// src/formatters.ts
// ============================================================================
// OUTPUT FORMATTERS
// ============================================================================
//
// Format search results and case content for Claude.
// Designed to be readable and include proper citations.
// ============================================================================

import type { SearchResult, CaseContent, CaseParagraph } from './types.js';

// ============================================================================
// PARAGRAPH RANGE UTILITIES
// ============================================================================

export function parseParaRange(range: string): { start: number; end: number } | null {
  const match = range.match(/^(\d+)\s*-\s*(\d+)$/);
  if (!match || !match[1] || !match[2]) return null;
  return {
    start: parseInt(match[1], 10),
    end: parseInt(match[2], 10),
  };
}

// Maximum characters to return (roughly 8000 tokens)
const MAX_OUTPUT_CHARS = 32000;

export function applyParaRange(
  paragraphs: CaseParagraph[],
  range: string | undefined
): { paragraphs: CaseParagraph[]; truncated: boolean; remaining: number } {
  if (!range) {
    // No range specified - apply token limit
    return truncateToLimit(paragraphs);
  }

  const parsed = parseParaRange(range);
  if (!parsed) {
    return truncateToLimit(paragraphs);
  }

  const filtered = paragraphs.filter(
    p => p.number >= parsed.start && p.number <= parsed.end
  );

  return truncateToLimit(filtered);
}

function truncateToLimit(paragraphs: CaseParagraph[]): {
  paragraphs: CaseParagraph[];
  truncated: boolean;
  remaining: number;
} {
  let totalChars = 0;
  const output: CaseParagraph[] = [];

  for (const para of paragraphs) {
    if (totalChars + para.text.length > MAX_OUTPUT_CHARS) {
      break;
    }
    output.push(para);
    totalChars += para.text.length;
  }

  return {
    paragraphs: output,
    truncated: output.length < paragraphs.length,
    remaining: paragraphs.length - output.length,
  };
}

// ============================================================================
// SEARCH RESULTS FORMATTER
// ============================================================================

export function formatSearchResults(results: SearchResult[]): string {
  if (results.length === 0) {
    return 'No cases found matching your search query.';
  }

  let output = `Found ${results.length} case${results.length === 1 ? '' : 's'}:\n\n`;

  for (const result of results) {
    // Citation or URI as header
    const citation = result.neutralCitation || result.documentUri;
    output += `**${citation}**\n`;

    // Title
    output += `${result.title}\n`;

    // Court and date
    const parts: string[] = [];
    if (result.court) parts.push(result.court);
    if (result.date) parts.push(result.date);
    if (parts.length > 0) {
      output += `${parts.join(' | ')}\n`;
    }

    // Snippet if available
    if (result.snippet) {
      const cleanSnippet = result.snippet
        .replace(/\s+/g, ' ')
        .trim()
        .substring(0, 200);
      output += `> ${cleanSnippet}${cleanSnippet.length >= 200 ? '...' : ''}\n`;
    }

    // Add document links
    output += `[View on TNA](${result.urls.web}) | [PDF](${result.urls.pdf})\n`;

    output += '\n';
  }

  return output.trim();
}

// ============================================================================
// CASE CONTENT FORMATTER
// ============================================================================

export interface FormatOptions {
  includeMetadata?: boolean;
  paragraphRange?: string;
}

export function formatCaseContent(
  caseData: CaseContent,
  options: FormatOptions = {}
): string {
  const { includeMetadata = true, paragraphRange } = options;

  let output = '';

  // Metadata header
  if (includeMetadata) {
    output += `# ${caseData.metadata.title}\n\n`;

    if (caseData.metadata.neutralCitation) {
      output += `**Citation:** ${caseData.metadata.neutralCitation}\n`;
    }

    output += `**Court:** ${caseData.metadata.courtName || caseData.metadata.court}\n`;

    if (caseData.metadata.date) {
      output += `**Date:** ${caseData.metadata.date}\n`;
    }

    if (caseData.judges && caseData.judges.length > 0) {
      output += `**Judges:** ${caseData.judges.join(', ')}\n`;
    }

    if (caseData.parties) {
      if (caseData.parties.claimants.length > 0) {
        output += `**Claimant(s):** ${caseData.parties.claimants.join(', ')}\n`;
      }
      if (caseData.parties.defendants.length > 0) {
        output += `**Defendant(s):** ${caseData.parties.defendants.join(', ')}\n`;
      }
    }

    // Add document links
    output += `\n[View on TNA](${caseData.metadata.urls.web}) | [PDF](${caseData.metadata.urls.pdf})\n`;

    output += '\n---\n\n';
  }

  // Apply paragraph range and truncation
  const { paragraphs, truncated, remaining } = applyParaRange(
    caseData.paragraphs,
    paragraphRange
  );

  // Format paragraphs with numbers for citation
  for (const para of paragraphs) {
    output += `[${para.number}] ${para.text}\n\n`;
  }

  // Truncation notice
  if (truncated) {
    output += `---\n\n`;
    output += `*Output truncated. ${remaining} paragraph${remaining === 1 ? '' : 's'} remaining. `;
    const lastPara = paragraphs[paragraphs.length - 1];
    if (lastPara) {
      output += `Use the paragraphs parameter (e.g., "${lastPara.number + 1}-${lastPara.number + 50}") to retrieve more.*\n`;
    }
  }

  return output.trim();
}

// ============================================================================
// CITATIONS FORMATTER
// ============================================================================

export function formatCitations(
  citations: { citing: any[]; cited: any[] },
  direction: 'citing' | 'cited' | 'both'
): string {
  let output = '';

  if (direction === 'citing' || direction === 'both') {
    output += `## Cases Citing This Decision\n\n`;
    if (citations.citing.length === 0) {
      output += `No citing cases found.\n\n`;
    } else {
      for (const c of citations.citing) {
        output += `- **${c.citation || c.title}** (${c.court}, ${c.date})\n`;
      }
      output += '\n';
    }
  }

  if (direction === 'cited' || direction === 'both') {
    output += `## Cases Cited By This Decision\n\n`;
    if (citations.cited.length === 0) {
      output += `No cited cases found.\n\n`;
    } else {
      for (const c of citations.cited) {
        output += `- **${c.citation || c.title}** (${c.court}, ${c.date})\n`;
      }
      output += '\n';
    }
  }

  return output.trim();
}