import { createHash } from "crypto";
import { BaseExecutor } from "./base.js";
import { CODEX_DEFAULT_INSTRUCTIONS } from "../config/codexInstructions.js";
import { PROVIDERS } from "../config/providers.js";
import { normalizeResponsesInput } from "../translator/helpers/responsesApiHelper.js";

// In-memory map: hash(first assistant content) → { sessionId, lastUsed }
const SESSION_TTL_MS = 60 * 60 * 1000; // 1 hour
const assistantSessionMap = new Map();

function hashContent(text) {
  return createHash("sha256").update(text).digest("hex").slice(0, 16);
}

function generateSessionId() {
  return `sess_${Date.now().toString(36)}_${Math.random().toString(36).slice(2, 9)}`;
}

// Extract text content from an input item
function extractItemText(item) {
  if (!item) return "";
  if (typeof item.content === "string") return item.content;
  if (Array.isArray(item.content)) {
    return item.content.map(c => c.text || c.output || "").filter(Boolean).join("");
  }
  return "";
}

// Resolve session_id from first assistant message in conversation history
function resolveConversationSessionId(input) {
  if (!Array.isArray(input) || input.length === 0) return generateSessionId();

  const firstAssistant = input.find(item => item.role === "assistant");
  if (!firstAssistant) return generateSessionId(); // Turn 1: no assistant yet

  const text = extractItemText(firstAssistant);
  if (!text) return generateSessionId();

  const hash = hashContent(text);
  const entry = assistantSessionMap.get(hash);
  if (entry) {
    entry.lastUsed = Date.now();
    return entry.sessionId;
  }


  const sessionId = generateSessionId();
  assistantSessionMap.set(hash, { sessionId, lastUsed: Date.now() });
  return sessionId;
}

// Cleanup expired entries periodically
setInterval(() => {
  const now = Date.now();
  for (const [key, entry] of assistantSessionMap) {
    if (now - entry.lastUsed > SESSION_TTL_MS) assistantSessionMap.delete(key);
  }
}, 10 * 60 * 1000);

/**
 * Codex Executor - handles OpenAI Codex API (Responses API format)
 * Automatically injects default instructions if missing
 */
export class CodexExecutor extends BaseExecutor {
  constructor() {
    super("codex", PROVIDERS.codex);
    this._currentSessionId = null;
  }

  /**
   * Override headers to add session_id per conversation
   * transformRequest runs BEFORE buildHeaders, sets this._currentSessionId
   */
  buildHeaders(credentials, stream = true) {
    const headers = super.buildHeaders(credentials, stream);
    headers["session_id"] = this._currentSessionId || credentials?.connectionId || "default";
    return headers;
  }

  /**
   * Transform request before sending - inject default instructions if missing
   */
  transformRequest(model, body, stream, credentials) {
    // Resolve conversation-stable session_id from input history
    this._currentSessionId = resolveConversationSessionId(body.input);
    // Convert string input to array format (Codex API requires input as array)
    const normalized = normalizeResponsesInput(body.input);
    if (normalized) body.input = normalized;

    // Ensure input is present and non-empty (Codex API rejects empty input)
    if (!body.input || (Array.isArray(body.input) && body.input.length === 0)) {
      body.input = [{ type: "message", role: "user", content: [{ type: "input_text", text: "..." }] }];
    }

    // Normalize image content: image_url → input_image (Responses API format)
    if (Array.isArray(body.input)) {
      for (const item of body.input) {
        if (Array.isArray(item.content)) {
          item.content = item.content.map(c => {
            if (c.type === "image_url") {
              const url = typeof c.image_url === "string" ? c.image_url : c.image_url?.url;
              return { type: "input_image", image_url: url, detail: c.image_url?.detail || "auto" };
            }
            return c;
          });
        }
      }
    }

    // Ensure streaming is enabled (Codex API requires it)
    body.stream = true;

    // If no instructions provided, inject default Codex instructions
    if (!body.instructions || body.instructions.trim() === "") {
      body.instructions = CODEX_DEFAULT_INSTRUCTIONS;
    }

    // Ensure store is false (Codex requirement)
    body.store = false;

    // Extract thinking level from model name suffix
    // e.g., gpt-5.3-codex-high → high, gpt-5.3-codex → medium (default)
    const effortLevels = ['none', 'low', 'medium', 'high', 'xhigh'];
    let modelEffort = null;
    for (const level of effortLevels) {
      if (model.endsWith(`-${level}`)) {
        modelEffort = level;
        // Strip suffix from model name for actual API call
        body.model = body.model.replace(`-${level}`, '');
        break;
      }
    }

    // Priority: explicit reasoning.effort > reasoning_effort param > model suffix > default (medium)
    if (!body.reasoning) {
      const effort = body.reasoning_effort || modelEffort || 'medium';
      body.reasoning = { effort, summary: "auto" };
    } else if (!body.reasoning.summary) {
      body.reasoning.summary = "auto";
    }
    delete body.reasoning_effort;

    // Include reasoning encrypted content (required by Codex backend for reasoning models)
    if (body.reasoning && body.reasoning.effort && body.reasoning.effort !== 'none') {
      body.include = ["reasoning.encrypted_content"];
    }

    // Remove unsupported parameters for Codex API
    delete body.temperature;
    delete body.top_p;
    delete body.frequency_penalty;
    delete body.presence_penalty;
    delete body.logprobs;
    delete body.top_logprobs;
    delete body.n;
    delete body.seed;
    delete body.max_tokens;
    delete body.user; // Cursor sends this but Codex doesn't support it
    delete body.prompt_cache_retention; // Cursor sends this but Codex doesn't support it
    delete body.metadata; // Cursor sends this but Codex doesn't support it
    delete body.stream_options; // Cursor sends this but Codex doesn't support it
    delete body.safety_identifier; // Droid CLI sends this but Codex doesn't support it

    return body;
  }
}