"use client"

import { AlertTriangle, Plus, Save } from "lucide-react"

import { Button } from "@/shared/components/ui/button"
import { Alert, AlertTitle } from "@/shared/components/ui/alert"
import { FieldGroup } from "@/shared/components/ui/field"
import { Card, CardContent, CardHeader, CardTitle } from "@/shared/components/ui/card"
import {
    Rhform,
    RhfTextField,
    RhfSelectField,
    RhfTextareaField,
    RhfAsyncSelectField,
    RhfAutoGenerateField,
    RhfCheckboxField,
    RhfDateField,
} from "@/shared/components/form"
import { toast } from "sonner"
import { useAuthApi } from "@/shared/useApi"
import { useResourceForm } from "@/shared/hooks/use-resource-form"
import { useFormMutation } from "@/shared/hooks/use-form-mutation"
import { toRelation, toId } from "@/shared/lib/utils"
import { formatTaxLabel } from "@/shared/utils/formatters"
import { useFormContext } from "react-hook-form"

import {
    invoiceFormSchema,
    type InvoiceFormValues,
} from "./invoice.schema"
import {
    INVOICE_ROUTES,
    DEPARTMENT_ROUTES,
    PAYMENT_TERM_ROUTES,
    INVOICE_SEQUENCE_ROUTES,
    TAX_ROUTES,
    InvoiceStatus,
    InvoiceDiscount,
} from "@garage/api"
import { RhfCustomerSelectField } from "@/modules/customers/rhf-customer-select-field"
import { InvoiceSequenceCrudDialog } from "./invoice-sequence-crud-dialog"
import { RhfVehicleSelectField } from "@/modules/vehicles/rhf-vehicle-select-field"
import { PartsSelectorField } from "@/modules/parts/parts-selector-field"
import { ServicesSelectorField } from "@/modules/services/services-selector-field"
import { ExpenseItemsSelectorField } from "@/modules/expense-items/expense-items-selector-field"
import { InvoiceFormSummary } from "./invoice-form-summary"

// ── Constants ──

const STATUS_OPTIONS = InvoiceStatus.map((v) => ({
    value: v,
    label: v.replace(/_/g, " ").replace(/\b\w/g, (c) => c.toUpperCase()),
}))

const DISCOUNT_OPTIONS = InvoiceDiscount.map((v) => ({
    value: v,
    label: v.replace(/_/g, " ").replace(/\b\w/g, (c) => c.toUpperCase()),
}))

// ── Props ──

export type InvoiceFormProps = {
    resourceId?: string | null
    initialData?: unknown
    onSuccess?: () => void
}

// ── Default values ──

const DEFAULT_VALUES: InvoiceFormValues = {
    subject: "",
    customer: null,
    vehicle: null,
    department: null,
    estimate: null,
    payment_terms: null,
    invoice_sequence: null,
    payment_mode: null,
    insurer: null,
    invoice_to: null,
    invoice_number: "",
    invoice_title: "",
    invoice_date: new Date().toISOString().split("T")[0],
    due_date: "",
    status: "draft",
    kms_in: undefined,
    has_insurance: false,
    discount: "no",
    discount_amount: undefined,
    tax: null,
    deposit_to: "",
    notes: "",
    terms_and_conditions: "",
    parts: [],
    services: [],
    expense_items: [],
}

// ── Mapping helpers ──

function mapToFormValues(data: unknown): InvoiceFormValues {
    const d = (data as any)?.data ?? data ?? {}

