import { Provider } from "@/provider/provider"

import { Log } from "@/util/log"

import { Cause, Effect, Layer, Record, ServiceMap } from "effect"

import * as Queue from "effect/Queue"

import * as Stream from "effect/Stream"

import { streamText, wrapLanguageModel, type ModelMessage, type Tool, tool, jsonSchema } from "ai"

import { mergeDeep, pipe } from "remeda"

import { GitLabWorkflowLanguageModel } from "gitlab-ai-provider"

import { ProviderTransform } from "@/provider/transform"

import { Config } from "@/config/config"

import { Instance } from "@/project/instance"

import type { Agent } from "@/agent/agent"

import type { MessageV2 } from "./message-v2"

import { Plugin } from "@/plugin"

import { SystemPrompt } from "./system"

import { Flag } from "@/flag/flag"

import { Permission } from "@/permission"

import { Auth } from "@/auth"

import { Installation } from "@/installation"

export namespace LLM {

const log = Log.create({ service: "llm" })

export const OUTPUT_TOKEN_MAX = ProviderTransform.OUTPUT_TOKEN_MAX

export type StreamInput = {

user: MessageV2.User

sessionID: string

model: Provider.Model

agent: Agent.Info

permission?: Permission.Ruleset

system: string[]

messages: ModelMessage[]

small?: boolean

tools: Record<string, Tool>

retries?: number

toolChoice?: "auto" | "required" | "none"

}

export type StreamRequest = StreamInput & {

abort: AbortSignal

}

export type Event = Awaited<ReturnType<typeof stream>>["fullStream"] extends AsyncIterable<infer T> ? T : never

export interface Interface {

readonly stream: (input: StreamInput) => Stream.Stream<Event, unknown>

}

export class Service extends ServiceMap.Service<Service, Interface>()("@opencode/LLM") {}

export const layer = Layer.effect(

Service,

Effect.gen(function* () {

return Service.of({

stream(input) {

return Stream.scoped(

Stream.unwrap(

Effect.gen(function* () {

const ctrl = yield* Effect.acquireRelease(

Effect.sync(() => new AbortController()),

(ctrl) => Effect.sync(() => ctrl.abort()),

)

const result = yield* Effect.promise(() => LLM.stream({ ...input, abort: ctrl.signal }))

return Stream.fromAsyncIterable(result.fullStream, (e) =>

e instanceof Error ? e : new Error(String(e)),

)

}),

),

)

},

})

}),

)

export const defaultLayer = layer

export async function stream(input: StreamRequest) {

const l = log

.clone()

.tag("providerID", input.model.providerID)

.tag("modelID", input.model.id)

.tag("sessionID", input.sessionID)

.tag("small", (input.small ?? false).toString())

.tag("agent", input.agent.name)

.tag("mode", input.agent.mode)

l.info("stream", {

modelID: input.model.id,

providerID: input.model.providerID,

})

const [language, cfg, provider, auth] = await Promise.all([

Provider.getLanguage(input.model),

Config.get(),

Provider.getProvider(input.model.providerID),

Auth.get(input.model.providerID),

])

// TODO: move this to a proper hook

const isOpenaiOauth = provider.id === "openai" && auth?.type === "oauth"

const system: string[] = []

system.push(

[

// use agent prompt otherwise provider prompt

...(input.agent.prompt ? [input.agent.prompt] : SystemPrompt.provider(input.model)),

// any custom prompt passed into this call

...input.system,

// any custom prompt from last user message

...(input.user.system ? [input.user.system] : []),

]

.filter((x) => x)

.join("\n"),

)

const header = system[0]

await Plugin.trigger(

"experimental.chat.system.transform",

{ sessionID: input.sessionID, model: input.model },

{ system },

)

// rejoin to maintain 2-part structure for caching if header unchanged

if (system.length > 2 && system[0] === header) {

const rest = system.slice(1)

system.length = 0

system.push(header, rest.join("\n"))

}

const variant =

!input.small && input.model.variants && input.user.variant ? input.model.variants[input.user.variant] : {}

const base = input.small

? ProviderTransform.smallOptions(input.model)

: ProviderTransform.options({

model: input.model,

sessionID: input.sessionID,

providerOptions: provider.options,

})

const options: Record<string, any> = pipe(

base,

mergeDeep(input.model.options),

mergeDeep(input.agent.options),

mergeDeep(variant),

)

if (isOpenaiOauth) {

options.instructions = system.join("\n")

}

const isWorkflow = language instanceof GitLabWorkflowLanguageModel

const messages = isOpenaiOauth

? input.messages

: isWorkflow

? input.messages

: [

...system.map(

(x): ModelMessage => ({

role: "system",

content: x,

}),

),

...input.messages,

]

const params = await Plugin.trigger(

"chat.params",

{

sessionID: input.sessionID,

agent: input.agent.name,

model: input.model,

provider,

message: input.user,

},

{

temperature: input.model.capabilities.temperature

? (input.agent.temperature ?? ProviderTransform.temperature(input.model))

: undefined,

topP: input.agent.topP ?? ProviderTransform.topP(input.model),

topK: ProviderTransform.topK(input.model),

options,

},

)

const { headers } = await Plugin.trigger(

"chat.headers",

{

sessionID: input.sessionID,

agent: input.agent.name,

model: input.model,

provider,

message: input.user,

},

{

headers: {},

},

)

const maxOutputTokens =

isOpenaiOauth || provider.id.includes("github-copilot")

? undefined

: ProviderTransform.maxOutputTokens(input.model)

const tools = await resolveTools(input)

// LiteLLM and some Anthropic proxies require the tools parameter to be present

// when message history contains tool calls, even if no tools are being used.

