// src/utils/dataService.ts - Enhanced for micro-task AI pipeline
import { promises as fs } from 'fs';
import { load } from 'js-yaml';
import path from 'path';
import { z } from 'zod';

const ToolSchema = z.object({
  name: z.string(),
  icon: z.string().optional().nullable(),
  type: z.enum(['software', 'method', 'concept']),
  description: z.string(),
  domains: z.array(z.string()).optional().nullable().default([]),
  phases: z.array(z.string()).optional().nullable().default([]),
  platforms: z.array(z.string()).default([]),
  skillLevel: z.string(),
  url: z.string(),
  license: z.string().optional().nullable(),
  tags: z.array(z.string()).default([]),
  projectUrl: z.string().optional().nullable(),
  knowledgebase: z.boolean().optional().nullable(),
  statusUrl: z.string().optional().nullable(),
  accessType: z.string().optional().nullable(),
  'domain-agnostic-software': z.array(z.string()).optional().nullable(),
  related_concepts: z.array(z.string()).optional().nullable().default([]),
  related_software: z.array(z.string()).optional().nullable().default([]),
});

const ToolsDataSchema = z.object({
  tools: z.array(ToolSchema),
  domains: z.array(z.object({
    id: z.string(),
    name: z.string(),
    description: z.string().optional() 
  })),
  phases: z.array(z.object({
    id: z.string(), 
    name: z.string(),
    description: z.string().optional(),
    typical_tools: z.array(z.string()).optional().default([]), 
    key_activities: z.array(z.string()).optional().default([]) 
  })),
  'domain-agnostic-software': z.array(z.object({
    id: z.string(),
    name: z.string(),
    description: z.string().optional(),
    use_cases: z.array(z.string()).optional().default([]) 
  })).optional().default([]),
  scenarios: z.array(z.object({
    id: z.string(),
    icon: z.string(),
    friendly_name: z.string(),
    description: z.string().optional(), 
    typical_phases: z.array(z.string()).optional().default([]), 
    complexity: z.enum(['low', 'medium', 'high']).optional() 
  })).optional().default([]),
  skill_levels: z.object({
    novice: z.string().optional(),
    beginner: z.string().optional(), 
    intermediate: z.string().optional(),
    advanced: z.string().optional(),
    expert: z.string().optional()
  }).optional().default({})
});

interface ToolsData {
  tools: any[];
  domains: any[];
  phases: any[];
  'domain-agnostic-software': any[];
  scenarios: any[];
  skill_levels?: any;
}

interface EnhancedCompressedToolsData {
  tools: any[];
  concepts: any[];
  domains: any[];
  phases: any[];
  'domain-agnostic-software': any[];
  scenarios?: any[];
  skill_levels: any;
}

let cachedData: ToolsData | null = null;
let cachedRandomizedData: ToolsData | null = null;
let cachedCompressedData: EnhancedCompressedToolsData | null = null;
let lastRandomizationDate: string | null = null;
let dataVersion: string | null = null;

function seededRandom(seed: number): () => number {
  let x = Math.sin(seed) * 10000;
  return function() {
    x = Math.sin(x) * 10000;
    return x - Math.floor(x);
  };
}

function getDailySeed(): number {
  const today = new Date().toDateString();
  const processStart = process.uptime();
  return today.split('').reduce((acc, char) => acc + char.charCodeAt(0), 0) + Math.floor(processStart);
}

function shuffleArray<T>(array: T[], randomFn: () => number): T[] {
  const shuffled = [...array];
  for (let i = shuffled.length - 1; i > 0; i--) {
    const j = Math.floor(randomFn() * (i + 1));
    [shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]];
  }
  return shuffled;
}

function generateDataVersion(data: any): string {
  const str = JSON.stringify(data, Object.keys(data).sort());
  let hash = 0;
  for (let i = 0; i < str.length; i++) {
    const char = str.charCodeAt(i);
    hash = ((hash << 5) - hash) + char;
    hash = hash & hash;
  }
  return Math.abs(hash).toString(36);
}

