diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6af67f68..639a9a0b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,6 +27,7 @@ Liste des changements notables dans GestioCOF depuis la version 0.1 (septembre
 
 - Les transferts apparaissent maintenant dans l'historique K-Fêt et l'historique
   personnel.
+- les statistiques K-Fêt remontent à plus d'un an (et le code est simplifié)
 
 ## Version 0.4.1 - 17/01/2020
 
diff --git a/kfet/static/kfet/js/statistic.js b/kfet/static/kfet/js/statistic.js
index 9baa08c4..4da17672 100644
--- a/kfet/static/kfet/js/statistic.js
+++ b/kfet/static/kfet/js/statistic.js
@@ -1,28 +1,15 @@
-(function($){
+(function ($) {
     window.StatsGroup = function (url, target) {
         // a class to properly display statictics
 
         // url : points to an ObjectResumeStat that lists the options through JSON
         // target : element of the DOM where to put the stats
 
-        var self = this;
         var element = $(target);
         var content = $("<div class='full'>");
         var buttons;
 
-        function dictToArray (dict, start) {
-            // converts the dicts returned by JSONResponse to Arrays
-            // necessary because for..in does not guarantee the order
-            if (start === undefined) start = 0;
-            var array = new Array();
-            for (var k in dict) {
-                array[k] = dict[k];
-            }
-            array.splice(0, start);
-            return array;
-        }
-
-        function handleTimeChart (data) {
+        function handleTimeChart(data) {
             // reads the balance data and put it into chartjs formatting
             chart_data = new Array();
             for (var i = 0; i < data.length; i++) {
@@ -36,7 +23,7 @@
             return chart_data;
         }
 
-        function showStats () {
+        function showStats() {
             // CALLBACK : called when a button is selected
 
             // shows the focus on the correct button
@@ -44,24 +31,20 @@
             $(this).addClass("focus");
 
             // loads data and shows it
-            $.getJSON(this.stats_target_url, {format: 'json'}, displayStats);
+            $.getJSON(this.stats_target_url, displayStats);
         }
 
-        function displayStats (data) {
+        function displayStats(data) {
             // reads the json data and updates the chart display
 
             var chart_datasets = [];
-            var charts = dictToArray(data.charts);
-
             // are the points indexed by timestamps?
             var is_time_chart = data.is_time_chart || false;
 
             // reads the charts data
-            for (var i = 0; i < charts.length; i++) {
-                var chart = charts[i];
-
+            for (let chart of data.charts) {
                 // format the data
-                var chart_data =  is_time_chart ? handleTimeChart(chart.values) : dictToArray(chart.values, 0);
+                var chart_data = is_time_chart ? handleTimeChart(chart.values) : chart.values;
 
                 chart_datasets.push(
                     {
@@ -76,29 +59,24 @@
 
             // options for chartjs
             var chart_options =
-                {
-                    responsive: true,
-                    maintainAspectRatio: false,
-                    tooltips: {
-                        mode: 'index',
-                        intersect: false,
-                    },
-                    hover: {
-                        mode: 'nearest',
-                        intersect: false,
-                    }
-                };
+            {
+                responsive: true,
+                maintainAspectRatio: false,
+                tooltips: {
+                    mode: 'index',
+                    intersect: false,
+                },
+                hover: {
+                    mode: 'nearest',
+                    intersect: false,
+                }
+            };
 
             // additionnal options for time-indexed charts
             if (is_time_chart) {
                 chart_options['scales'] = {
                     xAxes: [{
                         type: "time",
-                        display: true,
-                        scaleLabel: {
-                            display: false,
-                            labelString: 'Date'
-                        },
                         time: {
                             tooltipFormat: 'll HH:mm',
                             displayFormats: {
@@ -115,26 +93,19 @@
                         }
 
                     }],
-                    yAxes: [{
-                        display: true,
-                        scaleLabel: {
-                            display: false,
-                            labelString: 'value'
-                        }
-                    }]
                 };
             }
 
             // global object for the options
             var chart_model =
-                {
-                    type: 'line',
-                    options: chart_options,
-                    data: {
-                        labels: data.labels || [],
-                        datasets: chart_datasets,
-                    }
-                };
+            {
+                type: 'line',
+                options: chart_options,
+                data: {
+                    labels: data.labels || [],
+                    datasets: chart_datasets,
+                }
+            };
 
             // saves the previous charts to be destroyed
             var prev_chart = content.children();
@@ -151,27 +122,30 @@
         }
 
         // initialize the interface
-        function initialize (data) {
+        function initialize(data) {
             // creates the bar with the buttons
             buttons = $("<ul>",
-                        {class: "nav stat-nav",
-                         "aria-label": "select-period"});
+                {
+                    class: "nav stat-nav",
+                    "aria-label": "select-period"
+                });
 
             var to_click;
-            var context = data.stats;
 
