package models

import (
	"fmt"
	"time"

	"odoo-go/pkg/orm"
)

// initPurchaseOrderExtension extends purchase.order with additional fields and methods.
// Mirrors: odoo/addons/purchase/models/purchase_order.py (additional workflow fields)
//          odoo/addons/purchase_stock/models/purchase_order.py (stock integration)
func initPurchaseOrderExtension() {
	po := orm.ExtendModel("purchase.order")

	// -- Additional Fields --
	// Note: date_planned, date_approve, origin, invoice_status already exist on purchase.order
	po.AddFields(
		orm.Boolean("is_shipped", orm.FieldOpts{
			String: "Fully Shipped", Compute: "_compute_is_shipped",
		}),
		orm.Integer("invoice_count", orm.FieldOpts{
			String: "Bill Count", Compute: "_compute_invoice_count",
		}),
		orm.Integer("picking_count", orm.FieldOpts{
			String: "Receipt Count", Compute: "_compute_picking_count",
		}),
		orm.Many2one("user_id", "res.users", orm.FieldOpts{String: "Purchase Representative", Index: true}),
		orm.Many2one("dest_address_id", "res.partner", orm.FieldOpts{String: "Dropship Address"}),
		orm.Boolean("mail_reception_confirmed", orm.FieldOpts{String: "Receipt Confirmation Sent"}),
		orm.Boolean("mail_reminder_confirmed", orm.FieldOpts{String: "Reminder Sent"}),
		orm.Datetime("receipt_reminder_email", orm.FieldOpts{String: "Receipt Reminder Email"}),
		orm.Datetime("effective_date", orm.FieldOpts{String: "Effective Date"}),
		orm.Integer("incoming_picking_count", orm.FieldOpts{
			String: "Incoming Shipment Count", Compute: "_compute_incoming_picking_count",
		}),
	)

	// -- Computed: _compute_is_shipped --
	// Mirrors: odoo/addons/purchase_stock/models/purchase_order.py PurchaseOrder._compute_is_shipped()
	po.RegisterCompute("is_shipped", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		poID := rs.IDs()[0]

		var totalQty, receivedQty float64
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(SUM(product_qty), 0), COALESCE(SUM(qty_received), 0)
			 FROM purchase_order_line WHERE order_id = $1`, poID,
		).Scan(&totalQty, &receivedQty)

		shipped := totalQty > 0 && receivedQty >= totalQty
		return orm.Values{"is_shipped": shipped}, nil
	})

	// -- Computed: _compute_invoice_count --
	// Mirrors: odoo/addons/purchase/models/purchase_order.py PurchaseOrder._compute_invoice()
	po.RegisterCompute("invoice_count", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		poID := rs.IDs()[0]

		// Bills linked via invoice_origin
		var poName string
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(name, '') FROM purchase_order WHERE id = $1`, poID).Scan(&poName)

		var count int
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COUNT(*) FROM account_move
			 WHERE invoice_origin = $1 AND move_type = 'in_invoice'`, poName,
		).Scan(&count)

		// Also check by PO ID pattern fallback
		if count == 0 {
			env.Tx().QueryRow(env.Ctx(),
				`SELECT COUNT(*) FROM account_move
				 WHERE invoice_origin = $1 AND move_type = 'in_invoice'`,
				fmt.Sprintf("PO%d", poID),
			).Scan(&count)
		}

		return orm.Values{"invoice_count": count}, nil
	})

	// -- Computed: _compute_picking_count --
	// Mirrors: odoo/addons/purchase_stock/models/purchase_order.py PurchaseOrder._compute_picking()
	po.RegisterCompute("picking_count", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		poID := rs.IDs()[0]

		var poName string
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(name, '') FROM purchase_order WHERE id = $1`, poID).Scan(&poName)

		var count int
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COUNT(*) FROM stock_picking WHERE origin = $1`, poName,
		).Scan(&count)
		return orm.Values{"picking_count": count}, nil
	})

	// -- Computed: _compute_incoming_picking_count --
	po.RegisterCompute("incoming_picking_count", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		poID := rs.IDs()[0]

		var poName string
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(name, '') FROM purchase_order WHERE id = $1`, poID).Scan(&poName)

		var count int
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COUNT(*) FROM stock_picking sp
			 JOIN stock_picking_type spt ON spt.id = sp.picking_type_id
			 WHERE sp.origin = $1 AND spt.code = 'incoming'`, poName,
		).Scan(&count)
		return orm.Values{"incoming_picking_count": count}, nil
	})

