import { BaseExecutor } from "./base.ts";
import { PROVIDERS, OAUTH_ENDPOINTS } from "../config/constants.ts";
import { geminiCLIUserAgent, googApiClientHeader } from "../services/antigravityHeaders.ts";
import { scrubProxyAndFingerprintHeaders } from "../services/antigravityHeaderScrub.ts";
import { obfuscateSensitiveWords } from "../services/antigravityObfuscation.ts";

const LOAD_CODE_ASSIST_URL = "https://cloudcode-pa.googleapis.com/v1internal:loadCodeAssist";
const ONBOARD_USER_URL = "https://cloudcode-pa.googleapis.com/v1internal:onboardUser";
const PROJECT_TTL_MS = 30_000; // 30 seconds — matches native Gemini CLI
const MAX_CACHE_SIZE = 100;
const LOAD_CODE_ASSIST_TIMEOUT_MS = 10_000; // 10 seconds timeout
const ONBOARD_TIMEOUT_MS = 30_000;
const ONBOARD_MAX_ATTEMPTS = 10;
const ONBOARD_DELAY_MS = 5_000;
const DEFAULT_PROJECT_ID = "default-project";
const DEFAULT_ONBOARD_TIER = "free-tier";
const LOAD_CODE_ASSIST_METADATA = Object.freeze({
  ideType: "ANTIGRAVITY",
  platform: "PLATFORM_UNSPECIFIED",
  pluginType: "GEMINI",
  duetProject: DEFAULT_PROJECT_ID,
});
const ONBOARD_METADATA = Object.freeze({
  ideType: "ANTIGRAVITY",
  pluginType: "GEMINI",
  duetProject: DEFAULT_PROJECT_ID,
});

// Per-account cache: accessToken -> { projectId, expiresAt }
const projectCache = new Map<string, { projectId: string; expiresAt: number }>();
// In-flight deduplication: prevents thundering herd on cache miss
const inflightRefresh = new Map<string, Promise<string | null>>();

type LoadCodeAssistResponse = {
  cloudaicompanionProject?: string | { id?: string | null } | null;
  allowedTiers?: Array<{ id?: string | null; isDefault?: boolean | null }> | null;
};

type OnboardOptions = {
  attempts?: number;
  delayMs?: number;
};

function normalizeGeminiModel(model: string): string {
  return typeof model === "string" && model.trim().length > 0
    ? model.replace(/^models\//, "").trim()
    : "unknown";
}

function extractProjectId(payload: unknown): string {
  if (!payload || typeof payload !== "object") return "";
  const data = payload as LoadCodeAssistResponse;
  if (typeof data.cloudaicompanionProject === "string") {
    return data.cloudaicompanionProject.trim();
  }
  if (typeof data.cloudaicompanionProject?.id === "string") {
    return data.cloudaicompanionProject.id.trim();
  }
  return "";
}

function extractDefaultTierId(payload: unknown): string {
  if (!payload || typeof payload !== "object") return DEFAULT_ONBOARD_TIER;
  const tiers = Array.isArray((payload as LoadCodeAssistResponse).allowedTiers)
    ? (payload as LoadCodeAssistResponse).allowedTiers
    : [];
  for (const tier of tiers) {
    if (tier?.isDefault && typeof tier.id === "string" && tier.id.trim()) {
      return tier.id.trim();
    }
  }
  return DEFAULT_ONBOARD_TIER;
}

function cacheProject(accessToken: string, projectId: string): void {
  if (projectCache.size >= MAX_CACHE_SIZE) {
    const now = Date.now();
    for (const [key, val] of projectCache) {
      if (val.expiresAt <= now) projectCache.delete(key);
    }
    if (projectCache.size >= MAX_CACHE_SIZE) {
      const firstKey = projectCache.keys().next().value;
      if (firstKey !== undefined) projectCache.delete(firstKey);
    }
  }

  projectCache.set(accessToken, {
    projectId,
    expiresAt: Date.now() + PROJECT_TTL_MS,
  });
}

function sleep(ms: number): Promise<void> {
  if (!ms || ms <= 0) return Promise.resolve();
  return new Promise((resolve) => setTimeout(resolve, ms));
}

export class GeminiCLIExecutor extends BaseExecutor {
  constructor() {
    super("gemini-cli", PROVIDERS["gemini-cli"]);
  }

  buildUrl(model, stream, urlIndex = 0) {
    this._currentModel = normalizeGeminiModel(model);
    const action = stream ? "streamGenerateContent?alt=sse" : "generateContent";
    return `${this.config.baseUrl}:${action}`;
  }

  buildHeaders(credentials, stream = true) {
    const raw = {
      "Content-Type": "application/json",
      Authorization: `Bearer ${credentials.accessToken}`,
      // Dynamic headers matching native GeminiCLI client
      "User-Agent": geminiCLIUserAgent(this._currentModel || "unknown"),
      "X-Goog-Api-Client": googApiClientHeader(),
      ...(stream && { Accept: "text/event-stream" }),
    };
    return scrubProxyAndFingerprintHeaders(raw);
  }