-            for (var i = 0; i < context.length; i++) {
+            for (let stat of data.stats) {
                 // creates the button
-                var btn_wrapper = $("<li>", {role:"presentation"});
+                var btn_wrapper = $("<li>", { role: "presentation" });
                 var btn = $("<a>",
-                            {class: "btn btn-nav",
-                             type: "button"})
-                    .text(context[i].label)
-                    .prop("stats_target_url", context[i].url)
+                    {
+                        class: "btn btn-nav",
+                        type: "button"
+                    })
+                    .text(stat.label)
+                    .prop("stats_target_url", stat.url)
                     .on("click", showStats);
 
                 // saves the default option to select
-                if (i == data.default_stat || i == 0)
+                if (stat.default)
                     to_click = btn;
 
                 // append the elements to the parent
@@ -189,7 +163,7 @@
 
         // constructor
         (function () {
-            $.getJSON(url, {format: 'json'}, initialize);
+            $.getJSON(url, initialize);
         })();
     };
 })(jQuery);
diff --git a/kfet/statistic.py b/kfet/statistic.py
index 02171267..b2c1d882 100644
--- a/kfet/statistic.py
+++ b/kfet/statistic.py
@@ -1,21 +1,22 @@
 from datetime import date, datetime, time, timedelta
 
-import pytz
 from dateutil.parser import parse as dateutil_parse
 from dateutil.relativedelta import relativedelta
-from django.db.models import Sum
 from django.utils import timezone
 
-KFET_WAKES_UP_AT = time(7, 0)
+KFET_WAKES_UP_AT = time(5, 0)  # La K-Fêt ouvre à 5h (UTC) du matin
 
 
 def kfet_day(year, month, day, start_at=KFET_WAKES_UP_AT):
-    """datetime wrapper with time offset."""
-    naive = datetime.combine(date(year, month, day), start_at)
-    return pytz.timezone("Europe/Paris").localize(naive, is_dst=None)
+    """Étant donné une date, renvoie un objet `datetime`
+    correspondant au début du 'jour K-Fêt' correspondant."""
+    return datetime.combine(date(year, month, day), start_at)
 
 
 def to_kfet_day(dt, start_at=KFET_WAKES_UP_AT):
+    """
+    Retourne le 'jour K-Fêt' correspondant à un objet `datetime` donné
+    """
     kfet_dt = kfet_day(year=dt.year, month=dt.month, day=dt.day)
     if dt.time() < start_at:
         kfet_dt -= timedelta(days=1)
@@ -23,6 +24,17 @@ def to_kfet_day(dt, start_at=KFET_WAKES_UP_AT):
 
 
 class Scale(object):
+    """
+    Classe utilisée pour subdiviser un QuerySet (e.g. des opérations) sur
+    une échelle de temps donnée, avec un pas de temps fixe.
+    Cette échelle peut être spécifiée :
+    - par un début et une fin,
+    - par un début/une fin et un nombre de subdivisions.
+
+    Si le booléen `std_chunk` est activé, le début de la première subdivision
+    est généré via la fonction `get_chunk_start`.
+    """
+
     name = None
     step = None
 
@@ -52,7 +64,7 @@ class Scale(object):
                 "or use last and n_steps"
             )
 
-        self.datetimes = self.get_datetimes()
+        self._gen_datetimes()
 
     @staticmethod
     def by_name(name):
@@ -61,9 +73,6 @@ class Scale(object):
                 return cls
         return None
 
-    def get_from(self, dt):
-        return self.std_chunk and self.get_chunk_start(dt) or dt
-
     def __getitem__(self, i):
         return self.datetimes[i], self.datetimes[i + 1]
 
@@ -73,13 +82,13 @@ class Scale(object):
     def do_step(self, dt, n_steps=1):
         return dt + self.step * n_steps
 
-    def get_datetimes(self):
+    def _gen_datetimes(self):
         datetimes = [self.begin]
         tmp = self.begin
         while tmp < self.end:
             tmp = self.do_step(tmp)
             datetimes.append(tmp)
-        return datetimes
+        self.datetimes = datetimes
 
     def get_labels(self, label_fmt=None):
         if label_fmt is None:
@@ -89,93 +98,18 @@ class Scale(object):
             for i, (begin, end) in enumerate(self)
         ]
 
