////////////////////////////////////////////////////////////////////////////////
//
// Copyright 2006 - 2021, Tomas Babej, Paul Beckingham, Federico Hernandez.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
// https://www.opensource.org/licenses/mit-license.php
//
////////////////////////////////////////////////////////////////////////////////

#include <cmake.h>
// cmake.h include header must come first

#include <Context.h>
#include <DOM.h>
#include <Eval.h>
#include <Filter.h>
#include <Timer.h>
#include <Variant.h>
#include <format.h>
#include <shared.h>

#include <algorithm>

////////////////////////////////////////////////////////////////////////////////
// Take an input set of tasks and filter into a subset.
void Filter::subset(const std::vector<Task>& input, std::vector<Task>& output) {
  Timer timer;
  _startCount = (int)input.size();

  Context::getContext().cli2.prepareFilter();

  std::vector<std::pair<std::string, Lexer::Type>> precompiled;
  for (auto& a : Context::getContext().cli2._args)
    if (a.hasTag("FILTER")) precompiled.emplace_back(a.getToken(), a._lextype);

  if (precompiled.size()) {
    Eval eval;
    eval.addSource(domSource);

    // Debug output from Eval during compilation is useful.  During evaluation
    // it is mostly noise.
    eval.debug(Context::getContext().config.getInteger("debug.parser") >= 3 ? true : false);
    eval.compileExpression(precompiled);

    for (auto& task : input) {
      // Set up context for any DOM references.
      auto currentTask = Context::getContext().withCurrentTask(&task);

      Variant var;
      eval.evaluateCompiledExpression(var);
      if (var.get_bool()) output.push_back(task);
    }

    eval.debug(false);
  } else
    output = input;

  _endCount = (int)output.size();
  Context::getContext().debug(
      format("Filtered {1} tasks --> {2} tasks [list subset]", _startCount, _endCount));
  Context::getContext().time_filter_us += timer.total_us();
}

////////////////////////////////////////////////////////////////////////////////
// Take the set of all tasks and filter into a subset.
void Filter::subset(std::vector<Task>& output) {
  Timer timer;
  Context::getContext().cli2.prepareFilter();

  std::vector<std::pair<std::string, Lexer::Type>> precompiled;
  for (auto& a : Context::getContext().cli2._args)
    if (a.hasTag("FILTER")) precompiled.emplace_back(a.getToken(), a._lextype);

  // Shortcut indicates that only pending.data needs to be loaded.
  bool shortcut = false;

  if (precompiled.size()) {
    Timer timer_pending;
    auto pending = Context::getContext().tdb2.pending_tasks();
    Context::getContext().time_filter_us -= timer_pending.total_us();
    _startCount = (int)pending.size();

    Eval eval;
    eval.addSource(domSource);

    // Debug output from Eval during compilation is useful.  During evaluation
    // it is mostly noise.
    eval.debug(Context::getContext().config.getInteger("debug.parser") >= 3 ? true : false);
    eval.compileExpression(precompiled);

    output.clear();
    for (auto& task : pending) {
      // Set up context for any DOM references.
      auto currentTask = Context::getContext().withCurrentTask(&task);

      Variant var;
      eval.evaluateCompiledExpression(var);
      if (var.get_bool()) output.push_back(task);
    }

    shortcut = pendingOnly();
    if (!shortcut) {
      Timer timer_completed;
      auto completed = Context::getContext().tdb2.completed_tasks();
      Context::getContext().time_filter_us -= timer_completed.total_us();
      _startCount += (int)completed.size();

      for (auto& task : completed) {
        // Set up context for any DOM references.
        auto currentTask = Context::getContext().withCurrentTask(&task);

        Variant var;
        eval.evaluateCompiledExpression(var);
        if (var.get_bool()) output.push_back(task);
      }
    }

    eval.debug(false);
  } else {
    safety();

    Timer pending_completed;
    output = Context::getContext().tdb2.all_tasks();
    Context::getContext().time_filter_us -= pending_completed.total_us();
  }

