import type { HostApiContext } from '../context';
import type { NormalizedHostApiRequest } from '../route-utils';
import { fail, ok, parseJsonBody } from '../route-utils';
import {
  assignChannelToAgent,
  clearAllChannelBindings,
  clearChannelBinding,
  listAgentsSnapshot,
} from '../../utils/agent-config';
import {
  getChannelFormValues,
  hasStoredChannelAccount,
  isCanonicalChannelAccountId,
  listStoredChannelTypes,
  saveChannelConfig,
  setChannelDefaultAccount,
  setChannelEnabled,
  deleteChannelConfig,
} from '../../utils/channel-config';
import {
  listSelectedChannelAccountGroups,
  listSelectedChannelTargets,
} from '../../utils/channels';

function getProviderSnapshot(ctx: HostApiContext) {
  const accounts = ctx.providerApiService
    .getAccounts()
    .filter((account) => account.enabled !== false);
  const defaultAccountId = ctx.providerApiService.getDefault().accountId;
  return { accounts, defaultAccountId };
}

export async function handleChannelRoutes(
  request: NormalizedHostApiRequest,
  ctx: HostApiContext,
) {
  const { pathname, method } = request;
  const { accounts, defaultAccountId } = getProviderSnapshot(ctx);
  const snapshot = listAgentsSnapshot(accounts, defaultAccountId);

  if (pathname === '/api/channels/accounts' && method === 'GET') {
    return ok({
      success: true,
      channels: listSelectedChannelAccountGroups(snapshot),
    });
  }

  if (pathname === '/api/channels/configured' && method === 'GET') {
    return ok({
      success: true,
      channels: listStoredChannelTypes(),
    });
  }

  if (pathname === '/api/channels/targets' && method === 'GET') {
    const channelType = request.url.searchParams.get('channelType')?.trim() || '';
    const accountId = request.url.searchParams.get('accountId')?.trim() || null;
    const query = request.url.searchParams.get('query')?.trim() || null;

    if (!channelType) {
      return fail(400, 'channelType is required');
    }

    return ok({
      success: true,
      targets: listSelectedChannelTargets(channelType, accountId, query),
    });
  }

  if (pathname === '/api/channels/default-account' && method === 'PUT') {
    try {
      const body = parseJsonBody<{
        channelType?: string;
        accountId?: string | null;
      }>(request.body);
      const channelType = String(body?.channelType ?? '').trim();
      const accountId = String(body?.accountId ?? '').trim();

      if (!channelType) {
        return fail(400, 'channelType is required');
      }
      if (!accountId) {
        return fail(400, 'accountId is required');
      }

      setChannelDefaultAccount(channelType, accountId);
      ctx.gatewayManager.notifyRuntimeChanged({
        topics: ['channels', 'channel-targets', 'agents'],
        reason: 'channels:default-account-updated',
        channelType,
        accountId,
      });

      return ok({
        success: true,
        channels: listSelectedChannelAccountGroups(listAgentsSnapshot(accounts, defaultAccountId)),
      });
    } catch (error) {
      return fail(500, error instanceof Error ? error.message : String(error));
    }
  }

  if (pathname === '/api/channels/config/enabled' && method === 'PUT') {
    try {
      const body = parseJsonBody<{
        channelType?: string;
        enabled?: boolean;
      }>(request.body);
      const channelType = String(body?.channelType ?? '').trim();

      if (!channelType) {
        return fail(400, 'channelType is required');
      }

      setChannelEnabled(channelType, body?.enabled !== false);
      ctx.gatewayManager.notifyRuntimeChanged({
        topics: ['channels', 'channel-targets', 'agents'],
        reason: 'channels:enabled-updated',
        channelType,
      });

      return ok({
        success: true,
        channels: listSelectedChannelAccountGroups(listAgentsSnapshot(accounts, defaultAccountId)),
      });
    } catch (error) {
      return fail(500, error instanceof Error ? error.message : String(error));
    }
  }

  if (pathname === '/api/channels/binding' && method === 'PUT') {
    try {
      const body = parseJsonBody<{
        channelType?: string;
        accountId?: string | null;
        agentId?: string;
      }>(request.body);
      const channelType = String(body?.channelType ?? '').trim();
      const accountId = String(body?.accountId ?? '').trim();
      const agentId = String(body?.agentId ?? '').trim();

      if (!channelType) {
        return fail(400, 'channelType is required');
      }
      if (!accountId) {
        return fail(400, 'accountId is required');
      }
      if (!agentId) {
        return fail(400, 'agentId is required');
      }
      if (!snapshot.agents.some((agent) => agent.id === agentId)) {
        return fail(404, `Agent "${agentId}" not found`);
      }

