<?php
/**
 * Builds self-describing report tables.
 *
 * @package ProfitEngine
 */

declare( strict_types=1 );

namespace ProfitEngine\Reports;

use ProfitEngine\Costing\CostRecordRepository;
use ProfitEngine\Costing\CostSnapshotService;
use ProfitEngine\Profit\ProfitService;
use ProfitEngine\Purchasing\ProductSettingsRepository;
use ProfitEngine\PurchaseOrders\PORepository;
use ProfitEngine\Support\DateRange;
use ProfitEngine\Support\Money;
use ProfitEngine\Support\ProductResolver;

defined( 'ABSPATH' ) || exit;

/**
 * Produces reports as self-describing tables ({ title, columns, rows }) so the
 * UI can render any report generically and export it to CSV without bespoke code
 * per report.
 */
class ReportService {

	private ProfitService $profit;

	private CostRecordRepository $records;

	private CostSnapshotService $snapshotter;

	private PORepository $pos;

	private ProductSettingsRepository $settings;

	private ProductResolver $resolver;

	private InventoryValueService $inventory;

	/**
	 * Available report type slugs.
	 */
	public const TYPES = array(
		'profit_by_product',
		'profit_by_category',
		'sales_vs_cost',
		'supplier_spending',
		'purchase_history',
		'inventory_value',
	);

	/**
	 * Constructor.
	 *
	 * @param ProfitService             $profit      Profit service.
	 * @param CostRecordRepository      $records     Cost record repo.
	 * @param CostSnapshotService       $snapshotter Counted statuses.
	 * @param PORepository              $pos         PO repo.
	 * @param ProductSettingsRepository $settings    Settings repo.
	 * @param ProductResolver           $resolver    Product resolver.
	 * @param InventoryValueService     $inventory   Inventory value service.
	 */
	public function __construct(
		ProfitService $profit,
		CostRecordRepository $records,
		CostSnapshotService $snapshotter,
		PORepository $pos,
		ProductSettingsRepository $settings,
		ProductResolver $resolver,
		InventoryValueService $inventory
	) {
		$this->profit      = $profit;
		$this->records     = $records;
		$this->snapshotter = $snapshotter;
		$this->pos         = $pos;
		$this->settings    = $settings;
		$this->resolver    = $resolver;
		$this->inventory   = $inventory;
	}

	/**
	 * Build a report by type.
	 *
	 * @param string              $type Report type.
	 * @param array<string,mixed> $args Range args.
	 * @return array<string,mixed>
	 */
	public function build( string $type, array $args ): array {
		switch ( $type ) {
			case 'profit_by_category':
				return $this->profit_by_category( $args );
			case 'sales_vs_cost':
				return $this->sales_vs_cost( $args );
			case 'supplier_spending':
				return $this->supplier_spending( $args );
			case 'purchase_history':
				return $this->purchase_history( $args );
			case 'inventory_value':
				return $this->inventory_value();
			case 'profit_by_product':
			default:
				return $this->profit_by_product( $args );
		}
	}

	/**
	 * Profit by product/variation.
	 *
	 * @param array<string,mixed> $args Range args.
	 * @return array<string,mixed>
	 */
	private function profit_by_product( array $args ): array {
		$rows = array_map(
			static fn( array $r ): array => array(
				'product' => $r['label'],
				'sku'     => $r['sku'],
				'units'   => $r['units'],
				'revenue' => $r['revenue'],
				'cost'    => $r['cost'],
				'profit'  => $r['profit'],
				'margin'  => $r['margin'],
			),
			$this->profit->by_product( $args )
		);

