namespace BlueLaminate.Core.Tradeups;

/// <summary>One possible result of a contract and what it would net if it lands.</summary>
/// <param name="Probability">Chance this specific output is produced (single-collection: 1/k).</param>
/// <param name="NetSellPrice">
/// Realisable sale value after undercut + sell fee, or null when nothing comparable is
/// listed (treated as unsellable for the worst-case test).
/// </param>
/// <param name="Liquidity">Active listings backing the price, in the same wear band.</param>
/// <param name="PriceSource">Where the price came from: "market" (our stored listings) or
/// "csfloat-live" (re-priced from the CSFloat API because the stored liquidity was thin).</param>
public sealed record TradeupOutcome(
    int SkinId,
    string Name,
    decimal OutputFloat,
    WearBand Band,
    decimal Probability,
    decimal? NetSellPrice,
    int Liquidity,
    string PriceSource = "market");

/// <summary>
/// One collection's share of a (possibly multi-collection) contract: how many of the ten
/// inputs came from it, and which output tier those inputs roll into. Single-collection
/// contracts have exactly one of these.
/// </summary>
public sealed record TradeupContribution(
    int CollectionId,
    string CollectionName,
    WeaponRarity OutputRarity,
    int InputCount);

/// <summary>
/// A concrete, actionable tradeup: which ten copies to buy, what they cost, the output
/// distribution, and the resulting economics. The finder returns these ranked; a frontend
/// only formats them.
/// <para>
/// A contract may mix several collections (all inputs share the input rarity, but each
/// collection rolls into its own next tier). <see cref="Composition"/> records the per-
/// collection split; <see cref="CollectionCount"/> is its length. <see cref="OutputRarity"/>
/// is the tier of the largest contributor (a display convenience for the common case).
/// </para>
/// </summary>
public sealed record TradeupCandidate(
    int CollectionId,
    string CollectionName,
    WeaponRarity InputRarity,
    WeaponRarity OutputRarity,
    bool StatTrak,
    decimal AverageFraction,
    decimal InputCost,
    decimal ExpectedNet,
    decimal WorstCaseNet,
    bool Guaranteed,
    IReadOnlyList<InputListing> Inputs,
    IReadOnlyList<TradeupOutcome> Outcomes,
    IReadOnlyList<TradeupContribution> Composition)
{
    /// <summary>Number of distinct collections the inputs are drawn from (1 = single-collection).</summary>
    public int CollectionCount => Composition.Count;

    /// <summary>Expected profit across the output distribution, net of cost.</summary>
    public decimal ExpectedProfit => ExpectedNet - InputCost;

    /// <summary>Profit if the worst (lowest-value) output lands — negative unless guaranteed.</summary>
    public decimal WorstCaseProfit => WorstCaseNet - InputCost;
}