/**
 * SaaS Relay Gateway Client
 *
 * A lightweight GatewayClient-compatible adapter for browser-only mode.
 * Routes agent listing through SaaS agent-templates, Converts
 * chatStream() to OpenAI SSE streaming via SaaS relay.
 *
 * Used in connectionStore when running in a browser (non-Tauri) with
 * SaaS relay connection mode.
 */

import type { GatewayClient } from './gateway-client';
import { saasClient } from './saas-client';
import type { AgentTemplateAvailable } from './saas-types';
import { createLogger } from './logger';

const log = createLogger('SaaSRelayGateway');

// ---------------------------------------------------------------------------
// Memory injection helper — injects relevant memories into system prompt
// before sending to SaaS relay (mirrors MemoryMiddleware in Tauri kernel path)
// ---------------------------------------------------------------------------

/**
 * Attempt to inject relevant memories into the system prompt via Tauri IPC.
 * Falls back gracefully in non-Tauri contexts (browser mode).
 */
async function injectMemories(
  agentId: string | undefined,
  basePrompt: string,
  userInput: string,
): Promise<string> {
  try {
    // Dynamic import — only available in Tauri context
    const { invoke } = await import('@tauri-apps/api/core');
    const enhanced = await invoke<string>('viking_inject_prompt', {
      agentId: agentId ?? 'default',
      basePrompt,
      userInput,
      maxTokens: 500,
    });
    if (enhanced && enhanced !== basePrompt) {
      log.debug('Memory injection succeeded for relay request');
      return enhanced;
    }
  } catch {
    // Non-Tauri context or viking not initialized — skip silently
  }
  return basePrompt;
}

// ---------------------------------------------------------------------------
// Frontend DataMasking — mirrors Rust DataMasking middleware for SaaS Relay
// ---------------------------------------------------------------------------

const MASK_PATTERNS: RegExp[] = [
  /\b\d{17}[\dXx]\b/g,                                                     // ID card
  /1[3-9]\d-?\d{4}-?\d{4}/g,                                               // Phone
  /[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/g,                      // Email
  /[¥￥$]\s*[\d,.]+[万亿]?元?|[\d,.]+[万亿]元/g,                             // Money
  /[^\s]{1,20}(?:公司|厂|集团|工作室|商行|有限|股份)/g,                       // Company
];

let maskCounter = 0;
const entityMap = new Map<string, string>();

/** Mask sensitive entities in text before sending to SaaS relay. */
function maskSensitiveData(text: string): string {
  const entities: { text: string; token: string }[] = [];

  for (const pattern of MASK_PATTERNS) {
    pattern.lastIndex = 0;
    let match: RegExpExecArray | null;
    while ((match = pattern.exec(text)) !== null) {
      const entity = match[0];
      if (!entityMap.has(entity)) {
        maskCounter++;
        entityMap.set(entity, `__ENTITY_${maskCounter}__`);
      }
      entities.push({ text: entity, token: entityMap.get(entity)! });
    }
  }

  // Sort by length descending to replace longest entities first
  entities.sort((a, b) => b.text.length - a.text.length);

  let result = text;
  for (const { text: entity, token } of entities) {
    result = result.split(entity).join(token);
  }
  return result;
}

/** Restore masked tokens in AI response back to original entities. */
function unmaskSensitiveData(text: string): string {
  let result = text;
  for (const [entity, token] of entityMap) {
    result = result.split(token).join(entity);
  }
  return result;
}

// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------

interface CloneInfo {
  id: string;
  name: string;
  role?: string;
  nickname?: string;
  emoji?: string;
  personality?: string;
  scenarios?: string[];
  model?: string;
  status?: string;
  templateId?: string;
}

// ---------------------------------------------------------------------------
// Implementation
// ---------------------------------------------------------------------------

/**
 * Create a GatewayClient-compatible object that routes through SaaS APIs.
 * Only the methods needed by the stores are implemented; others return
 * sensible defaults.
 */
export function createSaaSRelayGatewayClient(
  _saasUrl: string,
  getModel: () => string,
): GatewayClient {
  // saasUrl preserved for future direct API routing (currently routed through saasClient singleton)
  void _saasUrl;

  // Local in-memory agent registry
  const agents = new Map<string, CloneInfo>();
  let defaultAgentId: string | null = null;

