<?php
require_once __DIR__ . '/../helpers.php';
runAuth();

/**
 * Look up tax rate by ZIP code
 * Uses Zippopotam.us for city/state, then Claude API for exact rate.
 *
 * GET: ?zip=90001
 */

$response = ['OK' => false, 'taxRate' => 0, 'message' => '', 'city' => '', 'state' => ''];

try {
    // Load Claude API key
    $CLAUDE_API_KEY = '';
    $configPath = __DIR__ . '/../../config/claude.json';
    if (file_exists($configPath)) {
        $configData = json_decode(file_get_contents($configPath), true);
        $CLAUDE_API_KEY = $configData['apiKey'] ?? '';
    }

    // Get ZIP code
    $zipCode = trim($_GET['zip'] ?? $_POST['zip'] ?? '');

    // Validate ZIP format
    if (!preg_match('/^\d{5}(-\d{4})?$/', $zipCode)) {
        $response['message'] = 'Invalid ZIP code format';
        jsonResponse($response);
    }

    $zipCode = substr($zipCode, 0, 5);

    // Zippopotam.us lookup
    $ch = curl_init("https://api.zippopotam.us/us/$zipCode");
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT => 10,
    ]);
    $zipResult = curl_exec($ch);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    if ($httpCode !== 200) {
        $response['message'] = 'ZIP lookup failed';
        jsonResponse($response);
    }

    $zipData = json_decode($zipResult, true);
    if (empty($zipData['places'][0])) {
        $response['message'] = 'No location data for ZIP';
        jsonResponse($response);
    }

    $place = $zipData['places'][0];
    $cityName = $place['place name'] ?? '';
    $stateAbbr = strtoupper($place['state abbreviation'] ?? '');
    $response['city'] = $cityName;
    $response['state'] = $stateAbbr;

    // State base rates fallback
    $stateTaxRates = [
        'AL' => 4, 'AK' => 0, 'AZ' => 5.6, 'AR' => 6.5, 'CA' => 7.25,
        'CO' => 2.9, 'CT' => 6.35, 'DE' => 0, 'FL' => 6, 'GA' => 4,
        'HI' => 4, 'ID' => 6, 'IL' => 6.25, 'IN' => 7, 'IA' => 6,
        'KS' => 6.5, 'KY' => 6, 'LA' => 4.45, 'ME' => 5.5, 'MD' => 6,
        'MA' => 6.25, 'MI' => 6, 'MN' => 6.875, 'MS' => 7, 'MO' => 4.225,
        'MT' => 0, 'NE' => 5.5, 'NV' => 6.85, 'NH' => 0, 'NJ' => 6.625,
        'NM' => 4.875, 'NY' => 4, 'NC' => 4.75, 'ND' => 5, 'OH' => 5.75,
        'OK' => 4.5, 'OR' => 0, 'PA' => 6, 'RI' => 7, 'SC' => 6,
        'SD' => 4.2, 'TN' => 7, 'TX' => 6.25, 'UT' => 6.1, 'VT' => 6,
        'VA' => 5.3, 'WA' => 6.5, 'WV' => 6, 'WI' => 5, 'WY' => 4, 'DC' => 6,
    ];

    if (empty($CLAUDE_API_KEY)) {
        if (isset($stateTaxRates[$stateAbbr])) {
            $response['taxRate'] = $stateTaxRates[$stateAbbr];
            $response['OK'] = true;
            $response['message'] = 'State base rate only (no API key)';
        }
        jsonResponse($response);
    }

    // Ask Claude for exact tax rate
    $requestBody = json_encode([
        'model' => 'claude-sonnet-4-20250514',
        'max_tokens' => 100,
        'temperature' => 0,
        'messages' => [[
            'role' => 'user',
            'content' => "What is the current combined sales tax rate (state + county + city + special districts) for $cityName, $stateAbbr (ZIP code $zipCode)? Return ONLY a single number representing the percentage, like 10.25 for 10.25%. No text, no explanation, just the number.",
        ]],
    ]);

    $ch = curl_init('https://api.anthropic.com/v1/messages');
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT => 30,
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => $requestBody,
        CURLOPT_HTTPHEADER => [
            'Content-Type: application/json',
            "x-api-key: $CLAUDE_API_KEY",
            'anthropic-version: 2023-06-01',
        ],
    ]);
    $claudeResult = curl_exec($ch);
    $claudeHttpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    if ($claudeHttpCode === 200) {
        $claudeResponse = json_decode($claudeResult, true);
        if (!empty($claudeResponse['content'][0]['text'])) {
            $rateText = trim($claudeResponse['content'][0]['text']);
            $rateText = preg_replace('/[^0-9.]/', '', $rateText);
            $rateVal = (float)$rateText;
            if ($rateVal > 0 && $rateVal < 20) {
                $response['taxRate'] = $rateVal;
                $response['OK'] = true;
                $response['message'] = "Tax rate for $cityName, $stateAbbr";
            } else {
                $response['message'] = 'Could not parse tax rate';
            }
        }
    } else {
        $response['message'] = 'Claude API error';
    }

} catch (Exception $e) {
    $response['message'] = 'Error: ' . $e->getMessage();
}

jsonResponse($response);