-    def chunkify_qs(self, qs, field=None):
-        if field is None:
-            field = "at"
+    def chunkify_qs(self, qs, field="at", aggregate=None):
+        """
+        Découpe un queryset en subdivisions, avec agrégation optionnelle des résultats
+        NB : on pourrait faire ça en une requête, au détriment de la lisibilité...
+        """
         begin_f = "{}__gte".format(field)
         end_f = "{}__lte".format(field)
-        return [qs.filter(**{begin_f: begin, end_f: end}) for begin, end in self]
-
-    def get_by_chunks(self, qs, field_callback=None, field_db="at"):
-        """Objects of queryset ranked according to the scale.
-
-        Returns a generator whose each item, corresponding to a scale chunk,
-        is a generator of objects from qs for this chunk.
-
-        Args:
-            qs: Queryset of source objects, must be ordered *first* on the
-                same field returned by `field_callback`.
-            field_callback: Callable which gives value from an object used
-                to compare against limits of the scale chunks.
-                Default to: lambda obj: getattr(obj, field_db)
-            field_db: Used to filter against `scale` limits.
-                Default to 'at'.
-
-        Examples:
-            If queryset `qs` use `values()`, `field_callback` must be set and
-                could be: `lambda d: d['at']`
-            If `field_db` use foreign attributes (eg with `__`), it should be
-                something like: `lambda obj: obj.group.at`.
-
-        """
-        if field_callback is None:
-
-            def field_callback(obj):
-                return getattr(obj, field_db)
-
-        begin_f = "{}__gte".format(field_db)
-        end_f = "{}__lte".format(field_db)
-
-        qs = qs.filter(**{begin_f: self.begin, end_f: self.end})
-
-        obj_iter = iter(qs)
-
-        last_obj = None
-
-        def _objects_until(obj_iter, field_callback, end):
-            """Generator of objects until `end`.
-
-            Ends if objects source is empty or when an object not verifying
-            field_callback(obj) <= end is met.
-
-            If this object exists, it is stored in `last_obj` which is found
-            from outer scope.
-            Also, if this same variable is non-empty when the function is
-            called, it first yields its content.
-
-            Args:
-                obj_iter: Source used to get objects.
-                field_callback: Returned value, when it is called on an object
-                    will be used to test ordering against `end`.
-                end
-
-            """
-            nonlocal last_obj
-
-            if last_obj is not None:
-                yield last_obj
-                last_obj = None
-
-            for obj in obj_iter:
-                if field_callback(obj) <= end:
-                    yield obj
-                else:
-                    last_obj = obj
-                    return
-
-        for begin, end in self:
-            # forward last seen object, if it exists, to the right chunk,
-            # and fill with empty generators for intermediate chunks of scale
-            if last_obj is not None:
-                if field_callback(last_obj) > end:
-                    yield iter(())
-                    continue
-
-            # yields generator for this chunk
-            # this set last_obj to None if obj_iter reach its end, otherwise
-            # it's set to the first met object from obj_iter which doesn't
-            # belong to this chunk
-            yield _objects_until(obj_iter, field_callback, end)
+        chunks = [qs.filter(**{begin_f: begin, end_f: end}) for begin, end in self]
+        if aggregate is None:
+            return chunks
+        else:
+            return [chunk.aggregate(agg=aggregate)["agg"] or 0 for chunk in chunks]
 
 
 class DayScale(Scale):
@@ -191,7 +125,7 @@ class DayScale(Scale):
 class WeekScale(Scale):
     name = "week"
     step = timedelta(days=7)
-    label_fmt = "Semaine %W"
+    label_fmt = "%d %b."
 
     @classmethod
     def get_chunk_start(cls, dt):
@@ -210,111 +144,67 @@ class MonthScale(Scale):
         return to_kfet_day(dt).replace(day=1)
 
 
-def stat_manifest(
-    scales_def=None, scale_args=None, scale_prefix=None, **other_url_params
-):
-    if scale_prefix is None:
-        scale_prefix = "scale_"
-    if scales_def is None:
-        scales_def = []
-    if scale_args is None:
-        scale_args = {}
-    manifest = []
-    for label, cls in scales_def:
-        url_params = {scale_prefix + "name": cls.name}
-        url_params.update(
-            {scale_prefix + key: value for key, value in scale_args.items()}
-        )
+def scale_url_params(scales_def, **other_url_params):
+    """
+    Convertit une spécification de scales en arguments GET utilisables par ScaleMixin.
+    La spécification est de la forme suivante :
+        - scales_def : liste de champs de la forme (label, scale)
+        - scale_args : arguments à passer à Scale.__init__
+        - other_url_params : paramètres GET supplémentaires
+    """
+
+    params_list = []
+    for label, cls, params, default in scales_def:
+        url_params = {"scale_name": cls.name}
+        url_params.update({"scale_" + key: value for key, value in params.items()})
         url_params.update(other_url_params)
-        manifest.append(dict(label=label, url_params=url_params))
-    return manifest
+        params_list.append(dict(label=label, url_params=url_params, default=default))
 
