package client

import (
	"bytes"
	"context"
	"encoding/json"
	"io"
	"net/http"
)

type rpcReq struct {
	JSONRPC string `json:"jsonrpc"`
	ID      int    `json:"id"`
	Method  string `json:"method"`
	Params  any    `json:"params"`
}

type rpcResp struct {
	Result json.RawMessage `json:"result"`
	Error  *struct {
		Message string `json:"message"`
	} `json:"error"`
}

func (c *Client) rpcCall(ctx context.Context, name string, args map[string]any) (json.RawMessage, error) {
	body, err := json.Marshal(rpcReq{
		JSONRPC: "2.0",
		ID:      1,
		Method:  "tools/call",
		Params:  map[string]any{"name": name, "arguments": args},
	})
	if err != nil {
		return nil, ToolErrorf(name, "%w", err)
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.URL, bytes.NewReader(body))
	if err != nil {
		return nil, ToolErrorf(name, "%w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json, text/event-stream")
	if c.Token != "" {
		req.Header.Set("Authorization", "Bearer "+c.Token)
	}
	httpClient := c.HTTP
	if httpClient == nil {
		httpClient = http.DefaultClient
	}
	resp, err := httpClient.Do(req)
	if err != nil {
		return nil, ToolErrorf(name, "%w", err)
	}
	defer resp.Body.Close()
	raw, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, ToolErrorf(name, "%w", err)
	}
	if resp.StatusCode >= 300 {
		return nil, ToolErrorf(name, "http %d: %s", resp.StatusCode, raw)
	}
	var out rpcResp
	if err := json.Unmarshal(raw, &out); err != nil {
		return nil, ToolErrorf(name, "%w", err)
	}
	if out.Error != nil {
		return nil, ToolErrorf(name, "%s", out.Error.Message)
	}
	return out.Result, nil
}