feat: integrate gemini through the same login flow as gemini cli

packages/opencode/src/plugin/gemini/auth.ts

@@ -0,0 +1,41 @@
+import type { AuthDetails, OAuthAuthDetails, PartialAuthDetails, PartialOAuthAuthDetails, RefreshParts } from "./types"
+
+const ACCESS_TOKEN_EXPIRY_BUFFER_MS = 60 * 1000
+
+export function isOAuthAuth(auth: AuthDetails | PartialAuthDetails): auth is OAuthAuthDetails | PartialOAuthAuthDetails {
+  return auth.type === "oauth"
+}
+
+export function isFullOAuthAuth(auth: AuthDetails | PartialAuthDetails): auth is OAuthAuthDetails {
+  return auth.type === "oauth" && typeof auth.access === "string" && typeof auth.expires === "number"
+}
+
+export function parseRefreshParts(refresh: string): RefreshParts {
+  const [refreshToken = "", projectId = "", managedProjectId = ""] = (refresh ?? "").split("|")
+  return {
+    refreshToken,
+    projectId: projectId || undefined,
+    managedProjectId: managedProjectId || undefined,
+  }
+}
+
+export function formatRefreshParts(parts: RefreshParts): string {
+  if (!parts.refreshToken) {
+    return ""
+  }
+
+  if (!parts.projectId && !parts.managedProjectId) {
+    return parts.refreshToken
+  }
+
+  const projectSegment = parts.projectId ?? ""
+  const managedSegment = parts.managedProjectId ?? ""
+  return `${parts.refreshToken}|${projectSegment}|${managedSegment}`
+}
+
+export function accessTokenExpired(auth: OAuthAuthDetails | PartialOAuthAuthDetails): boolean {
+  if (!auth.access || typeof auth.expires !== "number") {
+    return true
+  }
+  return auth.expires <= Date.now() + ACCESS_TOKEN_EXPIRY_BUFFER_MS
+}

packages/opencode/src/plugin/gemini/cache.ts

@@ -0,0 +1,59 @@
+import { accessTokenExpired } from "./auth"
+import type { OAuthAuthDetails, PartialOAuthAuthDetails } from "./types"
+
+const authCache = new Map<string, OAuthAuthDetails>()
+
+function normalizeRefreshKey(refresh?: string): string | undefined {
+  const key = refresh?.trim()
+  return key ? key : undefined
+}
+
+export function resolveCachedAuth(auth: OAuthAuthDetails | PartialOAuthAuthDetails): OAuthAuthDetails | PartialOAuthAuthDetails {
+  const key = normalizeRefreshKey(auth.refresh)
+  if (!key) {
+    return auth
+  }
+
+  const cached = authCache.get(key)
+  if (!cached) {
+    if (auth.access && typeof auth.expires === "number") {
+      authCache.set(key, auth as OAuthAuthDetails)
+    }
+    return auth
+  }
+
+  if (!accessTokenExpired(auth)) {
+    if (auth.access && typeof auth.expires === "number") {
+      authCache.set(key, auth as OAuthAuthDetails)
+    }
+    return auth
+  }
+
+  if (!accessTokenExpired(cached)) {
+    return cached
+  }
+
+  if (auth.access && typeof auth.expires === "number") {
+    authCache.set(key, auth as OAuthAuthDetails)
+  }
+  return auth
+}
+
+export function storeCachedAuth(auth: OAuthAuthDetails): void {
+  const key = normalizeRefreshKey(auth.refresh)
+  if (!key) {
+    return
+  }
+  authCache.set(key, auth)
+}
+
+export function clearCachedAuth(refresh?: string): void {
+  if (!refresh) {
+    authCache.clear()
+    return
+  }
+  const key = normalizeRefreshKey(refresh)
+  if (key) {
+    authCache.delete(key)
+  }
+}

packages/opencode/src/plugin/gemini/constants.ts

@@ -0,0 +1,21 @@
+export const GEMINI_CLIENT_ID = "681255809395-oo8ft2oprdrnp9e3aqf6av3hmdib135j.apps.googleusercontent.com"
+
+export const GEMINI_CLIENT_SECRET = "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"
+
+export const GEMINI_SCOPES = [
+  "https://www.googleapis.com/auth/cloud-platform",
+  "https://www.googleapis.com/auth/userinfo.email",
+  "https://www.googleapis.com/auth/userinfo.profile",
+] as const
+
+export const GEMINI_REDIRECT_URI = "http://localhost:8085/oauth2callback"
+
+export const GEMINI_CODE_ASSIST_ENDPOINT = "https://cloudcode-pa.googleapis.com"
+
+export const CODE_ASSIST_HEADERS = {
+  "User-Agent": "google-api-nodejs-client/9.15.1",
+  "X-Goog-Api-Client": "gl-node/22.17.0",
+  "Client-Metadata": "ideType=IDE_UNSPECIFIED,platform=PLATFORM_UNSPECIFIED,pluginType=GEMINI",
+} as const
+
+export const GEMINI_PROVIDER_ID = "google"

