import express, { type Request, type Response } from 'express';

import { providerAuthService } from '@/modules/providers/services/provider-auth.service.js';
import { providerMcpService } from '@/modules/providers/services/mcp.service.js';
import { sessionConversationsSearchService } from '@/modules/providers/services/session-conversations-search.service.js';
import { sessionsService } from '@/modules/providers/services/sessions.service.js';
import type { LLMProvider, McpScope, McpTransport, UpsertProviderMcpServerInput } from '@/shared/types.js';
import { AppError, asyncHandler, createApiSuccessResponse } from '@/shared/utils.js';

const router = express.Router();

const readPathParam = (value: unknown, name: string): string => {
  if (typeof value === 'string') {
    return value;
  }

  if (Array.isArray(value) && typeof value[0] === 'string') {
    return value[0];
  }

  throw new AppError(`${name} path parameter is invalid.`, {
    code: 'INVALID_PATH_PARAMETER',
    statusCode: 400,
  });
};

const normalizeProviderParam = (value: unknown): string =>
  readPathParam(value, 'provider').trim().toLowerCase();

const SESSION_ID_PATTERN = /^[a-zA-Z0-9._-]{1,120}$/;

const parseSessionId = (value: unknown): string => {
  const sessionId = readPathParam(value, 'sessionId').trim();
  if (!SESSION_ID_PATTERN.test(sessionId)) {
    throw new AppError('Invalid sessionId.', {
      code: 'INVALID_SESSION_ID',
      statusCode: 400,
    });
  }

  return sessionId;
};

const readOptionalQueryString = (value: unknown): string | undefined => {
  if (typeof value !== 'string') {
    return undefined;
  }

  const normalized = value.trim();
  return normalized.length > 0 ? normalized : undefined;
};

const parseOptionalBooleanQuery = (value: unknown, name: string): boolean | undefined => {
  if (value === undefined) {
    return undefined;
  }

  const normalized = readOptionalQueryString(value);
  if (!normalized) {
    return undefined;
  }

  if (normalized === 'true') {
    return true;
  }
  if (normalized === 'false') {
    return false;
  }

  throw new AppError(`${name} must be "true" or "false".`, {
    code: 'INVALID_QUERY_PARAMETER',
    statusCode: 400,
  });
};

const parseMcpScope = (value: unknown): McpScope | undefined => {
  if (value === undefined) {
    return undefined;
  }

  const normalized = readOptionalQueryString(value);
  if (!normalized) {
    return undefined;
  }

  if (normalized === 'user' || normalized === 'local' || normalized === 'project') {
    return normalized;
  }

  throw new AppError(`Unsupported MCP scope "${normalized}".`, {
    code: 'INVALID_MCP_SCOPE',
    statusCode: 400,
  });
};

const parseMcpTransport = (value: unknown): McpTransport => {
  const normalized = readOptionalQueryString(value);
  if (!normalized) {
    throw new AppError('transport is required.', {
      code: 'MCP_TRANSPORT_REQUIRED',
      statusCode: 400,
    });
  }

  if (normalized === 'stdio' || normalized === 'http' || normalized === 'sse') {
    return normalized;
  }

  throw new AppError(`Unsupported MCP transport "${normalized}".`, {
    code: 'INVALID_MCP_TRANSPORT',
    statusCode: 400,
  });
};

const parseMcpUpsertPayload = (payload: unknown): UpsertProviderMcpServerInput => {
  if (!payload || typeof payload !== 'object') {
    throw new AppError('Request body must be an object.', {
      code: 'INVALID_REQUEST_BODY',
      statusCode: 400,
    });
  }

  const body = payload as Record<string, unknown>;
  const name = readOptionalQueryString(body.name);
  if (!name) {
    throw new AppError('name is required.', {
      code: 'MCP_NAME_REQUIRED',
      statusCode: 400,
    });
  }

  const transport = parseMcpTransport(body.transport);
  const scope = parseMcpScope(body.scope);
  const workspacePath = readOptionalQueryString(body.workspacePath);

