#pragma once
#include <vector>
#include <cstdint>

// Civilization Step 7: trade & economy. Trade routes link nearby settlements (by sea / river / overland),
// prosperity accrues at well-connected hubs, and prosperity boosts population growth. Like territory and
// cultures, this is a PURE DETERMINISTIC function of the (saved) settlement set + geography + wars +
// diplomacy -- recomputed each sim year, not saved (no save-format change), no RNG, rewinds for free.

enum class TradeKind : uint8_t { Land, River, Sea };

struct TradeLink {
    int       a      = -1;   // settlement index of one endpoint
    int       b      = -1;   // settlement index of the other endpoint
    float     volume = 0.0f; // trade volume (drives both endpoints' prosperity)
    TradeKind kind   = TradeKind::Land;
};