		return array(
			'title'   => __( 'Profit by product', 'profit-engine' ),
			'columns' => array(
				array(
					'key'   => 'product',
					'label' => __( 'Product', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'sku',
					'label' => __( 'SKU', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'units',
					'label' => __( 'Units', 'profit-engine' ),
					'type'  => 'number',
				),
				array(
					'key'   => 'revenue',
					'label' => __( 'Revenue', 'profit-engine' ),
					'type'  => 'money',
				),
				array(
					'key'   => 'cost',
					'label' => __( 'Cost', 'profit-engine' ),
					'type'  => 'money',
				),
				array(
					'key'   => 'profit',
					'label' => __( 'Profit', 'profit-engine' ),
					'type'  => 'money',
				),
				array(
					'key'   => 'margin',
					'label' => __( 'Margin', 'profit-engine' ),
					'type'  => 'percent',
				),
			),
			'rows'    => $rows,
		);
	}

	/**
	 * Profit grouped by product category (first category wins).
	 *
	 * @param array<string,mixed> $args Range args.
	 * @return array<string,mixed>
	 */
	private function profit_by_category( array $args ): array {
		$by_product = $this->profit->by_product( $args );
		$groups     = array();

		foreach ( $by_product as $r ) {
			$cat = $this->primary_category( (int) $r['product_id'] );
			if ( ! isset( $groups[ $cat ] ) ) {
				$groups[ $cat ] = array(
					'category' => $cat,
					'revenue'  => 0.0,
					'cost'     => 0.0,
					'profit'   => 0.0,
					'units'    => 0.0,
				);
			}
			$groups[ $cat ]['revenue'] += (float) $r['revenue'];
			$groups[ $cat ]['cost']    += (float) $r['cost'];
			$groups[ $cat ]['profit']  += (float) $r['profit'];
			$groups[ $cat ]['units']   += (float) $r['units'];
		}

		$rows = array_values( $groups );
		foreach ( $rows as &$row ) {
			$row['margin'] = $row['revenue'] > 0 ? $row['profit'] / $row['revenue'] : 0.0;
		}
		unset( $row );
		usort( $rows, static fn( $a, $b ): int => $b['profit'] <=> $a['profit'] );

		return array(
			'title'   => __( 'Profit by category', 'profit-engine' ),
			'columns' => array(
				array(
					'key'   => 'category',
					'label' => __( 'Category', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'units',
					'label' => __( 'Units', 'profit-engine' ),
					'type'  => 'number',
				),
				array(
					'key'   => 'revenue',
					'label' => __( 'Revenue', 'profit-engine' ),
					'type'  => 'money',
				),
				array(
					'key'   => 'cost',
					'label' => __( 'Cost', 'profit-engine' ),
					'type'  => 'money',
				),
				array(
					'key'   => 'profit',
					'label' => __( 'Profit', 'profit-engine' ),
					'type'  => 'money',
				),
				array(
					'key'   => 'margin',
					'label' => __( 'Margin', 'profit-engine' ),
					'type'  => 'percent',
				),
			),
			'rows'    => $rows,
		);
	}

	/**
	 * Sales vs cost time series.
	 *
	 * @param array<string,mixed> $args Range args.
	 * @return array<string,mixed>
	 */
	private function sales_vs_cost( array $args ): array {
		[ $from, $to ] = DateRange::resolve( $args );
		$rows          = $this->records->series( $from, $to, $this->snapshotter->counted_statuses(), DateRange::bucket_for( $from, $to ) );

		return array(
			'title'   => __( 'Sales vs cost', 'profit-engine' ),
			'columns' => array(
				array(
					'key'   => 'period',
					'label' => __( 'Period', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'revenue',
					'label' => __( 'Revenue', 'profit-engine' ),
					'type'  => 'money',
				),
				array(
					'key'   => 'cost',
					'label' => __( 'Cost', 'profit-engine' ),
					'type'  => 'money',
				),
				array(
					'key'   => 'profit',
					'label' => __( 'Profit', 'profit-engine' ),
					'type'  => 'money',
				),
			),
			'rows'    => $rows,
			'chart'   => array(
				'x'      => 'period',
				'series' => array( 'revenue', 'cost', 'profit' ),
			),
		);
	}

