import Elementary
import Foundation
import Infrastructure
import Persistence

/// The new-listing form: what the copy is, its condition against the grading guide, photos of it, and its price.
///
/// Every field applies to some format or grading; without scripts they all show, labelled by what they are for, and the server checks what
/// applies. With scripts, `js/shared.js` hides the ones that do not.
struct NewListingPage {

    // MARK: Properties

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

    /// The values the form is filled with.
    let form: ListingForm

    /// What is wrong with the form, by field.
    let problems: [ListingForm.Field: String]

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

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

    // MARK: Initializers

    /// Creates the new-listing form.
    /// - Parameters:
    ///   - shop: the viewer's shop.
    ///   - form: the values the form is filled with; an empty form by default.
    ///   - problems: what is wrong with the form, by field; nothing by default.
    ///   - viewer: the signed-in viewer.
    ///   - 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,
        form: ListingForm = .init(),
        problems: [ListingForm.Field: String] = [:],
        viewer: Viewer? = nil,
        assetVersion: String? = nil,
        analytics: Analytics? = nil
    ) {
        self.analytics = analytics
        self.assetVersion = assetVersion
        self.form = form
        self.locale = .init(identifier: "en")
        self.problems = problems
        self.shop = shop
        self.viewer = viewer
    }

}

// MARK: - Page

extension NewListingPage: Page {

    // MARK: Constants

    /// The path the page is served at, and the form posted to.
    static let path = "\(String.Route.sellerDashboard)/new"

    // MARK: Computed

    var content: some HTML {
        SiteLayout(viewer: viewer) {
            div(.class("page listing-form")) {
                div(.class("listing-form__head")) {
                    p(.class("type-eyebrow")) {
                        "\(shop.name) · seller tools"
                    }
                    h1(.class("type-h1")) {
                        "New listing"
                    }
                }
                if !problems.isEmpty {
                    div(
                        .class("notice notice--bad"),
                        .custom(name: "role", value: "alert")
                    ) {
                        p {
                            strong {
                                problems.count == 1 ? "One thing to fix before publishing." : "\(problems.count) things to fix before publishing."
                            }
                            form.value(.photos) == nil ? " Photos have to be picked again: a browser never keeps a chosen file." : ""
                        }
                    }
                }
                Elementary.form(
                    .class("listing-form__form"),
                    .action(Self.path),
                    .method(.post),
                    .custom(name: "enctype", value: "multipart/form-data")
                ) {
                    what
                    condition
                    photos
                    price
                    div(.class("listing-form__submit")) {
                        a(
                            .class("button"),
                            .href(.Route.sellerDashboard)
                        ) {
                            "Cancel"
                        }
                        button(
                            .class("button button--primary button--lg"),
                            .type(.submit)
                        ) {
                            "Publish listing"
                        }
                    }
                }
            }
        }
    }

    @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 {
        "New listing · \(shop.name) — CCN"
    }

}

// MARK: - Sections

private extension NewListingPage {

    var what: some HTML {
        section(.class("card listing-form__section")) {
            h2(.class("type-panel")) {
                "1. What is it"
            }
            fieldset(.class("field")) {
                legend(.class("field__label")) {
                    "Format"
                }
                div(.class("segmented")) {
                    ForEach(Format.allCases) { format in
                        label(.class("segmented__option")) {
                            input(
                                .type(.radio),
                                .name(ListingForm.Field.format.rawValue),
                                .value(format.rawValue)
                            )
                            .attributes(.checked, when: form.has(.format, value: format.rawValue))
                            span {
                                format.singular
                            }
                        }
                    }
                }
                problem(.format)
            }
            div(.class("listing-form__grid")) {
                text(.series, "Series or title", placeholder: "Nightward", span: 2)
                text(.issue, "Issue or volume", placeholder: "1", hint: "Required for single issues")
                text(.publisher, "Publisher", placeholder: "Meridian Comics", span: 2)
                text(.year, "Cover year", placeholder: "2019", numeric: true)
                select(.printing, "Printing", options: [("1", "1st printing"), ("2", "2nd printing"), ("3", "3rd printing"), ("0", "Later / unknown")])
                select(.edition, "Edition", options: [("", "Not applicable"), ("Direct", "Direct"), ("Newsstand", "Newsstand")], scope: "single-issues")
                text(.keyNotes, "Key notes", placeholder: "1st app. of the Nightward", hint: "Leave empty unless the issue is a key")
            }
        }
    }

