/*
This Source Code Form is subject to the
terms of the Mozilla Public License, v.
2.0. If a copy of the MPL was not
distributed with this file, You can
obtain one at
http://mozilla.org/MPL/2.0/.
*/

#include "stdafx.h"
#include "editor/editorSwitchStore.hpp"
#include "editor/editorFormat.hpp"
#include "editor/editorGeometry.hpp"
#include "editor/editorAlignmentStore.hpp"

#include "world/Track.h"
#include "simulation/simulation.h"
#include "utilities/Logs.h"

#include <algorithm>
#include <cmath>
#include <set>
#include <sstream>

namespace switch_store
{

namespace
{

using geometry::plan_of;

std::string const kMark{"//$r"};
double const kTolerance{0.02};

std::vector<record> g_records;
std::vector<record> g_base; // as they were before the changes not yet in the undo history
bool g_changed{false};
bool g_loaded{false};

// format of the lines, coordinates in the space of the file:
//   <switch|slip|crossing> <name> <type> <rail> <R> <n of 1:n> <hand L|R|-> <a> <b> <R of the main track, + right, - left, 0 straight>
//     parts <count> <names>... shape <main end along, across> <diverging end along, across> start <x y z> dir <x z>
//     km <km|-> number <label|-> source <designed|measured>
std::string word(std::string const &Text)
{
	if (Text.empty())
		return "-";
	auto result{Text};
	std::replace(result.begin(), result.end(), ' ', '_');
	return result;
}

glm::dvec2 direction_of(TTrack const &Track)
{
	geometry::bezier const curve{Track.m_paths.front()};
	auto const direction{plan_of(curve.first(0.0))};
	return glm::length(direction) > 1e-12 ? glm::normalize(direction) : glm::dvec2{0.0, 1.0};
}

TTrack *usable(std::string const &Name)
{
	if (Name.empty() || Name == "-")
		return nullptr;
	auto *track{simulation::Paths.find(Name)};
	return track != nullptr && false == track->m_editorremoved && false == track->m_paths.empty() ? track : nullptr;
}

bool in_place(record const &Record, TTrack const &Track)
{
	return geometry::plan_distance(Track.m_paths.front().points[segment_data::point::start], Record.start) <= kTolerance && glm::dot(direction_of(Track), Record.direction) > 0.9999;
}

glm::dvec4 measure(TTrack const &Track)
{
	auto const &main{Track.m_paths.front()};
	auto const start{plan_of(main.points[segment_data::point::start])};
	auto const along{direction_of(Track)};
	glm::dvec2 const across{-along.y, along.x};
	auto const local = [&](glm::dvec3 const &Point) {
		auto const offset{plan_of(Point) - start};
		return glm::dvec2{glm::dot(offset, along), glm::dot(offset, across)};
	};
	auto const mainend{local(main.points[segment_data::point::end])};
	auto const branchend{Track.m_paths.size() > 1 ? local(Track.m_paths[1].points[segment_data::point::end]) : glm::dvec2{0.0}};
	return {mainend.x, mainend.y, branchend.x, branchend.y};
}

bool in_shape(record const &Record, TTrack const &Track)
{
	if (false == Record.shaped)
		return in_place(Record, Track);
	auto const now{measure(Track)};
	for (int i = 0; i < 4; ++i)
		if (std::abs(now[i] - Record.shape[i]) > kTolerance)
			return false;
	return true;
}

void mark(scene::layer_handle const Layer)
{
	if (false == scene::Layers.valid(Layer))
		return;
	auto const &context{scene::Layers.layer(Layer).context_insert()};
	std::vector<std::string> lines;
	for (auto const &entry : g_records)
	{
		if (entry.layer != Layer)
			continue;
		if (lines.empty())
			lines.emplace_back("# switches placed in the track editor, the simulation skips these lines");
		auto const start{context.to_local(entry.start)};
		auto const ahead{context.to_local(entry.start + glm::dvec3{entry.direction.x, 0.0, entry.direction.y})};
		auto direction{plan_of(ahead - start)};
		direction = glm::length(direction) > 1e-12 ? glm::normalize(direction) : entry.direction;
		auto text{format("%s %s %s %s %.3f %.3f %c %.3f %.3f %.3f parts %zu", entry.kind.c_str(), word(entry.name).c_str(), word(entry.type).c_str(), word(entry.rail).c_str(), entry.radius, entry.ratio, entry.hand, entry.a, entry.b, entry.main_radius,
		                 entry.parts.size())};
		for (auto const &part : entry.parts)
			text += ' ' + word(part);
		if (entry.shaped)
			text += format(" shape %.4f %.4f %.4f %.4f", entry.shape.x, entry.shape.y, entry.shape.z, entry.shape.w);
		text += format(" start %.4f %.4f %.4f dir %.9f %.9f km ", start.x, start.y, start.z, direction.x, direction.y);
		text += entry.km.has_value() ? format("%.3f", *entry.km / 1000.0) : std::string{"-"};
		text += " number " + word(entry.number) + " source " + word(entry.source);
		lines.push_back(text);
	}
	scene::Layers.mark(Layer, kMark, std::move(lines));
}

