ろう者・難聴者の方にとって本当に心地よいWebサイトと窓口とは？
視覚図解ファースト・日本手話の文法理解・テキスト完結導線の設計基準

#![forbid(unsafe_code)]
/// Channels available for delivering user-facing notifications or auth challenges.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct ModalityMask(pub u8);
impl ModalityMask {
    pub const AUDIO_SPEECH_OR_BEEP: u8 = 1 << 0;
    pub const VISUAL_TEXT_BANNER: u8   = 1 << 1;
    pub const VISUAL_ICON_BADGE: u8    = 1 << 2;
    pub const HAPTIC_VIBRATION: u8     = 1 << 3;
    pub const ASYNC_TEXT_CHANNEL: u8   = 1 << 4; — Web form, Email, Chat, Push
    #[inline]
    pub const fn has(self, flag: u8) -> bool {
        (self.0 & flag) != 0
    }
    /// Returns true if the event relies exclusively on audio without visual/haptic fallback.
    #[inline]
    pub const fn is_audio_only(self) -> bool {
        let non_audio = Self::VISUAL_TEXT_BANNER
            | Self::VISUAL_ICON_BADGE
            | Self::HAPTIC_VIBRATION
            | Self::ASYNC_TEXT_CHANNEL;
        self.has(Self::AUDIO_SPEECH_OR_BEEP) && (self.0 & non_audio) == 0
    }
}
/// Represents a customer workflow step (e.g., reservation, identity verification, cancellation).
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct WorkflowStepSpec {
    pub step_id: u16,
    pub requires_voice_phone_call: bool,
    pub accepts_telephone_relay_service: bool,
    pub supports_online_text_completion: bool,
    pub has_visual_diagram_summary: bool,
    pub notification_modalities: ModalityMask,
}
/// Sign language video stream telemetry for WCAG 2.2 AAA SC 1.2.6 inspection.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct SignVideoStreamSpec {
    pub frame_rate_fps: u16,
    pub signer_roi_height_px: u16,
    pub has_verified_captions_with_speaker_id: bool,
    pub preserves_nmm_facial_landmarks: bool,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum DeafUxViolation {
    VoicePhoneBarrierDetected { step_id: u16 },
    AudioOnlyNotification { step_id: u16 },
    MissingVisualDiagramSummary { step_id: u16 },
    InsufficientSignVideoFrameRate { actual_fps: u16 },
    InsufficientSignerResolution { height_px: u16 },
    MissingNmmFacialClarity,
    UnverifiedCaptions,
}
/// Audits a complete customer journey and media specification against Deaf-Inclusive UX standards.
pub fn audit_deaf_inclusive_journey(
    steps: &[WorkflowStepSpec],
    video: Option<SignVideoStreamSpec>,
) -> Result<(), DeafUxViolation> {
    for step in steps {
        // 01. Never lock a user into voice-only telephone calls without text or relay alternatives.
        if step.requires_voice_phone_call
            && !step.supports_online_text_completion
            && !step.accepts_telephone_relay_service
        {
            return Err(DeafUxViolation::VoicePhoneBarrierDetected {
                step_id: step.step_id,
            });
        }
        // 02. Every notification must include visual text + icon or haptic/async text channels.
        if step.notification_modalities.is_audio_only()
            || !step.notification_modalities.has(ModalityMask::VISUAL_TEXT_BANNER)
        {
            return Err(DeafUxViolation::AudioOnlyNotification {
                step_id: step.step_id,
            });
        }
        // 03. Visual-first structure requirement.
        if !step.has_visual_diagram_summary {
            return Err(DeafUxViolation::MissingVisualDiagramSummary {
                step_id: step.step_id,
            });
        }
    }
    if let Some(v) = video {
        if v.frame_rate_fps < 50 {
            return Err(DeafUxViolation::InsufficientSignVideoFrameRate {
                actual_fps: v.frame_rate_fps,
            });
        }
        if v.signer_roi_height_px < 360 {
            return Err(DeafUxViolation::InsufficientSignerResolution {
                height_px: v.signer_roi_height_px,
            });
        }
        if !v.preserves_nmm_facial_landmarks {
            return Err(DeafUxViolation::MissingNmmFacialClarity);
        }
        if !v.has_verified_captions_with_speaker_id {
            return Err(DeafUxViolation::UnverifiedCaptions);
        }
    }
    Ok(())
}