using System.Text.RegularExpressions;
using CareFix.Api.Infrastructure;

namespace CareFix.Api.Fixes;

/// <summary>Who must approve a fix. Kept separate from the service so it can be tested on its own.</summary>
public static class ApprovalRules
{
    public static string RuleText(string risk) => risk switch
    {
        "Low" => "1 approval from a Support Lead or Support Head",
        "Medium" => "2 approvals from different people: a Support Lead (or Head) and a Product Owner (or Head)",
        _ => "Support Head approval plus the hospital's written consent file",
    };

    /// <summary>Whether this role may record an approval at all. Four-eyes and duplicate checks live in the service.</summary>
    public static bool CanApprove(string role, string risk) => risk switch
    {
        "Low" => role is Roles.Lead or Roles.Head,
        "Medium" => role is Roles.Lead or Roles.ProductOwner or Roles.Head,
        _ => role is Roles.Head,
    };

    /// <summary>Whether the approvals collected so far are enough to run the fix.</summary>
    public static bool IsSatisfied(string risk, IReadOnlyList<ApprovalRow> approvals, bool hasConsent)
    {
        var ok = approvals.Where(a => a.Decision == "Approved").ToList();
        return risk switch
        {
            "Low" => ok.Any(a => a.ApproverRole is Roles.Lead or Roles.Head),
            "Medium" => ok.Where(a => a.ApproverRole is Roles.Lead or Roles.Head)
                          .Any(l => ok.Any(p => p.ApproverRole is Roles.ProductOwner or Roles.Head && p.ApproverId != l.ApproverId)),
            _ => hasConsent && ok.Any(a => a.ApproverRole == Roles.Head),
        };
    }
}

/// <summary>How a fix's risk level is worked out.</summary>
public static partial class RiskRules
{
    private static readonly string[] Order = ["Low", "Medium", "High"];

    [GeneratedRegex("(AMT|AMOUNT|RATE|PRICE|TOTAL|NETAMT|NET_AMT|DISC|PAID|REFUND|BALANCE|DUE|QTY|QUANTITY|TAX|GST|CGST|SGST|DEPOSIT|ADVANCE)", RegexOptions.IgnoreCase)]
    private static partial Regex AmountColumn();

    /// <summary>Columns holding money or quantities are always High risk, whatever the dictionary says.</summary>
    public static bool IsAmountColumn(string column) => AmountColumn().IsMatch(column);

    public static string Max(string a, string b) => Array.IndexOf(Order, a) >= Array.IndexOf(Order, b) ? a : b;
}