package shumei

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

// callDeviceAPI POSTs the encrypted payload to the Shumei device profile API
// and returns the deviceId from the response.
func callDeviceAPI(ctx context.Context, ep, data string) (string, error) {
	payload := map[string]any{
		"appId":        appId,
		"organization": organization,
		"ep":           ep,
		"data":         data,
		"os":           "web",
		"encode":       5,
		"compress":     2,
	}
	body, err := json.Marshal(payload)
	if err != nil {
		return "", fmt.Errorf("marshal payload: %w", err)
	}

	url := "https://" + apiHost + apiPath
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
	if err != nil {
		return "", fmt.Errorf("create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36")
	req.Header.Set("Origin", "https://chat.deepseek.com")
	req.Header.Set("Referer", "https://chat.deepseek.com/")

	resp, err := httpDoer.Do(req)
	if err != nil {
		return "", fmt.Errorf("http post: %w", err)
	}
	defer func() { _ = resp.Body.Close() }()

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

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("unexpected status %d: %s", resp.StatusCode, string(respBody))
	}

	var result map[string]any
	if err := json.Unmarshal(respBody, &result); err != nil {
		return "", fmt.Errorf("parse response: %w", err)
	}

	code, _ := result["code"].(float64)
	if int(code) != 1100 {
		return "", fmt.Errorf("api error code %v: %s", result["code"], string(respBody))
	}

	detail, _ := result["detail"].(map[string]any)
	deviceID, _ := detail["deviceId"].(string)
	if deviceID == "" {
		return "", fmt.Errorf("missing deviceId in response: %s", string(respBody))
	}

	return deviceID, nil
}

// httpDoer is the HTTP client used for Shumei API calls.
// Initialized in init() using the project's Chrome TLS transport.
var httpDoer httpDoerInterface

type httpDoerInterface interface {
	Do(req *http.Request) (*http.Response, error)
}

func init() {
	httpDoer = &http.Client{Timeout: defaultHTTPTimeout}
}

// SetHTTPDoer allows overriding the HTTP client (e.g. for testing or
// to use the project's Chrome TLS transport).
func SetHTTPDoer(d httpDoerInterface) {
	if d != nil {
		httpDoer = d
	}
}

const defaultHTTPTimeout = 15 * time.Second