    return {
        subject: d.subject || "",
        customer: toRelation(d.customer_id, d.customer_name),
        vehicle: toRelation(d.vehicle_id, d.vehicle_name),
        department: toRelation(d.department_id, d.department_name),
        estimate: toRelation(d.estimate_id, d.estimate_number ?? d.estimate_title),
        payment_terms: toRelation(d.payment_terms_id, d.payment_terms_name),
        invoice_sequence: toRelation(d.invoice_sequence_id, d.invoice_sequence_title ?? d.invoice_sequence?.title),
        payment_mode: toRelation(d.payment_mode_id, d.payment_mode_name),
        insurer: toRelation(d.insurer_id, d.insurer_name),
        invoice_to: toRelation(d.invoice_to_id, d.invoice_to_name),
        invoice_number: d.invoice_number || "",
        invoice_title: d.invoice_title || "",
        invoice_date: d.invoice_date ? d.invoice_date.split("T")[0] : "",
        due_date: d.due_date ? d.due_date.split("T")[0] : "",
        status: d.status || "draft",
        kms_in: d.kms_in ? Number(d.kms_in) : undefined,
        has_insurance: d.has_insurance ?? false,
        discount: d.discount || "no",
        discount_amount: d.discount_amount != null ? Number(d.discount_amount) : undefined,
        tax: toRelation(d.tax_id, d.tax_title ?? (formatTaxLabel(d.tax, "") || undefined)),
        deposit_to: d.deposit_to || "",
        notes: d.notes || "",
        terms_and_conditions: d.terms_and_conditions || "",
        parts: (d.invoice_parts ?? d.parts ?? []).map((p: any) => ({
            part_id: p.part_id ?? p.id,
            title: p.part?.title ?? p.title ?? "",
            quantity: Number(p.quantity) || 1,
            rate: Number(p.rate) || 0,
            discount_amount: p.discount_amount != null ? Number(p.discount_amount) : undefined,
            description: p.description ?? "",
        })),
        services: (d.invoice_services ?? d.services ?? []).map((s: any) => ({
            service_id: s.service_id ?? s.id,
            title: s.service?.labor_name ?? s.labor_name ?? s.title ?? "",
            quantity: Number(s.quantity) || 1,
            rate: Number(s.rate) || 0,
            discount_amount: s.discount_amount != null ? Number(s.discount_amount) : undefined,
            description: s.description ?? "",
        })),
        expense_items: (d.invoice_expenses ?? d.expenses ?? []).map((e: any) => ({
            expense_id: e.expense_id ?? e.id,
            title: e.expense?.item_name ?? e.item_name ?? e.title ?? "",
            quantity: Number(e.quantity) || 1,
            rate: Number(e.rate) || 0,
            discount_amount: e.discount_amount != null ? Number(e.discount_amount) : undefined,
            description: e.description ?? "",
        })),
    }
}

function mapFormToPayload(values: InvoiceFormValues) {
    return {
        subject: values.subject,
        customer_id: toId(values.customer),
        vehicle_id: toId(values.vehicle),
        department_id: toId(values.department),
        estimate_id: toId(values.estimate),
        payment_terms_id: toId(values.payment_terms),
        invoice_sequence_id: toId(values.invoice_sequence),
        payment_mode_id: toId(values.payment_mode),
        insurer_id: toId(values.insurer),
        invoice_to_id: toId(values.invoice_to),
        invoice_number: values.invoice_number || undefined,
        invoice_title: values.invoice_title || undefined,
        invoice_date: values.invoice_date || undefined,
        due_date: values.due_date || undefined,
        status: values.status || undefined,
        kms_in: values.kms_in || undefined,
        has_insurance: values.has_insurance,
        discount: values.discount || undefined,
        discount_amount: values.discount === "transaction_level" ? (values.discount_amount ?? 0) : undefined,
        tax_id: toId(values.tax) ? Number(toId(values.tax)) : undefined,
        deposit_to: values.deposit_to || undefined,
        notes: values.notes || undefined,
        terms_and_conditions: values.terms_and_conditions || undefined,
        parts: (values.parts ?? []).map((item) => ({
            part_id: item.part_id,
            quantity: item.quantity,
            rate: item.rate,
            discount_amount: values.discount === "line_item_level" ? (item.discount_amount ?? 0) : undefined,
            description: item.description || undefined,
        })),
        services: (values.services ?? []).map((item) => ({
            service_id: item.service_id,
            quantity: item.quantity,
            rate: item.rate,
            discount_amount: values.discount === "line_item_level" ? (item.discount_amount ?? 0) : undefined,
            description: item.description || undefined,
        })),
        expenses: (values.expense_items ?? []).map((item) => ({
            expense_id: item.expense_id,
            quantity: item.quantity,
            rate: item.rate,
            discount_amount: values.discount === "line_item_level" ? (item.discount_amount ?? 0) : undefined,
            description: item.description || undefined,
        })),
    }
}

