import { z } from "zod"
import { ExpenseStatus, InvoiceDiscount } from "@garage/api"

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

const requiredRelationFieldSchema = relationFieldSchema.superRefine((value, ctx) => {
    if (!value?.value) {
        ctx.addIssue({
            code: z.ZodIssueCode.custom,
            message: "This field is required",
        })
    }
})

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 labelItemSchema = z.object({
    id: z.number(),
    title: z.string(),
    color_code: z.string(),
})

const expenseLineItemSchema = 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(),
    chart_of_account: z.string().optional(),
    description: z.string().optional(),
})

const expenseFormSchema = z.object({
    // ── Relations ──
    job_card: requiredRelationFieldSchema,
    category: relationFieldSchema,
    vendor: relationFieldSchema,
    department: relationFieldSchema,
    tax: relationFieldSchema,

    // ── Basic info ──
    title: z.string().trim().min(1, "Title is required").max(255, "Title must be at most 255 characters"),
    invoice_number: optionalStringMax255Schema,
    expense_date: optionalDateSchema,
    notes: z.string().optional(),
    status: z.enum(ExpenseStatus).optional(),
    paid_through: z.coerce.number().int().optional(),

    // ── Discount / Tax ──
    discount: z.enum(InvoiceDiscount).optional(),
    discount_amount: z.coerce.number().min(0).optional(),

    labels: z.array(labelItemSchema).optional(),
    items: z.array(expenseLineItemSchema).optional(),
})

type ExpenseFormValues = z.infer<typeof expenseFormSchema>

export { expenseFormSchema, relationFieldSchema }
export type { ExpenseFormValues }