    var condition: some HTML {
        section(.class("card listing-form__section")) {
            div(.class("section-head")) {
                h2(.class("type-panel")) {
                    "2. Condition"
                }
                a(
                    .class("link-ink"),
                    .href(.Route.gradingGuide)
                ) {
                    "CCN grading guide"
                }
            }
            div(
                .class("listing-form__scope"),
                .custom(name: "data-scope", value: "single-issues")
            ) {
                p(.class("type-eyebrow")) {
                    "Single issues"
                }
                fieldset(.class("listing-form__modes")) {
                    legend(.class("visually-hidden")) {
                        "Slabbed or raw"
                    }
                    mode(.slabbed, "Slabbed (graded)", "CGC, CBCS or PGX. Buyers see the cert number to verify.")
                    mode(.raw, "Raw (seller-graded)", "You grade it against the guide and declare every defect.")
                }
                div(.class("listing-form__grid")) {
                    select(.grade, "Grade", options: [("", "Pick a grade")] + Grading.scale.map { ($0.grade.oneDecimal, "\($0.grade.oneDecimal) · \($0.code)") })
                    select(.grader, "Grader", options: [("", "—")] + Grading.graders.map { ($0, $0) }, scope: "slabbed")
                    select(.pageQuality, "Page quality", options: [("", "Not stated")] + Grading.pageQualities.map { ($0, $0) }, scope: "slabbed")
                    text(.cert, "Cert number", placeholder: "4312087-002", scope: "slabbed")
                }
            }
            div(
                .class("listing-form__scope"),
                .custom(name: "data-scope", value: "collected")
            ) {
                p(.class("type-eyebrow")) {
                    "Manga, trade paperbacks and hardcovers"
                }
                div(.class("listing-form__grid")) {
                    select(.condition, "Condition", options: [("", "Pick a condition")] + Grading.conditions.map { ($0, $0) })
                }
            }
            fieldset(.class("field")) {
                legend(.class("field__label")) {
                    "Defects"
                }
                p(.class("field__hint")) {
                    "Tick everything that applies. A buyer can't dispute a defect you declared; an undeclared one is always grounds."
                }
                div(.class("listing-form__checks")) {
                    ForEach(Grading.Defect.allCases) { defect in
                        label(.class("check")) {
                            input(
                                .type(.checkbox),
                                .name(ListingForm.Field.defects.rawValue),
                                .value(defect.rawValue)
                            )
                            .attributes(.checked, when: form.has(.defects, value: defect.rawValue))
                            defect == .caseScuffs ? "\(defect.label) (slab)" : defect.label
                        }
                    }
                }
                problem(.defects)
            }
        }
    }

    var photos: some HTML {
        section(.class("card listing-form__section")) {
            h2(.class("type-panel")) {
                "3. Photos of this copy"
            }
            div(.class("field")) {
                label(
                    .class("field__label"),
                    .for("photos")
                ) {
                    "Up to \(PhotoStore.maxCount) photos — front first, then back, spine, and the label for slabs"
                }
                input(
                    .class("listing-form__files"),
                    .id("photos"),
                    .type(.file),
                    .name(ListingForm.Field.photos.rawValue),
                    .custom(name: "accept", value: "image/jpeg,image/png,image/webp"),
                    .custom(name: "multiple", value: "")
                )
                p(.class("field__hint")) {
                    "JPEG, PNG or WebP, up to 3 MB each. No stock images. Without photos the listing shows a placeholder cover."
                }
                problem(.photos)
            }
            div(.class("field")) {
                label(
                    .class("field__label"),
                    .for("notes")
                ) {
                    "Seller's notes (provenance, case condition, anything a photo can't show)"
                }
                textarea(
                    .class("input"),
                    .id("notes"),
                    .name(ListingForm.Field.notes.rawValue),
                    .custom(name: "rows", value: "3"),
                    .custom(name: "maxlength", value: "1000")
                ) {
                    form.value(.notes) ?? ""
                }
                problem(.notes)
            }
        }
    }

