"""localStorage integration for Gradio via JavaScript injection.

Provides JavaScript code that syncs session state with browser localStorage.
"""

# localStorage keys
STORAGE_KEY_SESSION = "fdam_current_session"
STORAGE_KEY_HISTORY = "fdam_assessment_history"
STORAGE_KEY_IMAGES = "fdam_image_refs"  # References only, not actual bytes

# JavaScript code for localStorage operations
LOCALSTORAGE_JS = """
<script>
(function() {
    // FDAM localStorage utilities
    window.fdamStorage = {
        KEYS: {
            SESSION: 'fdam_current_session',
            HISTORY: 'fdam_assessment_history',
            IMAGE_REFS: 'fdam_image_refs'
        },

        // Save current session
        saveSession: function(sessionJson) {
            try {
                localStorage.setItem(this.KEYS.SESSION, sessionJson);
                console.log('[FDAM] Session saved to localStorage');
                return true;
            } catch (e) {
                console.error('[FDAM] Failed to save session:', e);
                return false;
            }
        },

        // Load current session
        loadSession: function() {
            try {
                const data = localStorage.getItem(this.KEYS.SESSION);
                if (data) {
                    console.log('[FDAM] Session loaded from localStorage');
                    return data;
                }
            } catch (e) {
                console.error('[FDAM] Failed to load session:', e);
            }
            return null;
        },

        // Save assessment history
        saveHistory: function(historyJson) {
            try {
                localStorage.setItem(this.KEYS.HISTORY, historyJson);
                console.log('[FDAM] History saved to localStorage');
                return true;
            } catch (e) {
                console.error('[FDAM] Failed to save history:', e);
                return false;
            }
        },

        // Load assessment history
        loadHistory: function() {
            try {
                const data = localStorage.getItem(this.KEYS.HISTORY);
                if (data) {
                    console.log('[FDAM] History loaded from localStorage');
                    return data;
                }
            } catch (e) {
                console.error('[FDAM] Failed to load history:', e);
            }
            return null;
        },

        // Clear all FDAM data
        clearAll: function() {
            try {
                localStorage.removeItem(this.KEYS.SESSION);
                localStorage.removeItem(this.KEYS.HISTORY);
                localStorage.removeItem(this.KEYS.IMAGE_REFS);
                console.log('[FDAM] All localStorage data cleared');
                return true;
            } catch (e) {
                console.error('[FDAM] Failed to clear storage:', e);
                return false;
            }
        },

        // Get storage usage info
        getStorageInfo: function() {
            try {
                let total = 0;
                for (let key in localStorage) {
                    if (key.startsWith('fdam_')) {
                        total += localStorage.getItem(key).length;
                    }
                }
                return {
                    used_bytes: total,
                    used_kb: (total / 1024).toFixed(2),
                    limit_kb: 5120  // ~5MB typical limit
                };
            } catch (e) {
                return { error: e.message };
            }
        }
    };

    // Expose to global scope for Gradio callbacks
    window.saveSession = window.fdamStorage.saveSession.bind(window.fdamStorage);
    window.loadSession = window.fdamStorage.loadSession.bind(window.fdamStorage);
    window.saveHistory = window.fdamStorage.saveHistory.bind(window.fdamStorage);
    window.loadHistory = window.fdamStorage.loadHistory.bind(window.fdamStorage);

    console.log('[FDAM] localStorage utilities loaded');
})();
</script>
"""

# JavaScript functions for Gradio event handlers
JS_SAVE_SESSION = """
async (sessionJson) => {
    if (window.fdamStorage) {
        window.fdamStorage.saveSession(sessionJson);
    }
    return sessionJson;
}
"""

JS_LOAD_SESSION = """
async () => {
    if (window.fdamStorage) {
        return window.fdamStorage.loadSession() || '{}';
    }
    return '{}';
}
"""

JS_SAVE_HISTORY = """
async (historyJson) => {
    if (window.fdamStorage) {
        window.fdamStorage.saveHistory(historyJson);
    }
    return historyJson;
}
"""

JS_LOAD_HISTORY = """
async () => {
    if (window.fdamStorage) {
        return window.fdamStorage.loadHistory() || '{"assessments":[],"current_session_id":null}';
    }
    return '{"assessments":[],"current_session_id":null}';
}
"""

# JavaScript to auto-load session on page load
JS_AUTO_LOAD = """
async () => {
    // Small delay to ensure Gradio is fully loaded
    await new Promise(resolve => setTimeout(resolve, 500));

    if (window.fdamStorage) {
        const session = window.fdamStorage.loadSession();
        const history = window.fdamStorage.loadHistory();
        return [session || '{}', history || '{"assessments":[],"current_session_id":null}'];
    }
    return ['{}', '{"assessments":[],"current_session_id":null}'];
}
"""


def get_head_html(additional_scripts: str = "") -> str:
    """Get HTML to inject into Gradio head for localStorage support.

    Args:
        additional_scripts: Optional additional HTML/JS to include.

    Returns:
        Combined HTML string for head injection.
    """
    return LOCALSTORAGE_JS + additional_scripts


def create_save_trigger_js(field_updates: dict[str, str]) -> str:
    """Create JavaScript that triggers save after field updates.

    Args:
        field_updates: Mapping of field name to value expression

    Returns:
        JavaScript code string
    """
    updates = ", ".join(f'"{k}": {v}' for k, v in field_updates.items())
    return f"""
async (currentSession, ...values) => {{
    try {{
        const session = JSON.parse(currentSession || '{{}}');
        const updates = {{ {updates} }};
        Object.assign(session, updates);
        session.updated_at = new Date().toISOString();
        const newSession = JSON.stringify(session);
        if (window.fdamStorage) {{
            window.fdamStorage.saveSession(newSession);
        }}
        return newSession;
    }} catch (e) {{
        console.error('[FDAM] Save trigger error:', e);
        return currentSession;
    }}
}}
"""