import Elementary
import Foundation
import Infrastructure
import Persistence

/// The seller dashboard: the offers waiting for an answer, the sales and their handshakes, and what is listed.
struct SellerDashboardPage {

    // MARK: Properties

    let analytics: Analytics?
    let assetVersion: String?
    let locale: Locale

    /// The upcoming events, each with whether the shop trades there.
    let events: [(event: Event, isTrading: Bool)]

    /// The shop's listings still for sale, newest first.
    let listings: [Listing]

    /// The moment stamps are read relative to.
    let now: Date

    /// The offers waiting for the seller's answer, the soonest to expire first.
    let offers: [Offer]

    /// The shop's sales, the latest agreed first.
    let sales: [Sale]

    /// The viewer's shop.
    let shop: Shop

    /// The signed-in viewer.
    let viewer: Viewer?

    // MARK: Initializers

    /// Creates the seller dashboard of a shop.
    /// - Parameters:
    ///   - shop: the viewer's shop.
    ///   - offers: the offers waiting for the seller's answer, the soonest to expire first.
    ///   - sales: the shop's sales, the latest agreed first.
    ///   - listings: the shop's listings still for sale, newest first.
    ///   - events: the upcoming events; none by default.
    ///   - viewer: the signed-in viewer.
    ///   - now: the moment stamps are read relative to; the present by default.
    ///   - assetVersion: the version token appended to the page's asset URLs, or `nil` (the default) to leave them unversioned.
    ///   - analytics: the analytics tracker embedded in the document head, or `nil` (the default) to omit it.
    init(
        shop: Shop,
        offers: [Offer],
        sales: [Sale],
        listings: [Listing],
        events: [Event] = [],
        viewer: Viewer? = nil,
        now: Date = .init(),
        assetVersion: String? = nil,
        analytics: Analytics? = nil
    ) {
        self.analytics = analytics
        self.assetVersion = assetVersion
        self.events = events.map { event in (event, event.shops.contains { $0.slug == shop.slug }) }
        self.listings = listings
        self.locale = .init(identifier: "en")
        self.now = now
        self.offers = offers
        self.sales = sales
        self.shop = shop
        self.viewer = viewer
    }

