// Entry object
function entry(){
    this.id=ko.observable();
    this.value_date=ko.observable();
    this.operation_date=ko.observable();
    this.label=ko.observable();
    this.value=ko.observable();
    this.account_id=ko.observable();
    this.sold=ko.observable();
    this.pointedsold=ko.observable();
    this.category=ko.observable();
}

// Account object
function account() {
    this.id=ko.observable();
    this.name=ko.observable();
    this.future=ko.observable();
    this.current=ko.observable();
    this.pointed=ko.observable();
}

// Month object
function month() {
    this.year=ko.observable();
    this.month=ko.observable();
}

// Util function to show a message in message placeholder.
function message(alertType, title, message) {
  $(".alert").alert('close');
  $("#message-placeholder").append('<div class="alert alert-' + alertType + '"><button type="button" class="close" data-dismiss="alert">&times;</button><h4>' + title + '</h4>' + message + '</div>');
}

// The ListViewModel used to instanciate viewmodel.
var ListViewModel = function() {
    var self = this;

    // Account store and selection
    self.account = ko.observable();
    self.accounts = ko.observableArray([]);

    // Month store and selection
    self.months = ko.observableArray();
    self.month = ko.observable();

    // Entry store and selection
    self.entries = ko.observableArray([]);
    self.selectedItem = ko.observable();

    // Placeholder for saved value to cancel entry edition
    self.savedItem = null;

    // Placeholder for entry to remove to be available in modal function "yes" click callback
    self.itemToRemove = ko.observable();

    // Returns the data for the categories by summing values with same category
    self.expenseCategoriesChart = ko.computed(function() {
      var unwrap = ko.utils.unwrapObservable;

      var entries=unwrap(self.entries);

      // First pass: get sum values for each category.
      var chartValuesTmp = {};
      $.each(entries, function(index, entry) {
        var category = unwrap(entry.category);
        var value = unwrap(entry.value) ? Number(unwrap(entry.value)) : null;

        if(category && value && value < 0.0) {
          var oldValue = 0.0;

          if(chartValuesTmp[category]) {
            oldValue = chartValuesTmp[category];
          }

          chartValuesTmp[category] = oldValue - value
        }
      });
 
      // Second pass: transform to an array readable by jqplot.
      var chartValues = [];
      $.each(chartValuesTmp, function(key, value) {
        chartValues.push([key, value]);
      });

      return chartValues;
    });

    // Return the data for the sold chart.
    self.entriesChart = ko.computed(function() {
      var unwrap = ko.utils.unwrapObservable;

      // We assume that entries are sorted by value date descending.
      var entries = unwrap(self.entries).slice().reverse();

      // First pass: get open, high, low and close values for each day.
      var chartValuesTmp = {};
      $.each(entries, function(index, entry) {
        //var date = entry.value_date() ? entry.value_date().toString() : null;
        var date = unwrap(entry.value_date);
        var value = unwrap(entry.value) ? Number(unwrap(entry.value())) : null;

        if(date && value) {
          var values = {};

          var sold = Number(unwrap(entry.sold));
          var open = Number((sold - value).toFixed(2));

          values['open'] = open;
          values['high'] = sold > open ? sold : open;
          values['low'] = sold < open ? sold : open;
          values['close'] = sold;

          if(chartValuesTmp[date]) {
            var oldValues = chartValuesTmp[date];

            if(oldValues['high'] > values['high']) {
              values['high'] = oldValues['high'];
            }

            if(oldValues['low'] < values['low']) {
              values['low'] = oldValues['low'];
            }

            values['open'] = oldValues['open'];
          }

          chartValuesTmp[date] = values;
        }
      });

      // Second pass: transform to an array readable by jqplot OHLC renderer.
      var chartValues = [];
      $.each(chartValuesTmp, function(key, value) {
        chartValues.push([key, value['open'], value['high'], value['low'], value['close']]);
      });

      return chartValues;
    }, self);

    // Function to load entries from server for a specific account and month.
    self.loadEntries = function(account, month) {
      $.get("api/entries/" + account.id() + "/" + month.year() + "/" + month.month()).success(function(data) {
          // Clean up selected entry.
          self.selectedItem(null);

          // Update entries
          self.entries(ko.utils.arrayMap($.parseJSON(data), ko.mapping.fromJS));
      });
    };

    // Function to load accounts
    self.loadAccounts = function() {
      $.get("api/accounts").success(function (data) {
        // Update accounts
        self.accounts(ko.utils.arrayMap($.parseJSON(data), ko.mapping.fromJS));

        // Reset selected account to the new instance corresponding to the old one.
        if(self.account()) {
          var oldId = self.account().id();

          // Reset to null
          self.account(null);

          // Find the new instance of the previously selected account.
          $.each(self.accounts(), function(index, account) {
            if(account.id() == oldId) {
              self.account(account);
            }
          });
        }