// ── Shared mapOption for async selects ──

const mapLookupOption = (item: any) => ({
    value: String(item.id),
    label: item.name ?? item.title ?? `#${item.id}`,
})

const STORE_OBJECT = { getOptionValue: (o: any) => o, getOptionLabel: (o: any) => o.label }

// ── Insurance fields (conditionally rendered) ──

function InsurerField() {
    const { watch } = useFormContext<InvoiceFormValues>()
    const hasInsurance = watch("has_insurance")

    if (!hasInsurance) return null

    return (
        <RhfCustomerSelectField<InvoiceFormValues, "insurer">
            name="insurer"
            label="Insurer"
            placeholder="Select insurer..."
        />
    )
}

// ── Transaction-level discount amount field ──

function TransactionDiscountField() {
    const { watch, register } = useFormContext<InvoiceFormValues>()
    const discount = watch("discount")

    if (discount !== "transaction_level") return null

    return (
        <RhfTextField
            
            name="discount_amount"
            label="Discount Amount"
            type="number"
            placeholder="0.00"
        />
    )
}

// ── Component ──

export function InvoiceForm({ resourceId, initialData, onSuccess }: InvoiceFormProps) {
    const api = useAuthApi()

    const { form, isEditing } = useResourceForm<InvoiceFormValues, any>({
        schema: invoiceFormSchema,
        defaultValues: DEFAULT_VALUES,
        resourceId,
        initialData,
        queryKey: [INVOICE_ROUTES.BY_ID, resourceId],
        mapToFormValues,
    })

    const discount = form.watch("discount")
    const isLineItemDiscount = discount === "line_item_level"

    const { mutate, error, isPending } = useFormMutation(form, {
        mutationFn: (values: InvoiceFormValues) => {
            const payload = mapFormToPayload(values)
            const promise = (isEditing && resourceId
                ? api.invoices.update(resourceId, payload)
                : api.invoices.create(payload)) as Promise<any>
            toast.promise(promise, {
                loading: isEditing ? "Updating invoice..." : "Creating invoice...",
                success: isEditing ? "Invoice updated successfully" : "Invoice created successfully",
                error: isEditing ? "Failed to update invoice" : "Failed to create invoice",
            })
            return promise
        },
        onSuccess: () => {
            form.reset()
            onSuccess?.()
        },
    })

    return (
        <Rhform form={form} onSubmit={(values) => mutate(values)}>
            {error && (
                <Alert variant="destructive" className="mb-4">
                    <AlertTriangle className="me-2 h-4 w-4" />
                    <AlertTitle>
                        {isEditing ? "Failed to update invoice" : "Failed to create invoice"}
                    </AlertTitle>
                    {error.message}
                </Alert>
            )}

            <div className="grid grid-cols-1 gap-6 lg:grid-cols-12">

                {/* ── Main column (8/12) ── */}
                <div className="lg:col-span-9">
                    <FieldGroup>
                        <RhfTextField name="subject" label="Subject" placeholder="Invoice subject" required />

                        <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
                            <RhfAutoGenerateField autoFetch table="invoices" name="invoice_number" label="Invoice Number" placeholder="INV-0001" />
                            <RhfTextField name="invoice_title" label="Invoice Title" placeholder="e.g. Tax Invoice" />
                        </div>

                        <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
                            <RhfSelectField name="status" label="Status" options={STATUS_OPTIONS} />
                            <RhfSelectField name="discount" label="Discount Type" options={DISCOUNT_OPTIONS} />
                        </div>

