/**
 * Voxyz Proposal Service
 * Core service for mission proposal creation, validation, and management
 * Phase 10: Autonomous Architecture
 */

import { 
  MissionProposal, 
  MissionProposalInsert, 
  CapGateCheckResult, 
  CapGateViolation,
  AIAnalysisSummary,
  ProposalStatus,
  ProposalServiceConfig
} from '@/lib/supabase/voxyz.types';
import { getServiceSupabase } from '@/lib/supabase/client';
import { Task } from '@/lib/data/tasks';
import { Project } from '@/lib/data/projects';

const DEFAULT_CONFIG: ProposalServiceConfig = {
  maxProposalsPerDay: 3,
  minProposalsPerDay: 1,
  defaultProposalExpiryHours: 24,
  priorityScoreThreshold: 50,
  autoApproveThreshold: 85,
};

/**
 * Priority scoring factors and their weights
 */
const PRIORITY_FACTORS = {
  deadlineUrgency: 0.30,
  taskPriority: 0.25,
  projectImportance: 0.20,
  blockedStatus: 0.15,
  staleTask: 0.10,
};

/**
 * Calculate priority score for a proposal
 */
export function calculatePriorityScore(
  task: Task,
  project: Project | undefined,
  context: ProposalContext
): number {
  let score = 50; // Base score
  const factors: { factor: string; weight: number; contribution: number }[] = [];

  // 1. Deadline urgency (30%)
  const deadlineScore = calculateDeadlineScore(task, context);
  const deadlineContribution = deadlineScore * PRIORITY_FACTORS.deadlineUrgency;
  score += deadlineContribution;
  factors.push({ factor: 'deadline_urgency', weight: PRIORITY_FACTORS.deadlineUrgency, contribution: deadlineContribution });

  // 2. Task priority (25%)
  const priorityScore = calculateTaskPriorityScore(task);
  const priorityContribution = priorityScore * PRIORITY_FACTORS.taskPriority;
  score += priorityContribution;
  factors.push({ factor: 'task_priority', weight: PRIORITY_FACTORS.taskPriority, contribution: priorityContribution });

  // 3. Project importance (20%)
  const projectScore = calculateProjectImportanceScore(project);
  const projectContribution = projectScore * PRIORITY_FACTORS.projectImportance;
  score += projectContribution;
  factors.push({ factor: 'project_importance', weight: PRIORITY_FACTORS.projectImportance, contribution: projectContribution });

  // 4. Blocked status (15%)
  const blockedScore = calculateBlockedScore(task, context);
  const blockedContribution = blockedScore * PRIORITY_FACTORS.blockedStatus;
  score += blockedContribution;
  factors.push({ factor: 'blocked_status', weight: PRIORITY_FACTORS.blockedStatus, contribution: blockedContribution });

  // 5. Stale task (10%)
  const staleScore = calculateStaleScore(task, context);
  const staleContribution = staleScore * PRIORITY_FACTORS.staleTask;
  score += staleContribution;
  factors.push({ factor: 'stale_task', weight: PRIORITY_FACTORS.staleTask, contribution: staleContribution });

  return Math.min(100, Math.max(0, Math.round(score)));
}

/**
 * Calculate deadline urgency score (0-100)
 */
function calculateDeadlineScore(task: Task, context: ProposalContext): number {
  if (!task.dueDate) return 0;
  
  const dueDate = new Date(task.dueDate);
  const now = context.currentTime;
  const hoursUntilDue = (dueDate.getTime() - now.getTime()) / (1000 * 60 * 60);
  
  if (hoursUntilDue < 0) return 100; // Overdue
  if (hoursUntilDue < 24) return 90; // Due within 24 hours
  if (hoursUntilDue < 72) return 70; // Due within 3 days
  if (hoursUntilDue < 168) return 50; // Due within a week
  if (hoursUntilDue < 336) return 30; // Due within 2 weeks
  return 10; // Due later
}

