import { z } from "zod"
import { BillStatus, DiscountType } from "@garage/api"

const relationFieldSchema = z
    .object({ value: z.string(), label: z.string() })
    .nullable()

const optionalDateSchema = z.preprocess(
    (value) => (value === "" || value == null ? undefined : value),
    z.string().date().optional(),
)

const optionalStringMax255Schema = z.preprocess(
    (value) => (value === "" || value == null ? undefined : value),
    z.string().max(255, "Must be at most 255 characters").optional(),
)

const requiredDateSchema = z
    .string()
    .min(1, "Bill date is required")
    .date("Enter a valid date")

const billPartItemSchema = z.object({
    part_id: z.number(),
    title: z.string(),
    quantity: z.number().min(1),
    rate: z.number().min(0),
    discount_amount: z.number().min(0).optional(),
    description: z.string().optional(),
})

const billServiceItemSchema = z.object({
    service_id: z.number(),
    title: z.string(),
    quantity: z.number().min(1),
    rate: z.number().min(0),
    discount_amount: z.number().min(0).optional(),
    description: z.string().optional(),
})

const billExpenseItemSchema = z.object({
    expense_id: z.number(),
    title: z.string(),
    quantity: z.number().min(1),
    rate: z.number().min(0),
    discount_amount: z.number().min(0).optional(),
    description: z.string().optional(),
})

const billFormSchema = z.object({
    // ── Required ──
    title: z.string().trim().min(1, "Title is required").max(255, "Title must be at most 255 characters"),

    // ── Relations ──
    vendor: relationFieldSchema,
    vendor_address: relationFieldSchema,
    purchase_order: relationFieldSchema,
    job_card: relationFieldSchema,
    payment_term: relationFieldSchema,
    department: relationFieldSchema,
    tax: relationFieldSchema,

    // ── Optional fields ──
    bill_number: optionalStringMax255Schema,
    bill_date: requiredDateSchema,
    bill_due_date: optionalDateSchema,
    status: z.enum(BillStatus).optional(),
    discount: z.enum(DiscountType).optional(),
    discount_amount: z.coerce.number().min(0).optional(),
    notes: z.string().optional(),
    label_ids: z.array(z.number()).optional(),

    // ── Line items ──
    part_items: z.array(billPartItemSchema).optional(),
    service_items: z.array(billServiceItemSchema).optional(),
    expense_items: z.array(billExpenseItemSchema).optional(),
})

type BillFormValues = z.infer<typeof billFormSchema>
type BillPartItem = z.infer<typeof billPartItemSchema>
type BillServiceItem = z.infer<typeof billServiceItemSchema>
type BillExpenseItem = z.infer<typeof billExpenseItemSchema>

export { billFormSchema, relationFieldSchema, billPartItemSchema, billServiceItemSchema, billExpenseItemSchema }
export type { BillFormValues, BillPartItem, BillServiceItem, BillExpenseItem }