                        <TransactionDiscountField />

                        <PartsSelectorField<InvoiceFormValues, "parts"> name="parts" showDiscount={isLineItemDiscount} />
                        <ServicesSelectorField<InvoiceFormValues, "services"> name="services" showDiscount={isLineItemDiscount} />
                        <ExpenseItemsSelectorField<InvoiceFormValues, "expense_items"> name="expense_items" showDiscount={isLineItemDiscount} />

                        <RhfTextareaField name="notes" label="Notes" placeholder="Additional notes" rows={3} />
                        <RhfTextareaField name="terms_and_conditions" label="Terms & Conditions" rows={3} />

                        <Button type="submit" variant="default" disabled={isPending}>
                            {isEditing ? <Save /> : <Plus />}
                            {isPending
                                ? (isEditing ? "Updating..." : "Creating...")
                                : (isEditing ? "Update Invoice" : "Create Invoice")}
                        </Button>
                    </FieldGroup>
                </div>

                {/* ── Sidebar column (4/12) ── */}
                <div className="lg:col-span-3">
                    <Card>
                        <CardHeader className="pb-3">
                            <CardTitle className="text-sm font-medium text-muted-foreground uppercase tracking-wide">Details</CardTitle>
                        </CardHeader>
                        <CardContent>
                            <FieldGroup>
                                <div className="grid grid-cols-1 gap-4 sm:grid-cols-2 lg:grid-cols-1">
                                    <RhfDateField name="invoice_date" label="Invoice Date" />
                                    <RhfDateField name="due_date" label="Due Date" />
                                </div>

                                <RhfCustomerSelectField<InvoiceFormValues, "customer"> name="customer" />
                                <RhfVehicleSelectField name="vehicle" />

                                <RhfAsyncSelectField
                                    name="tax"
                                    label="Tax"
                                    placeholder="Select tax rate"
                                    queryKey={[TAX_ROUTES.INDEX]}
                                    listFn={() => api.taxes.list()}
                                    mapOption={(item: any) => ({
                                        value: String(item.id),
                                        label: item.title ? `${item.title} (${item.rate}%)` : `#${item.id}`,
                                    })}
                                    {...STORE_OBJECT}
                                />

                                <RhfAsyncSelectField
                                    name="department"
                                    label="Department"
                                    placeholder="Select department"
                                    queryKey={[DEPARTMENT_ROUTES.INDEX]}
                                    listFn={() => api.departments.list()}
                                    mapOption={mapLookupOption}
                                    {...STORE_OBJECT}
                                />

                                <RhfAsyncSelectField
                                    name="payment_terms"
                                    label="Payment Terms"
                                    placeholder="Select payment terms"
                                    queryKey={[PAYMENT_TERM_ROUTES.INDEX]}
                                    listFn={() => api.paymentTerms.list()}
                                    mapOption={mapLookupOption}
                                    {...STORE_OBJECT}
                                />

                                <div>
                                    <div className="mb-1 flex items-center justify-between">
                                        <span className="text-sm font-medium">Invoice Sequence</span>
                                        <InvoiceSequenceCrudDialog />
                                    </div>
                                    <RhfAsyncSelectField
                                        name="invoice_sequence"
                                        label=""
                                        placeholder="Select sequence"
                                        queryKey={[INVOICE_SEQUENCE_ROUTES.INDEX]}
                                        listFn={() => api.invoiceSequences.list()}
                                        mapOption={(item: any) => ({
                                            value: String(item.id),
                                            label: item.title || `#${item.id}`,
                                        })}
                                        {...STORE_OBJECT}
                                    />
                                </div>

                                <RhfCheckboxField name="has_insurance" label="Has Insurance" />
                                <InsurerField />
                            </FieldGroup>
                        </CardContent>
                    </Card>
                    
                    <div className="mt-4">
                    <InvoiceFormSummary />
                    </div>
                </div>

            </div>
        </Rhform>
    )
}