////////////////////////////////////////////////////////////////////////////////
//
// Copyright 2006 - 2019, 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>
#include <iostream>
#include <algorithm>
#include <sstream>
#include <vector>
#include <string>
#include <stdlib.h>
#include <inttypes.h>
#include <Context.h>
#include <Datetime.h>
#include <Duration.h>
#include <Lexer.h>
#include <main.h>
#include <shared.h>
#include <format.h>

static void countTasks (const std::vector <Task>&, const std::string&, int&, int&);

////////////////////////////////////////////////////////////////////////////////
// Converts a vector of tasks to a human-readable string that represents the tasks.
std::string taskIdentifiers (const std::vector <Task>& tasks)
{
  std::vector <std::string> identifiers;
  for (auto task: tasks)
    identifiers.push_back (task.identifier (true));

  return join (", ", identifiers);
}

////////////////////////////////////////////////////////////////////////////////
std::string taskDifferences (const Task& before, const Task& after)
{
  // Attributes are all there is, so figure the different attribute names
  // between before and after.
  std::vector <std::string> beforeAtts;
  for (auto& att : before.data)
    beforeAtts.push_back (att.first);

  std::vector <std::string> afterAtts;
  for (auto& att : after.data)
    afterAtts.push_back (att.first);

  std::vector <std::string> beforeOnly;
  std::vector <std::string> afterOnly;
  listDiff (beforeAtts, afterAtts, beforeOnly, afterOnly);

  // Now start generating a description of the differences.
  std::stringstream out;
  for (auto& name : beforeOnly)
    out << "  - "
        << format ("{1} will be deleted.", Lexer::ucFirst (name))
        << "\n";

  for (auto& name : afterOnly)
  {
    if (name == "depends")
    {
      auto deps_after = after.getDependencyTasks ();

      out << "  - "
          << format ("Dependencies will be set to '{1}'.", taskIdentifiers (deps_after))
          << "\n";
    }
    else
      out << "  - "
          << format ("{1} will be set to '{2}'.",
                     Lexer::ucFirst (name),
                     renderAttribute (name, after.get (name)))
          << "\n";
  }

  for (auto& name : beforeAtts)
  {
    // Ignore UUID differences, and find values that changed, but are not also
    // in the beforeOnly and afterOnly lists, which have been handled above..
    if (name              != "uuid" &&
        before.get (name) != after.get (name) &&
        std::find (beforeOnly.begin (), beforeOnly.end (), name) == beforeOnly.end () &&
        std::find (afterOnly.begin (),  afterOnly.end (),  name) == afterOnly.end ())
    {
      if (name == "depends")
      {
        auto deps_before = before.getDependencyTasks ();
        std::string from = taskIdentifiers (deps_before);

        auto deps_after = after.getDependencyTasks ();
        std::string to = taskIdentifiers (deps_after);

        out << "  - "
            << format ("Dependencies will be changed from '{1}' to '{2}'.", from, to)
            << "\n";
      }
      else
        out << "  - "
            << format ("{1} will be changed from '{2}' to '{3}'.",
                       Lexer::ucFirst (name),
                       renderAttribute (name, before.get (name)),
                       renderAttribute (name, after.get (name)))
            << "\n";
    }
  }

  // Shouldn't just say nothing.
  if (out.str ().length () == 0)
    out << "  - No changes will be made.\n";

  return out.str ();
}

////////////////////////////////////////////////////////////////////////////////
std::string taskInfoDifferences (
  const Task& before,
  const Task& after,
  const std::string& dateformat,
  long& last_timestamp,
  const long current_timestamp)
{
  // Attributes are all there is, so figure the different attribute names
  // between before and after.
  std::vector <std::string> beforeAtts;
  for (auto& att : before.data)
    beforeAtts.push_back (att.first);

  std::vector <std::string> afterAtts;
  for (auto& att : after.data)
    afterAtts.push_back (att.first);

  std::vector <std::string> beforeOnly;
  std::vector <std::string> afterOnly;
  listDiff (beforeAtts, afterAtts, beforeOnly, afterOnly);

  // Now start generating a description of the differences.
  std::stringstream out;
  for (auto& name : beforeOnly)
  {
    if (name == "depends")
    {
        out << format ("Dependencies '{1}' deleted.", taskIdentifiers (before.getDependencyTasks ()))
            << "\n";
    }
    else if (name.substr (0, 11) == "annotation_")
    {
      out << format ("Annotation '{1}' deleted.\n", before.get (name));
    }
    else if (name == "start")
    {
      out << format ("{1} deleted (duration: {2}).",
                     Lexer::ucFirst (name),
                     Duration (current_timestamp - last_timestamp).format ())
          << "\n";
    }
    else
    {
      out << format ("{1} deleted.\n", Lexer::ucFirst (name));
    }
  }