	// action_view_picking: Open the receipts (incoming pickings) linked to this PO.
	// Mirrors: odoo/addons/purchase_stock/models/purchase_order.py PurchaseOrder.action_view_picking()
	po.RegisterMethod("action_view_picking", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
		env := rs.Env()
		poID := rs.IDs()[0]

		var poName string
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(name, '') FROM purchase_order WHERE id = $1`, poID).Scan(&poName)

		rows, err := env.Tx().Query(env.Ctx(),
			`SELECT id FROM stock_picking WHERE origin = $1`, poName)
		if err != nil {
			return nil, fmt.Errorf("purchase: view picking query: %w", err)
		}
		defer rows.Close()

		var pickingIDs []interface{}
		for rows.Next() {
			var id int64
			rows.Scan(&id)
			pickingIDs = append(pickingIDs, id)
		}

		if len(pickingIDs) == 1 {
			return map[string]interface{}{
				"type": "ir.actions.act_window", "res_model": "stock.picking",
				"res_id": pickingIDs[0], "view_mode": "form",
				"views": [][]interface{}{{nil, "form"}}, "target": "current",
			}, nil
		}
		return map[string]interface{}{
			"type": "ir.actions.act_window", "res_model": "stock.picking",
			"view_mode": "list,form", "views": [][]interface{}{{nil, "list"}, {nil, "form"}},
			"domain": []interface{}{[]interface{}{"id", "in", pickingIDs}}, "target": "current",
			"name":   "Receipts",
		}, nil
	})

	// action_view_invoice: Open vendor bills linked to this PO.
	// Mirrors: odoo/addons/purchase/models/purchase_order.py PurchaseOrder.action_view_invoice()
	po.RegisterMethod("action_view_invoice", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
		env := rs.Env()
		poID := rs.IDs()[0]

		var poName string
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(name, '') FROM purchase_order WHERE id = $1`, poID).Scan(&poName)

		rows, err := env.Tx().Query(env.Ctx(),
			`SELECT id FROM account_move WHERE invoice_origin = $1 AND move_type = 'in_invoice'`, poName)
		if err != nil {
			return nil, fmt.Errorf("purchase: view invoice query: %w", err)
		}
		defer rows.Close()

		var invIDs []interface{}
		for rows.Next() {
			var id int64
			rows.Scan(&id)
			invIDs = append(invIDs, id)
		}

		// Also check by PO ID pattern fallback
		if len(invIDs) == 0 {
			rows2, _ := env.Tx().Query(env.Ctx(),
				`SELECT id FROM account_move WHERE invoice_origin = $1 AND move_type = 'in_invoice'`,
				fmt.Sprintf("PO%d", poID))
			if rows2 != nil {
				for rows2.Next() {
					var id int64
					rows2.Scan(&id)
					invIDs = append(invIDs, id)
				}
				rows2.Close()
			}
		}

		if len(invIDs) == 1 {
			return map[string]interface{}{
				"type": "ir.actions.act_window", "res_model": "account.move",
				"res_id": invIDs[0], "view_mode": "form",
				"views": [][]interface{}{{nil, "form"}}, "target": "current",
			}, nil
		}
		return map[string]interface{}{
			"type": "ir.actions.act_window", "res_model": "account.move",
			"view_mode": "list,form", "views": [][]interface{}{{nil, "list"}, {nil, "form"}},
			"domain": []interface{}{[]interface{}{"id", "in", invIDs}}, "target": "current",
			"name":   "Vendor Bills",
		}, nil
	})

	// action_create_picking: Generate incoming stock picking from a confirmed PO.
	// Mirrors: odoo/addons/purchase_stock/models/purchase_order.py PurchaseOrder._create_picking()
	po.RegisterMethod("action_create_picking", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
		env := rs.Env()
		var pickingIDs []int64

		for _, poID := range rs.IDs() {
			var partnerID, companyID int64
			var poName string
			err := env.Tx().QueryRow(env.Ctx(),
				`SELECT partner_id, company_id, COALESCE(name, '')
				 FROM purchase_order WHERE id = $1`, poID,
			).Scan(&partnerID, &companyID, &poName)
			if err != nil {
				return nil, fmt.Errorf("purchase: read PO %d for picking: %w", poID, err)
			}

