package mcpclient

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

// Client is a client for the Sequential Thinking MCP server
type Client struct {
	baseURL    string
	httpClient *http.Client
}

// ToolRequest represents a request to call an MCP tool
type ToolRequest struct {
	Tool    string                 `json:"tool"`
	Payload map[string]interface{} `json:"payload"`
}

// ToolResponse represents the response from an MCP tool call
type ToolResponse struct {
	Result interface{} `json:"result,omitempty"`
	Error  string      `json:"error,omitempty"`
}

// New creates a new MCP client
func New(baseURL string) *Client {
	return &Client{
		baseURL: baseURL,
		httpClient: &http.Client{
			Timeout: 120 * time.Second, // Longer timeout for thinking operations
		},
	}
}

// Health checks if the MCP server is healthy
func (c *Client) Health(ctx context.Context) error {
	req, err := http.NewRequestWithContext(ctx, "GET", c.baseURL+"/health", nil)
	if err != nil {
		return fmt.Errorf("create request: %w", err)
	}

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("http request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("health check failed: status %d", resp.StatusCode)
	}

	return nil
}

// CallTool calls an MCP tool
func (c *Client) CallTool(ctx context.Context, req *ToolRequest) (*ToolResponse, error) {
	jsonData, err := json.Marshal(req)
	if err != nil {
		return nil, fmt.Errorf("marshal request: %w", err)
	}

	httpReq, err := http.NewRequestWithContext(ctx, "POST", c.baseURL+"/mcp/tool", bytes.NewReader(jsonData))
	if err != nil {
		return nil, fmt.Errorf("create request: %w", err)
	}

	httpReq.Header.Set("Content-Type", "application/json")

	resp, err := c.httpClient.Do(httpReq)
	if err != nil {
		return nil, fmt.Errorf("http request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("read response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("tool call failed: status %d, body: %s", resp.StatusCode, string(body))
	}

	var toolResp ToolResponse
	if err := json.Unmarshal(body, &toolResp); err != nil {
		return nil, fmt.Errorf("unmarshal response: %w", err)
	}

	if toolResp.Error != "" {
		return nil, fmt.Errorf("tool error: %s", toolResp.Error)
	}

	return &toolResp, nil
}