  for (auto& name : afterOnly)
  {
    if (name == "depends")
    {
      out << format ("Dependencies set to '{1}'.", taskIdentifiers (after.getDependencyTasks ()))
          << "\n";
    }
    else if (name.substr (0, 11) == "annotation_")
    {
      out << format ("Annotation of '{1}' added.\n", after.get (name));
    }
    else
    {
      if (name == "start")
          last_timestamp = current_timestamp;

      out << format ("{1} set to '{2}'.",
                     Lexer::ucFirst (name),
                     renderAttribute (name, after.get (name), dateformat))
          << "\n";
    }
  }

  for (auto& name : beforeAtts)
    if (name              != "uuid" &&
        name              != "modified" &&
        before.get (name) != after.get (name) &&
        before.get (name) != "" &&
        after.get (name)  != "")
    {
      if (name == "depends")
      {
        auto from = taskIdentifiers (before.getDependencyTasks ());
        auto to   = taskIdentifiers (after.getDependencyTasks ());

        out << format ("Dependencies changed from '{1}' to '{2}'.\n", from, to);
      }
      else if (name.substr (0, 11) == "annotation_")
      {
        out << format ("Annotation changed to '{1}'.\n", after.get (name));
      }
      else
        out << format ("{1} changed from '{2}' to '{3}'.",
                       Lexer::ucFirst (name),
                       renderAttribute (name, before.get (name), dateformat),
                       renderAttribute (name, after.get (name), dateformat))
            << "\n";
    }

  // Shouldn't just say nothing.
  if (out.str ().length () == 0)
    out << "No changes made.\n";

  return out.str ();
}

////////////////////////////////////////////////////////////////////////////////
std::string renderAttribute (const std::string& name, const std::string& value, const std::string& format /* = "" */)
{
  if (Context::getContext ().columns.find (name) != Context::getContext ().columns.end ())
  {
    Column* col = Context::getContext ().columns[name];
    if (col                    &&
        col->type () == "date" &&
        value != "")
    {
      Datetime d ((time_t)strtol (value.c_str (), nullptr, 10));
      if (format == "")
        return d.toString (Context::getContext ().config.get ("dateformat"));

      return d.toString (format);
    }
  }

  return value;
}

////////////////////////////////////////////////////////////////////////////////
// Implements:
//    <string>
void feedback_affected (const std::string& effect)
{
  if (Context::getContext ().verbose ("affected"))
    std::cout << effect << "\n";
}

////////////////////////////////////////////////////////////////////////////////
// Implements:
//    Deleted 3 tasks
//
// The 'effect' string should contain:
//    {1}    Quantity
void feedback_affected (const std::string& effect, int quantity)
{
  if (Context::getContext ().verbose ("affected"))
    std::cout << format (effect, quantity)
              << "\n";
}

////////////////////////////////////////////////////////////////////////////////
// Implements:
//    Deleting task 123 'This is a test'
//
// The 'effect' string should contain:
//    {1}    ID
//    {2}    Description
void feedback_affected (const std::string& effect, const Task& task)
{
  if (Context::getContext ().verbose ("affected"))
  {
    std::cout << format (effect,
                         task.identifier (true),
                         task.get ("description"))
              << "\n";
  }
}

////////////////////////////////////////////////////////////////////////////////
// Implements feedback and error when adding a reserved tag name.
void feedback_reserved_tags (const std::string& tag)
{
  // Note: This list must match that in Task::hasTag.
  // Note: This list must match that in CmdInfo::execute.
  if (tag == "ACTIVE"    ||
      tag == "ANNOTATED" ||
      tag == "BLOCKED"   ||
      tag == "BLOCKING"  ||
      tag == "CHILD"     ||   // Deprecated 2.6.0
      tag == "COMPLETED" ||
      tag == "DELETED"   ||
      tag == "DUE"       ||
      tag == "DUETODAY"  ||
      tag == "INSTANCE"  ||
      tag == "LATEST"    ||
      tag == "MONTH"     ||
      tag == "ORPHAN"    ||
      tag == "OVERDUE"   ||
      tag == "PARENT"    ||   // Deprecated 2.6.0
      tag == "PENDING"   ||
      tag == "PRIORITY"  ||
      tag == "PROJECT"   ||
      tag == "READY"     ||
      tag == "SCHEDULED" ||
      tag == "TAGGED"    ||
      tag == "TEMPLATE"  ||
      tag == "TODAY"     ||
      tag == "TOMORROW"  ||
      tag == "UDA"       ||
      tag == "UNBLOCKED" ||
      tag == "UNTIL"     ||
      tag == "WAITING"   ||
      tag == "WEEK"      ||
      tag == "YEAR"      ||
      tag == "YESTERDAY")
  {
    throw format ("Virtual tags (including '{1}') are reserved and may not be added or removed.", tag);
  }
}