-
-def last_stats_manifest(
-    scales_def=None, scale_args=None, scale_prefix=None, **url_params
-):
-    scales_def = [
-        ("Derniers mois", MonthScale),
-        ("Dernières semaines", WeekScale),
-        ("Derniers jours", DayScale),
-    ]
-    if scale_args is None:
-        scale_args = {}
-    scale_args.update(dict(last=True, n_steps=7))
-    return stat_manifest(
-        scales_def=scales_def,
-        scale_args=scale_args,
-        scale_prefix=scale_prefix,
-        **url_params
-    )
-
-
-# Étant donné un queryset d'operations
-# rend la somme des article_nb
-def tot_ventes(queryset):
-    res = queryset.aggregate(Sum("article_nb"))["article_nb__sum"]
-    return res and res or 0
+    return params_list
 
 
 class ScaleMixin(object):
-    scale_args_prefix = "scale_"
-
-    def get_scale_args(self, params=None, prefix=None):
-        """Retrieve scale args from params.
-
-        Should search the same args of Scale constructor.
-
-        Args:
-            params (dict, optional): Scale args are searched in this.
-                Default to GET params of request.
-            prefix (str, optional): Appended at the begin of scale args names.
-                Default to `self.scale_args_prefix`.
-
+    def parse_scale_args(self):
+        """
+        Récupère les paramètres de subdivision encodés dans une requête GET.
         """
-        if params is None:
-            params = self.request.GET
-        if prefix is None:
-            prefix = self.scale_args_prefix
-
         scale_args = {}
 
-        name = params.get(prefix + "name", None)
+        name = self.request.GET.get("scale_name", None)
         if name is not None:
             scale_args["name"] = name
 
-        n_steps = params.get(prefix + "n_steps", None)
+        n_steps = self.request.GET.get("scale_n_steps", None)
         if n_steps is not None:
             scale_args["n_steps"] = int(n_steps)
 
-        begin = params.get(prefix + "begin", None)
+        begin = self.request.GET.get("scale_begin", None)
         if begin is not None:
             scale_args["begin"] = dateutil_parse(begin)
 
-        end = params.get(prefix + "send", None)
+        end = self.request.GET.get("scale_send", None)
         if end is not None:
             scale_args["end"] = dateutil_parse(end)
 
-        last = params.get(prefix + "last", None)
+        last = self.request.GET.get("scale_last", None)
         if last is not None:
             scale_args["last"] = last in ["true", "True", "1"] and True or False
 
         return scale_args
 
     def get_context_data(self, *args, **kwargs):
-        context = super().get_context_data(*args, **kwargs)
+        # On n'hérite pas
 
-        scale_args = self.get_scale_args()
+        scale_args = self.parse_scale_args()
         scale_name = scale_args.pop("name", None)
         scale_cls = Scale.by_name(scale_name)
 
         if scale_cls is None:
-            scale = self.get_default_scale()
+            self.scale = self.get_default_scale()
         else:
-            scale = scale_cls(**scale_args)
+            self.scale = scale_cls(**scale_args)
 
-        self.scale = scale
-        context["labels"] = scale.get_labels()
-        return context
+        return {"labels": self.scale.get_labels()}
 
     def get_default_scale(self):
         return DayScale(n_steps=7, last=True)
diff --git a/kfet/tests/test_views.py b/kfet/tests/test_views.py
index 08d2cb32..bcd9a9b4 100644
--- a/kfet/tests/test_views.py
+++ b/kfet/tests/test_views.py
@@ -628,37 +628,51 @@ class AccountStatOperationListViewTests(ViewTestCaseMixin, TestCase):
 
