import { Controller } from '@hotwired/stimulus'
import { csrfToken } from './csrf'

// Drives the checkout page's left column: contact tabs, the same-as-billing
// toggle, and — the bulk of it — autosaving the address form and the shipping
// method with no submit buttons.
//
// Flow: any `change` in the address form is debounced ~400ms, then the whole
// form is POSTed to saveUrl. The server persists leniently and returns
// { errors, shippingOptionsHtml, summaryHtml }. We swap the shipping-options
// block in place and hand the summary fragment to the drawer's bbk-cart
// controller via the `bbk-cart:changed` window event (same mechanism the drawer
// already uses). Shipping-method radios post to selectShippingUrl the same way.
export default class extends Controller {
    static targets = [
        'guestTab', 'loginTab', 'guestPanel', 'loginPanel',
        'sameAsBilling', 'shippingFields',
        'form', 'shippingOptions', 'status',
    ]

    static values = {
        saveUrl: String,
        selectShippingUrl: String,
        statusSaving: String,
        statusSaved: String,
        statusError: String,
    }

    connect() {
        this.saveTimer = null
        this.saveController = null
        this.statusTimer = null

        if (this.hasSameAsBillingTarget) this.applySameAsBilling()
    }

    disconnect() {
        clearTimeout(this.saveTimer)
        clearTimeout(this.statusTimer)
        this.saveController?.abort()
    }

    // ── Contact tabs ────────────────────────────────────────────────────

    showGuest() {
        this.guestPanelTarget.hidden = false
        this.loginPanelTarget.hidden = true
        this.guestTabTarget.setAttribute('aria-selected', 'true')
        this.loginTabTarget.setAttribute('aria-selected', 'false')
    }

    showLogin() {
        this.guestPanelTarget.hidden = true
        this.loginPanelTarget.hidden = false
        this.guestTabTarget.setAttribute('aria-selected', 'false')
        this.loginTabTarget.setAttribute('aria-selected', 'true')
    }

    // ── Same as billing ────────────────────────────────────────────────

    toggleSameAsBilling() {
        this.applySameAsBilling()
    }

    applySameAsBilling() {
        const on = this.sameAsBillingTarget.checked

        // Checked: shipping *is* billing — copy every value across, then hide +
        // disable so the browser doesn't submit them; the server reuses billing.
        // Unchecked: reveal them pre-filled from billing wherever still empty.
        this.element.querySelectorAll('[name^="billing_"]').forEach((billingField) => {
            const shippingField = this.element.querySelector(
                `[name="${billingField.name.replace(/^billing_/, 'shipping_')}"]`,
            )
            if (shippingField && (on || !shippingField.value)) {
                shippingField.value = billingField.value
            }
        })

        this.shippingFieldsTarget.hidden = on
        this.shippingFieldsTarget.querySelectorAll('input, select, textarea').forEach((field) => {
            field.disabled = on
        })
    }

    // ── Autosave ───────────────────────────────────────────────────────

    scheduleSave(event) {
        // The shipping-method and payment radios live inside this controller's
        // element too, and this action is bound on .bbk-checkout-main to also
        // catch the contact email/consent that sit outside the <form>. Only
        // react to fields that actually belong to the address form.
        const el = event.target
        const belongsToForm = el.form?.id === 'bbk-address-form'
            || el.closest('[data-bbk-checkout-form-target="guestPanel"]')
        if (!belongsToForm) return

        // No status during the wait — it only shows once the request is in flight,
        // so the indicator isn't flickering "saving" on every keystroke.
        clearTimeout(this.saveTimer)
        this.saveTimer = setTimeout(() => this.save(), 700)
    }

    // Called by bbk-payment right before place-order — a debounced save (and
    // the shipping-option auto-select that happens as part of it) might still
    // be pending when the shopper clicks "place order"; this guarantees the
    // server has processed the current form state first.
    async flush() {
        clearTimeout(this.saveTimer)
        await this.save()
    }

    async save() {
        this.saveController?.abort()
        this.saveController = new AbortController()
        this.setStatus('saving')

        try {
            const response = await fetch(this.saveUrlValue, {
                method: 'POST',
                headers: {
                    'X-CSRF-TOKEN': csrfToken(),
                    'X-Requested-With': 'XMLHttpRequest',
                    Accept: 'application/json',
                },
                body: new FormData(this.formTarget),
                signal: this.saveController.signal,
            })

            if (!response.ok) return this.setStatus('error')

            this.applyResult(await response.json())
            this.setStatus('saved')
        } catch (error) {
            if (error.name !== 'AbortError') this.setStatus('error')
        }
    }

    async selectShipping(event) {
        this.saveController?.abort()
        this.setStatus('saving')

        const body = new FormData()
        body.append('shipping_option', event.target.value)

        try {
            const response = await fetch(this.selectShippingUrlValue, {
                method: 'POST',
                headers: {
                    'X-CSRF-TOKEN': csrfToken(),
                    'X-Requested-With': 'XMLHttpRequest',
                    Accept: 'application/json',
                },
                body,
            })

            if (!response.ok) return this.setStatus('error')

            this.applyResult(await response.json())
            this.setStatus('saved')
        } catch {
            this.setStatus('error')
        }
    }

    applyResult(data) {
        this.applyErrors(data.errors || {})

        if (data.shippingOptionsHtml != null) {
            this.shippingOptionsTarget.innerHTML = data.shippingOptionsHtml
        }

        if (data.summaryHtml != null) {
            window.dispatchEvent(new CustomEvent('bbk-cart:changed', {
                detail: { html: data.summaryHtml },
            }))
        }
    }

    applyErrors(errors) {
        this.element.querySelectorAll('[data-bbk-field-error]').forEach((el) => {
            const message = errors[el.dataset.bbkFieldError]
            el.textContent = message || ''
            el.hidden = !message

            const field = this.element.querySelector(`[name="${el.dataset.bbkFieldError}"]`)
            field?.classList.toggle('bbk-field-input--error', Boolean(message))
        })
    }

    setStatus(state) {
        if (!this.hasStatusTarget) return

        const text = {
            saving: this.statusSavingValue,
            saved: this.statusSavedValue,
            error: this.statusErrorValue,
        }[state]

        this.statusTarget.textContent = text
        this.statusTarget.hidden = false
        this.statusTarget.dataset.state = state

        clearTimeout(this.statusTimer)
        if (state === 'saved') {
            this.statusTimer = setTimeout(() => { this.statusTarget.hidden = true }, 2000)
        }
    }
}