/**
 * Calculate task priority score (0-100)
 */
function calculateTaskPriorityScore(task: Task): number {
  const priorityMap: Record<string, number> = {
    'urgent': 100,
    'high': 75,
    'medium': 50,
    'low': 25,
  };
  return priorityMap[task.priority] || 50;
}

/**
 * Calculate project importance score (0-100)
 */
function calculateProjectImportanceScore(project: Project | undefined): number {
  if (!project) return 50;
  
  // Check for high-priority keywords in project
  const highPriorityKeywords = ['ios', 'revenue', 'critical', 'milestone'];
  const projectNameLower = project.name.toLowerCase();
  
  for (const keyword of highPriorityKeywords) {
    if (projectNameLower.includes(keyword)) {
      return 80;
    }
  }
  
  return 50;
}

/**
 * Calculate blocked status score (0-100)
 */
function calculateBlockedScore(task: Task, context: ProposalContext): number {
  if (task.status === 'blocked') {
    // Check how long it's been blocked
    const blockedHours = task.comments?.reduce<number>((hours, comment) => {
      const item = comment as { text?: unknown; createdAt?: unknown };
      if (typeof item.text === 'string' && item.text.toLowerCase().includes('blocked') && typeof item.createdAt === 'string') {
        const commentTime = new Date(item.createdAt);
        const blockedHours = (context.currentTime.getTime() - commentTime.getTime()) / (1000 * 60 * 60);
        return Math.max(hours, blockedHours);
      }
      return hours;
    }, 0) || 0;
    
    if (blockedHours > 48) return 100;
    if (blockedHours > 24) return 80;
    return 60;
  }
  return 0;
}

/**
 * Calculate stale task score (0-100)
 */
function calculateStaleScore(task: Task, context: ProposalContext): number {
  const lastUpdate = new Date(task.updatedAt);
  const daysSinceUpdate = (context.currentTime.getTime() - lastUpdate.getTime()) / (1000 * 60 * 60 * 24);
  
  if (task.status === 'in-progress' || task.status === 'todo') {
    if (daysSinceUpdate > 14) return 100;
    if (daysSinceUpdate > 7) return 75;
    if (daysSinceUpdate > 3) return 50;
  }
  
  return 0;
}

/**
 * Generate AI analysis summary for a proposal
 */
export function generateAIAnalysis(
  task: Task,
  project: Project | undefined,
  priorityScore: number,
  factors: { factor: string; weight: number; contribution: number }[]
): AIAnalysisSummary {
  const urgencyScore = calculateDeadlineScore(task, { currentTime: new Date() });
  const impactScore = Math.round((priorityScore + urgencyScore) / 2);
  
  // Determine effort estimate based on task complexity
  const effortEstimate = estimateEffort(task);
  
  // Generate reasoning
  const reasoning = generateReasoning(task, project, factors);
  
  // Identify risks
  const risks = identifyRisks(task, project);
  
  // Identify opportunities
  const opportunities = identifyOpportunities(task, project);
  
  return {
    priority_factors: factors,
    urgency_score: urgencyScore,
    impact_score: impactScore,
    effort_estimate: effortEstimate,
    confidence: calculateConfidence(task, factors),
    reasoning,
    risks,
    opportunities,
  };
}

/**
 * Estimate effort required for a task
 */
function estimateEffort(task: Task): 'low' | 'medium' | 'high' {
  const description = (task.description || '').toLowerCase();
  const title = task.title.toLowerCase();
  
  // High effort indicators
  const highEffortKeywords = ['refactor', 'architecture', 'redesign', 'migration', 'integrate', 'implement'];
  for (const keyword of highEffortKeywords) {
    if (description.includes(keyword) || title.includes(keyword)) {
      return 'high';
    }
  }
  
