import Elementary
import Foundation
import Infrastructure
import Persistence

/// The events where shops trade in person: agree on the site, skip shipping, collect the copy at the con.
struct EventsPage {

    // MARK: Properties

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

    /// The events still to come, soonest first, each with the number of listings that can be picked up there.
    let events: [(event: Event, listingCount: Int)]

    /// The moment "this weekend" is judged from.
    let now: Date

    /// The signed-in viewer, or `nil` when signed out.
    let viewer: Viewer?

    // MARK: Initializers

    /// Creates the events screen.
    /// - Parameters:
    ///   - events: the events still to come, soonest first.
    ///   - listings: every listing for sale, counted per event by the shops trading there.
    ///   - viewer: the signed-in viewer, or `nil` (the default) when signed out.
    ///   - now: the moment "this weekend" is judged from; 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(
        events: [Event],
        listings: [Listing],
        viewer: Viewer? = nil,
        now: Date = .init(),
        assetVersion: String? = nil,
        analytics: Analytics? = nil
    ) {
        self.analytics = analytics
        self.assetVersion = assetVersion
        self.events = events.map { event in
            let shops = Set(event.shops.map(\.slug))

            return (event, listings.count { shops.contains($0.shop.slug) })
        }
        self.locale = .init(identifier: "en")
        self.now = now
        self.viewer = viewer
    }

}

// MARK: - Page

extension EventsPage: Page {

    // MARK: Computed

    var content: some HTML {
        SiteLayout(viewer: viewer) {
            div(.class("page wants")) {
                div(.class("events__intro")) {
                    h1(.class("type-h1")) {
                        "Pick up at a con"
                    }
                    p(.class("type-lead")) {
                        "Sellers mark which events they'll trade at. Agree on CCN, skip shipping, collect it in person."
                    }
                }
                if events.isEmpty {
                    div(.class("empty")) {
                        h2(.class("type-panel")) {
                            "No events coming up"
                        }
                        p(.class("type-body-sm")) {
                            "Every copy still ships, tracked."
                        }
                    }
                }
                ul(.class("wants__list")) {
                    ForEach(events) { entry in
                        li {
                            a(
                                .class("card events__event"),
                                .href(.Route.pickup(at: entry.event.slug))
                            ) {
                                span(.class("wants__top")) {
                                    span(.class("events__name")) {
                                        strong {
                                            entry.event.name
                                        }
                                        span(.class("type-small")) {
                                            Date.span(from: entry.event.startsOn, to: entry.event.endsOn)
                                        }
                                    }
                                    if entry.event.startsOn.isWithinAWeek(of: now) {
                                        Chip("This weekend", tone: .warn)
                                    }
                                }
                                span(.class("type-small")) {
                                    entry.event.venue
                                }
                                span(.class("events__chips")) {
                                    Chip("\(entry.event.shops.count) \(entry.event.shops.count == 1 ? "shop" : "shops") trading")
                                    Chip("\(entry.listingCount) \(entry.listingCount == 1 ? "listing" : "listings") for pickup")
                                }
                            }
                        }
                    }
                }
                p(.class("type-small wants__note")) {
                    "Selling? Pick the events you'll trade at on your seller dashboard."
                }
            }
        }
    }

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

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

    var summary: String? {
        "Comic cons where CCN shops trade in person: agree on a copy online, collect it at the event."
    }

    var title: String {
        "Events — CCN"
    }

}