<?php

// api.php

header('Content-Type: application/json');

header('Access-Control-Allow-Origin: *');

header('Access-Control-Allow-Methods: POST, OPTIONS');

header('Access-Control-Allow-Headers: Content-Type');

// Handle preflight requests

if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {

    http_response_code(200);

    exit();

}

// Only allow POST requests

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {

    http_response_code(405);

    echo json_encode(['error' => 'Method not allowed. Use POST.']);

    exit();

}

// Include required files

require_once 'functions.php';

require_once 'parse_colors.php';

require_once 'process_form.php';

// Set timezone

date_default_timezone_set('America/Chicago');

$start_time = microtime(true);

try {

    // Get raw input

    $raw_input = file_get_contents('php://input');

    // Try to decode as JSON first

    $json_data = json_decode($raw_input, true);

    $colors = null;

    $contrast_method = 'wcag'; // Default method

    $format = 'auto'; // auto, text, json

    if ($json_data !== null && json_last_error() === JSON_ERROR_NONE) {

        // Handle JSON input

        if (isset($json_data['colors'])) {

            if (is_array($json_data['colors'])) {

                // Array of colors

                $colors = implode("\n", $json_data['colors']);

                $format = 'json';

            } else {

                // String with newlines

                $colors = $json_data['colors'];

                $format = 'text';

            }

        }

        if (isset($json_data['contrast_method'])) {

            $contrast_method = $json_data['contrast_method'];

        }

        if (isset($json_data['format'])) {

            $format = $json_data['format'];

        }

    } else {

        // Handle form data or plain text

        if (isset($_POST['colors'])) {

            $colors = $_POST['colors'];

            $format = 'form';

            if (isset($_POST['contrast_method'])) {

                $contrast_method = $_POST['contrast_method'];

            }

        } else {

            // Treat as plain text input

            $colors = $raw_input;

            $format = 'text';

        }

    }

    // Validate input

    if (empty($colors)) {

        http_response_code(400);

        echo json_encode([

            'error' => 'No colors provided',

            'message' => 'Please provide colors in the request body'

        ]);

        exit();

    }

    // Validate contrast method

    $valid_methods = ['wcag', 'apca', 'both'];

    if (!in_array($contrast_method, $valid_methods)) {

        http_response_code(400);

        echo json_encode([

            'error' => 'Invalid contrast method',

            'message' => 'Valid methods are: ' . implode(', ', $valid_methods)

        ]);

        exit();

    }

    // Process colors

    $result = processColorForm($colors);

    $parsed_colors = $result['parsed_colors'];

    if (empty($parsed_colors)) {

        http_response_code(400);

        echo json_encode([

            'error' => 'No valid colors found',

            'invalid_colors' => $result['invalid_colors'],

            'duplicate_colors' => $result['duplicate_colors']

        ]);

        exit();

    }

    // Generate contrast data

    $contrast_data = generateContrastData($parsed_colors, $contrast_method);

    // Calculate processing time

    $processing_time = microtime(true) - $start_time;

    // Build response

    $response = [

        'success' => true,

        'meta' => [

            'colors_processed' => count($parsed_colors),

            'contrast_method' => $contrast_method,

            'processing_time_seconds' => round($processing_time, 6),

            'input_format' => $format,

            'timestamp' => date('c')

        ],

        'colors' => array_keys($parsed_colors),

        'contrast_data' => $contrast_data

    ];

    // Add warnings if any

    $warnings = [];

    if (!empty($result['invalid_colors'])) {

        $warnings['invalid_colors'] = $result['invalid_colors'];

    }

    if (!empty($result['duplicate_colors'])) {

        $warnings['duplicate_colors'] = $result['duplicate_colors'];

    }

    if (!empty($result['semantic_duplicates'])) {

        $warnings['semantic_duplicates'] = $result['semantic_duplicates'];

    }

    if ($result['excess_colors']) {

        $warnings['excess_colors'] = 'Only first ' . MAX_COLORS . ' colors were processed';

