import Foundation
import ManaCore

/// Zitare-spezifischer API-Client. Wrapper um `AuthenticatedTransport`
/// aus ManaCore, der die zitare-api-Endpoints kennt.
actor ZitareAPI {
    let transport: AuthenticatedTransport
    let decoder: JSONDecoder
    let encoder: JSONEncoder

    init(auth: AuthClient) {
        transport = AuthenticatedTransport(baseURL: AppConfig.apiBaseURL, auth: auth)
        decoder = JSONDecoder()
        encoder = JSONEncoder()
    }

    /// `GET /healthz` — verifiziert dass zitare-api erreichbar ist.
    /// Öffentlicher Endpoint, läuft direkt via `URLSession` (nicht
    /// `AuthenticatedTransport`), damit auch nicht-eingeloggte Apps
    /// die API-Erreichbarkeit prüfen können.
    func healthCheck() async throws -> Bool {
        let url = AppConfig.apiBaseURL.appendingPathComponent("healthz")
        let (_, response) = try await URLSession.shared.data(from: url)
        guard let http = response as? HTTPURLResponse else { return false }
        return http.statusCode == 200
    }

    /// `POST /api/v1/quotes` — Quote-Draft einreichen. Server-Schema:
    /// `zitare/apps/api/src/routes/quotes.ts:submissionSchema`. Pflicht:
    /// text + acceptedTos:true + (authorName ODER authorSlug). Optionale
    /// Source-Felder kommen mit, wenn der User sie ausgefüllt hat.
    func submitQuote(_ draft: QuoteDraft) async throws -> SubmittedQuote {
        let payload = try encoder.encode(draft)
        let (data, http) = try await transport.request(
            path: "/api/v1/quotes",
            method: "POST",
            body: payload
        )
        try ensureOK(http, data: data)
        return try decoder.decode(SubmittedQuote.self, from: data)
    }

    // MARK: - Helpers

    private func ensureOK(_ http: HTTPURLResponse, data: Data) throws {
        guard http.statusCode >= 400 else { return }
        let body = String(data: data, encoding: .utf8) ?? ""
        let code = Self.parseErrorCode(from: body)
        throw ZitareAPIError(status: http.statusCode, code: code, body: body)
    }

    private static func parseErrorCode(from body: String) -> String? {
        guard let data = body.data(using: .utf8),
              let obj = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
              let code = obj["error"] as? String
        else { return nil }
        return code
    }
}

// MARK: - DTOs

/// Submit-Payload für `POST /api/v1/quotes`. JSON-Keys matchen
/// `submissionSchema` aus `zitare/apps/api/src/routes/quotes.ts`.
struct QuoteDraft: Codable, Sendable, Equatable {
    var text: String
    var language: String
    var authorName: String?
    var authorSlug: String?
    var sourceTitle: String?
    var sourceKind: SourceKind?
    var sourceYear: Int?
    var editReason: String?
    var acceptedTos: Bool

    enum SourceKind: String, Codable, Sendable, CaseIterable, Identifiable {
        case book, article, talk, film, other
        var id: String { rawValue }
    }
}

/// Response von `POST /api/v1/quotes`. Server gibt das volle
/// QuoteRow zurück — wir brauchen für die UI nur slug + status.
struct SubmittedQuote: Codable, Sendable {
    let slug: String
    let status: String
}

/// Lokalisierter API-Fehler. `code` ist der server-seitige Code aus
/// `{ "error": "<code>" }`, der via `api.error.<code>` im
/// Localizable.xcstrings nachgeschlagen wird.
struct ZitareAPIError: LocalizedError {
    let status: Int
    let code: String?
    let body: String

    var errorDescription: String? {
        if let code, !code.isEmpty {
            let key = "api.error.\(code)"
            let localized = Bundle.main.localizedString(forKey: key, value: nil, table: nil)
            if localized != key { return localized }
            return "Fehler \(status): \(code)"
        }
        return "HTTP \(status)"
    }
}