//
//  ShieldConfigurationExtension.swift
//  OpenAppLockShieldConfig
//

import ManagedSettings
import ManagedSettingsUI
import UIKit

/// Customizes the system shield. Apps under an open-limit rule show how many
/// opens were used and offer an "Open" secondary button while opens remain;
/// everything else gets a plain blocked shield named after its rule.
final class ShieldConfigurationExtension: ShieldConfigurationDataSource {
    override func configuration(shielding application: Application) -> ShieldConfiguration {
        guard let token = application.token else { return blockedConfiguration(ruleName: nil) }
        return configuration(forApplicationToken: token)
    }

    override func configuration(
        shielding application: Application, in category: ActivityCategory
    ) -> ShieldConfiguration {
        guard let token = application.token else { return blockedConfiguration(ruleName: nil) }
        return configuration(forApplicationToken: token)
    }

    override func configuration(shielding webDomain: WebDomain) -> ShieldConfiguration {
        blockedConfiguration(ruleName: nil)
    }

    override func configuration(
        shielding webDomain: WebDomain, in category: ActivityCategory
    ) -> ShieldConfiguration {
        blockedConfiguration(ruleName: nil)
    }

    private func configuration(
        forApplicationToken token: ApplicationToken
    ) -> ShieldConfiguration {
        let snapshots = RuleSnapshotStore().load()
        guard
            let snapshot = ShieldLookup.openLimitSnapshot(
                containingApplication: token, in: snapshots)
        else {
            let name = ShieldLookup.snapshot(containingApplication: token, in: snapshots)?.name
            return blockedConfiguration(ruleName: name)
        }

        let usage = UsageLedger().usage(for: snapshot.id, onDayContaining: .now)
        let remaining = max(0, snapshot.maxOpens - usage.opensUsed)
        guard remaining > 0 else {
            return ShieldConfiguration(
                backgroundBlurStyle: .systemMaterial,
                title: .init(text: snapshot.name, color: .label),
                subtitle: .init(
                    text: "No opens left today — the block lifts tomorrow.",
                    color: .secondaryLabel),
                primaryButtonLabel: .init(text: "OK", color: .white),
                primaryButtonBackgroundColor: .systemBlue
            )
        }
        return ShieldConfiguration(
            backgroundBlurStyle: .systemMaterial,
            title: .init(text: snapshot.name, color: .label),
            subtitle: .init(
                text: "Opened \(usage.opensUsed) of \(snapshot.maxOpens) times today. "
                    + "Each open lasts \(MonitoringPlan.openSessionMinutes) minutes.",
                color: .secondaryLabel),
            primaryButtonLabel: .init(text: "OK", color: .white),
            primaryButtonBackgroundColor: .systemBlue,
            secondaryButtonLabel: .init(
                text: remaining == 1 ? "Open (1 left)" : "Open (\(remaining) left)",
                color: .systemBlue)
        )
    }

    private func blockedConfiguration(ruleName: String?) -> ShieldConfiguration {
        ShieldConfiguration(
            backgroundBlurStyle: .systemMaterial,
            title: .init(text: ruleName ?? "Blocked", color: .label),
            subtitle: .init(text: "This app is blocked by OpenAppLock.", color: .secondaryLabel),
            primaryButtonLabel: .init(text: "OK", color: .white),
            primaryButtonBackgroundColor: .systemBlue
        )
    }
}