    }

    if (!empty($warnings)) {

        $response['warnings'] = $warnings;

    }

    // Log usage

    $datetime = date('Y-m-d h:i:s A');

    $log_entry = $datetime . ", " . count($parsed_colors) . " colors, " . $contrast_method . " method, API" . PHP_EOL;

    file_put_contents('stats.txt', $log_entry, FILE_APPEND);

    echo json_encode($response, JSON_PRETTY_PRINT);

} catch (Exception $e) {

    http_response_code(500);

    echo json_encode([

        'error' => 'Internal server error',

        'message' => $e->getMessage()

    ]);

}

/**

 * Generate contrast data for all color combinations

 */

function generateContrastData($parsed_colors, $contrast_method) {

    $contrast_data = [];

    foreach ($parsed_colors as $bg_color => $bg_data) {

        $background_data = [

            'color' => $bg_color,

            'rgb' => $bg_data['rgb'],

            'alpha' => $bg_data['alpha'],

            'luminance' => $bg_data['luminance'],

            'combinations' => []

        ];

        foreach ($parsed_colors as $fg_color => $fg_data) {

            if ($fg_color === $bg_color) continue;

            $combination = [

                'foreground_color' => $fg_color,

                'foreground_rgb' => $fg_data['rgb'],

                'foreground_alpha' => $fg_data['alpha']

            ];

            if ($contrast_method === 'wcag') {

                $fg_lum = getLuminance($fg_data['rgb'], $fg_data['alpha'], $bg_data['rgb']);

                $contrast_ratio = getContrastRatio($bg_data['luminance'], $fg_lum);

                $wcag_level = getWCAGLevel($contrast_ratio);

                $combination['wcag'] = [

                    'contrast_ratio' => round($contrast_ratio, 2),

                    'level' => $wcag_level,

                    'passes_aa' => $contrast_ratio >= 4.5,

                    'passes_aa_large' => $contrast_ratio >= 3.0,

                    'passes_aaa' => $contrast_ratio >= 7.0

                ];

            } elseif ($contrast_method === 'apca') {

                $apca_contrast = getAPCAContrast($bg_data['rgb'], $fg_data['rgb'], $bg_data['alpha'], $fg_data['alpha']);

                $apca_level = getAPCALevel($apca_contrast);

                $combination['apca'] = [

                    'contrast_value' => round($apca_contrast, 1),

                    'level' => $apca_level,

                    'absolute_value' => round(abs($apca_contrast), 1)

                ];

            } else { // both

                // WCAG

                $fg_lum = getLuminance($fg_data['rgb'], $fg_data['alpha'], $bg_data['rgb']);

                $wcag_contrast = getContrastRatio($bg_data['luminance'], $fg_lum);

                $wcag_level = getWCAGLevel($wcag_contrast);

                // APCA

                $apca_contrast = getAPCAContrast($bg_data['rgb'], $fg_data['rgb'], $bg_data['alpha'], $fg_data['alpha']);

                $apca_level = getAPCALevel($apca_contrast);

                // Combined

                $combined_level = getCombinedLevel($wcag_contrast, $apca_contrast);

                $combination['wcag'] = [

                    'contrast_ratio' => round($wcag_contrast, 2),

                    'level' => $wcag_level,

                    'passes_aa' => $wcag_contrast >= 4.5,

                    'passes_aa_large' => $wcag_contrast >= 3.0,

                    'passes_aaa' => $wcag_contrast >= 7.0

                ];

                $combination['apca'] = [

                    'contrast_value' => round($apca_contrast, 1),

                    'level' => $apca_level,

                    'absolute_value' => round(abs($apca_contrast), 1)

                ];

                $combination['combined'] = [

                    'level' => $combined_level

                ];

            }

            $background_data['combinations'][] = $combination;

        }

        $contrast_data[] = $background_data;

    }

    return $contrast_data;

}

?>