<?php
header("Content-Type: application/json");

require "../config/db.php";
require_once "kyc_config.php";

/*****************************************************
 * HELPER: JSON Response
 *****************************************************/
function json_exit($arr) {
    echo json_encode($arr);
    exit;
}

/*****************************************************
 * 1. CHECK REQUIRED FIELDS
 *****************************************************/
if (
    !isset($_POST['email']) ||
    !isset($_POST['id_type']) ||
    !isset($_POST['id_number']) ||
    !isset($_FILES['id_file']) ||
    !isset($_FILES['police_file']) ||
    !isset($_FILES['selfie_file'])
) {
    json_exit([
        "success" => false,
        "message" => "Missing fields"
    ]);
}

$email    = trim($_POST['email']);
$idType   = trim($_POST['id_type']);
$idNumber = strtoupper(trim($_POST['id_number']));

/*****************************************************
 * 2. ID VALIDATION RULES
 *****************************************************/
function isValidAadhaar($num) {
    if (!preg_match('/^\d{12}$/', $num)) return false;

    $d = [
        [0,1,2,3,4,5,6,7,8,9],
        [1,2,3,4,0,6,7,8,9,5],
        [2,3,4,0,1,7,8,9,5,6],
        [3,4,0,1,2,8,9,5,6,7],
        [4,0,1,2,3,9,5,6,7,8],
        [5,9,8,7,6,0,4,3,2,1],
        [6,5,9,8,7,1,0,4,3,2],
        [7,6,5,9,8,2,1,0,4,3],
        [8,7,6,5,9,3,2,1,0,4],
        [9,8,7,6,5,4,3,2,1,0]
    ];
    $p = [
        [0,1,2,3,4,5,6,7,8,9],
        [1,5,7,6,2,8,3,0,9,4],
        [5,8,0,3,7,9,6,1,4,2],
        [8,9,1,6,0,4,3,5,2,7],
        [9,4,5,3,1,2,6,8,7,0],
        [4,2,8,6,5,7,3,9,0,1],
        [2,7,9,3,8,0,6,4,1,5],
        [7,0,4,6,9,1,3,2,5,8]
    ];

    $c = 0;
    $numRev = strrev($num);

    for ($i = 0; $i < strlen($numRev); $i++) {
        $c = $d[$c][$p[$i % 8][intval($numRev[$i])]];
    }

    return $c == 0;
}

function validate_id_number($type, $num, &$reason) {
    $typeLower = strtolower($type);

    if ($typeLower === "aadhaar") {
        if (!preg_match('/^[0-9]{12}$/', $num)) {
            $reason = "Invalid Aadhaar";
            return false;
        }
        return true;
    }

    if ($typeLower === "pan" || $typeLower === "pan card") {
        if (!preg_match('/^[A-Z]{5}[0-9]{4}[A-Z]$/', $num)) {
            $reason = "Invalid PAN";
            return false;
        }
        return true;
    }

    if ($typeLower === "driving license" || $typeLower === "dl") {
        if (!preg_match('/^[A-Z]{2}[0-9]{2}\s?[0-9]{11}$/', $num)) {
            $reason = "Invalid Driving License";
            return false;
        }
        return true;
    }

    if ($typeLower === "voter id" || $typeLower === "voter") {
        if (!preg_match('/^[A-Z]{3}[0-9]{7}$/', $num)) {
            $reason = "Invalid Voter ID";
            return false;
        }
        return true;
    }

    $reason = "Unknown ID type";
    return false;
}

$reason = "";
if (!validate_id_number($idType, $idNumber, $reason)) {
    json_exit(["success" => false, "message" => $reason]);
}

/*****************************************************
 * 3. SAVE FILES
 *****************************************************/
$uploadDir = "../uploads/worker_kyc/";
if (!is_dir($uploadDir)) mkdir($uploadDir, 0775, true);

function save_file($field, $prefix, $email, &$err) {
    global $uploadDir;

    if ($_FILES[$field]['error'] !== UPLOAD_ERR_OK) {
        $err = "Upload error ($field)";
        return null;
    }

    $ext = pathinfo($_FILES[$field]['name'], PATHINFO_EXTENSION);
    $fileName = $prefix . "_" . md5($email . time()) . "." . $ext;
    $dest = $uploadDir . $fileName;

    if (!move_uploaded_file($_FILES[$field]['tmp_name'], $dest)) {
        $err = "Cannot save $field";
        return null;
    }

    return "uploads/worker_kyc/" . $fileName;
}

$err = "";
$idFile = save_file("id_file", "id", $email, $err);
$policeFile = save_file("police_file", "police", $email, $err);
$selfieFile = save_file("selfie_file", "selfie", $email, $err);

if (!$idFile || !$policeFile || !$selfieFile) {
    json_exit(["success" => false, "message" => $err]);
}

