/*
 * Copyright 2025 John G Stroh
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Audit Controller
 * Serves audit logs from MemoryProxy for analytics dashboard
 */

const fs = require('fs').promises;
const path = require('path');
const logger = require('../utils/logger.util');

// Default cost factors (user-configurable)
const DEFAULT_COST_FACTORS = {
  CRITICAL: { amount: 50000, currency: 'USD', rationale: 'Average cost of critical security incident' },
  HIGH: { amount: 10000, currency: 'USD', rationale: 'Average cost of high-impact client-facing error' },
  MEDIUM: { amount: 2000, currency: 'USD', rationale: 'Average cost of medium-impact issue requiring hotfix' },
  LOW: { amount: 500, currency: 'USD', rationale: 'Average developer time cost to fix low-impact issue' }
};

let userCostFactors = { ...DEFAULT_COST_FACTORS };

/**
 * Get audit logs for analytics
 * GET /api/admin/audit-logs?days=7&environment=production
 */
async function getAuditLogs(req, res) {
  try {
    const { days = 7, limit = 10000, environment } = req.query;

    // Calculate date range
    const today = new Date();
    const startDate = new Date(today);
    startDate.setDate(today.getDate() - parseInt(days));

    // Build query
    const query = { timestamp: { $gte: startDate } };

    // Add environment filter if specified
    if (environment && environment !== 'all') {
      query.environment = environment;
    }

    // Read from MongoDB instead of JSONL files
    const db = require('../utils/db.util');
    const collection = await db.getCollection('auditLogs');

    const decisions = await collection
      .find(query)
      .sort({ timestamp: -1 })
      .limit(parseInt(limit))
      .toArray();

    res.json({
      success: true,
      decisions,
      total: decisions.length,
      limited: decisions.length,
      environment: environment || 'all',
      dateRange: {
        start: startDate.toISOString(),
        end: today.toISOString()
      }
    });

  } catch (error) {
    logger.error('Error fetching audit logs:', error);
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
}

/**
 * Get audit analytics summary
 * GET /api/admin/audit-analytics
 */
async function getAuditAnalytics(req, res) {
  try {
    const { days = 7 } = req.query;

    // Get audit logs
    const auditLogsResponse = await getAuditLogs(req, { json: data => data });
    const decisions = auditLogsResponse.decisions;

    // Calculate analytics
    const blockedDecisions = decisions.filter(d => !d.allowed);
    const allowedDecisions = decisions.filter(d => d.allowed);

    const analytics = {
      total: decisions.length,
      allowed: allowedDecisions.length,
      blocked: blockedDecisions.length,
      violations: decisions.filter(d => d.violations && d.violations.length > 0).length,

      // Block metrics
      blockRate: decisions.length > 0 ? ((blockedDecisions.length / decisions.length) * 100).toFixed(1) : 0,
      allowedRate: decisions.length > 0 ? ((allowedDecisions.length / decisions.length) * 100).toFixed(1) : 0,

      // Block breakdown
      blocksByReason: {},
      blocksBySeverity: {},
      frameworkSaves: [],  // High severity blocks

      byAction: {},
      byService: {},
      bySession: {},
      byDate: {},

      timeline: [],
      topViolations: [],

      // Business intelligence metrics
      byActivityType: {},
      byRiskLevel: {},
      byStakeholderImpact: {},
      riskHeatmap: [],
      businessImpactTotal: 0,
      roiProjections: {},

      dateRange: auditLogsResponse.dateRange
    };

    // Group by action
    decisions.forEach(d => {
      const action = d.action || 'unknown';
      analytics.byAction[action] = (analytics.byAction[action] || 0) + 1;
    });

    // Group by service
    decisions.forEach(d => {
      const service = d.service || 'unknown';
      analytics.byService[service] = (analytics.byService[service] || 0) + 1;
    });

    // Group by session
    decisions.forEach(d => {
      const session = d.sessionId || 'unknown';
      analytics.bySession[session] = (analytics.bySession[session] || 0) + 1;
    });

    // Group by date
    decisions.forEach(d => {
      const date = new Date(d.timestamp).toISOString().split('T')[0];
      analytics.byDate[date] = (analytics.byDate[date] || 0) + 1;
    });

    // Timeline (last 24 hours by hour)
    const hourCounts = {};
    decisions.forEach(d => {
      const hour = new Date(d.timestamp).getHours();
      hourCounts[hour] = (hourCounts[hour] || 0) + 1;
    });

    for (let i = 0; i < 24; i++) {
      analytics.timeline.push({
        hour: i,
        count: hourCounts[i] || 0
      });
    }