////////////////////////////////////////////////////////////////////////////////
// Implements feedback when adding special tags to a task.
void feedback_special_tags (const Task& task, const std::string& tag)
{
  if (Context::getContext ().verbose ("special"))
  {
    std::string msg;
    std::string explanation;
         if (tag == "nocolor") msg = "The 'nocolor' special tag will disable color rules for this task.";
    else if (tag == "nonag")   msg = "The 'nonag' special tag will prevent nagging when this task is modified.";
    else if (tag == "nocal")   msg = "The 'nocal' special tag will keep this task off the 'calendar' report.";
    else if (tag == "next")    msg = "The 'next' special tag will boost the urgency of this task so it appears on the 'next' report.";

    if (msg.length ())
    {
      std::cout << format (msg, task.identifier ())
                << "\n";
    }
  }
}

////////////////////////////////////////////////////////////////////////////////
// Called on completion, deletion and update.  If this task is blocking another
// task, then if this was the *only* blocking task, that other task is now
// unblocked.  Mention it.
//
// Implements:
//    Unblocked <id> '<description>'
void feedback_unblocked (const Task& task)
{
  if (Context::getContext ().verbose ("affected"))
  {
    // Get a list of tasks that depended on this task.
    auto blocked = dependencyGetBlocked (task);

    // Scan all the tasks that were blocked by this task
    for (auto& i : blocked)
    {
      auto blocking = dependencyGetBlocking (i);
      if (blocking.size () == 0)
      {
        if (i.id)
          std::cout << format ("Unblocked {1} '{2}'.",
                               i.id,
                               i.get ("description"))
                    << "\n";
        else
        {
          std::string uuid = i.get ("uuid");
          std::cout << format ("Unblocked {1} '{2}'.",
                               i.get ("uuid"),
                               i.get ("description"))
                    << "\n";
        }
      }
    }
  }
}

///////////////////////////////////////////////////////////////////////////////
void feedback_backlog ()
{
  if (Context::getContext ().config.get ("taskd.server") != "" &&
      Context::getContext ().verbose ("sync"))
  {
    int count = 0;
    std::vector <std::string> lines = Context::getContext ().tdb2.backlog.get_lines ();
    for (auto& line : lines)
      if ((line)[0] == '{')
        ++count;

    if (count)
      Context::getContext ().footnote (format (count > 1 ?  "There are {1} local changes.  Sync required."
                                                         : "There is {1} local change.  Sync required.", count));
  }
}

///////////////////////////////////////////////////////////////////////////////
std::string onProjectChange (Task& task, bool scope /* = true */)
{
  std::stringstream msg;
  std::string project = task.get ("project");

  if (project != "")
  {
    if (scope)
      msg << format ("The project '{1}' has changed.", project)
          << "  ";

    // Count pending and done tasks, for this project.
    int count_pending = 0;
    int count_done = 0;
    std::vector <Task> all = Context::getContext ().tdb2.all_tasks ();
    countTasks (all, project, count_pending, count_done);

    // count_done  count_pending  percentage
    // ----------  -------------  ----------
    //          0              0          0%
    //         >0              0        100%
    //          0             >0          0%
    //         >0             >0  calculated
    int percentage = 0;
    if (count_done == 0)
      percentage = 0;
    else if (count_pending == 0)
      percentage = 100;
    else
      percentage = (count_done * 100 / (count_done + count_pending));

    msg << format ("Project '{1}' is {2}% complete", project, percentage)
        << ' ';

    if (count_pending == 1 && count_done == 0)
      msg << format ("({1} task remaining).", count_pending);
    else
      msg << format ("({1} of {2} tasks remaining).", count_pending, count_pending + count_done);
  }

  return msg.str ();
}

///////////////////////////////////////////////////////////////////////////////
std::string onProjectChange (Task& task1, Task& task2)
{
  if (task1.get ("project") == task2.get ("project"))
    return onProjectChange (task1, false);

  std::string messages1 = onProjectChange (task1);
  std::string messages2 = onProjectChange (task2);

  if (messages1.length () && messages2.length ())
    return messages1 + '\n' + messages2;

  return messages1 + messages2;
}

///////////////////////////////////////////////////////////////////////////////
std::string onExpiration (Task& task)
{
  std::stringstream msg;

  if (Context::getContext ().verbose ("affected"))
    msg << format ("Task {1} '{2}' expired and was deleted.",
                   task.identifier (true),
                   task.get ("description"));

  return msg.str ();
}

///////////////////////////////////////////////////////////////////////////////
static void countTasks (
  const std::vector <Task>& all,
  const std::string& project,
  int& count_pending,
  int& count_done)
{
  for (auto& it : all)
  {
    if (it.get ("project") == project)
    {
      switch (it.getStatus ())
      {
      case Task::pending:
      case Task::waiting:
        ++count_pending;
        break;

      case Task::completed:
        ++count_done;
        break;

      case Task::deleted:
      case Task::recurring:
      default:
        break;
      }
    }
  }
}

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