<?php

if (!defined('ABSPATH')) {
    exit;
}

class AdGhost_CSV_Importer {

    const HEADERS = [
        'name'    => ['ad unit name', 'name', 'ad unit', 'ad unit display name'],
        'code'    => ['ad unit code', 'code', 'id', 'ad unit id code'],
        'sizes'   => ['sizes', 'size', 'size(s)', 'ad unit sizes', 'creative sizes'],
        'device'  => ['device'],
        'label'   => ['label', 'description'],
        'placement' => ['placement', 'placements', 'gam placement', 'slotname', 'slot name'],
        'status'  => ['status'],
    ];

    public static function parse($file_path) {
        if (!file_exists($file_path) || !is_readable($file_path)) {
            return new WP_Error('file_error', 'File not found or not readable');
        }
        $csv = file_get_contents($file_path); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- a local uploaded file, not a URL.
        if ($csv === false) {
            return new WP_Error('file_error', 'Could not open file');
        }
        return self::parse_string($csv);
    }

    public static function parse_string($csv) {
        $rows = [];
        foreach (self::csv_rows((string) $csv) as $row) {

            if (isset($row[0])) {
                $row[0] = preg_replace('/^\xEF\xBB\xBF/', '', (string) $row[0]);
            }
            if (count(array_filter($row, function ($c) { return trim((string) $c) !== ''; })) === 0) {
                continue;
            }
            $rows[] = array_map('trim', $row);
        }

        if (!$rows) {
            return new WP_Error('parse_error', 'Empty CSV file');
        }

        $map = null;
        foreach (array_slice($rows, 0, 10, true) as $i => $row) {
            $candidate = self::header_map($row);
            if (isset($candidate['sizes']) && (isset($candidate['name']) || isset($candidate['code']))) {
                $map  = $candidate;
                $rows = array_slice($rows, $i + 1);
                break;
            }
        }

        if ($map === null) {

            if (!preg_match('/^[A-Za-z0-9_.\-\/]+$/', $rows[0][0] ?? '')) {
                return new WP_Error('format_error', 'CSV format not recognized. Expected AdGhost rows (code,name,sizes,label,placement,target — as in ad-units-example.csv) or a Google Ad Manager export with Ad unit name, Ad unit code and Sizes columns.');
            }
            $map = ['code' => 0, 'name' => 1, 'sizes' => 2, 'label' => 3, 'placement' => 4];
        }

        $units = [];
        $seen  = [];
        foreach ($rows as $row) {
            $get = function ($field) use ($row, $map) {
                return isset($map[$field]) ? trim((string) ($row[$map[$field]] ?? '')) : '';
            };

            $name = $get('name');
            $code = AdGhost_Helper::sanitize_gam_code($get('code'));
            if ($name === '' && $code === '') {
                continue;
            }

            if (in_array(strtolower($get('status')), ['archived', 'inactive', 'deactivated'], true)) {
                continue;
            }

            if ($name === '') {
                $name = basename($code);
            }

            $name = trim(str_replace('_', ' ', $name));
            if ($code === '') {
                $code = AdGhost_Helper::generate_id($name);
            }
            if (isset($seen[$code])) {
                continue;
            }
            $seen[$code] = true;

            $sizes  = self::sizes($get('sizes'));
            $type   = 'standard';
            if ($sizes === 'out-of-page' || preg_match('/interstitial/i', $name . ' ' . $code)) {
                $type = preg_match('/reward/i', $name . ' ' . $code) ? 'reward' : 'interstitial';
            } elseif (preg_match('/reward/i', $name . ' ' . $code)) {
                $type = 'reward';
            }

