Hi,

Please refer to the code:

from odoo import models, fields, api

class Vehicle(models.Model):

    _name = 'fleet.vehicle'

    _description = 'Vehicle'

    name = fields.Char('VIN', copy=False, readonly=True)

    vehicle_type = fields.Selection([

        ('L1', '2 Wheel Max 50km/h'),

        ('L2', '3 Wheel Max 50km/h'),

        ('M2', 'Passenger 8-23 seats'),

        # add all types...

    ])

    battery_code = fields.Selection([

        ('S', '1-6 kWh'),

        ('M', '6.1-20 kWh'),

        ('L', '20.1-120 kWh'),

        ('H', 'More than 120 kWh'),

    ])

    model_code = fields.Selection([

        ('MSP', 'Motor Sport'), ('MCS', 'Custom Motorcycle'),

        ('MBM', 'Medium Bus Car'),

        # add all model codes...

    ])

    production_year = fields.Integer('Year of Production', default=2025)

    production_location = fields.Selection([

        ('J', 'West Java'), ('B', 'Jakarta'),  # etc.

    ])

    @api.model

    def create(self, vals):

        record = super().create(vals)

        # Step 1: WMI

        wmi = 'MG3'

        # Step 2: VDS

        vds = f"{record.vehicle_type}{record.battery_code}{record.model_code}"

        # Step 3: VIS

        year_map = {2025: 'S', 2026: 'T'}  # map years to letters

        year_code = year_map.get(record.production_year, 'X')

        loc_code = record.production_location or 'X'

        # Find last serial number for same year + location

        last_serial = self.env['fleet.vehicle'].search([

            ('production_year', '=', record.production_year),

            ('production_location', '=', record.production_location)

        ], order='id desc', limit=1).name

        if last_serial:

            # extract last 5 digits

            last_num = int(last_serial[-5:])

            serial = str(last_num + 1).zfill(5)

        else:

            serial = '00001'

        vis = f"{year_code}{loc_code}{serial}"

        vin = f"{wmi}{vds}{vis}"

        record.name = vin

        return record

Hope it helps.

1. Fixed WMI: "MG3" (constant).
2. VDS: Built from three input fields:
   • Vehicle Type Code (e.g. "M2")
   • Battery Capacity Code (e.g. "L")
   • Vehicle Model Code (e.g. "MBM")
3. VIS: Constructed as:
   • Year code "S" for 2025 (map your production year to letter)
   • Location code (e.g. "J")
   • Serial number: a 5-digit zero-padded sequence, unique per year+location.

Sample Python code (inside your Odoo model):

from odoo import models, fields, api

from datetime import datetime

class Vehicle(models.Model):

    _name = 'your_module.vehicle'

    _description = 'Vehicle'

    vehicle_type_code = fields.Selection([...], string="Vehicle Type Code")  # e.g. 'M2'

    battery_capacity_code = fields.Selection([...], string="Battery Capacity Code")  # e.g. 'L'

    vehicle_model_code = fields.Selection([...], string="Vehicle Model Code")  # e.g. 'MBM'

    production_year = fields.Integer(string="Production Year", default=lambda self: datetime.now().year)

    production_location_code = fields.Char(string="Production Location Code")  # e.g. 'J'

    vin = fields.Char(string="VIN", compute="_compute_vin", store=True, readonly=True)

    @api.depends('vehicle_type_code', 'battery_capacity_code', 'vehicle_model_code', 'production_year', 'production_location_code')

    def _compute_vin(self):

        for record in self:

            # Map production year to letter, example: 2025 = 'S'

            year_map = {2025: 'S'}  # Extend as needed

            year_code = year_map.get(record.production_year, 'X')  # Default 'X' if unknown

            # Serial number generation - find max serial for same year + location

            domain = [

                ('production_year', '=', record.production_year),

                ('production_location_code', '=', record.production_location_code),

            ]

            existing_vins = self.search(domain)

            max_serial = 0

            for v in existing_vins:

                if v.vin and len(v.vin) >= 17:

                    serial_str = v.vin[-5:]

                    if serial_str.isdigit():

                        max_serial = max(max_serial, int(serial_str))

            new_serial = str(max_serial + 1).zfill(5)  # zero padded 5 digit

            # Compose VIN

            wmi = "MG3"

            vds = (record.vehicle_type_code or '') + (record.battery_capacity_code or '') + (record.vehicle_model_code or '')

            vis = year_code + (record.production_location_code or '') + new_serial

            record.vin = wmi + vds + vis

The VIN is automatically computed combining WMI + VDS + VIS.

Serial numbers increment uniquely per production year and location.

Extend year_map as needed for other years.

Use dropdowns for the codes (Selection fields) to restrict inputs.