         expected_stats = [
             {
-                "label": "Derniers mois",
+                "label": "Tout le temps",
                 "url": {
                     "path": base_url,
                     "query": {
-                        "scale_n_steps": ["7"],
+                        "types": ["['purchase']"],
                         "scale_name": ["month"],
+                        "scale_last": ["True"],
+                        "scale_begin": [
+                            self.accounts["user1"].created_at.isoformat(" ")
+                        ],
+                    },
+                },
+            },
+            {
+                "label": "1 an",
+                "url": {
+                    "path": base_url,
+                    "query": {
                         "types": ["['purchase']"],
+                        "scale_n_steps": ["12"],
+                        "scale_name": ["month"],
                         "scale_last": ["True"],
                     },
                 },
             },
             {
-                "label": "Dernières semaines",
+                "label": "3 mois",
                 "url": {
                     "path": base_url,
                     "query": {
-                        "scale_n_steps": ["7"],
+                        "types": ["['purchase']"],
+                        "scale_n_steps": ["13"],
                         "scale_name": ["week"],
-                        "types": ["['purchase']"],
                         "scale_last": ["True"],
                     },
                 },
             },
             {
-                "label": "Derniers jours",
+                "label": "2 semaines",
                 "url": {
                     "path": base_url,
                     "query": {
-                        "scale_n_steps": ["7"],
-                        "scale_name": ["day"],
                         "types": ["['purchase']"],
+                        "scale_n_steps": ["14"],
+                        "scale_name": ["day"],
                         "scale_last": ["True"],
                     },
                 },
@@ -1524,6 +1538,21 @@ class ArticleStatSalesListViewTests(ViewTestCaseMixin, TestCase):
         self.article = Article.objects.create(
             name="Article", category=ArticleCategory.objects.create(name="Category")
         )
+        checkout = Checkout.objects.create(
+            name="Checkout",
+            created_by=self.accounts["team"],
+            balance=5,
+            valid_from=self.now,
+            valid_to=self.now + timedelta(days=5),
+        )
+
+        self.opegroup = create_operation_group(
+            on_acc=self.accounts["user"],
+            checkout=checkout,
+            content=[
+                {"type": Operation.PURCHASE, "article": self.article, "article_nb": 2},
+            ],
+        )
 
     def test_ok(self):
         r = self.client.get(self.url)
@@ -1535,33 +1564,44 @@ class ArticleStatSalesListViewTests(ViewTestCaseMixin, TestCase):
 
         expected_stats = [
             {
-                "label": "Derniers mois",
+                "label": "Tout le temps",
                 "url": {
                     "path": base_url,
                     "query": {
-                        "scale_n_steps": ["7"],
+                        "scale_name": ["month"],
+                        "scale_last": ["True"],
+                        "scale_begin": [self.opegroup.at.isoformat(" ")],
+                    },
+                },
+            },
+            {
+                "label": "1 an",
+                "url": {
+                    "path": base_url,
+                    "query": {
+                        "scale_n_steps": ["12"],
                         "scale_name": ["month"],
                         "scale_last": ["True"],
                     },
                 },
             },
             {
-                "label": "Dernières semaines",
+                "label": "3 mois",
                 "url": {
                     "path": base_url,
                     "query": {
-                        "scale_n_steps": ["7"],
+                        "scale_n_steps": ["13"],
                         "scale_name": ["week"],
                         "scale_last": ["True"],
                     },
                 },
             },
             {
-                "label": "Derniers jours",
+                "label": "2 semaines",
                 "url": {
                     "path": base_url,
                     "query": {
-                        "scale_n_steps": ["7"],
+                        "scale_n_steps": ["14"],
                         "scale_name": ["day"],
                         "scale_last": ["True"],
                     },
diff --git a/kfet/views.py b/kfet/views.py
index a04cda24..b6c49f72 100644
--- a/kfet/views.py
+++ b/kfet/views.py
@@ -2,6 +2,7 @@ import ast
 import heapq
 import statistics
 from collections import defaultdict
+from datetime import timedelta
 from decimal import Decimal
 from typing import List
 from urllib.parse import urlencode
@@ -76,7 +77,7 @@ from kfet.models import (
     Transfer,
     TransferGroup,
 )
-from kfet.statistic import ScaleMixin, WeekScale, last_stats_manifest
+from kfet.statistic import DayScale, MonthScale, ScaleMixin, WeekScale, scale_url_params
 
 from .auth import KFET_GENERIC_TRIGRAMME
 from .auth.views import (  # noqa
@@ -2199,7 +2200,7 @@ class SupplierUpdate(SuccessMessageMixin, UpdateView):
 # Vues génériques
 # ---------------
 # source : docs.djangoproject.com/fr/1.10/topics/class-based-views/mixins/
-class JSONResponseMixin(object):
+class JSONResponseMixin:
     """
     A mixin that can be used to render a JSON response.
     """
@@ -2228,34 +2229,39 @@ class JSONDetailView(JSONResponseMixin, BaseDetailView):
         return self.render_to_json_response(context)
 
 
-class PkUrlMixin(object):
-    def get_object(self, *args, **kwargs):
-        get_by = self.kwargs.get(self.pk_url_kwarg)
-        return get_object_or_404(self.model, **{self.pk_url_kwarg: get_by})
-
-
 class SingleResumeStat(JSONDetailView):
-    """Manifest for a kind of a stat about an object.
+    """
+    Génère l'interface de sélection pour les statistiques d'un compte/article.
+    L'interface est constituée d'une série de boutons, qui récupèrent et graphent
+    des statistiques du même type, sur le même objet mais avec des arguments différents.
 