    // Analyze blocks by reason and severity
    blockedDecisions.forEach(d => {
      // Extract reason from violations or metadata
      let reason = 'Unknown';
      let severity = 'MEDIUM';

      if (d.violations && d.violations.length > 0) {
        // Use first violation's rule ID as reason
        reason = d.violations[0].ruleId || d.violations[0].ruleText || 'Unknown';
        severity = d.violations[0].severity || 'MEDIUM';

        // Count by severity
        analytics.blocksBySeverity[severity] = (analytics.blocksBySeverity[severity] || 0) + 1;

        // Track high severity blocks as "Framework Saves"
        if (severity === 'HIGH' || severity === 'CRITICAL') {
          analytics.frameworkSaves.push({
            timestamp: d.timestamp,
            reason: d.violations[0].ruleText || d.violations[0].details,
            ruleId: d.violations[0].ruleId,
            severity: severity,
            file: d.metadata?.filePath || d.metadata?.file || 'N/A',
            service: d.service
          });
        }
      } else if (d.metadata?.reason) {
        reason = d.metadata.reason;
      }

      // Count by reason
      analytics.blocksByReason[reason] = (analytics.blocksByReason[reason] || 0) + 1;
    });

    // Sort framework saves by timestamp (most recent first)
    analytics.frameworkSaves.sort((a, b) => new Date(b.timestamp) - new Date(a.timestamp));
    analytics.frameworkSaves = analytics.frameworkSaves.slice(0, 10); // Top 10 saves

    // Top violations (enhanced with more detail)
    const violationCounts = {};
    decisions.forEach(d => {
      if (d.violations && d.violations.length > 0) {
        d.violations.forEach(v => {
          const key = v.ruleId || v.ruleText || 'unknown';
          if (!violationCounts[key]) {
            violationCounts[key] = {
              ruleId: v.ruleId,
              ruleText: v.ruleText,
              severity: v.severity,
              count: 0
            };
          }
          violationCounts[key].count++;
        });
      }
    });

    analytics.topViolations = Object.values(violationCounts)
      .sort((a, b) => b.count - a.count)
      .slice(0, 10);

    // === BUSINESS INTELLIGENCE METRICS ===

    // Activity type breakdown
    decisions.forEach(d => {
      const activityType = d.activityType || 'Unknown';
      if (!analytics.byActivityType[activityType]) {
        analytics.byActivityType[activityType] = {
          total: 0,
          allowed: 0,
          blocked: 0,
          blockRate: 0
        };
      }
      analytics.byActivityType[activityType].total++;
      if (d.allowed) {
        analytics.byActivityType[activityType].allowed++;
      } else {
        analytics.byActivityType[activityType].blocked++;
      }
    });

    // Calculate block rates for each activity type
    Object.keys(analytics.byActivityType).forEach(type => {
      const data = analytics.byActivityType[type];
      data.blockRate = data.total > 0 ? ((data.blocked / data.total) * 100).toFixed(1) : '0.0';
    });

    // Risk level distribution
    decisions.forEach(d => {
      const riskLevel = d.riskLevel || 'low';
      if (!analytics.byRiskLevel[riskLevel]) {
        analytics.byRiskLevel[riskLevel] = {
          total: 0,
          blocked: 0
        };
      }
      analytics.byRiskLevel[riskLevel].total++;
      if (!d.allowed) {
        analytics.byRiskLevel[riskLevel].blocked++;
      }
    });

    // Stakeholder impact distribution
    decisions.forEach(d => {
      const impact = d.stakeholderImpact || 'individual';
      if (!analytics.byStakeholderImpact[impact]) {
        analytics.byStakeholderImpact[impact] = {
          total: 0,
          blocked: 0,
          businessImpact: 0
        };
      }
      analytics.byStakeholderImpact[impact].total++;
      if (!d.allowed) {
        analytics.byStakeholderImpact[impact].blocked++;
        analytics.byStakeholderImpact[impact].businessImpact += (d.businessImpact || 0);
      }
    });

    // Risk heatmap: Activity Type vs Risk Level
    const heatmapData = {};
    decisions.forEach(d => {
      const activityType = d.activityType || 'Unknown';
      const riskLevel = d.riskLevel || 'low';
      const key = `${activityType}|${riskLevel}`;

      if (!heatmapData[key]) {
        heatmapData[key] = {
          activityType,
          riskLevel,
          total: 0,
          blocked: 0
        };
      }
      heatmapData[key].total++;
      if (!d.allowed) {
        heatmapData[key].blocked++;
      }
    });
    analytics.riskHeatmap = Object.values(heatmapData);