  // Track current model for dynamic UA. BaseExecutor calls buildUrl before buildHeaders.
  private _currentModel = "unknown";

  async onboardManagedProject(
    accessToken: string,
    tierId = DEFAULT_ONBOARD_TIER,
    options: OnboardOptions = {}
  ): Promise<string | null> {
    const attempts =
      Number.isInteger(options.attempts) && options.attempts! > 0
        ? Number(options.attempts)
        : ONBOARD_MAX_ATTEMPTS;
    const delayMs =
      typeof options.delayMs === "number" &&
      Number.isFinite(options.delayMs) &&
      options.delayMs >= 0
        ? options.delayMs
        : ONBOARD_DELAY_MS;

    const requestBody = {
      tierId: tierId || DEFAULT_ONBOARD_TIER,
      metadata: { ...ONBOARD_METADATA },
    };

    for (let attempt = 0; attempt < attempts; attempt += 1) {
      try {
        const controller = new AbortController();
        const timeoutId = setTimeout(() => controller.abort(), ONBOARD_TIMEOUT_MS);

        let response;
        try {
          response = await fetch(ONBOARD_USER_URL, {
            method: "POST",
            headers: {
              "Content-Type": "application/json",
              Authorization: `Bearer ${accessToken}`,
              "User-Agent": "GeminiCLI/1.0.0",
            },
            body: JSON.stringify(requestBody),
            signal: controller.signal,
          });
        } finally {
          clearTimeout(timeoutId);
        }

        if (response.ok) {
          const payload = await response.json();
          const managedProjectId = extractProjectId(payload?.response);

          if (payload?.done === true && managedProjectId) {
            return managedProjectId;
          }

          if (payload?.done === true) {
            return DEFAULT_PROJECT_ID;
          }
        } else {
          console.warn(
            `[OmniRoute] onboardUser returned ${response.status} on attempt ${attempt + 1}`
          );
        }
      } catch (error) {
        const msg = error instanceof Error ? error.message : String(error);
        console.warn(`[OmniRoute] onboardUser attempt ${attempt + 1} failed (${msg})`);
      }

      if (attempt < attempts - 1) {
        await sleep(delayMs);
      }
    }

    return null;
  }

  /**
   * Fetch the current cloudaicompanionProject via loadCodeAssist API.
   * Native Gemini CLI refreshes this every 30 seconds — OmniRoute stores it once
   * at OAuth connection time, so it goes stale. This method keeps it fresh.
   */
  async refreshProject(accessToken: string): Promise<string | null> {
    // Check cache
    const cached = projectCache.get(accessToken);
    if (cached && cached.expiresAt > Date.now()) {
      return cached.projectId;
    }

    // Deduplicate in-flight requests (thundering herd prevention)
    const inflight = inflightRefresh.get(accessToken);
    if (inflight) return inflight;

    const promise = this._doRefresh(accessToken);
    inflightRefresh.set(accessToken, promise);
    try {
      return await promise;
    } finally {
      inflightRefresh.delete(accessToken);
    }
  }

  async _doRefresh(accessToken: string): Promise<string | null> {
    try {
      const controller = new AbortController();
      const timeoutId = setTimeout(() => controller.abort(), LOAD_CODE_ASSIST_TIMEOUT_MS);

      let response;
      try {
        response = await fetch(LOAD_CODE_ASSIST_URL, {
          method: "POST",
          headers: {
            Authorization: `Bearer ${accessToken}`,
            "Content-Type": "application/json",
          },
          body: JSON.stringify({
            cloudaicompanionProject: DEFAULT_PROJECT_ID,
            metadata: { ...LOAD_CODE_ASSIST_METADATA },
          }),
          signal: controller.signal,
        });
      } finally {
        clearTimeout(timeoutId);
      }

      if (!response.ok) {
        console.warn(
          `[OmniRoute] loadCodeAssist returned ${response.status} — falling back to stored projectId`
        );
        return null;
      }

      const data = (await response.json()) as LoadCodeAssistResponse;
      let projectId = extractProjectId(data);

      if (!projectId) {
        console.warn(
          "[OmniRoute] loadCodeAssist returned no project — attempting managed project onboarding"
        );
        projectId = await this.onboardManagedProject(accessToken, extractDefaultTierId(data));
      }

      if (!projectId) {
        console.warn(
          "[OmniRoute] managed project onboarding failed — falling back to stored projectId"
        );
        return null;
      }

      cacheProject(accessToken, projectId);

      return projectId;
    } catch (error) {
      const msg = error instanceof Error ? error.message : String(error);
      console.warn(`[OmniRoute] loadCodeAssist failed (${msg}) — falling back to stored projectId`);
      return null;
    }
  }

  async transformRequest(model, body, stream, credentials) {
    this._currentModel = normalizeGeminiModel(model);

    // Refresh the project ID via loadCodeAssist (cached for 30s).
    if (body && typeof body === "object" && body.request && credentials.accessToken) {
      const freshProject = await this.refreshProject(credentials.accessToken);
      if (freshProject) {
        body.project = freshProject;
      }

      // Obfuscate sensitive client names in user content
      const contents = body.request?.contents;
      if (Array.isArray(contents)) {
        for (const msg of contents) {
          if (Array.isArray(msg.parts)) {
            for (const part of msg.parts) {
              if (typeof part.text === "string") {
                part.text = obfuscateSensitiveWords(part.text);
              }
            }
          }
        }
      }
    }
    return body;
  }

  async refreshCredentials(credentials, log) {
    if (!credentials.refreshToken) return null;

    try {
      const response = await fetch(OAUTH_ENDPOINTS.google.token, {
        method: "POST",
        headers: {
          "Content-Type": "application/x-www-form-urlencoded",
          Accept: "application/json",
        },
        body: new URLSearchParams({
          grant_type: "refresh_token",
          refresh_token: credentials.refreshToken,
          client_id: this.config.clientId,
          client_secret: this.config.clientSecret,
        }),
      });

      if (!response.ok) return null;

      const tokens = await response.json();
      log?.info?.("TOKEN", "Gemini CLI refreshed");

      return {
        accessToken: tokens.access_token,
        refreshToken: tokens.refresh_token || credentials.refreshToken,
        expiresIn: tokens.expires_in,
        projectId: credentials.projectId,
      };
    } catch (error) {
      log?.error?.("TOKEN", `Gemini CLI refresh error: ${error.message}`);
      return null;
    }
  }
}

export default GeminiCLIExecutor;