  // Medium effort indicators
  const mediumEffortKeywords = ['update', 'modify', 'enhance', 'improve', 'fix', 'add'];
  for (const keyword of mediumEffortKeywords) {
    if (description.includes(keyword) || title.includes(keyword)) {
      return 'medium';
    }
  }
  
  return 'low';
}

/**
 * Generate reasoning for the proposal
 */
function generateReasoning(
  task: Task,
  project: Project | undefined,
  factors: { factor: string; weight: number; contribution: number }[]
): string {
  const parts: string[] = [];
  
  // Sort factors by contribution
  const sortedFactors = [...factors].sort((a, b) => b.contribution - a.contribution);
  
  // Add top factor
  const topFactor = sortedFactors[0];
  if (topFactor) {
    parts.push(`Primary driver: ${topFactor.factor.replace('_', ' ')} (+${Math.round(topFactor.contribution)} points)`);
  }
  
  // Add deadline context
  if (task.dueDate) {
    const dueDate = new Date(task.dueDate);
    const daysUntil = Math.ceil((dueDate.getTime() - Date.now()) / (1000 * 60 * 60 * 24));
    if (daysUntil <= 3) {
      parts.push(`Urgent: Due in ${daysUntil} day${daysUntil !== 1 ? 's' : ''}`);
    }
  }
  
  // Add project context
  if (project) {
    parts.push(`Part of ${project.name}`);
  }
  
  return parts.join('. ');
}

/**
 * Identify risks for the task
 */
function identifyRisks(task: Task, project: Project | undefined): string[] {
  const risks: string[] = [];
  
  if (task.status === 'blocked') {
    risks.push('Task is currently blocked');
  }
  
  if (task.dueDate) {
    const dueDate = new Date(task.dueDate);
    const daysUntil = Math.ceil((dueDate.getTime() - Date.now()) / (1000 * 60 * 60 * 24));
    if (daysUntil < 0) {
      risks.push('Task is overdue');
    } else if (daysUntil <= 2) {
      risks.push('Very tight deadline');
    }
  }
  
  if (task.priority === 'urgent') {
    risks.push('High priority task may have dependencies');
  }
  
  return risks;
}

/**
 * Identify opportunities for the task
 */
function identifyOpportunities(task: Task, project: Project | undefined): string[] {
  const opportunities: string[] = [];
  
  if (project?.name.toLowerCase().includes('ios')) {
    opportunities.push('Contributes to iOS portfolio growth');
  }
  
  if (task.tags.some(tag => tag.toLowerCase().includes('revenue'))) {
    opportunities.push('May impact revenue directly');
  }
  
  if (task.tags.some(tag => tag.toLowerCase().includes('milestone'))) {
    opportunities.push('Advances key milestone');
  }
  
  return opportunities;
}

/**
 * Calculate confidence in the proposal
 */
function calculateConfidence(task: Task, factors: { factor: string; weight: number; contribution: number }[]): number {
  let confidence = 70; // Base confidence
  
  // Boost confidence if we have clear signals
  const hasDeadline = !!task.dueDate;
  const hasClearPriority = task.priority === 'urgent' || task.priority === 'high';
  const hasDescription = (task.description || '').length > 50;
  
  if (hasDeadline) confidence += 10;
  if (hasClearPriority) confidence += 10;
  if (hasDescription) confidence += 5;
  
  // Reduce confidence if factors are contradictory
  const factorValues = factors.map(f => f.contribution);
  const variance = calculateVariance(factorValues);
  if (variance > 400) confidence -= 10; // High variance = conflicting signals
  
  return Math.min(95, Math.max(50, confidence));
}

/**
 * Calculate variance of an array
 */
function calculateVariance(values: number[]): number {
  if (values.length === 0) return 0;
  const mean = values.reduce((a, b) => a + b, 0) / values.length;
  const squaredDiffs = values.map(v => Math.pow(v - mean, 2));
  return squaredDiffs.reduce((a, b) => a + b, 0) / values.length;
}