packages/opencode/src/plugin/gemini/debug.ts

@@ -0,0 +1,165 @@
+import { createWriteStream } from "node:fs"
+import { join } from "node:path"
+import { cwd, env } from "node:process"
+
+const DEBUG_FLAG = env.OPENCODE_GEMINI_DEBUG ?? ""
+const MAX_BODY_PREVIEW_CHARS = 2000
+const debugEnabled = DEBUG_FLAG.trim() === "1"
+const logFilePath = debugEnabled ? defaultLogFilePath() : undefined
+const logWriter = createLogWriter(logFilePath)
+
+export interface GeminiDebugContext {
+  id: string
+  streaming: boolean
+  startedAt: number
+}
+
+interface GeminiDebugRequestMeta {
+  originalUrl: string
+  resolvedUrl: string
+  method?: string
+  headers?: HeadersInit
+  body?: BodyInit | null
+  streaming: boolean
+  projectId?: string
+}
+
+interface GeminiDebugResponseMeta {
+  body?: string
+  note?: string
+  error?: unknown
+  headersOverride?: HeadersInit
+}
+
+let requestCounter = 0
+
+export function startGeminiDebugRequest(meta: GeminiDebugRequestMeta): GeminiDebugContext | null {
+  if (!debugEnabled) {
+    return null
+  }
+
+  const id = `GEMINI-${++requestCounter}`
+  const method = meta.method ?? "GET"
+  logDebug(`[Gemini Debug ${id}] ${method} ${meta.resolvedUrl}`)
+  if (meta.originalUrl && meta.originalUrl !== meta.resolvedUrl) {
+    logDebug(`[Gemini Debug ${id}] Original URL: ${meta.originalUrl}`)
+  }
+  if (meta.projectId) {
+    logDebug(`[Gemini Debug ${id}] Project: ${meta.projectId}`)
+  }
+  logDebug(`[Gemini Debug ${id}] Streaming: ${meta.streaming ? "yes" : "no"}`)
+  logDebug(`[Gemini Debug ${id}] Headers: ${JSON.stringify(maskHeaders(meta.headers))}`)
+  const bodyPreview = formatBodyPreview(meta.body)
+  if (bodyPreview) {
+    logDebug(`[Gemini Debug ${id}] Body Preview: ${bodyPreview}`)
+  }
+
+  return { id, streaming: meta.streaming, startedAt: Date.now() }
+}
+
+export function logGeminiDebugResponse(
+  context: GeminiDebugContext | null | undefined,
+  response: Response,
+  meta: GeminiDebugResponseMeta = {},
+): void {
+  if (!debugEnabled || !context) {
+    return
+  }
+
+  const durationMs = Date.now() - context.startedAt
+  logDebug(`[Gemini Debug ${context.id}] Response ${response.status} ${response.statusText} (${durationMs}ms)`)
+  logDebug(
+    `[Gemini Debug ${context.id}] Response Headers: ${JSON.stringify(maskHeaders(meta.headersOverride ?? response.headers))}`,
+  )
+
+  if (meta.note) {
+    logDebug(`[Gemini Debug ${context.id}] Note: ${meta.note}`)
+  }
+
+  if (meta.error) {
+    logDebug(`[Gemini Debug ${context.id}] Error: ${formatError(meta.error)}`)
+  }
+
+  if (meta.body) {
+    logDebug(`[Gemini Debug ${context.id}] Response Body Preview: ${truncateForLog(meta.body)}`)
+  }
+}
+
+function maskHeaders(headers?: HeadersInit | Headers): Record<string, string> {
+  if (!headers) {
+    return {}
+  }
+
+  const result: Record<string, string> = {}
+  const parsed = headers instanceof Headers ? headers : new Headers(headers)
+  parsed.forEach((value, key) => {
+    if (key.toLowerCase() === "authorization") {
+      result[key] = "[redacted]"
+    } else {
+      result[key] = value
+    }
+  })
+  return result
+}
+
+function formatBodyPreview(body?: BodyInit | null): string | undefined {
+  if (body == null) {
+    return undefined
+  }
+
+  if (typeof body === "string") {
+    return truncateForLog(body)
+  }
+
+  if (body instanceof URLSearchParams) {
+    return truncateForLog(body.toString())
+  }
+
+  if (typeof Blob !== "undefined" && body instanceof Blob) {
+    return `[Blob size=${body.size}]`
+  }
+
+  if (typeof FormData !== "undefined" && body instanceof FormData) {
+    return "[FormData payload omitted]"
+  }
+
+  return `[${body.constructor?.name ?? typeof body} payload omitted]`
+}
+
+function truncateForLog(text: string): string {
+  if (text.length <= MAX_BODY_PREVIEW_CHARS) {
+    return text
+  }
+  return `${text.slice(0, MAX_BODY_PREVIEW_CHARS)}... (truncated ${text.length - MAX_BODY_PREVIEW_CHARS} chars)`
+}
+
+function logDebug(line: string): void {
+  logWriter(line)
+}
+
+function formatError(error: unknown): string {
+  if (error instanceof Error) {
+    return error.stack ?? error.message
+  }
+  try {
+    return JSON.stringify(error)
+  } catch {
+    return String(error)
+  }
+}
+
+function defaultLogFilePath(): string {
+  const timestamp = new Date().toISOString().replace(/[:.]/g, "-")
+  return join(cwd(), `gemini-debug-${timestamp}.log`)
+}
+
+function createLogWriter(filePath?: string): (line: string) => void {
+  if (!filePath) {
+    return () => {}
+  }
+
+  const stream = createWriteStream(filePath, { flags: "a" })
+  return (line: string) => {
+    stream.write(`${line}\n`)
+  }
+}