        // Set selected account to first one if not yet selected
        if(!self.account()){
          self.account(self.accounts()[0]);
        }

        // Load months
        self.loadMonths(self.account());
      });
    };

    // Function to load months
    self.loadMonths = function(account){
      $.get("api/accounts/" + account.id() + "/months").success(function (data) {
        // Update months
        self.months(ko.utils.arrayMap($.parseJSON(data), ko.mapping.fromJS));
        
        // Reset selected month to the new instance corresponding to the old one
        if(self.month()) {
          var oldYear = self.month().year();
          var oldMonth = self.month().month();

          // Reset to null
          self.month(null);

          // Find the new instance of the previously selected month.
          $.each(self.months(), function(index, month) {
            if(month.year() == oldYear && month.month() == oldMonth) {
              self.month(month);
            }
          });
        }

        // Set selected month to the last one if not yet selected.
        if(!self.month()) {
          self.month(self.months()[self.months().length - 1]);
        }

        // Load entries
        self.loadEntries(self.account(), self.month());
      });
    };

    // Function to select template in function of selected item.
    self.templateToUse = function (item) {
      return self.selectedItem() === item ? 'editTmpl' : 'itemsTmpl';
    };

    // Function to edit an item
    self.edit = function(item) {
      // Cancel previous editing.
      if(self.savedItem) {
        self.cancel();
      }

      // Save current item
      self.savedItem=ko.toJS(item);
      self.selectedItem(item);

      // Initialize date picker for value date column.
      $("#value_date").datepicker().on('changeDate', function(ev){
        self.selectedItem().value_date(ev.date.format(ev.currentTarget.dataset.dateFormat));
      });

      // Initialize date picker for operation date column.
      $("#operation_date").datepicker().on('changeDate', function(ev){
        self.selectedItem().operation_date(ev.date.format(ev.currentTarget.dataset.dateFormat));
      });
    };

    // Function to cancel current editing.
    self.cancel = function() {
      // Reset selected item fields to saved item ones.
      if(self.selectedItem() && self.savedItem) {
        self.selectedItem().id(self.savedItem.id); // id should not change, but just in case...
        self.selectedItem().operation_date(self.savedItem.operation_date);
        self.selectedItem().value_date(self.savedItem.value_date);
        self.selectedItem().label(self.savedItem.label);
        self.selectedItem().value(self.savedItem.value);
        self.selectedItem().account_id(self.savedItem.account_id); // account_id should not change, but just in case...
      }

      // This item was just added: remove it from the entries array.
      if(self.selectedItem() && !self.selectedItem().id()) {
        self.entries.remove(self.selectedItem());
      }

      // Reset saved and selected items to null.
      self.savedItem = null;
      self.selectedItem(null);
    };

    // Function to add a new entry.
    self.add = function() {
      self.entries.unshift(ko.mapping.fromJS({
        id: null,
        value_date: null,
        operation_date: null,
        label: null,
        value: null,
        sold: null,
        pointedsold: null,
        category: null,
        account_id: self.account().id()
      }));

      self.edit(self.entries()[0]);
    };

    // Function to save the current selected entry.
    self.save = function() {
      var item = self.selectedItem();

      // Ajax call to save the entry.
      var type;
      var url = "api/entries/";

      if(item.id()) {
        type = "PUT";
        url += "save/" + item.id();
      } else {
        type = "POST";
        url += "add";
      }

      $.ajax({url: url, type: type, data:ko.toJSON(item)}).success(function(data) {
        message("success", "Save", data);

        self.selectedItem(null);
        self.savedItem = null;

        // Reload accounts to update solds.
        self.loadAccounts();
      });
    };

    // Function to remove an entry.
    self.remove = function (item) {
      // Cancel current editing.
      self.cancel();

      if (item.id()) {
        // This entry is saved in database, we show a modal dialog to confirm the removal.
        self.removedItem = item;
        $('#remove-confirm').modal();
      } else {
        // This entry was not saved in database yet, we just remove it from the list.
        self.entries.remove(item);
      }
    };

    // Function to confirm the removal of an entry.
    self.confirmRemove = function() {
      var item = self.removedItem;

      $.ajax("api/entries/" + ko.utils.unwrapObservable(item.id), {type: "DELETE"}).success(function (result) {
        // Reload accounts to update solds.
        self.loadAccounts();
      }).complete(function (result) {
        // Reset removed item to null and hide the modal dialog.
        self.removedItem = null;
        $('#remove-confirm').modal('hide');
      });
    };

    // Callback function to select a new month.
    self.selectMonth = function(month) {
      if(month) {
        self.month(month);
        self.loadEntries(self.account(), month);
      }
    };

    // Callback function to select a new account.
    self.selectAccount = function(account) {
      if(account) {
        self.account(account);
        self.loadMonths(account);
      }
    };
};