}

// MARK: - Page

extension SellerDashboardPage: Page {

    // MARK: Computed

    var content: some HTML {
        SiteLayout(viewer: viewer) {
            div(.class("page sell")) {
                div(.class("sell__head")) {
                    div(.class("sell__heading")) {
                        p(.class("type-eyebrow")) {
                            "\(shop.name) · seller dashboard"
                        }
                        h1(.class("type-h1")) {
                            "Hello, \(viewer?.firstName ?? shop.name)"
                        }
                        p(.class("type-body-sm sell__summary")) {
                            summary
                        }
                    }
                    div(.class("sell__actions")) {
                        a(
                            .class("button button--outline"),
                            .href(shop.path)
                        ) {
                            "View public shop"
                        }
                        a(
                            .class("button button--primary"),
                            .href(NewListingPage.path)
                        ) {
                            "New listing"
                        }
                    }
                }
                ul(.class("tiles")) {
                    tile("\(listings.count)", "Active listings", nil)
                    tile("\(offers.count)", "Open offers", offers.first.map { "next: \($0.expiresAt.countdown(from: now))" })
                    tile("\(viewer?.unreadMessages ?? 0)", "Unread conversations", nil)
                    tile("\(sales.count)", "Sales", "\(sales.count { $0.next == .sent }) awaiting your dispatch")
                    tile(shop.rating.oneDecimal, "Rating", "\(shop.ratedSales) rated sales")
                }
                section(.class("card sell__panel")) {
                    div(.class("section-head")) {
                        h2(.class("type-panel")) {
                            "Offers"
                        }
                        span(.class("type-small")) {
                            "Offers under 80% of asking are auto-declined"
                        }
                    }
                    if offers.isEmpty {
                        p(.class("sell__none")) {
                            "No offers waiting."
                        }
                    } else {
                        ul(.class("rows")) {
                            ForEach(offers) { offer in
                                li(.class("rows__row rows__row--offer")) {
                                    span {
                                        a(
                                            .class("rows__title"),
                                            .href(.Route.conversation(offer.conversationID))
                                        ) {
                                            offer.listing.title
                                        }
                                        span(.class("type-small")) {
                                            " · \(offer.listing.chip.label)"
                                        }
                                    }
                                    span(.class("type-small")) {
                                        "asks \(offer.listing.priceCents.euros)"
                                    }
                                    strong(.class("type-price-card")) {
                                        offer.amountCents.euros
                                    }
                                    span(.class("type-small")) {
                                        offer.expiresAt.countdown(from: now)
                                    }
                                    span(.class("type-small")) {
                                        "from \(offer.buyer.displayName)"
                                    }
                                    AnswerOffer(
                                        offer: offer,
                                        returnPath: .Route.sellerDashboard
                                    )
                                }
                            }
                        }
                    }
                }
                section(.class("card sell__panel")) {
                    h2(.class("type-panel")) {
                        "Recent sales"
                    }
                    if sales.isEmpty {
                        p(.class("sell__none")) {
                            "No sales yet. Accepting an offer opens the first sale record."
                        }
                    } else {
                        ul(.class("rows")) {
                            ForEach(sales) { sale in
                                li {
                                    a(
                                        .class("rows__row rows__row--sale"),
                                        .href(.Route.sale(sale.number))
                                    ) {
                                        strong {
                                            sale.reference
                                        }
                                        span {
                                            "\(sale.listing.title) · \(sale.listing.chip.label)"
                                        }
                                        span {
                                            sale.priceCents.euros
                                        }
                                        span(.class("type-small")) {
                                            sale.buyer.displayName
                                        }
                                        Handshake(completed: sale.completed)
                                        span(.class("type-small")) {
                                            sale.agreedAt.stamp(relativeTo: now)
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
                section(.class("card sell__panel")) {
                    div(.class("section-head")) {
                        h2(.class("type-panel")) {
                            "Active listings"
                        }
                        a(
                            .class("link-ink"),
                            .href(shop.path)
                        ) {
                            "All \(listings.count)"
                        }
                    }
                    ul(.class("rows")) {
                        ForEach(listings) { listing in
                            li(.class("rows__row rows__row--listing")) {
                                span {
                                    a(
                                        .class("rows__title"),
                                        .href(listing.path)
                                    ) {
                                        listing.title
                                    }
                                    span(.class("type-small")) {
                                        " · \(listing.chip.label)"
                                    }
                                }
                                span {
                                    listing.priceCents.euros
                                }
                                span(.class("type-small")) {
                                    listing.acceptsOffers ? "accepts offers" : "fixed price"
                                }
                            }
                        }
                    }
                }
                if !events.isEmpty {
                    form(
                        .class("card sell__panel"),
                        .action("\(String.Route.sellerDashboard)/events"),
                        .method(.post)
                    ) {
                        div(.class("section-head")) {
                            h2(.class("type-panel")) {
                                "Events you'll trade at"
                            }
                            span(.class("type-small")) {
                                "Buyers can agree online and collect at the con"
                            }
                        }
                        div(.class("listing-form__checks")) {
                            ForEach(events) { entry in
                                label(.class("check")) {
                                    input(
                                        .type(.checkbox),
                                        .name("events"),
                                        .value(entry.event.slug)
                                    )
                                    .attributes(.checked, when: entry.isTrading)
                                    "\(entry.event.name) · \(Date.span(from: entry.event.startsOn, to: entry.event.endsOn))"
                                }
                            }
                        }
                        div(.class("listing-form__submit")) {
                            button(
                                .class("button button--dark button--sm"),
                                .type(.submit)
                            ) {
                                "Save events"
                            }
                        }
                    }
                }
            }
        }
    }

    @HTMLBuilder
    var metadata: some HTML {
        meta(
            .name("robots"),
            .content("noindex")
        )
        siteMetadata
    }

    var scripts: [any Asset] {
        [StaticFile.shared]
    }

    var stylesheets: [any Asset] {
        [StaticFile.shared, StaticFile.trade]
    }

    var title: String {
        "Seller dashboard · \(shop.name) — CCN"
    }

}

// MARK: - Helpers

private extension SellerDashboardPage {

    // MARK: Computed

    /// What needs the seller's attention, in a line.
    var summary: String {
        let dispatch = sales.count { $0.next == .sent }

        return [
            offers.isEmpty ? "No offers waiting" : "\(offers.count) \(offers.count == 1 ? "offer" : "offers") waiting",
            dispatch == 0 ? nil : "\(dispatch) \(dispatch == 1 ? "sale" : "sales") to dispatch",
            (viewer?.unreadMessages ?? 0) == 0 ? nil : "\(viewer?.unreadMessages ?? 0) unread",
        ]
        .compactMap(\.self)
        .joined(separator: " · ")
    }

    // MARK: Methods

    /// A figure, what it counts, and an optional note under it.
    func tile(
        _ figure: String,
        _ label: String,
        _ note: String?
    ) -> some HTML {
        li(.class("card tiles__tile")) {
            span(.class("type-stat")) {
                figure
            }
            span(.class("type-label")) {
                label
            }
            if let note {
                span(.class("type-small")) {
                    note
                }
            }
        }
    }

}