<?php
// api/fee_structures_post.php

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

require_once __DIR__ . '/../db/config.php';
require_once __DIR__ . '/../includes/uuid.php';

$response = [
    'status' => 'error',
    'message' => 'Invalid request.'
];

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $input = json_decode(file_get_contents('php://input'), true);

    if (json_last_error() !== JSON_ERROR_NONE) {
        $response['message'] = 'Invalid JSON payload.';
        http_response_code(400);
        echo json_encode($response);
        exit;
    }

    // Basic validation
    if (empty($input['name']) || empty($input['academic_year']) || empty($input['lines']) || !is_array($input['lines'])) {
        $response['message'] = 'Missing required fields: name, academic_year, and lines array.';
        http_response_code(400);
        echo json_encode($response);
        exit;
    }

    $pdo = db();
    $pdo->beginTransaction();

    try {
        $fee_structure_id = uuid_v4();
        $status = $input['status'] ?? 'Draft';

        $stmt = $pdo->prepare(
            "INSERT INTO fee_structures (id, name, academic_year, status) VALUES (?, ?, ?, ?)"
        );
        $stmt->execute([$fee_structure_id, $input['name'], $input['academic_year'], $status]);

        $lines = [];
        foreach ($input['lines'] as $line) {
            if (empty($line['description']) || !isset($line['amount']) || empty($line['revenue_account_code'])) {
                throw new Exception('Each line must have a description, amount, and revenue_account_code.');
            }

            // Get revenue_account_id from code
            $stmt_acc = $pdo->prepare("SELECT id FROM accounts WHERE account_code = ? AND account_type = 'Revenue'");
            $stmt_acc->execute([$line['revenue_account_code']]);
            $revenue_account = $stmt_acc->fetch(PDO::FETCH_ASSOC);

            if (!$revenue_account) {
                throw new Exception("Invalid or non-revenue account code provided: {" . $line['revenue_account_code'] . "}");
            }
            $revenue_account_id = $revenue_account['id'];

            $line_id = uuid_v4();
            $stmt_line = $pdo->prepare(
                "INSERT INTO fee_structure_lines (id, fee_structure_id, description, amount, revenue_account_id) VALUES (?, ?, ?, ?, ?)"
            );
            $stmt_line->execute([$line_id, $fee_structure_id, $line['description'], $line['amount'], $revenue_account_id]);
            
            $lines[] = [
                'id' => $line_id,
                'description' => $line['description'],
                'amount' => $line['amount'],
                'revenue_account_code' => $line['revenue_account_code']
            ];
        }

        $pdo->commit();

        $response['status'] = 'success';
        $response['message'] = 'Fee structure created successfully.';
        $response['data'] = [
            'id' => $fee_structure_id,
            'name' => $input['name'],
            'academic_year' => $input['academic_year'],
            'status' => $status,
            'lines' => $lines
        ];
        http_response_code(201);

    } catch (Exception $e) {
        if ($pdo->inTransaction()) {
            $pdo->rollBack();
        }
        $response['message'] = 'Error creating fee structure: ' . $e->getMessage();
        http_response_code(500);
    }
}

echo json_encode($response);