package service

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"github.com/robfig/cron/v3"
	"io"
	"kra/internal/biz"
	"net"
	"net/http"
	"net/url"
	"strings"
	"time"
)

type TaskService struct{ uc *biz.TaskUsecase }

func NewTaskService(uc *biz.TaskUsecase) *TaskService { return &TaskService{uc: uc} }
func (s *TaskService) Validate(v *biz.TimedTask) error {
	if v.Name == "" {
		return errors.New("任务名不能为空")
	}
	var err error
	if v.WithSeconds {
		_, err = cron.NewParser(cron.Second | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor).Parse(v.Spec)
	} else {
		_, err = cron.ParseStandard(v.Spec)
	}
	if err != nil {
		return fmt.Errorf("cron 表达式非法: %w", err)
	}
	switch v.ExecutorType {
	case "method":
		if v.MethodName != "ClearDB" {
			return errors.New("方法未注册")
		}
		if len(v.Params) > 0 && !json.Valid(v.Params) {
			return errors.New("params 必须是合法 JSON")
		}
	case "http":
		parsed, parseErr := url.Parse(v.HTTPURL)
		if parseErr != nil || (parsed.Scheme != "http" && parsed.Scheme != "https") || parsed.Hostname() == "" || parsed.User != nil {
			return errors.New("httpUrl 必须是合法的 http/https 地址")
		}
		if len(v.HTTPHeader) > 0 {
			headers := map[string]string{}
			if json.Unmarshal(v.HTTPHeader, &headers) != nil {
				return errors.New("httpHeader 必须是 JSON 对象")
			}
		}
	default:
		return errors.New("executorType 必须为 method 或 http")
	}
	return nil
}
func (s *TaskService) Create(ctx context.Context, v *biz.TimedTask) error {
	if err := s.Validate(v); err != nil {
		return err
	}
	return s.uc.Repo().CreateTask(ctx, v)
}
func (s *TaskService) Update(ctx context.Context, v *biz.TimedTask) error {
	if v.ID == 0 {
		return errors.New("缺少任务 ID")
	}
	if err := s.Validate(v); err != nil {
		return err
	}
	return s.uc.Repo().UpdateTask(ctx, v)
}
func (s *TaskService) Delete(ctx context.Context, id uint) error {
	return s.uc.Repo().DeleteTask(ctx, id)
}
func (s *TaskService) Toggle(ctx context.Context, id uint, enabled bool) error {
	return s.uc.Repo().ToggleTask(ctx, id, enabled)
}
func (s *TaskService) Task(ctx context.Context, id uint) (*biz.TimedTask, error) {
	return s.uc.Repo().FindTask(ctx, id)
}
func taskDTO(v *biz.TimedTask, next *time.Time) map[string]any {
	return map[string]any{"ID": v.ID, "CreatedAt": v.CreatedAt, "UpdatedAt": v.UpdatedAt, "DeletedAt": nil, "name": v.Name, "description": v.Description, "spec": v.Spec, "withSeconds": v.WithSeconds, "executorType": v.ExecutorType, "methodName": v.MethodName, "params": json.RawMessage(v.Params), "httpUrl": v.HTTPURL, "httpMethod": v.HTTPMethod, "httpHeader": json.RawMessage(v.HTTPHeader), "httpBody": v.HTTPBody, "httpAllowPrivate": v.HTTPAllowPrivate, "enabled": v.Enabled, "nextRunAt": next}
}
func (s *TaskService) Tasks(ctx context.Context, page, size int, q *biz.TimedTask, next map[uint]time.Time) ([]map[string]any, int64, error) {
	items, total, err := s.uc.Repo().ListTasks(ctx, page, size, q)
	if err != nil {
		return nil, 0, err
	}
	out := make([]map[string]any, 0, len(items))
	for _, v := range items {
		var ptr *time.Time
		if value, ok := next[v.ID]; ok {
			copy := value
			ptr = &copy
		}
		out = append(out, taskDTO(v, ptr))
	}
	return out, total, nil
}