  // -----------------------------------------------------------------------
  // Helper: list agents as clones
  // -----------------------------------------------------------------------
  async function listClones(): Promise<{ clones: CloneInfo[] }> {
    try {
      const templates: AgentTemplateAvailable[] = await saasClient.fetchAvailableTemplates();

      const clones: CloneInfo[] = templates.map((t) => {
        const id = t.id || `agent-${t.name}`;
        const clone: CloneInfo = {
          id,
          name: t.name,
          role: t.description || t.category,
          emoji: t.emoji,
          personality: t.category,
          scenarios: [],
          model: getModel(),
          status: 'active',
          templateId: t.id,
        };
        agents.set(id, clone);
        return clone;
      });

      // Set first as default
      if (clones.length > 0 && !defaultAgentId) {
        defaultAgentId = clones[0].id;
      }

      return { clones };
    } catch (err) {
      log.warn('Failed to list templates', err);
      return { clones: [] };
    }
  }

  // -----------------------------------------------------------------------
  // Helper: OpenAI SSE streaming via SaaS relay
  // -----------------------------------------------------------------------
  // AbortController for cancelling active streams
  let activeAbortController: AbortController | null = null;

  async function chatStream(
    message: string,
    callbacks: {
      onDelta: (delta: string) => void;
      onThinkingDelta?: (delta: string) => void;
      onTool?: (tool: string, input: string, output: string) => void;
      onHand?: (name: string, status: string, result?: unknown) => void;
      onComplete: (inputTokens?: number, outputTokens?: number) => void;
      onError: (error: string) => void;
    },
    opts?: {
      sessionKey?: string;
      agentId?: string;
      thinking_enabled?: boolean;
      reasoning_effort?: string;
      plan_mode?: boolean;
      subagent_enabled?: boolean;
      history?: Array<{ role: string; content: string }>;
    },
  ): Promise<{ runId: string }> {
    const runId = `run_${Date.now()}`;
    const abortController = new AbortController();
    activeAbortController = abortController;
    const aborted = () => abortController.signal.aborted;

    try {
      // Build messages array: use history if available, fallback to current message only
      // Apply DataMasking to protect sensitive data before sending to relay
      const history = opts?.history || [];
      const maskedMessage = maskSensitiveData(message);
      const messages = history.length > 0
        ? [...history, { role: 'user' as const, content: maskedMessage }]
        : [{ role: 'user' as const, content: maskedMessage }];

      // BUG-M5 fix: Inject relevant memories into system prompt via Tauri IPC.
      // This mirrors the MemoryMiddleware that runs in the kernel path.
      const enhancedSystemPrompt = await injectMemories(
        opts?.agentId,
        '',
        message,
      );
      if (enhancedSystemPrompt) {
        messages.unshift({ role: 'system', content: enhancedSystemPrompt });
      }

      const model = getModel();
      if (!model) {
        callbacks.onError('No model available — please check SaaS relay configuration');
        callbacks.onComplete();
        return { runId };
      }

      const body: Record<string, unknown> = {
        model,
        messages,
        stream: true,
      };

      // P3-06: Pass sessionKey/agentId to relay for session continuity
      if (opts?.sessionKey) body['session_key'] = opts.sessionKey;
      if (opts?.agentId) body['agent_id'] = opts.agentId;
      if (opts?.thinking_enabled) body['thinking_enabled'] = true;
      if (opts?.reasoning_effort) body['reasoning_effort'] = opts.reasoning_effort;
      if (opts?.plan_mode) body['plan_mode'] = true;
      if (opts?.subagent_enabled) body['subagent_enabled'] = true;

      const response = await saasClient.chatCompletion(body, abortController.signal);

      if (!response.ok) {
        const errText = await response.text().catch(() => '');
        callbacks.onError(`Relay error: ${response.status} ${errText}`);
        callbacks.onComplete();
        return { runId };
      }

      // Parse SSE stream
      const reader = response.body?.getReader();
      if (!reader) {
        callbacks.onError('No response body');
        callbacks.onComplete();
        return { runId };
      }

      const decoder = new TextDecoder();
      let buffer = '';

      while (!aborted()) {
        const { done, value } = await reader.read();
        if (done) break;

        buffer += decoder.decode(value, { stream: true });

        // Normalize CRLF to LF for SSE spec compliance
        buffer = buffer.replace(/\r\n/g, '\n');

        // Optimized SSE parsing: split by double-newline (event boundaries)
        let boundary: number;
        while ((boundary = buffer.indexOf('\n\n')) !== -1) {
          const eventBlock = buffer.slice(0, boundary);
          buffer = buffer.slice(boundary + 2);

          // Process each line in the event block
          const lines = eventBlock.split('\n');
          for (const line of lines) {
            if (!line.startsWith('data: ')) continue;
            const data = line.slice(6).trim();
            if (data === '[DONE]') continue;

            try {
              const parsed = JSON.parse(data);

