[budget] add option to disable rollover

see #84

docs/reference/budget.md

@@ -116,7 +116,7 @@ next month, assuming you haven't made any further transaction.
 
 ![Next month Budget](/images/budget-4.png)
 
-You can see a new element in the UI called Rollover. This is basically
+You can see a new element in the UI called Rollover[^1]. This is basically
 the amount you have budgeted last month, but haven't spent. This will
 automatically rollover to the next month. That's pretty much it.
 
@@ -126,3 +126,5 @@ To recap, there are just two things you need to do.
 you get your salary.
 
 2) Adjust your budget as you spend and make sure there is no deficit.
+
+[^1]: If you prefer to not have rollover feature, it can be disabled in the [configuration](../reference/config.md) page.

docs/reference/config.md

@@ -50,6 +50,12 @@ locale: en-IN
 # OPTIONAL, DEFAULT: 4
 financial_year_starting_month: 4
 
+## Budget
+budget:
+  # Rollover unspent money to next month
+  # OPTIONAL, ENUM: yes, no DEFAULT: yes
+  rollover: "yes"
+
 ## Retirement
 retirement:
   # Safe Withdrawal Rate

internal/config/config.go

@@ -39,6 +39,13 @@ const (
 	Unknown    CommodityType = "unknown"
 )
 
+type BoolType string
+
+const (
+	Yes BoolType = "yes"
+	No  BoolType = "no"
+)
+
 type ImportTemplate struct {
 	Name    string `json:"name" yaml:"name"`
 	Content string `json:"content" yaml:"content"`
@@ -74,6 +81,10 @@ type ScheduleAL struct {
 	Accounts []string `json:"accounts" yaml:"accounts"`
 }
 
+type Budget struct {
+	Rollover BoolType `json:"rollover" yaml:"rollover"`
+}
+
 type AllocationTarget struct {
 	Name     string   `json:"name" yaml:"name"`
 	Target   float64  `json:"target" yaml:"target"`
@@ -92,6 +103,8 @@ type Config struct {
 
 	Retirement Retirement `json:"retirement" yaml:"retirement"`
 
+	Budget Budget `json:"budget" yaml:"budget"`
+
 	ScheduleALs []ScheduleAL `json:"schedule_al" yaml:"schedule_al"`
 
 	AllocationTargets []AllocationTarget `json:"allocation_targets" yaml:"allocation_targets"`
@@ -113,6 +126,7 @@ var defaultConfig = Config{
 	DisplayPrecision:           0,
 	Locale:                     "en-IN",
 	Retirement:                 Retirement{SWR: 4, Savings: []string{"Assets:*"}, Expenses: []string{"Expenses:*"}, YearlyExpenses: 0},
+	Budget:                     Budget{Rollover: Yes},
 	FinancialYearStartingMonth: 4,
 	ScheduleALs:                []ScheduleAL{},
 	AllocationTargets:          []AllocationTarget{},

internal/config/schema.json

@@ -77,6 +77,19 @@
       },
       "additionalProperties": false
     },
+    "budget": {
+      "description": "Budget configuration",
+      "type": "object",
+      "properties": {
+        "rollover": {
+          "ui:widget": "boolean",
+          "type": "string",
+          "description": "Rollover unspent money to next month",
+          "enum": ["", "yes", "no"]
+        }
+      },
+      "additionalProperties": false
+    },
     "schedule_al": {
       "description": "Schedule AL configuration",
       "type": "array",

internal/server/budget.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/ananthakumaran/paisa/internal/accounting"
+	"github.com/ananthakumaran/paisa/internal/config"
 	"github.com/ananthakumaran/paisa/internal/model/posting"
 	"github.com/ananthakumaran/paisa/internal/query"
 	"github.com/ananthakumaran/paisa/internal/utils"
@@ -59,6 +60,8 @@ func computeBudet(db *gorm.DB, forecastPostings, expensesPostings []posting.Post
 	budgetsByMonth := make(map[string]Budget)
 	balance := make(map[string]decimal.Decimal)
 
+	currentMonth := lo.Must(time.Parse("2006-01", utils.Now().Format("2006-01")))
+
 	if len(forecastPostings) > 0 {
 		start := utils.BeginningOfMonth(forecastPostings[0].Date)
 		end := utils.EndOfMonth(forecastPostings[len(forecastPostings)-1].Date)
@@ -84,7 +87,7 @@ func computeBudet(db *gorm.DB, forecastPostings, expensesPostings []posting.Post
 					es = []posting.Posting{}
 				}
 
-				budget := buildBudget(date, account, balance[account], fs, es)
+				budget := buildBudget(date, account, balance[account], fs, es, date.Before(currentMonth))
 				if budget.Available.IsPositive() {
 					balance[account] = budget.Available
 				} else {
@@ -110,8 +113,8 @@ func computeBudet(db *gorm.DB, forecastPostings, expensesPostings []posting.Post
 					return decimal.Zero
 				})
 
-			endOfMonthBalance := checkingBalance.Sub(availableThisMonth)
-			availableForBudgeting = endOfMonthBalance
+			availableForBudgeting = availableForBudgeting.Sub(availableThisMonth)
+			endOfMonthBalance := availableForBudgeting
 
 			budgetsByMonth[month] = Budget{
 				Date:               date,
@@ -130,15 +133,26 @@ func computeBudet(db *gorm.DB, forecastPostings, expensesPostings []posting.Post
 	}
 }
 
-func buildBudget(date time.Time, account string, balance decimal.Decimal, forecasts []posting.Posting, expenses []posting.Posting) AccountBudget {
+func buildBudget(date time.Time, account string, balance decimal.Decimal, forecasts []posting.Posting, expenses []posting.Posting, past bool) AccountBudget {
 	forecast := accounting.CostSum(forecasts)
 	actual := accounting.CostSum(expenses)
+
+	rollover := decimal.Zero
+	available := forecast.Sub(actual)
+	if past {
+		available = decimal.Zero
+	}
+	if config.GetConfig().Budget.Rollover == config.Yes {
+		rollover = balance
+		available = balance.Add(forecast.Sub(actual))
+	}
+
 	return AccountBudget{
 		Account:   account,
 		Forecast:  forecast,
 		Actual:    actual,
-		Rollover:  balance,
-		Available: balance.Add(forecast.Sub(actual)),
+		Rollover:  rollover,
+		Available: available,
 		Date:      date,
 		Expenses:  expenses,
 	}

src/lib/components/JsonSchemaForm.svelte

@@ -96,6 +96,26 @@
       </div>
     </div>
   </div>
+{:else if schema["ui:widget"] == "boolean"}
+  <div class="field is-horizontal">
+    <div class="field-label is-small">
+      <label for="" data-tippy-content={documentation(schema)} class="label">{title}</label>
+    </div>
+    <div class="field-body">
+      <div class="field">
+        <div class="control">
+          <label class="radio">
+            <input value="yes" bind:group={value} type="radio" name="yes" />
+            Yes
+          </label>
+          <label class="radio">
+            <input value="no" bind:group={value} type="radio" name="no" />
+            No
+          </label>
+        </div>
+      </div>
+    </div>
+  </div>
 {:else if schema.type === "string" || _.isEqual(schema.type, ["string", "integer"])}
   <div class="field is-horizontal">
     <div class="field-label is-small">