) {
                $slides[] = $slide;
            }
        }
    } else {
        $mystery_set = $mysteries[$session['mystery_set']] ?? $mysteries['sorrowful'];

        for ($d = 1; $d <= 5; $d++) {
            [$of_idx, $hm_idx] = $decade_bead_map[$d];
            $mystery_slide = $mystery_set[$d - 1];

            $decade_slides = build_decade_slides($d, $mystery_slide, $of_idx, $hm_idx);
            foreach ($decade_slides as $slide) {
                $slides[] = $slide;
            }
        }
    }

    // -----------------------------------------------------------------------
    // 4. Post-decade prayers by occasion
    // -----------------------------------------------------------------------
    switch ($session['occasion']) {
        case 'novena_deceased':
            // Hail Holy Queen
            foreach ($hail_holy_queen as $slide) {
                $slides[] = $slide;
            }
            // Day-specific novena prayer
            $day = (int)($session['novena_day'] ?? 1);
            if (isset($novena_prayers[$day])) {
                $slides[] = $novena_prayers[$day];
            }
            // Litany of the Passion
            foreach ($litany_passion as $slide) {
                $slides[] = $slide;
            }
            // Litany for the Departed
            foreach ($litany_departed as $slide) {
                $slides[] = $slide;
            }
            break;

        case 'divine_mercy_novena':
            // Holy God, Holy Mighty One, Holy Immortal One × 3
            foreach ($divine_mercy_chaplet_close as $slide) {
                $slides[] = $slide;
            }
            break;

        case 'memorial':
        case 'general_rosary':
        default:
            foreach ($hail_holy_queen as $slide) {
                $slides[] = $slide;
            }
            $slides[] = $rosary_closing_prayer;
            break;
    }

    // -----------------------------------------------------------------------
    // 5. Closing slide — inject photo for personal occasions
    // -----------------------------------------------------------------------
    $occasion_key = $session['occasion'];
    if (!isset($closing[$occasion_key])) {
        $occasion_key = 'general_rosary';
    }
    $closing_slide = $closing[$occasion_key];
    if (in_array($occasion_key, ['novena_deceased', 'memorial'])) {
        $closing_slide['photo_path'] = $session['photo_path'] ?? null;
    }
    $slides[] = $closing_slide;

    // -----------------------------------------------------------------------
    // 6. Variable substitution
    // -----------------------------------------------------------------------
    $name    = $session['subject_name']    ?? '';
    $pronoun = $session['subject_pronoun'] ?? 'he'; // 'he' or 'she'
    $dates   = $session['subject_dates']   ?? '';

    $pronoun_obj  = ($pronoun === 'she') ? 'her'  : 'him';
    $pronoun_poss = ($pronoun === 'she') ? 'her'  : 'his';
    $pronoun_cap  = ucfirst($pronoun);

    $find    = ['{name}', '{pronoun}', '{pronoun_obj}', '{pronoun_poss}', '{subject_dates}'];
    $replace = [$name,    $pronoun,    $pronoun_obj,    $pronoun_poss,    $dates];

    foreach ($slides as &$slide) {
        $slide['title']  = str_replace($find, $replace, $slide['title']  ?? '');
        $slide['leader'] = str_replace($find, $replace, $slide['leader'] ?? '');
        $slide['all']    = str_replace($find, $replace, $slide['all']    ?? '');
        if (isset($slide['subtitle'])) {
            $slide['subtitle'] = str_replace($find, $replace, $slide['subtitle']);
        }
    }
    unset($slide);

    return $slides;
}