Deep dive: Account, Stock, Sale, Purchase — +800 LOC business logic

Account:
- Multi-currency: company_currency_id, amount_total_signed
- Lock dates on res.company (period, fiscal year, tax) + enforcement in action_post
- Recurring entries: account.move.recurring with action_generate (copy+advance)
- Tax groups: amount_type='group' computes child taxes with include_base_amount
- ComputeTaxes batch function, findTaxAccount helper

Stock:
- Lot/Serial tracking: enhanced stock.lot with expiration dates + qty compute
- Routes: stock.route model with product/category/warehouse selectable flags
- Rules: stock.rule model with pull/push/buy/manufacture actions + procure methods
- Returns: action_return on picking (swap locations, copy moves)
- Product tracking extension (none/lot/serial) + route_ids M2M

Sale:
- Pricelist: get_product_price with fixed/percentage/formula computation
- Margin: purchase_price, margin, margin_percent on line + order totals
- Down payments: action_create_down_payment (deposit invoice at X%)

Purchase:
- 3-way matching: action_create_bill now updates qty_invoiced on PO lines
- Purchase agreements: purchase.requisition + line with state machine

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

addons/account/models/account_recurring.go

@@ -0,0 +1,116 @@
+package models
+
+import "odoo-go/pkg/orm"
+
+// initAccountRecurring registers account.move.recurring — recurring entry templates.
+// Mirrors: odoo/addons/account/models/account_move.py (recurring entries feature)
+//
+// Allows defining templates that automatically generate journal entries
+// on a schedule (daily, weekly, monthly, quarterly, yearly).
+func initAccountRecurring() {
+	m := orm.NewModel("account.move.recurring", orm.ModelOpts{
+		Description: "Recurring Entry",
+		Order:       "name",
+	})
+
+	m.AddFields(
+		orm.Char("name", orm.FieldOpts{String: "Name", Required: true}),
+		orm.Many2one("journal_id", "account.journal", orm.FieldOpts{String: "Journal", Required: true}),
+		orm.Many2one("company_id", "res.company", orm.FieldOpts{String: "Company"}),
+		orm.Selection("period", []orm.SelectionItem{
+			{Value: "daily", Label: "Daily"},
+			{Value: "weekly", Label: "Weekly"},
+			{Value: "monthly", Label: "Monthly"},
+			{Value: "quarterly", Label: "Quarterly"},
+			{Value: "yearly", Label: "Yearly"},
+		}, orm.FieldOpts{String: "Period", Required: true, Default: "monthly"}),
+		orm.Date("date_next", orm.FieldOpts{String: "Next Date", Required: true}),
+		orm.Date("date_end", orm.FieldOpts{String: "End Date"}),
+		orm.Many2one("template_move_id", "account.move", orm.FieldOpts{String: "Template Entry"}),
+		orm.Boolean("active", orm.FieldOpts{String: "Active", Default: true}),
+		orm.Selection("state", []orm.SelectionItem{
+			{Value: "draft", Label: "Draft"},
+			{Value: "running", Label: "Running"},
+			{Value: "done", Label: "Done"},
+		}, orm.FieldOpts{String: "Status", Default: "draft"}),
+	)
+
+	// action_start: draft -> running
+	m.RegisterMethod("action_start", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
+		env := rs.Env()
+		for _, id := range rs.IDs() {
+			env.Tx().Exec(env.Ctx(),
+				`UPDATE account_move_recurring SET state = 'running' WHERE id = $1 AND state = 'draft'`, id)
+		}
+		return true, nil
+	})
+
+	// action_done: running -> done
+	m.RegisterMethod("action_done", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
+		env := rs.Env()
+		for _, id := range rs.IDs() {
+			env.Tx().Exec(env.Ctx(),
+				`UPDATE account_move_recurring SET state = 'done' WHERE id = $1`, id)
+		}
+		return true, nil
+	})
+
+	// action_generate: create journal entries from the template and advance next date.
+	// Mirrors: odoo/addons/account/models/account_move.py _cron_recurring_entries()
+	m.RegisterMethod("action_generate", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
+		env := rs.Env()
+		for _, recID := range rs.IDs() {
+			var templateID *int64
+			var dateNext, period string
+			var dateEnd *string
+			err := env.Tx().QueryRow(env.Ctx(),
+				`SELECT template_move_id, date_next::text, period, date_end::text
+				 FROM account_move_recurring WHERE id = $1 AND state = 'running'`, recID,
+			).Scan(&templateID, &dateNext, &period, &dateEnd)
+			if err != nil {
+				continue // not running or not found
+			}
+
+			if templateID == nil || *templateID == 0 {
+				continue
+			}
+
+			// Check if past end date
+			if dateEnd != nil && dateNext > *dateEnd {
+				env.Tx().Exec(env.Ctx(),
+					`UPDATE account_move_recurring SET state = 'done' WHERE id = $1`, recID)
+				continue
+			}
+
+			// Copy the template move with the next date
+			templateRS := env.Model("account.move").Browse(*templateID)
+			newMove, err := templateRS.Copy(orm.Values{"date": dateNext})
+			if err != nil {
+				continue
+			}
+			_ = newMove
+
+			// Advance next date based on period
+			var interval string
+			switch period {
+			case "daily":
+				interval = "1 day"
+			case "weekly":
+				interval = "7 days"
+			case "monthly":
+				interval = "1 month"
+			case "quarterly":
+				interval = "3 months"
+			case "yearly":
+				interval = "1 year"
+			default:
+				interval = "1 month"
+			}
+
+			env.Tx().Exec(env.Ctx(),
+				`UPDATE account_move_recurring SET date_next = date_next + $1::interval WHERE id = $2`,
+				interval, recID)
+		}
+		return true, nil
+	})
+}