import { processCommand } from '../cli/process';
import { getDayDetail, getDays, getProjects, getStats, updateProjectStatus } from '../core/db';
import type { ProjectStatus } from '../types';

type ApiHandler = (req: Request, url: URL) => Promise<Response>;

interface URLWithParams extends URL {
  params?: Record<string, string>;
}

const routes: Record<string, ApiHandler> = {
  'GET /api/days': handleGetDays,
  'GET /api/days/:date': handleGetDayDetail,
  'GET /api/days/:date/brag': handleGetDayBrag,
  'GET /api/stats': handleGetStats,
  'POST /api/refresh': handleRefresh,
  'GET /api/projects': handleGetProjects,
  'PATCH /api/projects/status': handleUpdateProjectStatus,
};

export async function handleApiRequest(req: Request, url: URL): Promise<Response> {
  const method = req.method;
  const path = url.pathname;

  // Match routes
  for (const [route, handler] of Object.entries(routes)) {
    const [routeMethod, routePath] = route.split(' ');
    if (method !== routeMethod) continue;

    const params = matchPath(routePath, path);
    if (params !== null) {
      try {
        // Attach params to URL for handler access
        (url as URLWithParams).params = params;
        return await handler(req, url);
      } catch (error) {
        console.error('API error:', error);
        return jsonResponse({ error: 'Internal server error' }, 500);
      }
    }
  }

  return jsonResponse({ error: 'Not found' }, 404);
}

function matchPath(pattern: string, path: string): Record<string, string> | null {
  const patternParts = pattern.split('/');
  const pathParts = path.split('/');

  if (patternParts.length !== pathParts.length) return null;

  const params: Record<string, string> = {};

  for (const [i, patternPart] of patternParts.entries()) {
    // pathPart is guaranteed to exist since we verified lengths match
    const pathPart = pathParts[i] ?? '';

    if (patternPart.startsWith(':')) {
      params[patternPart.slice(1)] = pathPart;
    } else if (patternPart !== pathPart) {
      return null;
    }
  }

  return params;
}

function jsonResponse(data: unknown, status = 200): Response {
  return new Response(JSON.stringify(data), {
    status,
    headers: {
      'Content-Type': 'application/json',
      'Access-Control-Allow-Origin': '*',
    },
  });
}

// Handlers

function handleGetDays(_req: Request, url: URL): Promise<Response> {
  const limitParam = url.searchParams.get('limit');
  const days = limitParam !== null ? getDays(parseInt(limitParam, 10)) : getDays();
  return Promise.resolve(jsonResponse(days));
}

function handleGetDayDetail(_req: Request, url: URL): Promise<Response> {
  const params = (url as { params?: Record<string, string> }).params;
  const date = params?.date;

  if (date === undefined) {
    return Promise.resolve(jsonResponse({ error: 'Missing date parameter' }, 400));
  }

  const detail = getDayDetail(date);
  if (detail === null) {
    return Promise.resolve(jsonResponse({ error: 'Day not found' }, 404));
  }

  return Promise.resolve(jsonResponse(detail));
}

function handleGetDayBrag(_req: Request, url: URL): Promise<Response> {
  const params = (url as { params?: Record<string, string> }).params;
  const date = params?.date;

  if (date === undefined) {
    return Promise.resolve(jsonResponse({ error: 'Missing date parameter' }, 400));
  }

  const detail = getDayDetail(date);
  if (detail === null) {
    return Promise.resolve(jsonResponse({ error: 'Day not found' }, 404));
  }

  return Promise.resolve(
    jsonResponse({
      date,
      bragSummary: detail.bragSummary ?? 'No summary available',
      projectCount: detail.projects.length,
      sessionCount: detail.stats.totalSessions,
    }),
  );
}

function handleGetStats(_req: Request, _url: URL): Promise<Response> {
  const stats = getStats();
  return Promise.resolve(jsonResponse(stats));
}

async function handleRefresh(_req: Request, _url: URL): Promise<Response> {
  // Run processing in background
  const startTime = Date.now();

  try {
    const result = await processCommand({
      force: false,
      verbose: false,
    });

    return jsonResponse({
      success: true,
      sessionsProcessed: result.sessionsProcessed,
      errors: result.errors,
      durationMs: Date.now() - startTime,
    });
  } catch (error) {
    return jsonResponse(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Unknown error',
      },
      500,
    );
  }
}

function handleGetProjects(_req: Request, url: URL): Promise<Response> {
  const status = url.searchParams.get('status') as ProjectStatus | null;
  const projects = getProjects(status ?? undefined);
  return Promise.resolve(jsonResponse(projects));
}

async function handleUpdateProjectStatus(req: Request, _url: URL): Promise<Response> {
  const body = (await req.json()) as { path?: string; status?: ProjectStatus };

  if (body.path === undefined || body.status === undefined) {
    return jsonResponse({ error: 'Missing path or status' }, 400);
  }

  const validStatuses: ProjectStatus[] = [
    'shipped',
    'in_progress',
    'ready_to_ship',
    'abandoned',
    'ignore',
    'one_off',
    'experiment',
  ];
  if (!validStatuses.includes(body.status)) {
    return jsonResponse({ error: 'Invalid status' }, 400);
  }

  const updated = updateProjectStatus(body.path, body.status);
  if (!updated) {
    return jsonResponse({ error: 'Project not found' }, 404);
  }

  return jsonResponse({ success: true });
}