package hostmode

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

// heartbeatResponse is what the orchestrator sends back.
// Phase 1 only populates Ok. Phase 2 adds Cmd + RunID.
type heartbeatResponse struct {
	Ok    bool   `json:"ok"`
	Cmd   string `json:"cmd,omitempty"`
	RunID int64  `json:"run_id,omitempty"`
}

type hostClient struct {
	base string
	h    *http.Client
}

func newHostClient(base string) *hostClient {
	return &hostClient{
		base: base,
		h:    &http.Client{Timeout: 5 * time.Second},
	}
}

func (c *hostClient) heartbeat(ctx context.Context, mac string) (*heartbeatResponse, error) {
	url := fmt.Sprintf("%s/api/v1/hosts/%s/heartbeat", c.base, mac)
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url,
		bytes.NewReader([]byte(`{}`)))
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/json")
	resp, err := c.h.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(io.LimitReader(resp.Body, 1024))
		return nil, fmt.Errorf("status %d: %s", resp.StatusCode, string(body))
	}
	var out heartbeatResponse
	if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
		return nil, fmt.Errorf("decode: %w", err)
	}
	return &out, nil
}