} // namespace

void reset()
{
	g_records.clear();
	g_base.clear();
	g_changed = false;
	g_loaded = false;
}

void load()
{
	if (g_loaded || scene::Layers.empty())
		return;
	g_loaded = true;
	g_records.clear();
	for (auto const layer : scene::Layers.marked_layers(kMark))
	{
		auto const &context{scene::Layers.layer(layer).context_insert()};
		for (auto const &text : scene::Layers.marked(layer, kMark))
		{
			std::istringstream line{text};
			record entry;
			entry.layer = layer;
			std::string keyword, hand, km;
			std::size_t count{0};
			line >> entry.kind;
			if (entry.kind != "switch" && entry.kind != "slip" && entry.kind != "crossing")
				continue;
			line >> entry.name >> entry.type >> entry.rail >> entry.radius >> entry.ratio >> hand >> entry.a >> entry.b >> entry.main_radius >> keyword >> count;
			if (line.fail() || keyword != "parts" || count > 64)
				continue;
			entry.hand = hand.empty() ? '-' : hand.front();
			entry.parts.resize(count);
			for (auto &part : entry.parts)
				line >> part;
			glm::dvec3 start{0.0}, ahead{0.0};
			glm::dvec2 direction{0.0, 1.0};
			line >> keyword;
			if (keyword == "shape")
			{
				line >> entry.shape.x >> entry.shape.y >> entry.shape.z >> entry.shape.w >> keyword;
				entry.shaped = true;
			}
			line >> start.x >> start.y >> start.z >> keyword >> direction.x >> direction.y >> keyword >> km >> keyword >> entry.number >> keyword >> entry.source;
			if (line.fail())
				continue;
			entry.start = context.to_world(start);
			ahead = context.to_world(start + glm::dvec3{direction.x, 0.0, direction.y});
			entry.direction = plan_of(ahead - entry.start);
			entry.direction = glm::length(entry.direction) > 1e-12 ? glm::normalize(entry.direction) : glm::dvec2{0.0, 1.0};
			if (km != "-")
				entry.km = std::stod(km) * 1000.0;
			g_records.push_back(std::move(entry));
		}
	}
	g_base = g_records;
	g_changed = false;
	if (false == g_records.empty())
		WriteLog("Editor: " + std::to_string(g_records.size()) + " switch record(s) read from the scenery", logtype::generic);
}

std::vector<record> const &records()
{
	load();
	return g_records;
}

std::optional<record> named(TTrack const &Track)
{
	load();
	auto const &name{Track.name()};
	if (name.empty())
		return std::nullopt;
	for (auto const &entry : g_records)
		if (std::find(entry.parts.begin(), entry.parts.end(), name) != entry.parts.end())
			return entry;
	return std::nullopt;
}

std::optional<record> of(TTrack const &Track)
{
	auto const found{named(Track)};
	if (false == found.has_value())
		return std::nullopt;
	auto const *first{usable(found->parts.front())};
	if (first == nullptr || false == in_shape(*found, *first))
		return std::nullopt;
	return found;
}

std::vector<std::string> follow()
{
	load();
	std::vector<std::string> moved;
	std::set<scene::layer_handle> layers;
	for (auto &entry : g_records)
	{
		auto const *first{usable(entry.parts.front())};
		if (first == nullptr || false == entry.shaped || false == in_shape(entry, *first) || in_place(entry, *first))
			continue;
		entry.start = first->m_paths.front().points[segment_data::point::start];
		entry.direction = direction_of(*first);
		entry.km = alignment_store::chainage_at(entry.start);
		moved.push_back(entry.name);
		layers.insert(entry.layer);
	}
	for (auto const layer : layers)
		mark(layer);
	g_changed = g_changed || false == moved.empty();
	return moved;
}

double branch_radius(record const &Record)
{
	if (Record.radius <= 0.0)
		return 0.0;
	auto const side{Record.hand == 'L' ? -1.0 : 1.0};
	auto const curvature{side / Record.radius + (Record.main_radius != 0.0 ? 1.0 / Record.main_radius : 0.0)};
	return std::abs(curvature) > 1e-9 ? 1.0 / std::abs(curvature) : 0.0;
}

void put(record Entry, scene::layer_handle const Layer)
{
	load();
	if (auto const *first{usable(Entry.parts.empty() ? std::string{} : Entry.parts.front())})
	{
		Entry.shape = measure(*first);
		Entry.shaped = true;
	}
	auto const existing{std::find_if(g_records.begin(), g_records.end(), [&](record const &Other) { return Other.name == Entry.name && Other.kind == Entry.kind; })};
	if (existing != g_records.end())
	{
		Entry.layer = existing->layer;
		if (Entry.number == "-")
			Entry.number = existing->number;
		*existing = std::move(Entry);
		g_changed = true;
		mark(existing->layer);
		return;
	}
	Entry.layer = Layer;
	g_records.push_back(std::move(Entry));
	g_changed = true;
	mark(g_records.back().layer);
}

