// src/server.ts
// ============================================================================
// UK CASE LAW MCP SERVER
// ============================================================================
//
// Provides Claude with tools to search and retrieve UK case law.
//
// Tools provided:
// - uklaw_search: Search across all case law
// - uklaw_get_case: Get full text of a specific case
// ============================================================================

import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';
import { z } from 'zod';

import { searchCaseLaw } from './search.js';
import { getCaseByUri, getCaseByCitation } from './cases.js';
import { formatSearchResults, formatCaseContent } from './formatters.js';
import type { SearchParams } from './search.js';

// ============================================================================
// SERVER INITIALIZATION
// ============================================================================

const server = new McpServer({
  name: 'uk-case-law',
  version: '1.0.0',
});

// ============================================================================
// TOOL: uklaw_search
// ============================================================================
//
// Primary search tool. Searches TNA API (2003+).
// ============================================================================

server.tool(
  'uklaw_search',
  `Search UK case law across all courts and tribunals.

Returns ranked results with:
- Neutral citations (e.g., [2024] UKSC 1)
- Case titles
- Courts and dates
- Brief snippets

Use filters to narrow results by court, legal area, or date range.

Examples:
- "patent obviousness test" - finds patent validity cases
- "unfair dismissal procedure" - finds employment cases
- "breach of fiduciary duty director" - finds company law cases`,

  {
    query: z.string()
      .min(2)
      .describe('Search terms - legal concepts, party names, or keywords'),

    legal_area: z.enum([
      'any',
      'intellectual_property',
      'commercial',
      'company',
      'employment',
      'property',
      'family',
      'criminal',
      'public_law',
      'immigration',
      'personal_injury'
    ])
      .default('any')
      .describe('Filter by area of law'),

    court: z.enum([
      'any',
      'supreme_court',
      'court_of_appeal',
      'high_court',
      'crown_court',
      'tribunals'
    ])
      .default('any')
      .describe('Filter by court level'),

    year_from: z.number()
      .int()
      .min(1800)
      .max(2025)
      .optional()
      .describe('Earliest decision year'),

    year_to: z.number()
      .int()
      .min(1800)
      .max(2025)
      .optional()
      .describe('Latest decision year'),

    limit: z.number()
      .int()
      .min(1)
      .max(50)
      .default(10)
      .describe('Maximum results to return'),

    page: z.number()
      .int()
      .min(1)
      .default(1)
      .describe('Page number for pagination. If results seem truncated or date range is not met, try next page.'),
  },

  async ({ query, legal_area, court, year_from, year_to, limit, page }) => {
    try {
      const params: SearchParams = {
        query,
        legalArea: legal_area === 'any' ? undefined : legal_area,
        court: court === 'any' ? undefined : court,
        yearFrom: year_from,
        yearTo: year_to,
        limit,
        page,
      };

      const results = await searchCaseLaw(params);
      const formatted = formatSearchResults(results);

      return {
        content: [{ type: 'text', text: formatted }]
      };
    } catch (error) {
      return {
        content: [{
          type: 'text',
          text: `Search failed: ${error instanceof Error ? error.message : 'Unknown error'}`
        }],
        isError: true
      };
    }
  }
);

// ============================================================================
// TOOL: uklaw_get_case
// ============================================================================
//
// Retrieves full text of a specific case. For TNA cases, fetches from API.
//
// Output includes numbered paragraphs for precise citation.
// ============================================================================

server.tool(
  'uklaw_get_case',
  `Retrieve the full text of a specific UK case.

Accepts either:
- Neutral citation: "[2007] EWCA Civ 588"
- Document URI: "ewca/civ/2007/588"

Returns the judgment with numbered paragraphs. Use paragraph numbers
when citing specific passages, e.g., "as stated at [23]".

For long judgments, use the paragraphs parameter to request a specific
range (e.g., "1-50" for the first 50 paragraphs).`,

  {
    citation: z.string()
      .describe('Neutral citation (e.g., "[2024] UKSC 1") or document URI (e.g., "uksc/2024/1")'),

    paragraphs: z.string()
      .optional()
      .describe('Paragraph range to retrieve, e.g., "1-50" or "23-45". Omit for full text.'),

    include_metadata: z.boolean()
      .default(true)
      .describe('Include case metadata (judges, date, court)')
  },

  async ({ citation, paragraphs, include_metadata }) => {
    try {
      // Determine if this is a neutral citation or URI
      const isNeutralCitation = citation.startsWith('[');

      const caseData = isNeutralCitation
        ? await getCaseByCitation(citation)
        : await getCaseByUri(citation);

      if (!caseData) {
        return {
          content: [{ type: 'text', text: `Case not found: ${citation}` }],
          isError: true
        };
      }

      const formatted = formatCaseContent(caseData, {
        includeMetadata: include_metadata,
        paragraphRange: paragraphs,
      });

      return {
        content: [{ type: 'text', text: formatted }]
      };
    } catch (error) {
      return {
        content: [{
          type: 'text',
          text: `Failed to retrieve case: ${error instanceof Error ? error.message : 'Unknown error'}`
        }],
        isError: true
      };
    }
  }
);

// ============================================================================
// START SERVER
// ============================================================================

async function main() {
  const transport = new StdioServerTransport();
  await server.connect(transport);
  console.error('UK Case Law MCP server running');
}

main().catch(console.error);