  return {
    name,
    transport,
    scope,
    workspacePath,
    command: readOptionalQueryString(body.command),
    args: Array.isArray(body.args) ? body.args.filter((entry): entry is string => typeof entry === 'string') : undefined,
    env: typeof body.env === 'object' && body.env !== null
      ? Object.fromEntries(
        Object.entries(body.env as Record<string, unknown>).filter(
          (entry): entry is [string, string] => typeof entry[1] === 'string',
        ),
      )
      : undefined,
    cwd: readOptionalQueryString(body.cwd),
    url: readOptionalQueryString(body.url),
    headers: typeof body.headers === 'object' && body.headers !== null
      ? Object.fromEntries(
        Object.entries(body.headers as Record<string, unknown>).filter(
          (entry): entry is [string, string] => typeof entry[1] === 'string',
        ),
      )
      : undefined,
    envVars: Array.isArray(body.envVars)
      ? body.envVars.filter((entry): entry is string => typeof entry === 'string')
      : undefined,
    bearerTokenEnvVar: readOptionalQueryString(body.bearerTokenEnvVar),
    envHttpHeaders: typeof body.envHttpHeaders === 'object' && body.envHttpHeaders !== null
      ? Object.fromEntries(
        Object.entries(body.envHttpHeaders as Record<string, unknown>).filter(
          (entry): entry is [string, string] => typeof entry[1] === 'string',
        ),
      )
      : undefined,
  };
};

const parseProvider = (value: unknown): LLMProvider => {
  const normalized = normalizeProviderParam(value);
  if (normalized === 'claude' || normalized === 'codex' || normalized === 'cursor' || normalized === 'gemini') {
    return normalized;
  }

  throw new AppError(`Unsupported provider "${normalized}".`, {
    code: 'UNSUPPORTED_PROVIDER',
    statusCode: 400,
  });
};

const parseSessionRenameSummary = (payload: unknown): string => {
  if (!payload || typeof payload !== 'object') {
    throw new AppError('Request body must be an object.', {
      code: 'INVALID_REQUEST_BODY',
      statusCode: 400,
    });
  }

  const body = payload as Record<string, unknown>;
  const summary = typeof body.summary === 'string' ? body.summary.trim() : '';
  if (!summary) {
    throw new AppError('Summary is required.', {
      code: 'INVALID_SESSION_SUMMARY',
      statusCode: 400,
    });
  }

  if (summary.length > 500) {
    throw new AppError('Summary must not exceed 500 characters.', {
      code: 'INVALID_SESSION_SUMMARY',
      statusCode: 400,
    });
  }

  return summary;
};

const parseSessionSearchQuery = (value: unknown): string => {
  const query = readOptionalQueryString(value) ?? '';
  if (query.length < 2) {
    throw new AppError('Query must be at least 2 characters', {
      code: 'INVALID_SEARCH_QUERY',
      statusCode: 400,
    });
  }

  return query;
};

const parseSessionSearchLimit = (value: unknown): number => {
  const raw = readOptionalQueryString(value);
  if (!raw) {
    return 50;
  }

  const parsed = Number.parseInt(raw, 10);
  if (Number.isNaN(parsed)) {
    throw new AppError('limit must be a valid integer.', {
      code: 'INVALID_QUERY_PARAMETER',
      statusCode: 400,
    });
  }

  return Math.max(1, Math.min(parsed, 100));
};

router.get(
  '/:provider/auth/status',
  asyncHandler(async (req: Request, res: Response) => {
    const provider = parseProvider(req.params.provider);
    const status = await providerAuthService.getProviderAuthStatus(provider);
    res.json(createApiSuccessResponse(status));
  }),
);

// ----------------- MCP routes -----------------
router.get(
  '/:provider/mcp/servers',
  asyncHandler(async (req: Request, res: Response) => {
    const provider = parseProvider(req.params.provider);
    const workspacePath = readOptionalQueryString(req.query.workspacePath);
    const scope = parseMcpScope(req.query.scope);

    if (scope) {
      const servers = await providerMcpService.listProviderMcpServersForScope(provider, scope, { workspacePath });
      res.json(createApiSuccessResponse({ provider, scope, servers }));
      return;
    }

    const groupedServers = await providerMcpService.listProviderMcpServers(provider, { workspacePath });
    res.json(createApiSuccessResponse({ provider, scopes: groupedServers }));
  }),
);

router.post(
  '/:provider/mcp/servers',
  asyncHandler(async (req: Request, res: Response) => {
    const provider = parseProvider(req.params.provider);
    const payload = parseMcpUpsertPayload(req.body);
    const server = await providerMcpService.upsertProviderMcpServer(provider, payload);
    res.status(201).json(createApiSuccessResponse({ server }));
  }),
);

