import Foundation
import Observation
import OSLog

private let gameCenterLogger = Logger(subsystem: "com.treyt.mlbTVOS", category: "GameCenter")

private func logGameCenter(_ message: String) {
    gameCenterLogger.debug("\(message, privacy: .public)")
    print("[GameCenter] \(message)")
}

@Observable
@MainActor
final class GameCenterViewModel {
    var feed: LiveGameFeed?
    var highlights: [Highlight] = []
    var winProbabilityHome: Double?
    var winProbabilityAway: Double?
    var isLoading = false
    var errorMessage: String?
    var lastUpdated: Date?

    private let statsAPI = MLBStatsAPI()
    @ObservationIgnored
    private var lastHighlightsFetch: Date?

    func watch(game: Game) async {
        guard let gamePk = game.gamePk else {
            logGameCenter("watch: no gamePk for game id=\(game.id)")
            errorMessage = "No live game feed is available for this matchup."
            return
        }
        logGameCenter("watch: starting for gamePk=\(gamePk)")

        while !Task.isCancelled {
            await refresh(gamePk: gamePk)
            await refreshHighlightsIfNeeded(gamePk: gamePk, gameDate: game.gameDate)
            await refreshWinProbability(gamePk: gamePk)

            let liveState = feed?.gameData.status?.abstractGameState == "Live"
            if !liveState {
                break
            }

            try? await Task.sleep(for: .seconds(12))
        }
    }

    func refresh(gamePk: String) async {
        isLoading = true
        errorMessage = nil

        do {
            logGameCenter("refresh: fetching feed for gamePk=\(gamePk)")
            feed = try await statsAPI.fetchGameFeed(gamePk: gamePk)
            logGameCenter("refresh: success playEvents=\(feed?.currentPlay?.playEvents?.count ?? 0) allPlays=\(feed?.liveData.plays.allPlays.count ?? 0)")
            lastUpdated = Date()
        } catch {
            logGameCenter("refresh: FAILED gamePk=\(gamePk) error=\(error)")
            errorMessage = "Failed to load game center."
        }

        isLoading = false
    }

    private func refreshHighlightsIfNeeded(gamePk: String, gameDate: String) async {
        // Only fetch highlights every 60 seconds
        if let last = lastHighlightsFetch, Date().timeIntervalSince(last) < 60 {
            return
        }

        let serverAPI = MLBServerAPI()
        do {
            highlights = try await serverAPI.fetchHighlights(gamePk: gamePk, gameDate: gameDate)
            lastHighlightsFetch = Date()
        } catch {
            // Highlights are supplementary — don't surface errors
        }
    }

    private func refreshWinProbability(gamePk: String) async {
        do {
            let entries = try await statsAPI.fetchWinProbability(gamePk: gamePk)
            if let latest = entries.last,
               let home = latest.homeTeamWinProbability,
               let away = latest.awayTeamWinProbability {
                winProbabilityHome = home
                winProbabilityAway = away
            }
        } catch {
            // Win probability is supplementary — don't surface errors
        }
    }
}