/**
 * Create a mission proposal from a task
 */
export function createProposalFromTask(
  task: Task,
  project: Project | undefined,
  context: ProposalContext,
  config: ProposalServiceConfig = DEFAULT_CONFIG
): MissionProposalInsert {
  const priorityScore = calculatePriorityScore(task, project, context);
  const factors = getPriorityFactors(task, project, context);
  const aiAnalysis = generateAIAnalysis(task, project, priorityScore, factors);
  
  // Estimate duration based on effort
  const durationMap: Record<string, number> = {
    'low': 60,
    'medium': 180,
    'high': 360,
  };
  const estimatedDuration = durationMap[aiAnalysis.effort_estimate || 'medium'] || 120;
  
  // Calculate suggested time slot
  const suggestedStartTime = calculateSuggestedStartTime(context, estimatedDuration);
  const suggestedEndTime = suggestedStartTime 
    ? new Date(suggestedStartTime.getTime() + estimatedDuration * 60000)
    : null;
  
  // Generate rationale
  const rationale = aiAnalysis.reasoning || `High priority task: ${task.title}`;
  
  return {
    proposal_date: context.currentTime.toISOString().split('T')[0],
    status: 'pending',
    priority_score: priorityScore,
    passes_cap_gates: false, // Will be validated later
    cap_gate_violations: [],
    source_task_ids: [task.id],
    source_project_ids: project ? [project.id] : [],
    title: task.title,
    description: task.description ?? null,
    rationale,
    ai_analysis: aiAnalysis,
    suggested_start_time: suggestedStartTime?.toISOString() || null,
    suggested_end_time: suggestedEndTime?.toISOString() || null,
    estimated_duration_minutes: estimatedDuration,
    approved_at: null,
    approved_by: null,
    rejected_at: null,
    rejection_reason: null,
    calendar_event_id: null,
    calendar_synced_at: null,
    executed_at: null,
    execution_notes: null,
    expires_at: new Date(context.currentTime.getTime() + config.defaultProposalExpiryHours * 60 * 60 * 1000).toISOString(),
  };
}

/**
 * Get priority factors for a task
 */
function getPriorityFactors(
  task: Task,
  project: Project | undefined,
  context: ProposalContext
): { factor: string; weight: number; contribution: number }[] {
  const factors: { factor: string; weight: number; contribution: number }[] = [];
  
  const deadlineScore = calculateDeadlineScore(task, context);
  factors.push({ factor: 'deadline_urgency', weight: PRIORITY_FACTORS.deadlineUrgency, contribution: deadlineScore * PRIORITY_FACTORS.deadlineUrgency });
  
  const priorityScore = calculateTaskPriorityScore(task);
  factors.push({ factor: 'task_priority', weight: PRIORITY_FACTORS.taskPriority, contribution: priorityScore * PRIORITY_FACTORS.taskPriority });
  
  const projectScore = calculateProjectImportanceScore(project);
  factors.push({ factor: 'project_importance', weight: PRIORITY_FACTORS.projectImportance, contribution: projectScore * PRIORITY_FACTORS.projectImportance });
  
  const blockedScore = calculateBlockedScore(task, context);
  factors.push({ factor: 'blocked_status', weight: PRIORITY_FACTORS.blockedStatus, contribution: blockedScore * PRIORITY_FACTORS.blockedStatus });
  
  const staleScore = calculateStaleScore(task, context);
  factors.push({ factor: 'stale_task', weight: PRIORITY_FACTORS.staleTask, contribution: staleScore * PRIORITY_FACTORS.staleTask });
  
  return factors;
}

/**
 * Calculate suggested start time for a proposal
 */
function calculateSuggestedStartTime(context: ProposalContext, durationMinutes: number): Date | null {
  // Start with tomorrow at 9 AM
  const tomorrow = new Date(context.currentTime);
  tomorrow.setDate(tomorrow.getDate() + 1);
  tomorrow.setHours(9, 0, 0, 0);
  
  // TODO: Consider calendar availability from context
  
  return tomorrow;
}

/**
 * Proposal context for calculations
 */
export interface ProposalContext {
  currentTime: Date;
  activeTasks?: Task[];
  recentProposals?: MissionProposal[];
  calendarAvailability?: unknown[];
}