router.delete(
  '/:provider/mcp/servers/:name',
  asyncHandler(async (req: Request, res: Response) => {
    const provider = parseProvider(req.params.provider);
    const scope = parseMcpScope(req.query.scope);
    const workspacePath = readOptionalQueryString(req.query.workspacePath);
    const result = await providerMcpService.removeProviderMcpServer(provider, {
      name: readPathParam(req.params.name, 'name'),
      scope,
      workspacePath,
    });
    res.json(createApiSuccessResponse(result));
  }),
);

router.post(
  '/mcp/servers/global',
  asyncHandler(async (req: Request, res: Response) => {
    const payload = parseMcpUpsertPayload(req.body);
    if (payload.scope === 'local') {
      throw new AppError('Global MCP add supports only "user" or "project" scopes.', {
        code: 'INVALID_GLOBAL_MCP_SCOPE',
        statusCode: 400,
      });
    }

    const results = await providerMcpService.addMcpServerToAllProviders({
      ...payload,
      scope: payload.scope === 'user' ? 'user' : 'project',
    });
    res.status(201).json(createApiSuccessResponse({ results }));
  }),
);

// ----------------- Session routes -----------------
router.delete(
  '/sessions/:sessionId',
  asyncHandler(async (req: Request, res: Response) => {
    const sessionId = parseSessionId(req.params.sessionId);
    const deletedFromDisk = parseOptionalBooleanQuery(req.query.deletedFromDisk, 'deletedFromDisk') ?? false;
    const result = await sessionsService.deleteSessionById(sessionId, deletedFromDisk);
    res.json(createApiSuccessResponse(result));
  }),
);

router.put(
  '/sessions/:sessionId',
  asyncHandler(async (req: Request, res: Response) => {
    const sessionId = parseSessionId(req.params.sessionId);
    const summary = parseSessionRenameSummary(req.body);
    const result = sessionsService.renameSessionById(sessionId, summary);
    res.json(createApiSuccessResponse(result));
  }),
);

router.get(
  '/sessions/:sessionId/messages',
  asyncHandler(async (req: Request, res: Response) => {
    const sessionId = parseSessionId(req.params.sessionId);
    const limitRaw = readOptionalQueryString(req.query.limit);
    const offsetRaw = readOptionalQueryString(req.query.offset);

    const limit = limitRaw === undefined ? null : Number.parseInt(limitRaw, 10);
    const offset = offsetRaw === undefined ? 0 : Number.parseInt(offsetRaw, 10);

    if (limitRaw !== undefined && Number.isNaN(limit)) {
      throw new AppError('limit must be a valid integer.', {
        code: 'INVALID_QUERY_PARAMETER',
        statusCode: 400,
      });
    }

    if (offsetRaw !== undefined && Number.isNaN(offset)) {
      throw new AppError('offset must be a valid integer.', {
        code: 'INVALID_QUERY_PARAMETER',
        statusCode: 400,
      });
    }

    const result = await sessionsService.fetchHistory(sessionId, {
      limit,
      offset,
    });
    res.json(result);
  }),
);

router.get('/search/sessions', asyncHandler(async (req: Request, res: Response) => {
  const query = parseSessionSearchQuery(req.query.q);
  const limit = parseSessionSearchLimit(req.query.limit);

  res.writeHead(200, {
    'Content-Type': 'text/event-stream',
    'Cache-Control': 'no-cache',
    Connection: 'keep-alive',
    'X-Accel-Buffering': 'no',
  });

  let closed = false;
  const abortController = new AbortController();
  req.on('close', () => {
    closed = true;
    abortController.abort();
  });

  try {
    await sessionConversationsSearchService.search({
      query,
      limit,
      signal: abortController.signal,
      onProgress: ({ projectResult, totalMatches, scannedProjects, totalProjects }) => {
        if (closed) {
          return;
        }

        if (projectResult) {
          res.write(`event: result\ndata: ${JSON.stringify({ projectResult, totalMatches, scannedProjects, totalProjects })}\n\n`);
          return;
        }

        res.write(`event: progress\ndata: ${JSON.stringify({ totalMatches, scannedProjects, totalProjects })}\n\n`);
      },
    });

    if (!closed) {
      res.write('event: done\ndata: {}\n\n');
    }
  } catch (error) {
    console.error('Error searching conversations:', error);
    if (!closed) {
      res.write(`event: error\ndata: ${JSON.stringify({ error: 'Search failed' })}\n\n`);
    }
  } finally {
    if (!closed) {
      res.end();
    }
  }
}));

export default router;