// Add a dummy tool that is never called to satisfy this validation.

// This is enabled for:

// 1. Providers with "litellm" in their ID or API ID (auto-detected)

// 2. Providers with explicit "litellmProxy: true" option (opt-in for custom gateways)

const isLiteLLMProxy =

provider.options?.["litellmProxy"] === true ||

input.model.providerID.toLowerCase().includes("litellm") ||

input.model.api.id.toLowerCase().includes("litellm")

// LiteLLM/Bedrock rejects requests where the message history contains tool

// calls but no tools param is present. When there are no active tools (e.g.

// during compaction), inject a stub tool to satisfy the validation requirement.

// The stub description explicitly tells the model not to call it.

if (isLiteLLMProxy && Object.keys(tools).length === 0 && hasToolCalls(input.messages)) {

tools["_noop"] = tool({

description: "Do not call this tool. It exists only for API compatibility and must never be invoked.",

inputSchema: jsonSchema({

type: "object",

properties: {

reason: { type: "string", description: "Unused" },

},

}),

execute: async () => ({ output: "", title: "", metadata: {} }),

})

}

// Wire up toolExecutor for DWS workflow models so that tool calls

// from the workflow service are executed via opencode's tool system

// and results sent back over the WebSocket.

if (language instanceof GitLabWorkflowLanguageModel) {

const workflowModel = language

workflowModel.systemPrompt = system.join("\n")

workflowModel.toolExecutor = async (toolName, argsJson, _requestID) => {

const t = tools[toolName]

if (!t || !t.execute) {

return { result: "", error: `Unknown tool: ${toolName}` }

}

try {

const result = await t.execute!(JSON.parse(argsJson), {

toolCallId: _requestID,

messages: input.messages,

abortSignal: input.abort,

})

const output = typeof result === "string" ? result : (result?.output ?? JSON.stringify(result))

return {

result: output,

metadata: typeof result === "object" ? result?.metadata : undefined,

title: typeof result === "object" ? result?.title : undefined,

}

} catch (e: any) {

return { result: "", error: e.message ?? String(e) }

}

}

}

return streamText({

onError(error) {

l.error("stream error", {

error,

})

},

async experimental_repairToolCall(failed) {

const lower = failed.toolCall.toolName.toLowerCase()

if (lower !== failed.toolCall.toolName && tools[lower]) {

l.info("repairing tool call", {

tool: failed.toolCall.toolName,

repaired: lower,

})

return {

...failed.toolCall,

toolName: lower,

}

}

return {

...failed.toolCall,

input: JSON.stringify({

tool: failed.toolCall.toolName,

error: failed.error.message,

}),

toolName: "invalid",

}

},

temperature: params.temperature,

topP: params.topP,

topK: params.topK,

providerOptions: ProviderTransform.providerOptions(input.model, params.options),

activeTools: Object.keys(tools).filter((x) => x !== "invalid"),

tools,

toolChoice: input.toolChoice,

maxOutputTokens,

abortSignal: input.abort,

headers: {

...(input.model.providerID.startsWith("opencode")

? {

"x-opencode-project": Instance.project.id,

"x-opencode-session": input.sessionID,

"x-opencode-request": input.user.id,

"x-opencode-client": Flag.OPENCODE_CLIENT,

}

: {

"User-Agent": `opencode/${Installation.VERSION}`,

}),

...input.model.headers,

...headers,

},

maxRetries: input.retries ?? 0,

messages,

model: wrapLanguageModel({

model: language,

middleware: [

{

specificationVersion: "v3" as const,

async transformParams(args) {

if (args.type === "stream") {

// @ts-expect-error

args.params.prompt = ProviderTransform.message(args.params.prompt, input.model, options)

}

return args.params

},

},

],

}),

experimental_telemetry: {

isEnabled: cfg.experimental?.openTelemetry,

metadata: {

userId: cfg.username ?? "unknown",

sessionId: input.sessionID,

},

},

})

}

function resolveTools(input: Pick<StreamInput, "tools" | "agent" | "permission" | "user">) {

const disabled = Permission.disabled(

Object.keys(input.tools),

Permission.merge(input.agent.permission, input.permission ?? []),

)

return Record.filter(input.tools, (_, k) => input.user.tools?.[k] !== false && !disabled.has(k))

}

// Check if messages contain any tool-call content

// Used to determine if a dummy tool should be added for LiteLLM proxy compatibility

export function hasToolCalls(messages: ModelMessage[]): boolean {

for (const msg of messages) {

if (!Array.isArray(msg.content)) continue

for (const part of msg.content) {

if (part.type === "tool-call" || part.type === "tool-result") return true

}

}

return false

}

}