void forget(std::string const &Name)
{
	load();
	std::set<scene::layer_handle> layers;
	for (auto const &entry : g_records)
		if (entry.name == Name)
			layers.insert(entry.layer);
	auto const count{g_records.size()};
	g_records.erase(std::remove_if(g_records.begin(), g_records.end(), [&](record const &Entry) { return Entry.name == Name; }), g_records.end());
	g_changed = g_changed || g_records.size() != count;
	for (auto const layer : layers)
		mark(layer);
}

void tidy()
{
	load();
	follow();
	std::set<scene::layer_handle> layers;
	for (auto &entry : g_records)
	{
		if (entry.kind != "switch" || usable(entry.parts.front()) != nullptr)
			continue;
		for (auto *track : simulation::Paths.sequence())
		{
			if (track == nullptr || track->m_editorremoved || track->eType != tt_Switch || track->m_paths.empty() || track->name().empty() || false == in_place(entry, *track))
				continue;
			entry.name = track->name();
			entry.parts = {entry.name};
			layers.insert(entry.layer);
			break;
		}
	}
	auto const gone = [](record const &Entry) { return std::any_of(Entry.parts.begin(), Entry.parts.end(), [](std::string const &Part) { return usable(Part) == nullptr; }); };
	for (auto const &entry : g_records)
		if (gone(entry))
			layers.insert(entry.layer);
	g_records.erase(std::remove_if(g_records.begin(), g_records.end(), gone), g_records.end());
	for (auto const layer : layers)
		mark(layer);
	g_changed = g_changed || false == layers.empty();
}

std::string label(record const &Record)
{
	auto text{Record.type};
	if (Record.rail != "-")
		text += ' ' + Record.rail + '-';
	else
		text += ' ';
	if (Record.radius > 0.0)
		text += format("%.0f-", Record.radius);
	if (Record.ratio > 0.0)
		text += format(std::abs(Record.ratio - std::round(Record.ratio)) < 1e-3 ? "1:%.0f" : "1:%.1f", Record.ratio);
	if (Record.hand == 'L' || Record.hand == 'R')
		text += ' ' + std::string(1, Record.hand == 'L' ? 'L' : 'P');
	if (Record.main_radius != 0.0)
		text += format(", Rg %.0f", std::abs(Record.main_radius));
	return text;
}

std::optional<std::vector<record>> take_changes()
{
	if (false == g_changed)
		return std::nullopt;
	auto before{std::move(g_base)};
	g_base = g_records;
	g_changed = false;
	return before;
}

void settle()
{
	g_base = g_records;
	g_changed = false;
}

void restore(std::vector<record> Records)
{
	std::set<scene::layer_handle> layers;
	for (auto const *list : {&g_records, &Records})
		for (auto const &entry : *list)
			layers.insert(entry.layer);
	g_records = std::move(Records);
	for (auto const layer : layers)
		mark(layer);
	settle();
}

void place(record &Entry, TTrack const &First)
{
	auto const &main{First.m_paths.front()};
	geometry::bezier const curve{main};
	Entry.start = main.points[segment_data::point::start];
	auto const direction{geometry::plan_of(curve.first(0.0))};
	Entry.direction = glm::length(direction) > 1e-12 ? glm::normalize(direction) : glm::dvec2{0.0, 1.0};
	Entry.km = alignment_store::chainage_at(Entry.start);
}

void classify(record &Entry, TTrack const &Switch)
{
	geometry::bezier const main{Switch.m_paths[0]};
	auto const &diverging{Switch.m_paths[1]};
	Entry.hand = geometry::cross(Entry.direction, geometry::plan_of(diverging.points[segment_data::point::end] - Entry.start)) > 0.0 ? 'R' : 'L';
	auto const first{geometry::plan_of(main.first(0.0))};
	auto const last{geometry::plan_of(main.first(1.0))};
	auto const turn{glm::length(first) > 1e-12 && glm::length(last) > 1e-12 ? geometry::signed_angle(glm::normalize(first), glm::normalize(last)) : 0.0};
	Entry.main_radius = std::abs(turn) > 1e-6 ? main.plan_length() / turn : 0.0;
	if (std::abs(Entry.main_radius) > 20000.0)
		Entry.main_radius = 0.0;
	if (Entry.type == "Rz" || Entry.type == "Rlj" || Entry.type == "Rld")
		Entry.type = Entry.main_radius == 0.0 ? "Rz" : (Entry.main_radius > 0.0) == (Entry.hand == 'R') ? "Rlj" : "Rld";
}

} // namespace switch_store