  _endCount = (int)output.size();
  Context::getContext().debug(format("Filtered {1} tasks --> {2} tasks [{3}]", _startCount,
                                     _endCount, (shortcut ? "pending only" : "all tasks")));
  Context::getContext().time_filter_us += timer.total_us();
}

////////////////////////////////////////////////////////////////////////////////
bool Filter::hasFilter() const {
  for (const auto& a : Context::getContext().cli2._args)
    if (a.hasTag("FILTER")) return true;

  return false;
}

////////////////////////////////////////////////////////////////////////////////
// If the filter contains no 'or', 'xor' or 'not' operators, and only includes
// status values 'pending', 'waiting' or 'recurring', then the filter is
// guaranteed to only need data from pending.data.
bool Filter::pendingOnly() const {
  // When GC is off, there are no shortcuts.
  if (!Context::getContext().config.getBoolean("gc")) return false;

  // To skip loading completed.data, there should be:
  // - 'status' in filter
  // - no 'completed'
  // - no 'deleted'
  // - no 'xor'
  // - no 'or'
  int countStatus = 0;
  int countPending = 0;
  int countWaiting = 0;
  int countRecurring = 0;
  int countId = (int)Context::getContext().cli2._id_ranges.size();
  int countUUID = (int)Context::getContext().cli2._uuid_list.size();
  int countOr = 0;
  int countXor = 0;
  int countNot = 0;
  bool pendingTag = false;
  bool activeTag = false;

  for (const auto& a : Context::getContext().cli2._args) {
    if (a.hasTag("FILTER")) {
      std::string raw = a.attribute("raw");
      std::string canonical = a.attribute("canonical");

      if (a._lextype == Lexer::Type::op && raw == "or") ++countOr;
      if (a._lextype == Lexer::Type::op && raw == "xor") ++countXor;
      if (a._lextype == Lexer::Type::op && raw == "not") ++countNot;
      if (a._lextype == Lexer::Type::dom && canonical == "status") ++countStatus;
      if (raw == "pending") ++countPending;
      if (raw == "waiting") ++countWaiting;
      if (raw == "recurring") ++countRecurring;
    }
  }

  for (const auto& word : Context::getContext().cli2._original_args) {
    if (word.attribute("raw") == "+PENDING") pendingTag = true;
    if (word.attribute("raw") == "+ACTIVE") activeTag = true;
  }

  if (countUUID) return false;

  if (countOr || countXor || countNot) return false;

  if (pendingTag || activeTag) return true;

  if (countStatus) {
    if (!countPending && !countWaiting && !countRecurring) return false;

    return true;
  }

  if (countId) return true;

  return false;
}

////////////////////////////////////////////////////////////////////////////////
// Disaster avoidance mechanism. If a !READONLY has no filter, then it can cause
// all tasks to be modified. This is usually not intended.
void Filter::safety() const {
  if (_safety) {
    bool readonly = true;
    bool filter = false;
    for (const auto& a : Context::getContext().cli2._args) {
      if (a.hasTag("CMD") && !a.hasTag("READONLY")) readonly = false;

      if (a.hasTag("FILTER")) filter = true;
    }

    if (!readonly && !filter) {
      if (!Context::getContext().config.getBoolean("allow.empty.filter"))
        throw std::string(
            "You did not specify a filter, and with the 'allow.empty.filter' value, no action is "
            "taken.");

      // If user is willing to be asked, this can be avoided.
      if (Context::getContext().config.getBoolean("confirmation") &&
          confirm("This command has no filter, and will modify all (including completed and "
                  "deleted) tasks.  Are you sure?"))
        return;

      // Sound the alarm.
      throw std::string("Command prevented from running.");
    }
  }
}

////////////////////////////////////////////////////////////////////////////////
void Filter::disableSafety() { _safety = false; }

////////////////////////////////////////////////////////////////////////////////