/* FleetCargo.cpp
Copyright (c) 2022 by warp-core

Endless Sky is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later version.

Endless Sky is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program. If not, see <https://www.gnu.org/licenses/>.
*/

#include "FleetCargo.h"

#include "DataNode.h"
#include "GameData.h"
#include "Outfit.h"
#include "Planet.h"
#include "Ship.h"
#include "StellarObject.h"
#include "System.h"
#include "Trade.h"

#include <algorithm>
#include <cmath>

using namespace std;

namespace {
	// Construct a list of all outfits for sale in this system and its linked neighbors.
	Sale<Outfit> GetOutfitsForSale(const System *here)
	{
		auto outfits = Sale<Outfit>();
		if(here)
		{
			for(const StellarObject &object : here->Objects())
			{
				const Planet *planet = object.GetPlanet();
				if(planet && planet->IsValid() && planet->HasOutfitter())
					outfits.Add(planet->OutfitterStock());
			}
		}
		return outfits;
	}

	// Construct a list of varying numbers of outfits that were either specified for
	// this fleet directly, or are sold in this system or its linked neighbors.
	vector<const Outfit *> OutfitChoices(const set<const Shop<Outfit> *> &outfitters, const System *hub, int maxSize)
	{
		auto outfits = vector<const Outfit *>();
		if(maxSize > 0)
		{
			auto choices = Sale<Outfit>();
			// If no outfits were directly specified, choose from those sold nearby.
			if(outfitters.empty() && hub)
			{
				choices = GetOutfitsForSale(hub);
				for(const System *other : hub->Links())
					choices.Add(GetOutfitsForSale(other));
			}
			else
				for(const auto outfitter : outfitters)
					choices.Add(outfitter->Stock());

			if(!choices.empty())
			{
				for(const auto outfit : choices)
				{
					double mass = outfit->Mass();
					// Avoid free outfits, massless outfits, and those too large to fit.
					if(mass > 0. && mass < maxSize && outfit->Cost() > 0)
					{
						// Also avoid outfits that add space (such as Outfits / Cargo Expansions)
						// or modify bunks.
						// TODO: Specify rejection criteria in datafiles as ConditionSets or similar.
						const auto &attributes = outfit->Attributes();
						if(attributes.Get("outfit space") > 0.
								|| attributes.Get("cargo space") > 0.
								|| attributes.Get("bunks"))
							continue;

						outfits.push_back(outfit);
					}
				}
			}
		}
		// Sort this list of choices ascending by mass, so it can be easily trimmed to just
		// the outfits that fit as the ship's free space decreases.
		sort(outfits.begin(), outfits.end(), [](const Outfit *a, const Outfit *b)
			{ return a->Mass() < b->Mass(); });
		return outfits;
	}

	// Add a random commodity from the list to the ship's cargo.
	void AddRandomCommodity(Ship &ship, int freeSpace, const vector<string> &commodities)
	{
		int index = Random::Int(GameData::Commodities().size());
		if(!commodities.empty())
		{
			// If a list of possible commodities was given, pick one of them at
			// random and then double-check that it's a valid commodity name.
			const string &name = commodities[Random::Int(commodities.size())];
			for(const auto &it : GameData::Commodities())
				if(it.name == name)
				{
					index = &it - &GameData::Commodities().front();
					break;
				}
		}

		const Trade::Commodity &commodity = GameData::Commodities()[index];
		int amount = Random::Int(freeSpace) + 1;
		ship.Cargo().Add(commodity.name, amount);
	}

	// Add a random outfit from the list to the ship's cargo.
	void AddRandomOutfit(Ship &ship, int freeSpace, const vector<const Outfit *> &outfits)
	{
		if(outfits.empty())
			return;
		int index = Random::Int(outfits.size());
		const Outfit *picked = outfits[index];
		int maxQuantity = floor(static_cast<double>(freeSpace) / picked->Mass());
		int amount = Random::Int(maxQuantity) + 1;
		ship.Cargo().Add(picked, amount);
	}
}



void FleetCargo::Load(const DataNode &node)
{
	for(const DataNode &child : node)
		LoadSingle(child);
}



void FleetCargo::LoadSingle(const DataNode &node)
{
	const string &key = node.Token(0);
	if(node.Size() < 2)
		node.PrintTrace("Error: Expected key to have a value:");
	else if(key == "cargo")
			cargo = static_cast<int>(node.Value(1));
	else if(key == "commodities")
	{
		commodities.clear();
		for(int i = 1; i < node.Size(); ++i)
			commodities.push_back(node.Token(i));
	}
	else if(key == "outfitters")
	{
		outfitters.clear();
		for(int i = 1; i < node.Size(); ++i)
			outfitters.insert(GameData::Outfitters().Get(node.Token(i)));
	}
	else
		node.PrintTrace("Skipping unrecognized attribute:");
}



// Choose the cargo associated with this ship.
// If outfits were specified, but not commodities, do not pick commodities.
// If commodities were specified, but not outfits, do not pick outfits.
// If neither or both were specified, choose commodities more often.
// Also adds a random amount of extra crew in addition to the required crew,
// up to the number of bunks remaining after required crew.
void FleetCargo::SetCargo(Ship *ship) const
{
	const bool canChooseOutfits = commodities.empty() || !outfitters.empty();
	const bool canChooseCommodities = outfitters.empty() || !commodities.empty();
	// Populate the possible outfits that may be chosen.
	int free = ship->Cargo().Free();
	auto outfits = OutfitChoices(outfitters, ship->GetSystem(), free);

	// Choose random outfits or commodities to transport.
	for(int i = 0; i < cargo; ++i)
	{
		if(free <= 0)
			break;
		// Remove any outfits that do not fit into remaining cargo.
		if(canChooseOutfits && !outfits.empty())
			outfits.erase(remove_if(outfits.begin(), outfits.end(),
					[&free](const Outfit *a) { return a->Mass() > free; }),
				outfits.end());

		if(canChooseCommodities && canChooseOutfits)
		{
			if(Random::Real() < .8)
				AddRandomCommodity(*ship, free, commodities);
			else
				AddRandomOutfit(*ship, free, outfits);
		}
		else if(canChooseCommodities)
			AddRandomCommodity(*ship, free, commodities);
		else
			AddRandomOutfit(*ship, free, outfits);

		free = ship->Cargo().Free();
	}
	int extraCrew = ship->Attributes().Get("bunks") - ship->RequiredCrew();
	if(extraCrew > 0)
		ship->AddCrew(Random::Int(extraCrew + 1));
}