      const groupedChannels = listSelectedChannelAccountGroups(snapshot);
      const group = groupedChannels.find((entry) => entry.channelType === channelType);
      if (!group || !group.accounts.some((entry) => entry.accountId === accountId)) {
        return fail(404, `Channel account "${channelType}:${accountId}" not found`);
      }

      const result = assignChannelToAgent(agentId, channelType, accountId, accounts, defaultAccountId);
      ctx.gatewayManager.notifyRuntimeChanged({
        topics: ['agents', 'channels', 'channel-targets'],
        reason: 'channels:binding-updated',
        channelType,
        accountId,
      });

      return ok({
        success: true,
        ...result,
      });
    } catch (error) {
      return fail(500, error instanceof Error ? error.message : String(error));
    }
  }

  if (pathname === '/api/channels/config' && method === 'POST') {
    try {
      const body = parseJsonBody<{
        channelType?: string;
        accountId?: string | null;
        channelLabel?: string | null;
        accountName?: string | null;
        channelUrl?: string | null;
        enabled?: boolean;
        config?: Record<string, unknown>;
        metadata?: Record<string, unknown>;
      }>(request.body);
      const channelType = String(body?.channelType ?? '').trim();
      const accountId = String(body?.accountId ?? '').trim();

      if (!channelType) {
        return fail(400, 'channelType is required');
      }

      if (accountId && !isCanonicalChannelAccountId(accountId) && !hasStoredChannelAccount(channelType, accountId)) {
        return fail(400, 'Invalid accountId format. Use lowercase letters, numbers, hyphens, or underscores only (max 64 chars, must start with a letter or number).');
      }

      saveChannelConfig({
        channelType,
        accountId: accountId || undefined,
        channelLabel: body?.channelLabel,
        accountName: body?.accountName,
        channelUrl: body?.channelUrl,
        enabled: body?.enabled,
        config: body?.config,
        metadata: body?.metadata,
      });

      ctx.gatewayManager.notifyRuntimeChanged({
        topics: ['channels', 'channel-targets', 'agents'],
        reason: 'channels:config-saved',
        channelType,
        accountId: accountId || undefined,
      });

      return ok({
        success: true,
        channels: listSelectedChannelAccountGroups(listAgentsSnapshot(accounts, defaultAccountId)),
      });
    } catch (error) {
      return fail(500, error instanceof Error ? error.message : String(error));
    }
  }

  if (pathname === '/api/channels/binding' && method === 'DELETE') {
    try {
      const body = parseJsonBody<{
        channelType?: string;
        accountId?: string | null;
      }>(request.body);
      const channelType = String(body?.channelType ?? '').trim();
      const accountId = String(body?.accountId ?? '').trim();

      if (!channelType) {
        return fail(400, 'channelType is required');
      }
      if (!accountId) {
        return fail(400, 'accountId is required');
      }

      const result = clearChannelBinding(channelType, accountId, accounts, defaultAccountId);
      ctx.gatewayManager.notifyRuntimeChanged({
        topics: ['agents', 'channels', 'channel-targets'],
        reason: 'channels:binding-cleared',
        channelType,
        accountId,
      });

      return ok({
        success: true,
        ...result,
      });
    } catch (error) {
      return fail(500, error instanceof Error ? error.message : String(error));
    }
  }

  if (pathname.startsWith('/api/channels/config/') && method === 'GET') {
    try {
      const channelType = decodeURIComponent(pathname.slice('/api/channels/config/'.length));
      const accountId = request.url.searchParams.get('accountId')?.trim() || null;
      return ok({
        success: true,
        values: getChannelFormValues(channelType, accountId) ?? {},
      });
    } catch (error) {
      return fail(500, error instanceof Error ? error.message : String(error));
    }
  }

  if (pathname.startsWith('/api/channels/config/') && method === 'DELETE') {
    try {
      const channelType = decodeURIComponent(pathname.slice('/api/channels/config/'.length));
      const accountId = request.url.searchParams.get('accountId')?.trim() || null;

      deleteChannelConfig(channelType, accountId);
      if (accountId) {
        clearChannelBinding(channelType, accountId, accounts, defaultAccountId);
      } else {
        clearAllChannelBindings(channelType, accounts, defaultAccountId);
      }

      ctx.gatewayManager.notifyRuntimeChanged({
        topics: ['channels', 'channel-targets', 'agents'],
        reason: 'channels:config-deleted',
        channelType,
        accountId: accountId || undefined,
      });

      return ok({
        success: true,
        channels: listSelectedChannelAccountGroups(listAgentsSnapshot(accounts, defaultAccountId)),
      });
    } catch (error) {
      return fail(500, error instanceof Error ? error.message : String(error));
    }
  }

  return null;
}