-    Returns JSON whose payload is an array containing descriptions of a stat:
-    url to retrieve data, label, ...
+    Attributs :
+        - url_stat : URL où récupérer les statistiques
+        - stats : liste de dictionnaires avec les clés suivantes :
+            - label : texte du bouton
+            - url_params : paramètres GET à rajouter à `url_stat`
+            - default : si `True`, graphe à montrer par défaut
 
+    On peut aussi définir `stats` dynamiquement, via la fonction `get_stats`.
     """
 
-    id_prefix = ""
-    nb_default = 0
-
-    stats = []
     url_stat = None
+    stats = []
+
+    def get_stats(self):
+        return self.stats
 
     def get_context_data(self, **kwargs):
         # On n'hérite pas
-        object_id = self.object.id
         context = {}
         stats = []
-        prefix = "{}_{}".format(self.id_prefix, object_id)
-        for i, stat_def in enumerate(self.stats):
+        # On peut avoir récupéré self.object via pk ou slug
+        if self.pk_url_kwarg in self.kwargs:
             url_pk = getattr(self.object, self.pk_url_kwarg)
+        else:
+            url_pk = getattr(self.object, self.slug_url_kwarg)
+
+        for stat_def in self.get_stats():
             url_params_d = stat_def.get("url_params", {})
             if len(url_params_d) > 0:
                 url_params = "?{}".format(urlencode(url_params_d))
@@ -2264,42 +2270,21 @@ class SingleResumeStat(JSONDetailView):
             stats.append(
                 {
                     "label": stat_def["label"],
-                    "btn": "btn_{}_{}".format(prefix, i),
                     "url": "{url}{params}".format(
                         url=reverse(self.url_stat, args=[url_pk]), params=url_params
                     ),
+                    "default": stat_def.get("default", False),
                 }
             )
-        context["id_prefix"] = prefix
-        context["content_id"] = "content_%s" % prefix
         context["stats"] = stats
-        context["default_stat"] = self.nb_default
-        context["object_id"] = object_id
         return context
 
 
-# -----------------------
-# Evolution Balance perso
-# -----------------------
-ID_PREFIX_ACC_BALANCE = "balance_acc"
-
-
-class AccountStatBalanceList(PkUrlMixin, SingleResumeStat):
-    """Manifest for balance stats of an account."""
-
-    model = Account
-    context_object_name = "account"
-    pk_url_kwarg = "trigramme"
-    url_stat = "kfet.account.stat.balance"
-    id_prefix = ID_PREFIX_ACC_BALANCE
-    stats = [
-        {"label": "Tout le temps"},
-        {"label": "1 an", "url_params": {"last_days": 365}},
-        {"label": "6 mois", "url_params": {"last_days": 183}},
-        {"label": "3 mois", "url_params": {"last_days": 90}},
-        {"label": "30 jours", "url_params": {"last_days": 30}},
-    ]
-    nb_default = 0
+class UserAccountMixin:
+    """
+    Mixin qui vérifie que le compte traité par la vue est celui de l'utilisateur·ice
+    actuel·le. Dans le cas contraire, renvoie un Http404.
+    """
 
     def get_object(self, *args, **kwargs):
         obj = super().get_object(*args, **kwargs)
@@ -2307,21 +2292,41 @@ class AccountStatBalanceList(PkUrlMixin, SingleResumeStat):
             raise Http404
         return obj
 
-    @method_decorator(login_required)
-    def dispatch(self, *args, **kwargs):
-        return super().dispatch(*args, **kwargs)
+
+# -----------------------
+# Evolution Balance perso
+# -----------------------
 
 
-class AccountStatBalance(PkUrlMixin, JSONDetailView):
-    """Datasets of balance of an account.
-
-    Operations and Transfers are taken into account.
-
+@method_decorator(login_required, name="dispatch")
+class AccountStatBalanceList(UserAccountMixin, SingleResumeStat):
+    """
+    Menu général pour l'historique de balance d'un compte
     """
 
     model = Account
-    pk_url_kwarg = "trigramme"
-    context_object_name = "account"
+    slug_url_kwarg = "trigramme"
+    slug_field = "trigramme"
+    url_stat = "kfet.account.stat.balance"
+    stats = [
+        {"label": "Tout le temps"},
+        {"label": "1 an", "url_params": {"last_days": 365}},
+        {"label": "6 mois", "url_params": {"last_days": 183}},
+        {"label": "3 mois", "url_params": {"last_days": 90}, "default": True},
+        {"label": "30 jours", "url_params": {"last_days": 30}},
+    ]
+
+
+@method_decorator(login_required, name="dispatch")
+class AccountStatBalance(UserAccountMixin, JSONDetailView):
+    """
+    Statistiques (JSON) d'historique de balance d'un compte.
+    Prend en compte les opérations et transferts sur la période donnée.
+    """
+
+    model = Account
+    slug_url_kwarg = "trigramme"
+    slug_field = "trigramme"
 
     def get_changes_list(self, last_days=None, begin_date=None, end_date=None):
         account = self.object
@@ -2420,57 +2425,50 @@ class AccountStatBalance(PkUrlMixin, JSONDetailView):
         # TODO: offset
         return context
 
