import Foundation

/// One `feed` event. `data` varies by kind; unknown kinds and fields
/// must render, not sink the feed.
nonisolated struct FeedEvent: Decodable, Sendable, Hashable, Identifiable {
    let id: Int64
    let repo: String
    let actor: String?
    let kind: String
    let data: Payload?
    let createdAt: Date

    enum CodingKeys: String, CodingKey {
        case id, repo, actor, kind, data
        case createdAt = "created_at"
    }

    nonisolated struct Payload: Decodable, Sendable, Hashable {
        let number: Int64?
        let sha: String?
        let tag: String?
        let title: String?
        let job: String?
    }

    /// The same verb and reference phrasing as the web dashboard.
    var phrase: String {
        let n = data?.number.map(String.init) ?? ""
        switch kind {
        case "mr.created": return "opened merge request !\(n)"
        case "mr.merged": return "merged !\(n)"
        case "mr.commented": return "commented on !\(n)"
        case "mr.closed": return "closed merge request !\(n)"
        case "issue.created": return "opened issue #\(n)"
        case "issue.closed": return "closed issue #\(n)"
        case "issue.reopened": return "reopened issue #\(n)"
        case "issue.commented": return "commented on #\(n)"
        case "build.success": return "build success \(data?.job ?? "")"
        case "build.failure": return "build failure \(data?.job ?? "")"
        case "release.created": return "released \(data?.tag ?? "")"
        case "push": return "pushed"
        case let value where value.hasPrefix("issue."):
            return "issue \(value.dropFirst("issue.".count)) #\(n)"
        case let value where value.hasPrefix("mr."):
            return "merge request \(value.dropFirst("mr.".count)) !\(n)"
        case let value where value.hasPrefix("build."):
            return "build \(value.dropFirst("build.".count)) \(data?.job ?? "")"
        case let value where value.hasPrefix("repo."):
            return "repository \(value.dropFirst("repo.".count))"
        default: return kind
        }
    }

    var displayActor: String {
        guard let actor, !actor.isEmpty else { return "gitbay" }
        return actor
    }

    var icon: (name: String, isPositive: Bool?) {
        switch kind {
        case "mr.created": ("arrow.triangle.merge", nil)
        case "mr.merged": ("arrow.triangle.merge", true)
        case "mr.closed": ("xmark.circle", false)
        case "issue.created", "issue.open", "issue.reopened": ("smallcircle.filled.circle", nil)
        case "issue.closed": ("checkmark.circle", true)
        case "issue.commented": ("bubble.left", nil)
        case "build.success": ("checkmark.circle.fill", true)
        case "build.failure": ("xmark.circle.fill", false)
        case "release.created": ("shippingbox", nil)
        case "push": ("arrow.up.circle", nil)
        default: ("circle", nil)
        }
    }

    /// Where tapping the row goes, when the event names something the app
    /// has a screen for.
    var destination: FeedDestination? {
        if kind == "release.created", let tag = data?.tag {
            return .release(repo: repo, tag: tag)
        }
        guard let number = data?.number else {
            return .repo(repo)
        }
        switch kind.split(separator: ".").first {
        case "mr": return .mr(repo: repo, number: number)
        case "issue": return .issue(repo: repo, number: number)
        case "build": return .build(repo: repo, number: number)
        default: return .repo(repo)
        }
    }
}

nonisolated enum FeedDestination: Hashable {
    case repo(String)
    case mr(repo: String, number: Int64)
    case issue(repo: String, number: Int64)
    case build(repo: String, number: Int64)
    case release(repo: String, tag: String)
}