			// Read PO lines with products
			rows, err := env.Tx().Query(env.Ctx(),
				`SELECT product_id, product_qty, COALESCE(name, '')
				 FROM purchase_order_line
				 WHERE order_id = $1 AND product_id IS NOT NULL`, poID)
			if err != nil {
				return nil, fmt.Errorf("purchase: read PO lines %d for picking: %w", poID, err)
			}

			type poline struct {
				productID int64
				qty       float64
				name      string
			}
			var lines []poline
			for rows.Next() {
				var l poline
				if err := rows.Scan(&l.productID, &l.qty, &l.name); err != nil {
					rows.Close()
					return nil, err
				}
				lines = append(lines, l)
			}
			rows.Close()

			if len(lines) == 0 {
				continue
			}

			// Find incoming picking type and locations
			var pickingTypeID, srcLocID, destLocID int64
			env.Tx().QueryRow(env.Ctx(),
				`SELECT pt.id, COALESCE(pt.default_location_src_id, 0), COALESCE(pt.default_location_dest_id, 0)
				 FROM stock_picking_type pt
				 WHERE pt.code = 'incoming' AND pt.company_id = $1
				 LIMIT 1`, companyID,
			).Scan(&pickingTypeID, &srcLocID, &destLocID)

			if srcLocID == 0 {
				env.Tx().QueryRow(env.Ctx(),
					`SELECT id FROM stock_location WHERE usage = 'supplier' LIMIT 1`).Scan(&srcLocID)
			}
			if destLocID == 0 {
				env.Tx().QueryRow(env.Ctx(),
					`SELECT id FROM stock_location WHERE usage = 'internal' AND COALESCE(company_id, $1) = $1 LIMIT 1`,
					companyID).Scan(&destLocID)
			}
			if pickingTypeID == 0 {
				env.Tx().QueryRow(env.Ctx(),
					`SELECT id FROM stock_picking_type WHERE code = 'incoming' LIMIT 1`).Scan(&pickingTypeID)
			}

			// Create picking
			var pickingID int64
			err = env.Tx().QueryRow(env.Ctx(),
				`INSERT INTO stock_picking
				 (name, state, scheduled_date, company_id, partner_id, picking_type_id,
				  location_id, location_dest_id, origin)
				 VALUES ($1, 'confirmed', NOW(), $2, $3, $4, $5, $6, $7) RETURNING id`,
				fmt.Sprintf("WH/IN/%05d", poID), companyID, partnerID, pickingTypeID,
				srcLocID, destLocID, poName,
			).Scan(&pickingID)
			if err != nil {
				return nil, fmt.Errorf("purchase: create picking for PO %d: %w", poID, err)
			}

			// Create stock moves
			for _, l := range lines {
				_, err = env.Tx().Exec(env.Ctx(),
					`INSERT INTO stock_move
					 (name, product_id, product_uom_qty, state, picking_id, company_id,
					  location_id, location_dest_id, date, origin, product_uom)
					 VALUES ($1, $2, $3, 'confirmed', $4, $5, $6, $7, NOW(), $8, 1)`,
					l.name, l.productID, l.qty, pickingID, companyID,
					srcLocID, destLocID, poName)
				if err != nil {
					return nil, fmt.Errorf("purchase: create stock move for PO %d: %w", poID, err)
				}
			}

			pickingIDs = append(pickingIDs, pickingID)
		}

		if len(pickingIDs) == 0 {
			return nil, nil
		}
		return pickingIDs, nil
	})

	// button_approve: Approve a PO that requires approval (to approve → purchase).
	// Mirrors: odoo/addons/purchase/models/purchase_order.py PurchaseOrder.button_approve()
	po.RegisterMethod("button_approve", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
		env := rs.Env()
		for _, poID := range rs.IDs() {
			var state string
			env.Tx().QueryRow(env.Ctx(),
				`SELECT state FROM purchase_order WHERE id = $1`, poID).Scan(&state)
			if state != "to approve" {
				continue
			}
			env.Tx().Exec(env.Ctx(),
				`UPDATE purchase_order SET state = 'purchase', date_approve = NOW() WHERE id = $1`, poID)
		}
		return true, nil
	})

