package rainyun

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

const defaultEndpoint = "https://api.v2.rainyun.com"

type client struct {
	httpClient *http.Client
	baseURL    string
	apiKey     string
}

func newClient(endpoint, apiKey string) *client {
	if endpoint == "" {
		endpoint = defaultEndpoint
	}
	return &client{
		httpClient: &http.Client{Timeout: 30 * time.Second},
		baseURL:    endpoint,
		apiKey:     apiKey,
	}
}

type apiResponse struct {
	Code int             `json:"code"`
	Msg  string          `json:"msg"`
	Data json.RawMessage `json:"data"`
}

func (c *client) get(ctx context.Context, path string, result any) error {
	return c.do(ctx, "GET", path, nil, result)
}

func (c *client) post(ctx context.Context, path string, body, result any) error {
	return c.do(ctx, "POST", path, body, result)
}

func (c *client) patch(ctx context.Context, path string, body, result any) error {
	return c.do(ctx, "PATCH", path, body, result)
}

func (c *client) delete(ctx context.Context, path string, result any) error {
	return c.do(ctx, "DELETE", path, nil, result)
}

func (c *client) do(ctx context.Context, method, path string, body, result any) error {
	url := c.baseURL + path

	var bodyReader io.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			return fmt.Errorf("marshal request: %w", err)
		}
		bodyReader = bytes.NewReader(b)
	}

	req, err := http.NewRequestWithContext(ctx, method, url, bodyReader)
	if err != nil {
		return fmt.Errorf("create request: %w", err)
	}
	req.Header.Set("X-Api-Key", c.apiKey)
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")

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

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

	if resp.StatusCode >= 400 {
		return &APIError{
			StatusCode: resp.StatusCode,
			Method:     method,
			URL:        url,
			Body:       respBody,
		}
	}

	var apiResp apiResponse
	if err := json.Unmarshal(respBody, &apiResp); err != nil {
		return fmt.Errorf("unmarshal response: %w", err)
	}
	if apiResp.Code != 0 {
		return &APIError{
			StatusCode: resp.StatusCode,
			Method:     method,
			URL:        url,
			Body:       respBody,
			APICode:    apiResp.Code,
			APIMsg:     apiResp.Msg,
		}
	}

	if result != nil {
		if err := json.Unmarshal(respBody, result); err != nil {
			return fmt.Errorf("unmarshal response: %w", err)
		}
	}
	return nil
}

type APIError struct {
	StatusCode int
	Method     string
	URL        string
	Body       []byte
	APICode    int
	APIMsg     string
}

func (e *APIError) Error() string {
	msg := e.APIMsg
	if msg == "" {
		msg = http.StatusText(e.StatusCode)
	}
	return msg
}