	/**
	 * Purchase spending by supplier.
	 *
	 * @param array<string,mixed> $args Range args.
	 * @return array<string,mixed>
	 */
	private function supplier_spending( array $args ): array {
		[ $from, $to ] = DateRange::resolve( $args );
		$rows          = array_map(
			static fn( array $r ): array => array(
				'supplier' => (string) ( $r['supplier_name'] ?? __( 'Unknown', 'profit-engine' ) ),
				'orders'   => (int) $r['orders'],
				'total'    => (float) $r['total'],
			),
			$this->pos->supplier_spending( $from, $to )
		);

		return array(
			'title'   => __( 'Supplier spending', 'profit-engine' ),
			'columns' => array(
				array(
					'key'   => 'supplier',
					'label' => __( 'Supplier', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'orders',
					'label' => __( 'Orders', 'profit-engine' ),
					'type'  => 'number',
				),
				array(
					'key'   => 'total',
					'label' => __( 'Spend', 'profit-engine' ),
					'type'  => 'money',
				),
			),
			'rows'    => $rows,
		);
	}

	/**
	 * Purchase history.
	 *
	 * @param array<string,mixed> $args Range args.
	 * @return array<string,mixed>
	 */
	private function purchase_history( array $args ): array {
		[ $from, $to ] = DateRange::resolve( $args );
		$rows          = array_map(
			static fn( array $po ): array => array(
				'po_number' => (string) $po['po_number'],
				'supplier'  => (string) ( $po['supplier_name'] ?? '' ),
				'status'    => (string) $po['status'],
				'date'      => (string) ( $po['ordered_at'] ?: $po['created_at'] ),
				'total'     => Money::to_float( $po['grand_total'] ),
			),
			$this->pos->history( $from, $to )
		);

		return array(
			'title'   => __( 'Purchase history', 'profit-engine' ),
			'columns' => array(
				array(
					'key'   => 'po_number',
					'label' => __( 'PO', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'supplier',
					'label' => __( 'Supplier', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'status',
					'label' => __( 'Status', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'date',
					'label' => __( 'Date', 'profit-engine' ),
					'type'  => 'date',
				),
				array(
					'key'   => 'total',
					'label' => __( 'Total', 'profit-engine' ),
					'type'  => 'money',
				),
			),
			'rows'    => $rows,
		);
	}

	/**
	 * Inventory value at cost.
	 *
	 * @return array<string,mixed>
	 */
	private function inventory_value(): array {
		$rows = $this->inventory->rows();

		return array(
			'title'   => __( 'Inventory value', 'profit-engine' ),
			'columns' => array(
				array(
					'key'   => 'product',
					'label' => __( 'Product', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'sku',
					'label' => __( 'SKU', 'profit-engine' ),
					'type'  => 'text',
				),
				array(
					'key'   => 'stock',
					'label' => __( 'Stock', 'profit-engine' ),
					'type'  => 'number',
				),
				array(
					'key'   => 'unit_cost',
					'label' => __( 'Unit cost', 'profit-engine' ),
					'type'  => 'money',
				),
				array(
					'key'   => 'value',
					'label' => __( 'Value', 'profit-engine' ),
					'type'  => 'money',
				),
			),
			'rows'    => $rows,
		);
	}

	/**
	 * The primary (first) category name for a unit's parent product.
	 *
	 * @param int $unit_id Purchasable-unit ID.
	 */
	private function primary_category( int $unit_id ): string {
		$product = $this->resolver->product( $unit_id );
		if ( ! $product ) {
			return __( 'Uncategorized', 'profit-engine' );
		}

		$parent_id = $product->get_parent_id() ? (int) $product->get_parent_id() : $unit_id;
		$terms     = get_the_terms( $parent_id, 'product_cat' );

		if ( is_array( $terms ) && ! empty( $terms ) ) {
			return $terms[0]->name;
		}
		return __( 'Uncategorized', 'profit-engine' );
	}
}