    // Business impact total
    analytics.businessImpactTotal = blockedDecisions.reduce((sum, d) => sum + (d.businessImpact || 0), 0);

    // === COST AVOIDANCE CALCULATIONS ===

    // Calculate cost avoided based on user-configured factors
    let totalCostAvoided = 0;
    const costBreakdown = { CRITICAL: 0, HIGH: 0, MEDIUM: 0, LOW: 0 };

    blockedDecisions.forEach(d => {
      if (d.violations && d.violations.length > 0) {
        d.violations.forEach(v => {
          const severity = v.severity || 'LOW';
          const costFactor = userCostFactors[severity];
          if (costFactor) {
            totalCostAvoided += costFactor.amount;
            costBreakdown[severity] += costFactor.amount;
          }
        });
      }
    });

    analytics.costAvoidance = {
      total: totalCostAvoided,
      currency: userCostFactors.CRITICAL.currency,
      breakdown: costBreakdown,
      costFactors: userCostFactors
    };

    // === AI vs HUMAN PERFORMANCE ===

    // Detect AI vs Human based on service patterns
    // AI = FileEditHook, Framework services
    // Human = Manual overrides, direct database operations
    const aiDecisions = decisions.filter(d =>
      d.service === 'FileEditHook' ||
      d.service === 'BoundaryEnforcer' ||
      d.service === 'ContextPressureMonitor' ||
      d.service === 'MetacognitiveVerifier'
    );
    const humanDecisions = decisions.filter(d =>
      !aiDecisions.includes(d)
    );

    const aiBlocked = aiDecisions.filter(d => !d.allowed).length;
    const humanBlocked = humanDecisions.filter(d => !d.allowed).length;

    analytics.teamComparison = {
      ai: {
        total: aiDecisions.length,
        blocked: aiBlocked,
        blockRate: aiDecisions.length > 0 ? ((aiBlocked / aiDecisions.length) * 100).toFixed(1) : '0.0',
        label: 'AI Assistant'
      },
      human: {
        total: humanDecisions.length,
        blocked: humanBlocked,
        blockRate: humanDecisions.length > 0 ? ((humanBlocked / humanDecisions.length) * 100).toFixed(1) : '0.0',
        label: 'Human Direct'
      }
    };

    // Framework Maturity Score (0-100)
    // Based on: block rate trend, severity distribution, learning curve
    const recentDays = 7;
    const recentDate = new Date();
    recentDate.setDate(recentDate.getDate() - recentDays);
    const recentDecisions = decisions.filter(d => new Date(d.timestamp) >= recentDate);
    const recentBlocked = recentDecisions.filter(d => !d.allowed).length;
    const recentBlockRate = recentDecisions.length > 0 ? (recentBlocked / recentDecisions.length) : 0;

    // Lower block rate = higher maturity (framework teaching good habits)
    const blockRateScore = Math.max(0, 100 - (recentBlockRate * 1000));

    // More AI decisions with low block rate = higher maturity
    const aiAdoptionScore = aiDecisions.length > 0 ? ((aiDecisions.length / decisions.length) * 100) : 0;

    // Fewer critical/high severity blocks = higher maturity
    const criticalCount = blockedDecisions.filter(d =>
      d.violations && d.violations.some(v => v.severity === 'CRITICAL' || v.severity === 'HIGH')
    ).length;
    const severityScore = Math.max(0, 100 - (criticalCount / decisions.length * 1000));

    analytics.frameworkMaturity = {
      score: Math.round((blockRateScore + aiAdoptionScore + severityScore) / 3),
      components: {
        blockRateScore: Math.round(blockRateScore),
        aiAdoptionScore: Math.round(aiAdoptionScore),
        severityScore: Math.round(severityScore)
      },
      trend: recentBlockRate < avgBlockRate ? 'improving' : 'stable',
      message: recentBlockRate < 0.05 ? 'Excellent - Framework teaching good practices' :
               recentBlockRate < 0.10 ? 'Good - Team adapting well to governance' :
               'Learning - Framework actively preventing violations'
    };

    // ROI Projections
    const totalDecisions = decisions.length;
    const totalBlocks = blockedDecisions.length;
    const avgBlockRate = totalDecisions > 0 ? (totalBlocks / totalDecisions) : 0;

    analytics.roiProjections = {
      // Current period metrics
      decisionsPerDay: days > 0 ? (totalDecisions / days).toFixed(1) : '0',
      blocksPerDay: days > 0 ? (totalBlocks / days).toFixed(1) : '0',

