package wecom

import (
	"bytes"
	"context"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"

	"github.com/bytedance/sonic"

	"github.com/break/junhong_cmp_fiber/internal/infrastructure/integrationlog"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// ApprovalInfoQuery 描述按审批单提交时间查询审批单号的过滤条件。
type ApprovalInfoQuery struct {
	ApplicationID uint
	StartTime     time.Time
	EndTime       time.Time
	TemplateID    string
	CreatorUserID string
	Cursor        string
	Size          int
}

// ApprovalInfoPage 是企业微信批量审批单号接口的一页结果。
type ApprovalInfoPage struct {
	SPNos      []string
	NextCursor string
}

// ApprovalInfoClient 按提交时间窗批量获取企业微信审批单号。
type ApprovalInfoClient struct {
	tokens      DirectoryTokenProvider
	integration TokenIntegrationLog
	httpClient  *http.Client
	baseURL     string
	now         func() time.Time
}

// NewApprovalInfoClient 创建企业微信批量审批单号客户端。
func NewApprovalInfoClient(tokens DirectoryTokenProvider, integration TokenIntegrationLog, baseURL string, timeout time.Duration) *ApprovalInfoClient {
	if timeout <= 0 {
		timeout = constants.WeComDefaultHTTPTimeout
	}
	return &ApprovalInfoClient{
		tokens: tokens, integration: integration, httpClient: &http.Client{Timeout: timeout},
		baseURL: strings.TrimRight(baseURL, "/"), now: time.Now,
	}
}

// List 获取一页审批单号，并为每次真实外呼写入 Integration Log。
func (c *ApprovalInfoClient) List(ctx context.Context, input ApprovalInfoQuery) (ApprovalInfoPage, error) {
	if c == nil || c.tokens == nil || c.integration == nil || c.httpClient == nil {
		return ApprovalInfoPage{}, errors.New(errors.CodeServiceUnavailable, "企业微信批量审批单号客户端未配置")
	}
	if err := validateApprovalInfoQuery(input); err != nil {
		return ApprovalInfoPage{}, err
	}
	token, err := c.tokens.GetAccessToken(ctx, input.ApplicationID)
	if err != nil {
		return ApprovalInfoPage{}, err
	}
	request, err := c.newRequest(ctx, token, input)
	if err != nil {
		return ApprovalInfoPage{}, err
	}
	resourceID := strconv.FormatUint(uint64(input.ApplicationID), 10)
	attempt, err := c.integration.Start(ctx, integrationlog.Attempt{
		Provider: constants.IntegrationProviderWeCom, Direction: constants.IntegrationDirectionOutbound,
		Operation: constants.IntegrationOperationWeComApprovalInfo, ResourceType: constants.WeComApprovalInstanceResourceType,
		ResourceID: &resourceID, RequestSummary: map[string]any{
			"application_id": input.ApplicationID, "starttime": input.StartTime.Unix(), "endtime": input.EndTime.Unix(),
			"template_id": input.TemplateID, "creator_userid": input.CreatorUserID, "size": input.Size,
			"cursor_present": strings.TrimSpace(input.Cursor) != "",
		},
	})
	if err != nil {
		return ApprovalInfoPage{}, err
	}
	startedAt := c.now()
	response, err := c.httpClient.Do(request)
	if err != nil {
		return ApprovalInfoPage{}, c.completeFailure(ctx, attempt.IntegrationID, 0, "request_failed", "企业微信批量审批单号请求失败", startedAt)
	}
	defer response.Body.Close()
	body, err := io.ReadAll(io.LimitReader(response.Body, constants.WeComMaxResponseBodyBytes+1))
	if err != nil || int64(len(body)) > constants.WeComMaxResponseBodyBytes {
		return ApprovalInfoPage{}, c.completeFailure(ctx, attempt.IntegrationID, response.StatusCode, "invalid_response", "企业微信批量审批单号响应无效", startedAt)
	}
	var result struct {
		ErrCode       int64    `json:"errcode"`
		ErrMsg        string   `json:"errmsg"`
		SPNoList      []string `json:"sp_no_list"`
		NewNextCursor string   `json:"new_next_cursor"`
	}
	if err := sonic.Unmarshal(body, &result); err != nil {
		return ApprovalInfoPage{}, c.completeFailure(ctx, attempt.IntegrationID, response.StatusCode, "invalid_response", "企业微信批量审批单号响应无效", startedAt)
	}
	if response.StatusCode < http.StatusOK || response.StatusCode >= http.StatusMultipleChoices || result.ErrCode != 0 {
		return ApprovalInfoPage{}, c.completeFailure(ctx, attempt.IntegrationID, response.StatusCode, strconv.FormatInt(result.ErrCode, 10), result.ErrMsg, startedAt)
	}
	spNos := normalizeSPNos(result.SPNoList)
	_, err = c.integration.Complete(ctx, attempt.IntegrationID, integrationlog.Completion{
		Result: constants.IntegrationResultSuccess, HTTPStatus: response.StatusCode,
		ProviderCode: strconv.FormatInt(result.ErrCode, 10), ProviderMessage: result.ErrMsg,
		ResponseSummary: map[string]any{
			"sp_no_count": len(spNos), "next_cursor_present": strings.TrimSpace(result.NewNextCursor) != "",
		},
		DurationMS: c.now().Sub(startedAt).Milliseconds(),
	})
	return ApprovalInfoPage{SPNos: spNos, NextCursor: strings.TrimSpace(result.NewNextCursor)}, err
}

