import Anthropic from "@anthropic-ai/sdk";
import type { ChatRequest, LLMProvider, Message, StopReason, StreamEvent } from "@magiccode/core";

function toAnthropicMessages(messages: Message[]): Anthropic.MessageParam[] {
  return messages.map((m) => ({
    role: m.role,
    content: m.content.map((b) => {
      switch (b.type) {
        case "text":
          return { type: "text" as const, text: b.text };
        case "tool_use":
          return { type: "tool_use" as const, id: b.id, name: b.name, input: b.input };
        case "tool_result":
          return {
            type: "tool_result" as const,
            tool_use_id: b.toolUseId,
            content: b.content,
            is_error: b.isError ?? false,
          };
      }
    }),
  }));
}

function toStopReason(r: string | null): StopReason {
  if (r === "end_turn" || r === "tool_use" || r === "max_tokens") return r;
  return "other";
}

/** Utilise ANTHROPIC_API_KEY depuis l'environnement. */
export function createAnthropicProvider(model: string): LLMProvider {
  const client = new Anthropic();
  return {
    id: "anthropic",
    model,
    capabilities: { tools: true },
    async *chat(req: ChatRequest, signal?: AbortSignal): AsyncIterable<StreamEvent> {
      const stream = client.messages.stream(
        {
          model,
          max_tokens: req.maxTokens ?? 8192,
          system: req.system,
          tools: req.tools.map((t) => ({
            name: t.name,
            description: t.description,
            input_schema: t.inputSchema as Anthropic.Tool.InputSchema,
          })),
          messages: toAnthropicMessages(req.messages),
        },
        { signal },
      );

      for await (const ev of stream) {
        if (ev.type === "content_block_delta" && ev.delta.type === "text_delta") {
          yield { type: "text_delta", text: ev.delta.text };
        }
      }

      const final = await stream.finalMessage();
      for (const block of final.content) {
        if (block.type === "tool_use") {
          yield {
            type: "tool_use",
            id: block.id,
            name: block.name,
            input: block.input as Record<string, unknown>,
          };
        }
      }
      yield { type: "done", stopReason: toStopReason(final.stop_reason) };
    },
  };
}