/**
 * Validate a proposal against cap gates
 */
export async function validateProposalAgainstCapGates(
  proposal: MissionProposalInsert,
  existingProposals: MissionProposal[],
  config: ProposalServiceConfig = DEFAULT_CONFIG
): Promise<CapGateCheckResult> {
  const violations: CapGateViolation[] = [];
  const checks: CapGateCheckResult['checks'] = [];
  
  // Check 1: Daily mission limit
  const todayProposals = existingProposals.filter(p => 
    p.proposal_date === proposal.proposal_date && 
    p.status !== 'rejected' && 
    p.status !== 'expired'
  );
  
  const dailyLimitGate = {
    gate: {
      id: 'daily_limit',
      name: 'Daily Mission Limit',
      description: 'Maximum number of missions per day',
      gate_type: 'daily_mission_limit' as const,
      max_value: config.maxProposalsPerDay,
      min_value: config.minProposalsPerDay,
      unit: 'count',
      current_value: todayProposals.length,
      last_evaluated_at: new Date().toISOString(),
      policy_id: null,
      is_active: true,
      is_blocking: false,
      evaluation_window_hours: 24,
      created_at: new Date().toISOString(),
      updated_at: new Date().toISOString(),
      created_by: null,
      updated_by: null,
    },
    passed: todayProposals.length < config.maxProposalsPerDay,
    currentValue: todayProposals.length,
  };
  
  if (!dailyLimitGate.passed) {
    dailyLimitGate.gate.is_blocking = true;
    violations.push({
      gate_name: dailyLimitGate.gate.name,
      gate_type: dailyLimitGate.gate.gate_type,
      current_value: dailyLimitGate.currentValue,
      max_value: config.maxProposalsPerDay,
      violation_message: `Daily mission limit of ${config.maxProposalsPerDay} reached`,
    });
  }
  
  checks.push(dailyLimitGate);
  
  // Check 2: Workload capacity
  const totalWorkload = todayProposals.reduce((sum, p) => 
    sum + (p.estimated_duration_minutes || 120), 0
  );
  const proposedWorkload = totalWorkload + (proposal.estimated_duration_minutes || 120);
  const maxWorkloadMinutes = 480; // 8 hours
  
  const workloadGate = {
    gate: {
      id: 'workload_capacity',
      name: 'Workload Capacity',
      description: 'Daily workload capacity in minutes',
      gate_type: 'workload_capacity' as const,
      max_value: maxWorkloadMinutes,
      min_value: 0,
      unit: 'minutes',
      current_value: proposedWorkload,
      last_evaluated_at: new Date().toISOString(),
      policy_id: null,
      is_active: true,
      is_blocking: false,
      evaluation_window_hours: 24,
      created_at: new Date().toISOString(),
      updated_at: new Date().toISOString(),
      created_by: null,
      updated_by: null,
    },
    passed: proposedWorkload <= maxWorkloadMinutes,
    currentValue: proposedWorkload,
  };
  
  if (!workloadGate.passed) {
    workloadGate.gate.is_blocking = true;
    violations.push({
      gate_name: workloadGate.gate.name,
      gate_type: workloadGate.gate.gate_type,
      current_value: proposedWorkload,
      max_value: maxWorkloadMinutes,
      violation_message: `Workload would exceed ${maxWorkloadMinutes} minutes (${Math.round(proposedWorkload)} proposed)`,
    });
  }
  
  checks.push(workloadGate);
  
  // Check 3: Priority threshold
  if (proposal.priority_score < config.priorityScoreThreshold) {
    violations.push({
      gate_name: 'Priority Threshold',
      gate_type: 'prioritization',
      current_value: proposal.priority_score,
      max_value: config.priorityScoreThreshold,
      violation_message: `Priority score ${proposal.priority_score} below threshold ${config.priorityScoreThreshold}`,
    });
  }
  
  return {
    allPassed: violations.length === 0,
    checks,
    violations,
    summary: violations.length === 0 
      ? 'All cap gates passed'
      : `${violations.length} cap gate violation${violations.length !== 1 ? 's' : ''}`,
  };
}