/*****************************************************
 * 4. IMAGE QUALITY CHECK
 *****************************************************/
function is_image_ok($path, &$msg) {
    $full = "../" . $path;
    $size = @getimagesize($full);

    if (!$size) {
        $msg = "Invalid image";
        return false;
    }
    if ($size[0] < 200) {
        $msg = "Image too small";
        return false;
    }
    return true;
}

if (!is_image_ok($idFile, $reason))
    json_exit([
      "success" => false,
      "field" => "id_file",
      "message" => "ID Error: $reason"
    ]);

if (!is_image_ok($selfieFile, $reason))
    json_exit([
      "success" => false,
      "field" => "selfie_file",
      "message" => "Selfie Error: $reason"
    ]);

/*****************************************************
 * 5. OCR FIXED
 *****************************************************/
function ocr_extract_text($apiKey, $filePath, &$rawText, &$error) {
    global $OCR_ENDPOINT;

    $full = "../" . $filePath;

    $post = [
        "apikey" => $apiKey,
        "language" => "eng",
        "OCREngine" => 2,
        "file" => new CURLFile($full)
    ];

    $ch = curl_init($OCR_ENDPOINT);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $post);

    $result = curl_exec($ch);
    curl_close($ch);

    $data = json_decode($result, true);

    if (!isset($data['ParsedResults'][0]['ParsedText'])) {
        $error = "OCR failed";
        return false;
    }

    $rawText = strtoupper($data['ParsedResults'][0]['ParsedText']);
    return true;
}

$rawText = "";
if (!ocr_extract_text($OCR_API_KEY, $idFile, $rawText, $reason)) {
    json_exit([
        "success" => false,
        "field" => "id_file",
        "kyc_status" => "retry_id",
        "message" => "OCR failed. Please upload a clearer ID card."
    ]);
}

$cleanText = preg_replace('/\s+/', '', $rawText);
$cleanID   = preg_replace('/\s+/', '', $idNumber);

if (strpos($cleanText, $cleanID) === false) {
    json_exit([
        "success" => false,
        "field" => "id_file",
        "kyc_status" => "retry_id",
        "message" => "ID number not detected. Please re-upload a clearer ID image."
    ]);
}

/*****************************************************
 * 6. FACE MATCH FIXED
 *****************************************************/
function face_compare($apiKey, $apiSecret, $idPath, $selfiePath, &$score, &$error) {
    global $FACEPP_COMPARE;

    $idAbs = "../" . $idPath;
    $selfieAbs = "../" . $selfiePath;

    $post = [
        "api_key" => $apiKey,
        "api_secret" => $apiSecret,
        "image_file1" => new CURLFILE($idAbs),
        "image_file2" => new CURLFILE($selfieAbs)
    ];

    $ch = curl_init($FACEPP_COMPARE);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $post);

    $result = curl_exec($ch);
    curl_close($ch);

    $data = json_decode($result, true);

    if (!isset($data["confidence"])) {
        $error = "Face++ Error";
        return false;
    }

    $score = floatval($data["confidence"]);
    return true;
}

$faceScore = 0;
if (!face_compare($FACEPP_API_KEY, $FACEPP_API_SECRET, $idFile, $selfieFile, $faceScore, $reason)) {
    json_exit(["success" => false, "message" => "Face comparison failed"]);
}

if ($faceScore < 75) {
    $stmt = $conn->prepare("
        UPDATE workers SET 
            kyc_status='rejected',
            status='rejected',
            kyc_id_type=?, 
            kyc_id_number=?,
            kyc_id_file=?,
            kyc_police_file=?, 
            kyc_selfie_file=?,
            verification_notes=CONCAT('Face mismatch (score=', ?, ')')
        WHERE email=?
    ");

    $scoreStr = strval($faceScore);

    $stmt->bind_param(
        "sssssss",
        $idType, $idNumber, $idFile, $policeFile, $selfieFile, $scoreStr, $email
    );

    $stmt->execute();

    json_exit([
        "success" => false,
        "kyc_status" => "rejected",
        "message" => "Face mismatch – verification failed",
        "score" => $faceScore
    ]);
}

/*****************************************************
 * 7. VERIFIED
 *****************************************************/
$stmt = $conn->prepare("
    UPDATE workers SET 
        kyc_status='verified',
        status='verified',
        kyc_id_type=?, 
        kyc_id_number=?, 
        kyc_id_file=?, 
        kyc_police_file=?, 
        kyc_selfie_file=?, 
        verified_at=NOW(),
        verification_notes='Auto Verified'
    WHERE email=?
");

$stmt->bind_param(
    "ssssss",
    $idType, $idNumber, $idFile, $policeFile, $selfieFile, $email
);

$stmt->execute();

json_exit([
    "success" => true,
    "message" => "KYC Auto-Verified",
    "face_score" => $faceScore
]);