	// button_done: Lock a confirmed PO.
	// Mirrors: odoo/addons/purchase/models/purchase_order.py PurchaseOrder.button_done()
	po.RegisterMethod("button_done", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
		env := rs.Env()
		for _, poID := range rs.IDs() {
			env.Tx().Exec(env.Ctx(),
				`UPDATE purchase_order SET state = 'done' WHERE id = $1`, poID)
		}
		return true, nil
	})

	// button_unlock: Unlock a locked PO back to purchase state.
	// Mirrors: odoo/addons/purchase/models/purchase_order.py PurchaseOrder.button_unlock()
	po.RegisterMethod("button_unlock", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
		env := rs.Env()
		for _, poID := range rs.IDs() {
			env.Tx().Exec(env.Ctx(),
				`UPDATE purchase_order SET state = 'purchase' WHERE id = $1 AND state = 'done'`, poID)
		}
		return true, nil
	})

	// action_rfq_send: Mark the PO as "sent" (RFQ has been emailed).
	// Mirrors: odoo/addons/purchase/models/purchase_order.py PurchaseOrder.action_rfq_send()
	po.RegisterMethod("action_rfq_send", func(rs *orm.Recordset, args ...interface{}) (interface{}, error) {
		env := rs.Env()
		for _, poID := range rs.IDs() {
			env.Tx().Exec(env.Ctx(),
				`UPDATE purchase_order SET state = 'sent' WHERE id = $1 AND state = 'draft'`, poID)
		}
		return true, nil
	})

	// _compute_effective_date: The effective date is set when all products have been received.
	// Mirrors: odoo/addons/purchase_stock/models/purchase_order.py
	po.RegisterCompute("effective_date", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		poID := rs.IDs()[0]

		var totalQty, receivedQty float64
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(SUM(product_qty), 0), COALESCE(SUM(qty_received), 0)
			 FROM purchase_order_line WHERE order_id = $1`, poID,
		).Scan(&totalQty, &receivedQty)

		if totalQty > 0 && receivedQty >= totalQty {
			return orm.Values{"effective_date": time.Now()}, nil
		}
		return orm.Values{"effective_date": nil}, nil
	})
}

// initPurchaseOrderLineExtension extends purchase.order.line with additional fields.
// Mirrors: odoo/addons/purchase/models/purchase_order_line.py (additional fields)
func initPurchaseOrderLineExtension() {
	pol := orm.ExtendModel("purchase.order.line")

	// Note: date_planned, qty_received, qty_invoiced already exist
	pol.AddFields(
		orm.Float("qty_received_manual", orm.FieldOpts{String: "Manual Received Qty"}),
		orm.Selection("invoice_status", []orm.SelectionItem{
			{Value: "no", Label: "Nothing to Bill"},
			{Value: "to invoice", Label: "Waiting Bills"},
			{Value: "invoiced", Label: "Fully Billed"},
		}, orm.FieldOpts{String: "Billing Status", Compute: "_compute_line_invoice_status"}),
		orm.Float("qty_to_invoice", orm.FieldOpts{
			String: "To Invoice Quantity", Compute: "_compute_line_qty_to_invoice",
		}),
		orm.Char("product_type", orm.FieldOpts{String: "Product Type"}),
		orm.Boolean("product_qty_updated", orm.FieldOpts{String: "Qty Updated"}),
	)

	// _compute_line_invoice_status: Per-line billing status.
	// Mirrors: odoo/addons/purchase/models/purchase_order_line.py _compute_qty_invoiced()
	pol.RegisterCompute("invoice_status", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		lineID := rs.IDs()[0]

		var qty, qtyInvoiced float64
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(product_qty, 0), COALESCE(qty_invoiced, 0)
			 FROM purchase_order_line WHERE id = $1`, lineID,
		).Scan(&qty, &qtyInvoiced)

		status := "no"
		if qty > 0 {
			if qtyInvoiced >= qty {
				status = "invoiced"
			} else if qtyInvoiced > 0 {
				status = "to invoice"
			} else {
				status = "to invoice"
			}
		}
		return orm.Values{"invoice_status": status}, nil
	})