    var price: some HTML {
        section(.class("card listing-form__section")) {
            h2(.class("type-panel")) {
                "4. Price and shipping"
            }
            div(.class("listing-form__grid")) {
                text(.price, "Asking price (EUR)", placeholder: "240", numeric: true)
                select(.offers, "Offers", options: [("1", "Accept offers · auto-decline under 80%"), ("0", "Fixed price, no offers")])
                text(.shipping, "Tracked shipping to NL (EUR)", placeholder: "6", numeric: true)
            }
            p(.class("gate-note")) {
                Icon(.info, size: 16)
                span {
                    "Ships from \(shop.location) · \(shop.handlingDays) business days handling. Payment is settled between you and the buyer off-platform; CCN records the sale, the agreed price and shipping, and holds the message history for both sides."
                }
            }
        }
    }

}

// MARK: - Fields

private extension NewListingPage {

    /// A way of grading a single issue, as a radio card.
    func mode(
        _ mode: Grading.Mode,
        _ title: String,
        _ text: String
    ) -> some HTML {
        label(.class("listing-form__mode")) {
            input(
                .type(.radio),
                .name(ListingForm.Field.grading.rawValue),
                .value(mode.rawValue)
            )
            .attributes(.checked, when: form.has(.grading, value: mode.rawValue))
            span {
                strong {
                    title
                }
                span(.class("type-small")) {
                    text
                }
            }
        }
    }

    /// What is wrong with a field, tied to it by its identifier; nothing when it is fine.
    @HTMLBuilder
    func problem(
        _ field: ListingForm.Field
    ) -> some HTML {
        if let problem = problems[field] {
            p(
                .class("field__error"),
                .id("\(field.rawValue)-error")
            ) {
                problem
            }
        }
    }

    /// A select, showing the form's value. A scoped one applies to one format or grading only.
    func select(
        _ field: ListingForm.Field,
        _ title: String,
        options: [(value: String, label: String)],
        scope: String? = nil
    ) -> some HTML {
        div(.class("field"))  {
            label(
                .class("field__label"),
                .for(field.rawValue)
            ) {
                title
            }
            Elementary.select(
                .class("select select--block"),
                .id(field.rawValue),
                .name(field.rawValue)
            ) {
                ForEach(options) { option in
                    Elementary.option(.value(option.value)) {
                        option.label
                    }
                    .attributes(.selected, when: form.value(field) == option.value)
                }
            }
            .attributes(
                .custom(name: "aria-invalid", value: "true"),
                .custom(name: "aria-describedby", value: "\(field.rawValue)-error"),
                when: problems[field] != nil
            )
            problem(field)
        }
        .attributes(.custom(name: "data-scope", value: scope ?? ""), when: scope != nil)
    }

    /// A text field, showing the form's value.
    func text(
        _ field: ListingForm.Field,
        _ title: String,
        placeholder: String,
        hint: String? = nil,
        numeric: Bool = false,
        span: Int = 1,
        scope: String? = nil
    ) -> some HTML {
        div(.class(span == 2 ? "field field--wide" : "field")) {
            label(
                .class("field__label"),
                .for(field.rawValue)
            ) {
                title
            }
            input(
                .class("input"),
                .id(field.rawValue),
                .type(.text),
                .name(field.rawValue),
                .value(form.value(field) ?? ""),
                .placeholder(placeholder)
            )
            .attributes(.custom(name: "inputmode", value: "numeric"), when: numeric)
            .attributes(
                .custom(name: "aria-invalid", value: "true"),
                .custom(name: "aria-describedby", value: "\(field.rawValue)-error"),
                when: problems[field] != nil
            )
            if let hint, problems[field] == nil {
                p(.class("field__hint")) {
                    hint
                }
            }
            problem(field)
        }
        .attributes(.custom(name: "data-scope", value: scope ?? ""), when: scope != nil)
    }

}