// Function to draw the sold evolution chart.
drawChart = function(entries, element) {
  // Clear previous chart
  $(element).html("");

  if(entries && entries.length > 0) {
    // Prepare for today vertical line.
    var today = new Date();
    today.setHours(0);
    today.setMinutes(0);

    // Find first and last days to set limits of the x axis.
    var day = 24 * 60 * 60 * 1000;
    var firstDate = new Date(Date.parse(entries[0][0]).valueOf() - day).format('yyyy-mm-dd');
    var lastDate = new Date(Date.parse(entries[entries.length -1][0]).valueOf() + day).format('yyyy-mm-dd');

    // Plot chart, and store it in a window parameter for resize callback (need to be done better than it...)
    window.chart = $.jqplot(element.id, [entries], {
        // Title of the chart
        title: "&Eacute;volution du solde",
        axes:{
          // Parameters for the date axis
          xaxis:{
            autoscale: true,

            // Date rendere for this axis
            renderer:$.jqplot.DateAxisRenderer,

            // Limits
            min: firstDate,
            max: lastDate,

            // Tick options
            tickOptions: {
              // Format date for x axis.
              formatString: "%F"
            }
          },
          // Parameters for the value axis
          yaxis: {
            autoscale: true,
          }
        },

        // Highlighter parameters
        highlighter: {
          show: true,
          yvalues: 4,
          formatString: '<table class="jqplot-highlighter"><tr><td>date:</td><td>%s</td></tr><tr><td>open:</td><td>%s</td></tr><tr><td>hi:</td><td>%s</td></tr><tr><td>low:</td><td>%s</td></tr><tr><td>close:</td><td>%s</td></tr></table>'
        },

        // Series parameters
        series: [{
          // We use the OHLC (open, high, low, close) rendered.
          renderer:$.jqplot.OHLCRenderer,
          color: "blue",
        }],

        // To display horizontal (0) and vertical (today) lines
        canvasOverlay: {
          show: true,
          objects: [
            // Red horizontal line for 0 limit
            {dashedHorizontalLine: {
              name: "zero",
              y: 0,
              lineWidth: 1,
              color: "red",
              shadow: false
            }},
            // Gray vertical line for today
            { dashedVerticalLine: {
              name: "today",
              x: today,
              lineWidth: 1,
              color: "gray",
              shadow: false
            }}
          ]
        }
    });
  } else {
    // Reset chart to null to avoid redraw of a non existing chart in resize callback.
    window.chart = null;
  }
};

// Function to draw the expense category pie chart.
drawPieChart = function(entries, element) {
  // Clear previous chart
  $(element).html("");

  if(entries && entries.length > 0) {
    // Plot chart, and store it in a window parameter for resize callback (need to be done better than it...)
    window.pieChart = $.jqplot(element.id, [entries], {
        // Title of the chart
        title: "D&eacute;penses",

        // Series parameters.
        seriesDefaults: {
          // Pie chart renderer
          renderer: $.jqplot.PieRenderer,
          rendererOptions: {
            showDataLabels: true
          }
        },

        // Legend parameters.
        legend: {
          show: true,
          location: 'e'
        },

        // Highlighter parameters;
        highlighter: {
          show: true,
          formatString:'%s: %s', 
          tooltipLocation:'sw', 
          useAxesFormatters:false
        }
    });
  } else {
    // Reset chart to null to avoid redraw of a non existing chart in resize callback.
    window.pieChart = null;
  }
};

// Chart binding to redraw the chart on entries update.
ko.bindingHandlers.chart = {
    init: function (element, valueAccessor, allBindingsAccessor, viewModel) {
      // empty - left as placeholder if needed later
    },

    update: function (element, valueAccessor, allBindingsAccessor, viewModel) {
      var unwrap = ko.utils.unwrapObservable;
      var dataSource = valueAccessor();

      var entries = dataSource ? unwrap(dataSource) : null;
      drawChart(entries, element);
    }
};

// Pie chart binding to redraw expense chart on entries update.
ko.bindingHandlers.pieChart = {
    init: function (element, valueAccessor, allBindingsAccessor, viewModel) {
      // empty - left as placeholder if needed later
    },

    update: function (element, valueAccessor, allBindingsAccessor, viewModel) {
      var unwrap = ko.utils.unwrapObservable;
      var dataSource = valueAccessor();

      var entries = dataSource ? unwrap(dataSource) : null;
      drawPieChart(entries, element);
    }
};

// Default AJAX error handler.
$(document).ajaxError(function(event, xhr, settings) {
  message("error", xhr.statusText, xhr.responseText);
});

// Resize callback.
$(window).resize(function() {
  if(window.chart) {
    window.chart.replot({resetAxes: true});
  }

  if(window.pieChart) {
    window.pieChart.replot({resetAxes: true});
  }
});

// ViewModal instanciation.
var viewModel = new ListViewModel();
ko.applyBindings(viewModel);

// Load accounts after page initialization.
$(viewModel.loadAccounts);