import { Document } from '@/types'
import { estimateTokens, extractSiteName } from './parser'

/**
 * Generates the llms-full.md consolidated document with table of contents
 */
export function generateFullDocument(
  documents: Document[],
  rawContent: string,
  sourceUrl: string
): Document {
  const siteName = extractSiteName(sourceUrl)
  const title = `${siteName.charAt(0).toUpperCase() + siteName.slice(1)} Documentation`
  
  // Build table of contents
  const tocLines = documents.map((doc, index) => {
    const anchor = doc.title.toLowerCase().replace(/[^\w\s-]/g, '').replace(/\s+/g, '-')
    return `${index + 1}. [${doc.title}](#${anchor})`
  })
  
  const toc = tocLines.length > 0 
    ? `## Table of Contents\n\n${tocLines.join('\n')}\n\n---\n\n`
    : ''
  
  // Build full content
  const header = `# ${title}\n\n> Source: ${sourceUrl}\n\n${toc}`
  
  // Combine all document contents
  const bodyParts = documents.map(doc => doc.content)
  const body = bodyParts.join('\n\n---\n\n')
  
  const fullContent = `${header}${body}`
  
  return {
    filename: 'llms-full.md',
    title,
    content: fullContent,
    tokens: estimateTokens(fullContent)
  }
}

/**
 * Generates the AGENT-GUIDE.md file with instructions for AI assistants
 */
export function generateAgentGuide(
  documents: Document[],
  sourceUrl: string,
  siteName: string
): Document {
  const formattedSiteName = siteName.charAt(0).toUpperCase() + siteName.slice(1)
  const extractionDate = new Date().toISOString().split('T')[0]
  
  // Build file list with descriptions
  const fileList = documents.map(doc => {
    const tokenInfo = `(${doc.tokens.toLocaleString()} tokens)`
    return `- **${doc.filename}** - ${doc.title} ${tokenInfo}`
  }).join('\n')
  
  // Determine topics from document titles
  const topics = documents.map(d => d.title).slice(0, 5).join(', ')
  const topicSummary = documents.length > 5 
    ? `${topics}, and more`
    : topics
  
  const content = `# Agent Guide for ${formattedSiteName} Documentation

This package contains documentation extracted from ${formattedSiteName}'s official documentation.

## Source Information

- **Original URL**: ${sourceUrl}
- **Extraction Date**: ${extractionDate}
- **Total Documents**: ${documents.length}
- **Total Tokens**: ${documents.reduce((sum, d) => sum + d.tokens, 0).toLocaleString()}

## Included Files

### Main Files
- **llms-full.md** - Complete documentation compiled into a single file with table of contents
- **AGENT-GUIDE.md** - This file, containing usage instructions

### Individual Documentation Files
${fileList}

## How to Use This Documentation

As an AI assistant, you can use these files to:

1. **Answer questions** about ${formattedSiteName} features, APIs, and functionality
2. **Provide code examples** from the official documentation
3. **Explain concepts** and best practices as documented by ${formattedSiteName}
4. **Troubleshoot issues** by referencing relevant documentation sections
5. **Guide users** through setup, configuration, and implementation

## Recommended Reading Order

1. Start with **llms-full.md** for complete context and overview
2. Reference individual files when focusing on specific topics:
${documents.slice(0, 5).map((d, i) => `   ${i + 1}. ${d.filename} - for ${d.title}`).join('\n')}

## Topics Covered

This documentation covers: ${topicSummary}

## Important Notes

- This documentation was automatically extracted and may not include all content from the original source
- For the most up-to-date information, refer to the original documentation at ${sourceUrl}
- Code examples should be verified against the current API version

## Source Reference

Original documentation: ${sourceUrl}

---

*Generated by llm.energy - Documentation Extraction Tool*
`

  return {
    filename: 'AGENT-GUIDE.md',
    title: 'Agent Guide',
    content,
    tokens: estimateTokens(content)
  }
}

/**
 * Main generation function: creates all output documents from parsed content
 */
export function generateAllDocuments(
  documents: Document[],
  rawContent: string,
  sourceUrl: string
): {
  documents: Document[]
  fullDocument: Document
  agentGuide: Document
} {
  const siteName = extractSiteName(sourceUrl)
  
  const fullDocument = generateFullDocument(documents, rawContent, sourceUrl)
  const agentGuide = generateAgentGuide(documents, sourceUrl, siteName)
  
  return {
    documents,
    fullDocument,
    agentGuide
  }
}