-    def get_object(self, *args, **kwargs):
-        obj = super().get_object(*args, **kwargs)
-        if self.request.user != obj.user:
-            raise Http404
-        return obj
-
-    @method_decorator(login_required)
-    def dispatch(self, *args, **kwargs):
-        return super().dispatch(*args, **kwargs)
-
 
 # ------------------------
 # Consommation personnelle
 # ------------------------
-ID_PREFIX_ACC_LAST = "last_acc"
-ID_PREFIX_ACC_LAST_DAYS = "last_days_acc"
-ID_PREFIX_ACC_LAST_WEEKS = "last_weeks_acc"
-ID_PREFIX_ACC_LAST_MONTHS = "last_months_acc"
 
 
-class AccountStatOperationList(PkUrlMixin, SingleResumeStat):
-    """Manifest for operations stats of an account."""
+@method_decorator(login_required, name="dispatch")
+class AccountStatOperationList(UserAccountMixin, SingleResumeStat):
+    """
+    Menu général pour l'historique de consommation d'un compte
+    """
 
     model = Account
-    context_object_name = "account"
-    pk_url_kwarg = "trigramme"
-    id_prefix = ID_PREFIX_ACC_LAST
-    nb_default = 2
-    stats = last_stats_manifest(types=[Operation.PURCHASE])
+    slug_url_kwarg = "trigramme"
+    slug_field = "trigramme"
     url_stat = "kfet.account.stat.operation"
 
-    def get_object(self, *args, **kwargs):
-        obj = super().get_object(*args, **kwargs)
-        if self.request.user != obj.user:
-            raise Http404
-        return obj
+    def get_stats(self):
+        scales_def = [
+            (
+                "Tout le temps",
+                MonthScale,
+                {"last": True, "begin": self.object.created_at},
+                False,
+            ),
+            ("1 an", MonthScale, {"last": True, "n_steps": 12}, False),
+            ("3 mois", WeekScale, {"last": True, "n_steps": 13}, True),
+            ("2 semaines", DayScale, {"last": True, "n_steps": 14}, False),
+        ]
 
-    @method_decorator(login_required)
-    def dispatch(self, *args, **kwargs):
-        return super().dispatch(*args, **kwargs)
+        return scale_url_params(scales_def, types=[Operation.PURCHASE])
 
 
-class AccountStatOperation(ScaleMixin, PkUrlMixin, JSONDetailView):
-    """Datasets of operations of an account."""
+@method_decorator(login_required, name="dispatch")
+class AccountStatOperation(UserAccountMixin, ScaleMixin, JSONDetailView):
+    """
+    Statistiques (JSON) de consommation (nb d'items achetés) d'un compte.
+    """
 
     model = Account
-    pk_url_kwarg = "trigramme"
-    context_object_name = "account"
-    id_prefix = ""
+    slug_url_kwarg = "trigramme"
+    slug_field = "trigramme"
 
-    def get_operations(self, scale, types=None):
+    def get_operations(self, types=None):
         # On selectionne les opérations qui correspondent
         # à l'article en question et qui ne sont pas annulées
         # puis on choisi pour chaques intervalle les opérations
@@ -2482,28 +2480,20 @@ class AccountStatOperation(ScaleMixin, PkUrlMixin, JSONDetailView):
         )
         if types is not None:
             all_operations = all_operations.filter(type__in=types)
-        chunks = scale.get_by_chunks(
-            all_operations,
-            field_db="group__at",
-            field_callback=(lambda d: d["group__at"]),
-        )
-        return chunks
+        return all_operations
 
     def get_context_data(self, *args, **kwargs):
-        old_ctx = super().get_context_data(*args, **kwargs)
-        context = {"labels": old_ctx["labels"]}
-        scale = self.scale
+        context = super().get_context_data(*args, **kwargs)
 
         types = self.request.GET.get("types", None)
         if types is not None:
             types = ast.literal_eval(types)
 
-        operations = self.get_operations(types=types, scale=scale)
+        operations = self.get_operations(types=types)
         # On compte les opérations
-        nb_ventes = []
-        for chunk in operations:
-            ventes = sum(ope["article_nb"] for ope in chunk)
-            nb_ventes.append(ventes)
+        nb_ventes = self.scale.chunkify_qs(
+            operations, field="group__at", aggregate=Sum("article_nb")
+        )
 
         context["charts"] = [
             {
@@ -2514,50 +2504,54 @@ class AccountStatOperation(ScaleMixin, PkUrlMixin, JSONDetailView):
         ]
         return context
 