func validateApprovalInfoQuery(input ApprovalInfoQuery) error {
	if input.ApplicationID == 0 || input.StartTime.IsZero() || input.EndTime.IsZero() || !input.StartTime.Before(input.EndTime) {
		return errors.New(errors.CodeInvalidParam, "企业微信批量审批单号查询参数无效")
	}
	if input.EndTime.Sub(input.StartTime) > constants.WeComApprovalInfoMaxWindow {
		return errors.New(errors.CodeInvalidParam, "企业微信批量审批单号查询时间跨度不能超过 31 天")
	}
	if input.Size <= 0 || input.Size > constants.WeComApprovalInfoMaxPageSize {
		return errors.New(errors.CodeInvalidParam, "企业微信批量审批单号查询每页数量无效")
	}
	return nil
}

// newRequest 组装企业微信批量审批单号请求，筛选值仅来自本地稳定提交快照。
func (c *ApprovalInfoClient) newRequest(ctx context.Context, token string, input ApprovalInfoQuery) (*http.Request, error) {
	endpoint, err := url.Parse(c.baseURL + "/cgi-bin/oa/getapprovalinfo")
	if err != nil || endpoint.Scheme == "" || endpoint.Host == "" {
		return nil, errors.New(errors.CodeWeComCredentialInvalid, "企业微信 API 地址配置无效")
	}
	query := endpoint.Query()
	query.Set("access_token", token)
	endpoint.RawQuery = query.Encode()
	filters := make([]map[string]string, 0, 2)
	if value := strings.TrimSpace(input.TemplateID); value != "" {
		filters = append(filters, map[string]string{"key": "template_id", "value": value})
	}
	if value := strings.TrimSpace(input.CreatorUserID); value != "" {
		filters = append(filters, map[string]string{"key": "creator", "value": value})
	}
	payload := map[string]any{
		"starttime": input.StartTime.Unix(), "endtime": input.EndTime.Unix(),
		"new_cursor": strings.TrimSpace(input.Cursor), "size": input.Size, "filters": filters,
	}
	body, err := sonic.Marshal(payload)
	if err != nil {
		return nil, errors.Wrap(errors.CodeInternalError, err, "编码企业微信批量审批单号请求失败")
	}
	request, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint.String(), bytes.NewReader(body))
	if err != nil {
		return nil, errors.Wrap(errors.CodeInternalError, err, "创建企业微信批量审批单号请求失败")
	}
	request.Header.Set("Content-Type", "application/json")
	return request, nil
}

func (c *ApprovalInfoClient) completeFailure(ctx context.Context, integrationID string, status int, providerCode, message string, startedAt time.Time) error {
	if strings.TrimSpace(message) == "" {
		message = "企业微信批量审批单号接口返回失败"
	}
	_, err := c.integration.Complete(ctx, integrationID, integrationlog.Completion{
		Result: constants.IntegrationResultFailed, HTTPStatus: status, ProviderCode: providerCode,
		ProviderMessage: message, ResponseSummary: map[string]any{"success": false},
		DurationMS: c.now().Sub(startedAt).Milliseconds(),
	})
	if err != nil {
		return err
	}
	return errors.New(errors.CodeServiceUnavailable, "获取企业微信审批单号失败")
}

func normalizeSPNos(values []string) []string {
	seen := make(map[string]struct{}, len(values))
	result := make([]string, 0, len(values))
	for _, value := range values {
		value = strings.TrimSpace(value)
		if value == "" {
			continue
		}
		if _, exists := seen[value]; exists {
			continue
		}
		seen[value] = struct{}{}
		result = append(result, value)
	}
	return result
}