import { humanizeSettingId } from '../utils/humanizer';

export interface FlattenedSetting {
  policyName: string;
  policyType: string;
  settingName: string;
  settingValue: string;
  graphPolicyId: string;
}

type GraphPolicy = Record<string, any>;

/**
 * Detect policy type from @odata.type field
 */
export function detectPolicyType(policy: GraphPolicy): string {
  const odataType = policy['@odata.type'] || '';

  if (odataType.includes('deviceManagementConfigurationPolicy')) {
    return 'deviceConfiguration';
  }
  if (odataType.includes('deviceCompliancePolicy') || odataType.includes('windows10CompliancePolicy')) {
    return 'compliancePolicy';
  }
  if (odataType.includes('windowsUpdateForBusinessConfiguration')) {
    return 'windowsUpdateForBusiness';
  }
  if (odataType.includes('configurationPolicy')) {
    return 'endpointSecurity';
  }

  // Default fallback
  return 'deviceConfiguration';
}

/**
 * Parse Settings Catalog policies (deviceManagementConfigurationPolicy)
 */
function parseSettingsCatalog(policy: GraphPolicy): FlattenedSetting[] {
  const results: FlattenedSetting[] = [];
  const policyName = policy.name || policy.displayName || 'Unnamed Policy';
  const graphPolicyId = policy.id;
  const policyType = detectPolicyType(policy);

  const settings = policy.settings || [];

  for (const setting of settings) {
    const instances = setting.settingInstance || [];
    
    for (const instance of instances) {
      const defId = instance.settingDefinitionId || '';
      const settingName = humanizeSettingId(defId);

      // Extract value based on value type
      let value = '';
      
      if (instance.simpleSettingValue) {
        value = String(instance.simpleSettingValue.value ?? '');
      } else if (instance.choiceSettingValue) {
        value = String(instance.choiceSettingValue.value ?? '');
      } else if (instance.simpleSettingCollectionValue) {
        const values = (instance.simpleSettingCollectionValue || []).map((v: any) => v.value);
        value = values.join(', ');
      } else if (instance.groupSettingCollectionValue) {
        // Nested group settings - flatten recursively
        const children = instance.groupSettingCollectionValue || [];
        for (const child of children) {
          const childSettings = child.children || [];
          for (const childSetting of childSettings) {
            const childDefId = childSetting.settingDefinitionId || '';
            const childName = humanizeSettingId(childDefId);
            let childValue = '';
            
            if (childSetting.simpleSettingValue) {
              childValue = String(childSetting.simpleSettingValue.value ?? '');
            } else if (childSetting.choiceSettingValue) {
              childValue = String(childSetting.choiceSettingValue.value ?? '');
            }

            if (childValue) {
              results.push({
                policyName,
                policyType,
                settingName: `${settingName} > ${childName}`,
                settingValue: childValue,
                graphPolicyId,
              });
            }
          }
        }
        continue;
      } else {
        value = JSON.stringify(instance);
      }

      if (value) {
        results.push({
          policyName,
          policyType,
          settingName,
          settingValue: value,
          graphPolicyId,
        });
      }
    }
  }

  return results;
}

/**
 * Parse OMA-URI policies (legacy deviceConfiguration)
 */
function parseOmaUri(policy: GraphPolicy): FlattenedSetting[] {
  const results: FlattenedSetting[] = [];
  const policyName = policy.displayName || policy.name || 'Unnamed Policy';
  const graphPolicyId = policy.id;
  const policyType = detectPolicyType(policy);

  const omaSettings = policy.omaSettings || [];

  for (const setting of omaSettings) {
    const omaUri = setting.omaUri || '';
    const settingName = humanizeSettingId(omaUri.split('/').pop() || omaUri);
    
    let value = '';
    
    if (setting.value !== undefined && setting.value !== null) {
      value = String(setting.value);
    } else if (setting.stringValue) {
      value = setting.stringValue;
    } else if (setting.intValue !== undefined) {
      value = String(setting.intValue);
    } else if (setting.boolValue !== undefined) {
      value = String(setting.boolValue);
    }

    if (value) {
      results.push({
        policyName,
        policyType,
        settingName,
        settingValue: value,
        graphPolicyId,
      });
    }
  }

  return results;
}

/**
 * Parse standard property-based policies (compliance, etc.)
 */
function parseStandardProperties(policy: GraphPolicy): FlattenedSetting[] {
  const results: FlattenedSetting[] = [];
  const policyName = policy.displayName || policy.name || 'Unnamed Policy';
  const graphPolicyId = policy.id;
  const policyType = detectPolicyType(policy);

  // Common properties to extract
  const ignoredKeys = ['@odata.type', '@odata.context', 'id', 'displayName', 'name', 
                       'description', 'createdDateTime', 'lastModifiedDateTime', 
                       'version', 'assignments'];

  for (const [key, value] of Object.entries(policy)) {
    if (ignoredKeys.includes(key) || value === null || value === undefined) {
      continue;
    }

    const settingName = humanizeSettingId(key);
    let settingValue = '';

    if (typeof value === 'object') {
      settingValue = JSON.stringify(value);
    } else {
      settingValue = String(value);
    }

    if (settingValue && settingValue !== 'false' && settingValue !== '0') {
      results.push({
        policyName,
        policyType,
        settingName,
        settingValue,
        graphPolicyId,
      });
    }
  }

  return results;
}

/**
 * Default empty setting for policies with no extractable settings
 */
function defaultEmptySetting(policy: GraphPolicy): FlattenedSetting[] {
  const policyName = policy.displayName || policy.name || 'Unnamed Policy';
  const graphPolicyId = policy.id;
  const policyType = detectPolicyType(policy);

  return [{
    policyName,
    policyType,
    settingName: '(No settings found)',
    settingValue: 'Policy exists but no extractable settings',
    graphPolicyId,
  }];
}

/**
 * Main parser router - detects type and calls appropriate parser
 */
export function parsePolicySettings(policy: GraphPolicy): FlattenedSetting[] {
  const odataType = policy['@odata.type'] || '';

  // Settings Catalog
  if (odataType.includes('deviceManagementConfigurationPolicy')) {
    const settings = parseSettingsCatalog(policy);
    return settings.length > 0 ? settings : defaultEmptySetting(policy);
  }

  // OMA-URI based
  if (policy.omaSettings && Array.isArray(policy.omaSettings) && policy.omaSettings.length > 0) {
    return parseOmaUri(policy);
  }

  // Standard properties
  const settings = parseStandardProperties(policy);
  return settings.length > 0 ? settings : defaultEmptySetting(policy);
}

export default parsePolicySettings;