            $device = strtolower($get('device'));
            $unit = [
                'id'            => $code,
                'name'          => sanitize_text_field($name),
                'sizes'         => sanitize_text_field($type === 'standard' ? ($sizes ?: '300x250') : ($type === 'interstitial' ? 'out-of-page' : '1x1')),
                'type'          => $type,
                'device'        => in_array($device, ['both', 'desktop', 'mobile'], true) ? $device : 'both',
                'placementMode' => 'auto',
                'isImported'    => true,
            ];
            $position = $type === 'standard' ? self::position_from($get('placement') . ' ' . $get('label')) : '';
            if ($position !== '') {
                $unit['position'] = $position;
            }
            foreach (['label' => 'label', 'placement' => 'gamPlacement'] as $field => $key) {
                if ($get($field) !== '') {
                    $unit[$key] = sanitize_text_field($get($field));
                }
            }
            $units[] = $unit;
        }

        if (!$units) {
            return new WP_Error('parse_error', 'The CSV has a header but no ad units.');
        }

        return $units;
    }

    public static function position_from($text) {
        $t = strtolower((string) $text);
        if ($t === '' || trim($t) === '') {
            return '';
        }

        $w = function ($words) {
            return '/(?<![a-z])(?:' . $words . ')(?![a-z])/';
        };
        $rules = [
            '/sticky[\s_-]*footer|anchor/'                  => 'anchor',
            '/in[\s_-]*(article|content)|incontent/'        => 'incontent',
            '/side[\s_-]*bar|skyscraper/'                   => 'sidebar',
            $w('rail')                                      => 'sidebar',
            '/leaderboard|header/'                          => 'header',
            '/pre[\s_-]*footer|footer/'                     => 'footer',
            $w('top|atf')                                   => 'header',
            $w('bottom|btf')                                => 'footer',
        ];
        foreach ($rules as $pattern => $position) {
            if (preg_match($pattern, $t)) {
                return $position;
            }
        }
        return '';
    }

    private static function header_map(array $row) {
        $map = [];
        foreach ($row as $index => $cell) {
            $cell = strtolower(trim(preg_replace('/^[#\s]+/', '', (string) $cell)));
            foreach (self::HEADERS as $field => $spellings) {
                if (!isset($map[$field]) && in_array($cell, $spellings, true)) {
                    $map[$field] = $index;
                }
            }
        }
        return $map;
    }

    public static function sizes($raw) {
        $raw = strtolower((string) $raw);
        if ($raw !== '' && preg_match('/out[\s_-]*of[\s_-]*page/', $raw) && !preg_match('/\d+\s*x\s*\d+/', $raw)) {
            return 'out-of-page';
        }
        preg_match_all('/(\d{1,4})\s*[x×]\s*(\d{1,4})|fluid/u', $raw, $m, PREG_SET_ORDER);
        $out = [];
        foreach ($m as $match) {
            $size = $match[0] === 'fluid' ? 'fluid' : $match[1] . 'x' . $match[2];
            $out[$size] = true;
        }
        return implode(';', array_keys($out));
    }

    private static function csv_rows($csv) {
        $rows  = [];
        $row   = [];
        $field = '';
        $quoted = false;
        $length = strlen($csv);
        for ($i = 0; $i < $length; $i++) {
            $char = $csv[$i];
            if ($quoted) {
                if ($char === '"') {
                    if ($i + 1 < $length && $csv[$i + 1] === '"') {
                        $field .= '"';
                        $i++;
                    } else {
                        $quoted = false;
                    }
                } else {
                    $field .= $char;
                }
                continue;
            }
            if ($char === '"') {
                $quoted = true;
            } elseif ($char === ',') {
                $row[] = $field;
                $field = '';
            } elseif ($char === "\n" || $char === "\r") {
                if ($char === "\r" && $i + 1 < $length && $csv[$i + 1] === "\n") {
                    $i++;
                }
                $row[]  = $field;
                $rows[] = $row;
                $row    = [];
                $field  = '';
            } else {
                $field .= $char;
            }
        }
        if ($field !== '' || $row) {
            $row[]  = $field;
            $rows[] = $row;
        }
        return $rows;
    }
}