      // Projections for scaled deployment
      projections: [
        {
          userCount: 1000,
          decisionsPerMonth: Math.round((totalDecisions / days) * 30 * 1000 / decisions.length * 10), // Estimated
          blocksPerMonth: Math.round((totalBlocks / days) * 30 * 1000 / decisions.length * 10),
          highSeverityBlocks: Math.round(analytics.frameworkSaves.length / days * 30 * 1000 / decisions.length * 10),
          businessImpactSaved: Math.round(analytics.businessImpactTotal / days * 30 * 1000 / decisions.length * 10)
        },
        {
          userCount: 10000,
          decisionsPerMonth: Math.round((totalDecisions / days) * 30 * 10000 / decisions.length * 10),
          blocksPerMonth: Math.round((totalBlocks / days) * 30 * 10000 / decisions.length * 10),
          highSeverityBlocks: Math.round(analytics.frameworkSaves.length / days * 30 * 10000 / decisions.length * 10),
          businessImpactSaved: Math.round(analytics.businessImpactTotal / days * 30 * 10000 / decisions.length * 10)
        },
        {
          userCount: 70000,
          decisionsPerMonth: Math.round((totalDecisions / days) * 30 * 70000 / decisions.length * 10),
          blocksPerMonth: Math.round((totalBlocks / days) * 30 * 70000 / decisions.length * 10),
          highSeverityBlocks: Math.round(analytics.frameworkSaves.length / days * 30 * 70000 / decisions.length * 10),
          businessImpactSaved: Math.round(analytics.businessImpactTotal / days * 30 * 70000 / decisions.length * 10)
        }
      ]
    };

    res.json({
      success: true,
      analytics
    });

  } catch (error) {
    logger.error('Error calculating audit analytics:', error);
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
}

/**
 * Get cost configuration
 * GET /api/admin/cost-config
 */
async function getCostConfig(req, res) {
  try {
    res.json({
      success: true,
      costFactors: userCostFactors
    });
  } catch (error) {
    logger.error('Error fetching cost config:', error);
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
}

/**
 * Update cost configuration
 * POST /api/admin/cost-config
 */
async function updateCostConfig(req, res) {
  try {
    const { costFactors } = req.body;

    if (!costFactors) {
      return res.status(400).json({
        success: false,
        error: 'costFactors required'
      });
    }

    // Validate and update
    ['CRITICAL', 'HIGH', 'MEDIUM', 'LOW'].forEach(severity => {
      if (costFactors[severity]) {
        userCostFactors[severity] = {
          amount: parseFloat(costFactors[severity].amount) || userCostFactors[severity].amount,
          currency: costFactors[severity].currency || userCostFactors[severity].currency,
          rationale: costFactors[severity].rationale || userCostFactors[severity].rationale
        };
      }
    });

    logger.info('Cost factors updated by', req.user?.username || 'admin');

    res.json({
      success: true,
      costFactors: userCostFactors
    });
  } catch (error) {
    logger.error('Error updating cost config:', error);
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
}

/**
 * Export audit logs for cross-environment research (privacy-preserving)
 * GET /api/admin/audit-export?since=YYYY-MM-DD
 */
async function exportAuditLogs(req, res) {
  try {
    const { since } = req.query;

    if (!since) {
      return res.status(400).json({
        success: false,
        error: 'since parameter required (ISO date format)'
      });
    }

    // Parse date
    const sinceDate = new Date(since);
    if (isNaN(sinceDate.getTime())) {
      return res.status(400).json({
        success: false,
        error: 'Invalid date format for since parameter'
      });
    }

    // Fetch logs since date
    const logs = await AuditLog.find({
      timestamp: { $gte: sinceDate }
    }).sort({ timestamp: 1 }).lean();

    // Sanitize for privacy
    const { sanitizeBatch } = require('../utils/audit-sanitizer.util');
    const sanitized = sanitizeBatch(logs);

    logger.info(`Exported ${sanitized.length} audit logs since ${since} for ${req.user?.username || 'unknown'}`);

    res.json({
      success: true,
      count: sanitized.length,
      since: sinceDate,
      exported_at: new Date(),
      logs: sanitized
    });
  } catch (error) {
    logger.error('Error exporting audit logs:', error);
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
}

module.exports = {
  getAuditLogs,
  getAuditAnalytics,
  getCostConfig,
  updateCostConfig,
  exportAuditLogs
};