<?php
namespace App\DevExtreme;
class DataSourceLoader {
    public static function Load($dbSet, $params, $module = null) {
        $result = NULL;
        if (isset($dbSet) && get_class($dbSet) == "App\DevExtreme\DbSet" && isset($params) && is_array($params)) {
            // Check if distinctColumn parameter is provided (for header filter unique values)
            // distinctColumn can come as string (from GET) or already parsed
            $distinctColumn = null;
            if (isset($params["distinctColumn"])) {
                $distinctColumn = $params["distinctColumn"];
                // If it's a JSON string, decode it
                if (is_string($distinctColumn) && (substr($distinctColumn, 0, 1) === '[' || substr($distinctColumn, 0, 1) === '{')) {
                    $decoded = json_decode($distinctColumn, true);
                    if ($decoded !== null) {
                        $distinctColumn = $decoded;
                    }
                }
                // Log for debugging
                error_log("DataSourceLoader: distinctColumn parameter received: " . var_export($distinctColumn, true) . " (type: " . gettype($distinctColumn) . ")");
            }
            
            if (!empty($distinctColumn) && is_string($distinctColumn)) {
                
                // Apply filters first
                $dbSet->Filter(Utils::GetItemValueOrDefault($params, "filter"));
                
                if ($module === 'weldlog-employer-view' && $dbSet->getTableName() === 'weld_logs') {
                    self::ApplyEmployerViewFilters($dbSet);
                }
                
                // Get distinct values
                error_log("DataSourceLoader: Getting distinct values for column: " . $distinctColumn . " in table: " . $dbSet->getTableName());
                $distinctValues = $dbSet->GetDistinctValues($distinctColumn);
                if ($dbSet->GetLastError() !== NULL) {
                    error_log("GetDistinctValues error: " . $dbSet->GetLastError());
                    // Return error response instead of NULL
                    $result = array();
                    $result["data"] = array();
                    $result["hasBlanks"] = false;
                    $result["error"] = $dbSet->GetLastError();
                    return $result;
                }
                error_log("DataSourceLoader: Found " . count($distinctValues) . " distinct values");
                
                // Check for blanks
                $hasBlanks = $dbSet->HasBlanks($distinctColumn);
                if ($dbSet->GetLastError() !== NULL) {
                    error_log("HasBlanks error: " . $dbSet->GetLastError());
                    // Continue even if HasBlanks fails
                }
                
                // Format response for header filter
                $result = array();
                $result["data"] = array_map(function($value) {
                    return array("value" => $value, "text" => $value);
                }, $distinctValues);
                $result["hasBlanks"] = $hasBlanks;
                
                return $result;
            }
            
            // Normal data loading
            $dbSet->Select(Utils::GetItemValueOrDefault($params, "select"))
                  ->Filter(Utils::GetItemValueOrDefault($params, "filter"));
            
            if ($module === 'weldlog-employer-view' && $dbSet->getTableName() === 'weld_logs') {
                self::ApplyEmployerViewFilters($dbSet);
            }
            $totalSummary = $dbSet->GetTotalSummary(Utils::GetItemValueOrDefault($params, "totalSummary"),
                                                    Utils::GetItemValueOrDefault($params, "filter"));
            if ($dbSet->GetLastError() !== NULL) {
                error_log("GetTotalSummary error: " . $dbSet->GetLastError());
                return $result;
            }
            $totalCount = (isset($params["requireTotalCount"]) && $params["requireTotalCount"] === true)
                          ? $dbSet->GetCount() : NULL;
            if ($dbSet->GetLastError() !== NULL) {
                return $result;
            }
            
            $dbSet->Sort(Utils::GetItemValueOrDefault($params, "sort"));
            $groupCount = NULL;
            $skip = Utils::GetItemValueOrDefault($params, "skip");
            $take = Utils::GetItemValueOrDefault($params, "take");
            if (isset($params["group"])) {
                $groupExpression = $params["group"];
                $groupSummary = Utils::GetItemValueOrDefault($params, "groupSummary");
                $dbSet->Group($groupExpression, $groupSummary, $skip, $take);
                if (isset($params["requireGroupCount"]) && $params["requireGroupCount"] === true) {
                    $groupCount = $dbSet->GetGroupCount();
                }
            }
            else {
                $dbSet->SkipTake($skip, $take);
            }
            $result = array();
            $result["data"] = $dbSet->AsArray();
            if ($dbSet->GetLastError() !== NULL) {
                return $result;
            }
            if (isset($totalCount)) {
                $result["totalCount"] = $totalCount;
            }
            if (isset($totalSummary)) {
                $result["summary"] = $totalSummary;
            }
            if (isset($groupCount)) {
                $result["groupCount"] = $groupCount;
            }
        }
        else {
            throw new \Exception("Invalid params");
        }
        return $result;
    }
    
    /**
     * Apply employer view specific filters to weld_logs table
     * Filters:
     * 1. Exclude records with repair_status = 'Repair' in repair_logs
     * 2. Exclude records with NDT results other than 'Accept / Годен' or empty/null
     */
    private static function ApplyEmployerViewFilters($dbSet) {
        $weldLogsTable = $dbSet->getTableName();
        
        $repairFilter = "NOT EXISTS (
            SELECT 1 FROM repair_logs
            WHERE repair_logs.iso_number = {$weldLogsTable}.iso_number
              AND repair_logs.new_joint_no = {$weldLogsTable}.no_of_the_joint_as_per_as_built_survey
              AND repair_logs.repair_status = 'Repair'
        )";
        
        $ndtFields = [
            'vt_result',
            'rt_result',
            'ut_result',
            'pt_result',
            'mt_result',
            'pmi_result',
            'ferrite_result',
            'ht_result'
        ];
        
        $ndtFilters = [];
        foreach ($ndtFields as $field) {
            $ndtFilters[] = "({$weldLogsTable}.{$field} IN ('Accept / Годен', '') OR {$weldLogsTable}.{$field} IS NULL)";
        }
        
        $ndtFilter = implode(' AND ', $ndtFilters);
        
        $combinedFilter = "({$repairFilter}) AND ({$ndtFilter})";
        
        $dbSet->AddCustomWhere($combinedFilter);
    }
    
}