package zhanlu

import (
	"bytes"
	"context"
	"crypto/rand"
	"fmt"
	"net/http"
	"time"

	"git.misaka.ren/M1saka/zhanlu_proxy/internal/auth"
	"git.misaka.ren/M1saka/zhanlu_proxy/internal/sign"
)

type Client struct {
	BaseURL    string
	Path       string
	Creds      auth.Credentials
	Signer     sign.Signer
	HTTPClient *http.Client
}

func NewClient(baseURL, path string, creds auth.Credentials, signer sign.Signer, timeout time.Duration) *Client {
	return &Client{
		BaseURL: baseURL,
		Path:    path,
		Creds:   creds,
		Signer:  signer,
		HTTPClient: &http.Client{
			Timeout: timeout,
		},
	}
}

func (c *Client) ChatCompletions(ctx context.Context, body []byte) (*http.Response, error) {
	baseURL := c.BaseURL
	if c.Creds.BaseURL != "" {
		baseURL = c.Creds.BaseURL
	}
	signedURL, err := c.Signer.BuildOpURL(c.Path, c.Creds, baseURL, http.MethodPost)
	if err != nil {
		return nil, err
	}
	encryptedBody, err := auth.EncryptCredential(string(body), c.Creds.Token)
	if err != nil {
		return nil, err
	}
	wrappedBody := []byte(fmt.Sprintf(`{"data":%q}`, encryptedBody))
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, signedURL, bytes.NewReader(wrappedBody))
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "text/event-stream, application/json")
	req.Header.Set("plugin_type", "vscode")
	req.Header.Set("plugin_version", "2.8.0")
	req.Header.Set("service_type", "code")
	req.Header.Set("request", randomRequestID())
	return c.HTTPClient.Do(req)
}

func randomRequestID() string {
	b := make([]byte, 16)
	if _, err := rand.Read(b); err != nil {
		return fmt.Sprintf("%d", time.Now().UnixNano())
	}
	b[6] = (b[6] & 0x0f) | 0x40
	b[8] = (b[8] & 0x3f) | 0x80
	return fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
}