func (s *TaskService) Logs(ctx context.Context, page, size int, taskID uint, status string) ([]map[string]any, int64, error) {
	items, total, err := s.uc.Repo().ListTaskLogs(ctx, page, size, taskID, status)
	if err != nil {
		return nil, 0, err
	}
	out := make([]map[string]any, 0, len(items))
	for _, v := range items {
		out = append(out, map[string]any{"ID": v.ID, "CreatedAt": v.CreatedAt, "DeletedAt": nil, "taskId": v.TaskID, "taskName": v.TaskName, "triggerType": v.TriggerType, "startedAt": v.StartedAt, "finishedAt": v.FinishedAt, "durationMs": v.DurationMS, "status": v.Status, "errorMsg": v.ErrorMsg, "output": v.Output})
	}
	return out, total, nil
}
func privateIP(ip net.IP) bool {
	return ip.IsLoopback() || ip.IsPrivate() || ip.IsLinkLocalMulticast() || ip.IsLinkLocalUnicast() || ip.IsUnspecified()
}
func (s *TaskService) runHTTP(ctx context.Context, v *biz.TimedTask) (string, error) {
	parsed, _ := url.Parse(v.HTTPURL)
	if !v.HTTPAllowPrivate {
		ips, err := net.DefaultResolver.LookupIP(ctx, "ip", parsed.Hostname())
		if err != nil {
			return "", err
		}
		for _, ip := range ips {
			if privateIP(ip) {
				return "", errors.New("禁止访问内网或环回地址")
			}
		}
	}
	method := strings.ToUpper(v.HTTPMethod)
	if method == "" {
		method = http.MethodGet
	}
	request, err := http.NewRequestWithContext(ctx, method, v.HTTPURL, bytes.NewBufferString(v.HTTPBody))
	if err != nil {
		return "", err
	}
	headers := map[string]string{}
	_ = json.Unmarshal(v.HTTPHeader, &headers)
	for key, value := range headers {
		request.Header.Set(key, value)
	}
	response, err := (&http.Client{Timeout: 30 * time.Second}).Do(request)
	if err != nil {
		return "", err
	}
	defer response.Body.Close()
	body, _ := io.ReadAll(io.LimitReader(response.Body, 4096))
	output := fmt.Sprintf("HTTP %d: %s", response.StatusCode, string(body))
	if response.StatusCode < 200 || response.StatusCode >= 300 {
		return output, fmt.Errorf("HTTP 状态码 %d", response.StatusCode)
	}
	return output, nil
}
func (s *TaskService) Run(ctx context.Context, v *biz.TimedTask, trigger string) (log *biz.TimedTaskLog) {
	started := time.Now()
	log = &biz.TimedTaskLog{TaskID: v.ID, TaskName: v.Name, TriggerType: trigger, StartedAt: started, Status: "success"}
	defer func() {
		if recovered := recover(); recovered != nil {
			log.Status = "fail"
			log.ErrorMsg = fmt.Sprint(recovered)
		}
		log.FinishedAt = time.Now()
		log.DurationMS = log.FinishedAt.Sub(started).Milliseconds()
		_ = s.uc.Repo().RecordTaskLog(context.Background(), log)
	}()
	runCtx, cancel := context.WithTimeout(ctx, 35*time.Second)
	defer cancel()
	var err error
	switch v.ExecutorType {
	case "method":
		if v.MethodName == "ClearDB" {
			days := 30
			var params struct {
				Days int `json:"days"`
			}
			_ = json.Unmarshal(v.Params, &params)
			if params.Days > 0 {
				days = params.Days
			}
			err = s.uc.Repo().CleanupLogs(runCtx, time.Now().AddDate(0, 0, -days))
			log.Output = "过期日志清理完成"
		}
	case "http":
		log.Output, err = s.runHTTP(runCtx, v)
	}
	if err != nil {
		log.Status = "fail"
		log.ErrorMsg = err.Error()
	}
	return log
}
func (s *TaskService) RegisteredMethods() []map[string]any {
	return []map[string]any{{"name": "ClearDB", "description": "清理数据库过期日志（操作记录、登录日志、定时任务日志）"}}
}