async function loadRawData(): Promise<ToolsData> {
  if (!cachedData) {
    const yamlPath = path.join(process.cwd(), 'src/data/tools.yaml');
    const yamlContent = await fs.readFile(yamlPath, 'utf8');
    const rawData = load(yamlContent);
    
    try {
      cachedData = ToolsDataSchema.parse(rawData);
      
      if (!cachedData.skill_levels || Object.keys(cachedData.skill_levels).length === 0) {
        cachedData.skill_levels = {
          novice: "Minimal technical background required, guided interfaces",
          beginner: "Basic IT knowledge, some command-line familiarity helpful",
          intermediate: "Solid technical foundation, comfortable with various tools",
          advanced: "Extensive experience, deep technical understanding required",
          expert: "Specialist knowledge, cutting-edge techniques and complex scenarios"
        };
      }
      
      dataVersion = generateDataVersion(cachedData);
      console.log(`[DATA SERVICE] Loaded enhanced data version: ${dataVersion}`);
      
    } catch (error) {
      console.error('YAML validation failed:', error);
      throw new Error('Invalid tools.yaml structure');
    }
  }
  return cachedData;
}

export async function getToolsData(): Promise<ToolsData> {
  const today = new Date().toDateString();
  
  if (!cachedRandomizedData || lastRandomizationDate !== today) {
    const rawData = await loadRawData();
    const seed = getDailySeed();
    const randomFn = seededRandom(seed);
    
    const randomizedTools = shuffleArray(rawData.tools, randomFn);
    
    cachedRandomizedData = {
      ...rawData,
      tools: randomizedTools
    };
    
    lastRandomizationDate = today;
    cachedCompressedData = null;
  }
  
  return cachedRandomizedData;
}

export async function getCompressedToolsDataForAI(): Promise<EnhancedCompressedToolsData> {
  if (!cachedCompressedData) {
    const data = await getToolsData();
    
    const compressedTools = data.tools
      .filter(tool => tool.type !== 'concept') 
      .map(tool => {
        const { projectUrl, statusUrl, ...compressedTool } = tool;
        return {
          ...compressedTool,
          is_hosted: projectUrl !== undefined && projectUrl !== null && projectUrl !== "" && projectUrl.trim() !== "",
          is_open_source: tool.license && tool.license !== 'Proprietary',
          complexity_score: tool.skillLevel === 'expert' ? 5 :
                           tool.skillLevel === 'advanced' ? 4 :
                           tool.skillLevel === 'intermediate' ? 3 :
                           tool.skillLevel === 'beginner' ? 2 : 1,
          phase_suitability: tool.phases?.map(phase => ({
            phase,
            primary_use: tool.tags?.find(tag => tag.includes(phase)) ? 'primary' : 'secondary'
          })) || []
        };
      });
    
    const concepts = data.tools
      .filter(tool => tool.type === 'concept')
      .map(concept => {
        const { projectUrl, statusUrl, platforms, accessType, license, ...compressedConcept } = concept;
        return {
          ...compressedConcept,
          learning_complexity: concept.skillLevel === 'expert' ? 'very_high' :
                              concept.skillLevel === 'advanced' ? 'high' :
                              concept.skillLevel === 'intermediate' ? 'medium' :
                              'low'
        };
      });
    
    cachedCompressedData = {
      tools: compressedTools,
      concepts: concepts,
      domains: data.domains,
      phases: data.phases,
      'domain-agnostic-software': data['domain-agnostic-software'],
      scenarios: data.scenarios,
      skill_levels: data.skill_levels || {},
    };
    
  }
  
  return cachedCompressedData;
}

export function getDataVersion(): string | null {
  return dataVersion;
}

export function clearCache(): void {
  cachedData = null;
  cachedRandomizedData = null;
  cachedCompressedData = null;
  lastRandomizationDate = null;
  dataVersion = null;
  
  console.log('[DATA SERVICE] Enhanced cache cleared');
}