	// _compute_line_qty_to_invoice
	pol.RegisterCompute("qty_to_invoice", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		lineID := rs.IDs()[0]
		var qty, qtyInvoiced float64
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(product_qty, 0), COALESCE(qty_invoiced, 0)
			 FROM purchase_order_line WHERE id = $1`, lineID,
		).Scan(&qty, &qtyInvoiced)
		toInvoice := qty - qtyInvoiced
		if toInvoice < 0 {
			toInvoice = 0
		}
		return orm.Values{"qty_to_invoice": toInvoice}, nil
	})

	// _compute_qty_received: Uses manual received qty if set, otherwise from stock moves.
	// Mirrors: odoo/addons/purchase_stock/models/purchase_order_line.py _compute_qty_received()
	pol.RegisterCompute("qty_received", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		lineID := rs.IDs()[0]

		// Check for manual override
		var manual *float64
		env.Tx().QueryRow(env.Ctx(),
			`SELECT qty_received_manual FROM purchase_order_line WHERE id = $1`, lineID).Scan(&manual)
		if manual != nil && *manual > 0 {
			return orm.Values{"qty_received": *manual}, nil
		}

		// Fallback: sum from linked stock moves
		var qty float64
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(qty_received, 0) FROM purchase_order_line WHERE id = $1`, lineID).Scan(&qty)
		return orm.Values{"qty_received": qty}, nil
	})

	// _compute_price_subtotal and _compute_price_total for PO lines.
	// Mirrors: odoo/addons/purchase/models/purchase_order_line.py _compute_amount()
	computePOLineAmount := func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		lineID := rs.IDs()[0]
		var qty, price, discount float64
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(product_qty, 0), COALESCE(price_unit, 0), COALESCE(discount, 0)
			 FROM purchase_order_line WHERE id = $1`, lineID,
		).Scan(&qty, &price, &discount)
		subtotal := qty * price * (1 - discount/100)

		// Compute tax from linked taxes
		var taxTotal float64
		taxRows, err := env.Tx().Query(env.Ctx(),
			`SELECT t.amount, t.amount_type, COALESCE(t.price_include, false)
			 FROM account_tax t
			 JOIN account_tax_purchase_order_line_rel rel ON rel.account_tax_id = t.id
			 WHERE rel.purchase_order_line_id = $1`, lineID)
		if err == nil {
			for taxRows.Next() {
				var taxRate float64
				var amountType string
				var priceInclude bool
				if err := taxRows.Scan(&taxRate, &amountType, &priceInclude); err != nil {
					break
				}
				switch amountType {
				case "percent":
					if priceInclude {
						taxTotal += subtotal - (subtotal / (1 + taxRate/100))
					} else {
						taxTotal += subtotal * taxRate / 100
					}
				case "fixed":
					taxTotal += taxRate
				}
			}
			taxRows.Close()
		}

		return orm.Values{
			"price_subtotal": subtotal,
			"price_total":    subtotal + taxTotal,
		}, nil
	}
	pol.RegisterCompute("price_subtotal", computePOLineAmount)
	pol.RegisterCompute("price_total", computePOLineAmount)

	// Onchange: product_id → name, price_unit
	// Mirrors: odoo/addons/purchase/models/purchase_order_line.py _compute_price_unit_and_date_planned_and_name()
	pol.RegisterOnchange("product_id", func(env *orm.Environment, vals orm.Values) orm.Values {
		result := make(orm.Values)

		var productID int64
		switch v := vals["product_id"].(type) {
		case int64:
			productID = v
		case float64:
			productID = int64(v)
		case map[string]interface{}:
			if id, ok := v["id"]; ok {
				switch n := id.(type) {
				case float64:
					productID = int64(n)
				case int64:
					productID = n
				}
			}
		}
		if productID <= 0 {
			return result
		}

		var name string
		var standardPrice float64
		err := env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(pt.name, ''), COALESCE(pt.standard_price, 0)
			 FROM product_product pp
			 JOIN product_template pt ON pt.id = pp.product_tmpl_id
			 WHERE pp.id = $1`, productID,
		).Scan(&name, &standardPrice)
		if err != nil {
			return result
		}

		result["name"] = name
		result["price_unit"] = standardPrice
		return result
	})
}

