package osi

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"strconv"
	"strings"
	"time"

	"chis_osi/contract"
)

type ClientConfig struct {
	BaseURL     string
	OrgCode     string
	DeviceSN    string
	UserName    string
	Ask         string
	OperateUser string
	OperateUnit string
	Transport   *Transport
	NowMillis   func() string
}

type Client struct {
	config    ClientConfig
	transport *Transport
}

type Result struct {
	HTTPStatus int
	Code       string
	Message    string
	Raw        []byte
	Success    bool
	Retryable  bool
}

type responseEnvelope struct {
	Code    string          `json:"code"`
	Message string          `json:"message"`
	Data    json.RawMessage `json:"data"`
}

func NewClient(config ClientConfig) *Client {
	return &Client{config: config, transport: config.Transport}
}

func (c *Client) Call(ctx context.Context, serviceID string, baseInfo any, out any) (Result, error) {
	if c.transport == nil {
		transport, err := NewTransport(TransportConfig{})
		if err != nil {
			return Result{}, err
		}
		c.transport = transport
	}

	path, err := PathOf(serviceID)
	if err != nil {
		return Result{}, err
	}

	payload := contract.Envelope{
		ServiceID: serviceID,
		UploadInfo: contract.UploadInfo{
			BaseInfo: baseInfo,
			ManageInfo: contract.ManageInfo{
				DSFMC:       c.config.UserName,
				OperateUser: c.config.OperateUser,
				OperateUnit: c.operateUnit(),
			},
		},
	}

	targetURL := c.urlFor(path)
	status, raw, err := c.transport.PostJSON(ctx, targetURL, payload, c.headers())
	result := Result{HTTPStatus: status, Raw: raw, Retryable: isRetryableHTTPStatus(status)}
	if err != nil {
		result.Retryable = true
		return result, err
	}

	var resp responseEnvelope
	if err := json.Unmarshal(raw, &resp); err != nil {
		return result, fmt.Errorf("decode osi response: %w", err)
	}
	result.Code = resp.Code
	result.Message = resp.Message
	result.Success = IsSuccessCode(resp.Code)
	result.Retryable = result.Retryable || IsRetryableCode(resp.Code)

	if !result.Success {
		return result, fmt.Errorf("osi call failed code=%s message=%s", resp.Code, resp.Message)
	}
	if out != nil && len(resp.Data) > 0 && string(resp.Data) != "null" {
		if err := json.Unmarshal(resp.Data, out); err != nil {
			return result, fmt.Errorf("decode osi data: %w", err)
		}
	}
	return result, nil
}

func (c *Client) headers() map[string]string {
	ts := strconv.FormatInt(time.Now().UnixMilli(), 10)
	if c.config.NowMillis != nil {
		ts = c.config.NowMillis()
	}
	return BuildHeaders(HeaderInput{
		OrgCode:  c.config.OrgCode,
		DeviceSN: c.config.DeviceSN,
		UserName: c.config.UserName,
		Ask:      c.config.Ask,
		TS:       ts,
	})
}

func (c *Client) operateUnit() string {
	if c.config.OperateUnit != "" {
		return c.config.OperateUnit
	}
	return c.config.OrgCode
}

func (c *Client) urlFor(path string) string {
	baseURL := strings.TrimRight(c.config.BaseURL, "/")
	if strings.HasSuffix(baseURL, "/osi/api") {
		return baseURL + path
	}
	return baseURL + "/osi/api" + path
}

func isRetryableHTTPStatus(status int) bool {
	return status == http.StatusTooManyRequests || status >= 500
}