/**
 * Save a proposal to the database
 */
export async function saveProposal(
  proposal: MissionProposalInsert,
  capGateResult: CapGateCheckResult
): Promise<MissionProposal | null> {
  const supabase = getServiceSupabase();
  
  const proposalWithCapGates: MissionProposalInsert = {
    ...proposal,
    passes_cap_gates: capGateResult.allPassed,
    cap_gate_violations: capGateResult.violations,
  };
  
  const { data, error } = await supabase
    .from('ops_mission_proposals')
    .insert(proposalWithCapGates)
    .select()
    .single();
  
  if (error) {
    console.error('Error saving proposal:', error);
    return null;
  }
  
  return data as MissionProposal;
}

/**
 * Get proposals for a specific date
 */
export async function getProposalsForDate(date: Date): Promise<MissionProposal[]> {
  const supabase = getServiceSupabase();
  const dateString = date.toISOString().split('T')[0];
  
  const { data, error } = await supabase
    .from('ops_mission_proposals')
    .select('*')
    .eq('proposal_date', dateString)
    .order('priority_score', { ascending: false });
  
  if (error) {
    console.error('Error fetching proposals:', error);
    return [];
  }
  
  return (data || []) as MissionProposal[];
}

/**
 * Approve a proposal
 */
export async function approveProposal(
  proposalId: string,
  userId: string
): Promise<boolean> {
  const supabase = getServiceSupabase();
  
  const { error } = await supabase
    .from('ops_mission_proposals')
    .update({
      status: 'approved',
      approved_at: new Date().toISOString(),
      approved_by: userId,
    })
    .eq('id', proposalId);
  
  if (error) {
    console.error('Error approving proposal:', error);
    return false;
  }
  
  return true;
}

/**
 * Reject a proposal
 */
export async function rejectProposal(
  proposalId: string,
  reason: string
): Promise<boolean> {
  const supabase = getServiceSupabase();
  
  const { error } = await supabase
    .from('ops_mission_proposals')
    .update({
      status: 'rejected',
      rejected_at: new Date().toISOString(),
      rejection_reason: reason,
    })
    .eq('id', proposalId);
  
  if (error) {
    console.error('Error rejecting proposal:', error);
    return false;
  }
  
  return true;
}

/**
 * Mark proposal as completed
 */
export async function completeProposal(
  proposalId: string,
  notes?: string
): Promise<boolean> {
  const supabase = getServiceSupabase();
  
  const { error } = await supabase
    .from('ops_mission_proposals')
    .update({
      status: 'completed',
      executed_at: new Date().toISOString(),
      execution_notes: notes || null,
    })
    .eq('id', proposalId);
  
  if (error) {
    console.error('Error completing proposal:', error);
    return false;
  }
  
  return true;
}

/**
 * Get top proposals for today
 */
export async function getTopProposalsForToday(limit: number = 3): Promise<MissionProposal[]> {
  const today = new Date();
  const proposals = await getProposalsForDate(today);
  
  // Filter to pending and approved proposals
  const activeProposals = proposals.filter(p => 
    p.status === 'pending' || p.status === 'approved'
  );
  
  // Sort by priority score
  activeProposals.sort((a, b) => b.priority_score - a.priority_score);
  
  return activeProposals.slice(0, limit);
}

/**
 * Expire old proposals
 */
export async function expireOldProposals(): Promise<number> {
  const supabase = getServiceSupabase();
  const now = new Date().toISOString();
  
  const { data, error } = await supabase
    .from('ops_mission_proposals')
    .update({ status: 'expired' })
    .lt('expires_at', now)
    .eq('status', 'pending')
    .select('id');
  
  if (error) {
    console.error('Error expiring proposals:', error);
    return 0;
  }
  
  return data?.length || 0;
}