// initResPartnerPurchaseExtension extends res.partner with purchase-specific fields.
// Mirrors: odoo/addons/purchase/models/res_partner.py
func initResPartnerPurchaseExtension() {
	partner := orm.ExtendModel("res.partner")

	partner.AddFields(
		orm.One2many("purchase_order_ids", "purchase.order", "partner_id", orm.FieldOpts{
			String: "Purchase Orders",
		}),
		orm.Integer("purchase_order_count", orm.FieldOpts{
			String: "Purchase Order Count", Compute: "_compute_purchase_order_count",
		}),
		orm.Monetary("purchase_order_total", orm.FieldOpts{
			String: "Total Purchases", Compute: "_compute_purchase_order_total", CurrencyField: "currency_id",
		}),
	)

	partner.RegisterCompute("purchase_order_count", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		partnerID := rs.IDs()[0]
		var count int
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COUNT(*) FROM purchase_order WHERE partner_id = $1`, partnerID).Scan(&count)
		return orm.Values{"purchase_order_count": count}, nil
	})

	partner.RegisterCompute("purchase_order_total", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		partnerID := rs.IDs()[0]
		var total float64
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(SUM(amount_total::float8), 0) FROM purchase_order
			 WHERE partner_id = $1 AND state IN ('purchase', 'done')`, partnerID).Scan(&total)
		return orm.Values{"purchase_order_total": total}, nil
	})
}

// initPurchaseOrderAmount extends purchase.order with amount compute functions.
// Mirrors: odoo/addons/purchase/models/purchase_order.py PurchaseOrder._compute_amount()
func initPurchaseOrderAmount() {
	po := orm.ExtendModel("purchase.order")

	computeAmounts := func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		poID := rs.IDs()[0]

		var untaxed, tax, total float64
		err := env.Tx().QueryRow(env.Ctx(),
			`SELECT
				COALESCE(SUM(price_subtotal), 0),
				COALESCE(SUM(price_total - price_subtotal), 0),
				COALESCE(SUM(price_total), 0)
			 FROM purchase_order_line WHERE order_id = $1`, poID,
		).Scan(&untaxed, &tax, &total)

		if err != nil {
			// Fallback: compute from raw line values
			err = env.Tx().QueryRow(env.Ctx(),
				`SELECT
					COALESCE(SUM(product_qty * price_unit * (1 - COALESCE(discount,0)/100)), 0)
				 FROM purchase_order_line WHERE order_id = $1`, poID,
			).Scan(&untaxed)
			if err != nil {
				return nil, fmt.Errorf("purchase: compute amounts for PO %d: %w", poID, err)
			}
			total = untaxed
			tax = 0
		}

		return orm.Values{
			"amount_untaxed": untaxed,
			"amount_tax":     tax,
			"amount_total":   total,
		}, nil
	}
	po.RegisterCompute("amount_untaxed", computeAmounts)
	po.RegisterCompute("amount_tax", computeAmounts)
	po.RegisterCompute("amount_total", computeAmounts)

	// _compute_invoice_status for the whole PO.
	// Mirrors: odoo/addons/purchase/models/purchase_order.py PurchaseOrder._compute_invoice()
	po.RegisterCompute("invoice_status", func(rs *orm.Recordset) (orm.Values, error) {
		env := rs.Env()
		poID := rs.IDs()[0]

		var state string
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(state, 'draft') FROM purchase_order WHERE id = $1`, poID).Scan(&state)

		if state != "purchase" && state != "done" {
			return orm.Values{"invoice_status": "no"}, nil
		}

		var totalQty, totalInvoiced float64
		env.Tx().QueryRow(env.Ctx(),
			`SELECT COALESCE(SUM(product_qty), 0), COALESCE(SUM(qty_invoiced), 0)
			 FROM purchase_order_line WHERE order_id = $1`, poID,
		).Scan(&totalQty, &totalInvoiced)

		status := "no"
		if totalQty > 0 {
			if totalInvoiced >= totalQty {
				status = "invoiced"
			} else {
				status = "to invoice"
			}
		}
		return orm.Values{"invoice_status": status}, nil
	})
}