              // Handle SSE error events from relay (e.g. stream_timeout)
              if (parsed.error) {
                const errMsg = parsed.message || parsed.error || 'Unknown stream error';
                log.warn('SSE stream error:', errMsg);
                callbacks.onError(errMsg);
                callbacks.onComplete();
                return { runId };
              }

              const choices = parsed.choices?.[0];
              if (!choices) continue;

              const delta = choices.delta;

              // Handle thinking/reasoning content
              if (delta?.reasoning_content) {
                callbacks.onThinkingDelta?.(delta.reasoning_content);
              }

              // Handle regular content — unmask tokens so user sees original entities
              if (delta?.content) {
                callbacks.onDelta(unmaskSensitiveData(delta.content));
              }

              // Check for completion
              if (choices.finish_reason) {
                const usage = parsed.usage;
                callbacks.onComplete(
                  usage?.prompt_tokens,
                  usage?.completion_tokens,
                );
                return { runId };
              }
            } catch {
              // Skip malformed SSE lines
            }
          }
        }
      }

      // If aborted, cancel the reader
      if (aborted()) {
        try { reader.cancel(); } catch { /* already closed */ }
      }

      // Stream ended without explicit finish_reason
      callbacks.onComplete();
    } catch (err) {
      if (aborted()) {
        // Cancelled by user — don't report as error
        callbacks.onComplete();
        return { runId };
      }
      const msg = err instanceof Error ? err.message : String(err);
      callbacks.onError(msg);
      callbacks.onComplete();
    } finally {
      if (activeAbortController === abortController) {
        activeAbortController = null;
      }
    }

    return { runId };
  }

  // -----------------------------------------------------------------------
  // Build the client object with GatewayClient-compatible shape
  // -----------------------------------------------------------------------
  return {
    // --- Connection ---
    connect: async () => { log.debug('SaaS relay client connect'); },
    disconnect: async () => {},
    getState: () => 'connected' as const,
    onStateChange: undefined,
    onLog: undefined,

    // --- Agents (Clones) ---
    listClones,
    createClone: async (opts: Record<string, unknown>) => {
      const id = `agent-${Date.now()}`;
      const clone: CloneInfo = {
        id,
        name: (opts.name as string) || 'New Agent',
        role: opts.role as string,
        nickname: opts.nickname as string,
        emoji: opts.emoji as string,
        model: getModel(),
        status: 'active',
      };
      agents.set(id, clone);
      if (!defaultAgentId) defaultAgentId = id;
      return { clone };
    },
    updateClone: async (id: string, updates: Record<string, unknown>) => {
      const existing = agents.get(id);
      if (existing) agents.set(id, { ...existing, ...updates });
      return { clone: agents.get(id) };
    },
    deleteClone: async (id: string) => {
      agents.delete(id);
      if (defaultAgentId === id) defaultAgentId = null;
    },
    getDefaultAgentId: () => defaultAgentId,
    setDefaultAgentId: (id: string) => { defaultAgentId = id; },

    // --- Chat ---
    chatStream,
    cancelStream: () => {
      if (activeAbortController) {
        activeAbortController.abort();
        activeAbortController = null;
        log.info('SSE stream cancelled by user');
      }
    },

    // --- Hands ---
    listHands: async () => ({ hands: [] }),
    getHand: async () => null,
    triggerHand: async () => ({ runId: `hand_${Date.now()}`, status: 'completed' }),

    // --- Skills ---
    listSkills: async () => ({ skills: [] }),
    getSkill: async () => null,
    createSkill: async () => null,
    updateSkill: async () => null,
    deleteSkill: async () => {},

    // --- Config ---
    getQuickConfig: async () => ({}),
    saveQuickConfig: async () => {},
    getWorkspaceInfo: async () => null,

    // --- Health ---
    health: async () => ({ status: 'ok', mode: 'saas-relay' }),
    status: async () => ({ version: 'saas-relay', mode: 'browser' }),

    // --- Usage ---
    getUsageStats: async () => null,
    getSessionStats: async () => null,

    // --- REST helpers (not used in browser mode) ---
    restGet: async () => { throw new Error('REST not available in browser mode'); },
    restPost: async () => { throw new Error('REST not available in browser mode'); },
    restPut: async () => { throw new Error('REST not available in browser mode'); },
    restDelete: async () => { throw new Error('REST not available in browser mode'); },
    restPatch: async () => { throw new Error('REST not available in browser mode'); },
  } as unknown as GatewayClient;
}