-    def get_object(self, *args, **kwargs):
-        obj = super().get_object(*args, **kwargs)
-        if self.request.user != obj.user:
-            raise Http404
-        return obj
-
-    @method_decorator(login_required)
-    def dispatch(self, *args, **kwargs):
-        return super().dispatch(*args, **kwargs)
-
 
 # ------------------------
 # Article Satistiques Last
 # ------------------------
-ID_PREFIX_ART_LAST = "last_art"
-ID_PREFIX_ART_LAST_DAYS = "last_days_art"
-ID_PREFIX_ART_LAST_WEEKS = "last_weeks_art"
-ID_PREFIX_ART_LAST_MONTHS = "last_months_art"
 
 
+@method_decorator(teamkfet_required, name="dispatch")
 class ArticleStatSalesList(SingleResumeStat):
-    """Manifest for sales stats of an article."""
+    """
+    Menu pour les statistiques de vente d'un article.
+    """
 
     model = Article
-    context_object_name = "article"
-    id_prefix = ID_PREFIX_ART_LAST
     nb_default = 2
     url_stat = "kfet.article.stat.sales"
-    stats = last_stats_manifest()
 
-    @method_decorator(teamkfet_required)
-    def dispatch(self, *args, **kwargs):
-        return super().dispatch(*args, **kwargs)
+    def get_stats(self):
+        first_conso = (
+            Operation.objects.filter(article=self.object)
+            .order_by("group__at")
+            .values_list("group__at", flat=True)
+            .first()
+        )
+        if first_conso is None:
+            # On le crée dans le passé au cas où
+            first_conso = timezone.now() - timedelta(seconds=1)
+        scales_def = [
+            ("Tout le temps", MonthScale, {"last": True, "begin": first_conso}, False),
+            ("1 an", MonthScale, {"last": True, "n_steps": 12}, False),
+            ("3 mois", WeekScale, {"last": True, "n_steps": 13}, True),
+            ("2 semaines", DayScale, {"last": True, "n_steps": 14}, False),
+        ]
+
+        return scale_url_params(scales_def)
 
 
+@method_decorator(teamkfet_required, name="dispatch")
 class ArticleStatSales(ScaleMixin, JSONDetailView):
-    """Datasets of sales of an article."""
+    """
+    Statistiques (JSON) de vente d'un article.
+    Sépare LIQ et les comptes K-Fêt, et rajoute le total.
+    """
 
     model = Article
     context_object_name = "article"
 
     def get_context_data(self, *args, **kwargs):
-        old_ctx = super().get_context_data(*args, **kwargs)
-        context = {"labels": old_ctx["labels"]}
+        context = super().get_context_data(*args, **kwargs)
         scale = self.scale
 
         all_purchases = (
@@ -2570,23 +2564,13 @@ class ArticleStatSales(ScaleMixin, JSONDetailView):
         liq_only = all_purchases.filter(group__on_acc__trigramme="LIQ")
         liq_exclude = all_purchases.exclude(group__on_acc__trigramme="LIQ")
 
-        chunks_liq = scale.get_by_chunks(
-            liq_only, field_db="group__at", field_callback=lambda d: d["group__at"]
+        nb_liq = scale.chunkify_qs(
+            liq_only, field="group__at", aggregate=Sum("article_nb")
         )
-        chunks_no_liq = scale.get_by_chunks(
-            liq_exclude, field_db="group__at", field_callback=lambda d: d["group__at"]
+        nb_accounts = scale.chunkify_qs(
+            liq_exclude, field="group__at", aggregate=Sum("article_nb")
         )
-
-        # On compte les opérations
-        nb_ventes = []
-        nb_accounts = []
-        nb_liq = []
-        for chunk_liq, chunk_no_liq in zip(chunks_liq, chunks_no_liq):
-            sum_accounts = sum(ope["article_nb"] for ope in chunk_no_liq)
-            sum_liq = sum(ope["article_nb"] for ope in chunk_liq)
-            nb_ventes.append(sum_accounts + sum_liq)
-            nb_accounts.append(sum_accounts)
-            nb_liq.append(sum_liq)
+        nb_ventes = [n1 + n2 for n1, n2 in zip(nb_liq, nb_accounts)]
 
         context["charts"] = [
             {
@@ -2602,7 +2586,3 @@ class ArticleStatSales(ScaleMixin, JSONDetailView):
             },
         ]
         return context
-
-    @method_decorator(teamkfet_required)
-    def dispatch(self, *args, **kwargs):
-        return super().dispatch(*args, **kwargs)