//
// Copyright 2026 Novaloop AG
//
// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
// Please see LICENSE files in the repository root for full details.
//

import Compound
import SwiftUI
import UIKit

/// Recolours Compound's accent token family to the HealthChat brand.
/// Applied once at startup from `AppCoordinator` via `AppHooks.compoundHook`. Because the override
/// runs at app startup (not in previews), preview snapshots keep the default Compound colours.
struct HealthChatCompoundHook: CompoundHookProtocol {
    func override(colors: CompoundColors, uiColors: CompoundUIColors) {
        let brand = HealthChatBrandColors.brand
        let tint = HealthChatBrandColors.tint
        
        // Solid accent → brand blue (primary + send buttons, links, accent icons, badges, borders).
        // NB: bgAccentRest is a SOLID fill (behind a white icon on the send button), not a subtle tint.
        let solidColorTokens: [KeyPath<CompoundColorTokens, Color>] = [
            \.bgActionPrimaryRest,
            \.bgAccentRest,
            \.iconAccentPrimary,
            \.iconAccentTertiary,
            \.textActionPrimary,
            \.textActionAccent,
            \.textLinkExternal,
            \.borderInteractivePrimary,
            \.borderAccentPrimary,
            \.textBadgeAccent
        ]
        let solidUIColorTokens: [KeyPath<CompoundUIColorTokens, UIColor> & Sendable] = [
            \.bgActionPrimaryRest,
            \.bgAccentRest,
            \.iconAccentPrimary,
            \.iconAccentTertiary,
            \.textActionPrimary,
            \.textActionAccent,
            \.textLinkExternal,
            \.borderInteractivePrimary,
            \.borderAccentPrimary,
            \.textBadgeAccent
        ]
        for keyPath in solidColorTokens {
            colors.override(keyPath, with: Color(brand))
        }
        for keyPath in solidUIColorTokens {
            uiColors.override(keyPath, with: brand)
        }
        
        // Primary button pressed state. The disabled state stays Compound's neutral grey.
        colors.override(\.bgActionPrimaryPressed, with: Color(HealthChatBrandColors.brandPressed))
        uiColors.override(\.bgActionPrimaryPressed, with: HealthChatBrandColors.brandPressed)
        
        // Gradient "super"/action buttons → brand blue (SwiftUI-only concept).
        let gradientTokens: [KeyPath<CompoundColorTokens, Color>] = [
            \.gradientActionStop1,
            \.gradientActionStop2,
            \.gradientActionStop3,
            \.gradientActionStop4
        ]
        for keyPath in gradientTokens {
            colors.override(keyPath, with: Color(brand))
        }
        
        // Subtle gradient (home screen bloom, highlighted timeline item) → brand blue fading out,
        // at the opacities Compound uses for its green stops. Stop 6 stays transparent.
        let subtleGradientTokens: [KeyPath<CompoundColorTokens, Color>] = [
            \.gradientSubtleStop1,
            \.gradientSubtleStop2,
            \.gradientSubtleStop3,
            \.gradientSubtleStop4,
            \.gradientSubtleStop5
        ]
        for (keyPath, opacity) in zip(subtleGradientTokens, [0.41, 0.23, 0.11, 0.06, 0.03]) {
            colors.override(keyPath, with: Color(brand).opacity(opacity))
        }
        
        // Subtle accent backgrounds (paired with accent-coloured foregrounds) → brand tint.
        let tintColorTokens: [KeyPath<CompoundColorTokens, Color>] = [
            \.bgAccentSelected,
            \.bgBadgeAccent,
            \.borderAccentSubtle
        ]
        let tintUIColorTokens: [KeyPath<CompoundUIColorTokens, UIColor> & Sendable] = [
            \.bgAccentSelected,
            \.bgBadgeAccent,
            \.borderAccentSubtle
        ]
        for keyPath in tintColorTokens {
            colors.override(keyPath, with: Color(tint))
        }
        for keyPath in tintUIColorTokens {
            uiColors.override(keyPath, with: tint)
        }
    }
}