package service

import (
	"errors"
	"time"

	"gorm.io/gorm"

	"laic-backend/common"
	"laic-backend/logger"
	"laic-backend/model"
	"laic-backend/tool"
	"laic-backend/vo"
)

type RouteService struct{}

var DefaultRouteService = &RouteService{}

// GetPage 航线分页列表
func (s *RouteService) GetPage(userID int64, isAdmin bool, req *vo.RoutePageReq) (*common.PageResponse[model.Route], *common.BusiError) {
	db := common.DB.Model(&model.Route{}).Scopes(withUserFilter(userID, isAdmin))
	if req.Keyword != "" {
		kw := "%" + req.Keyword + "%"
		db = db.Where("name LIKE ? OR description LIKE ?", kw, kw)
	}

	var total int64
	if err := db.Count(&total).Error; err != nil {
		logger.ERROR("统计航线失败", err)
		return nil, common.ErrInternal
	}
	var list []model.Route
	if err := db.Scopes(req.Paginate).Order("created_at DESC, id DESC").Find(&list).Error; err != nil {
		logger.ERROR("查询航线列表失败", err)
		return nil, common.ErrInternal
	}
	return common.Page(req.Pagination, total, list), nil
}

// GetDetail 航线详情（含航点）
func (s *RouteService) GetDetail(userID int64, isAdmin bool, id int64) (*vo.RouteVO, *common.BusiError) {
	var route model.Route
	if err := common.DB.Scopes(withUserFilter(userID, isAdmin)).First(&route, id).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, common.ErrRouteNotFound
		}
		return nil, common.ErrInternal
	}
	waypoints, err := s.waypoints(id)
	if err != nil {
		logger.ERROR("查询航点失败", err)
		return nil, common.ErrInternal
	}
	return &vo.RouteVO{Route: &route, Waypoints: waypoints}, nil
}

// Create 新增航线（含航点）
func (s *RouteService) Create(userID int64, req *vo.RouteCreateReq) (*vo.RouteVO, *common.BusiError) {
	id, err := tool.NextID()
	if err != nil {
		return nil, common.ErrInternal
	}
	now := time.Now()
	route := &model.Route{
		ID:          id,
		UserID:      userID,
		Name:        req.Name,
		Description: req.Description,
		CreatedAt:   now,
		UpdatedAt:   now,
	}
	waypoints, err := buildWaypoints(id, req.Waypoints)
	if err != nil {
		return nil, common.ErrInternal
	}

	err = common.DB.Transaction(func(tx *gorm.DB) error {
		if err := tx.Create(route).Error; err != nil {
			return err
		}
		if len(waypoints) > 0 {
			return tx.Create(&waypoints).Error
		}
		return nil
	})
	if err != nil {
		logger.ERROR("新增航线失败", err)
		return nil, common.ErrInternal
	}
	return &vo.RouteVO{Route: route, Waypoints: waypoints}, nil
}

// Update 编辑航线（提供 waypoints 则整体替换航点）
func (s *RouteService) Update(userID int64, isAdmin bool, id int64, req *vo.RouteUpdateReq) (*vo.RouteVO, *common.BusiError) {
	var route model.Route
	if err := common.DB.Scopes(withUserFilter(userID, isAdmin)).First(&route, id).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, common.ErrRouteNotFound
		}
		return nil, common.ErrInternal
	}

	err := common.DB.Transaction(func(tx *gorm.DB) error {
		updates := map[string]any{"updated_at": time.Now()}
		if req.Name != "" {
			updates["name"] = req.Name
		}
		if req.Description != "" {
			updates["description"] = req.Description
		}
		if err := tx.Model(&route).Updates(updates).Error; err != nil {
			return err
		}
		if req.Waypoints != nil {
			if err := tx.Where("route_id = ?", id).Delete(&model.RouteWaypoint{}).Error; err != nil {
				return err
			}
			waypoints, err := buildWaypoints(id, *req.Waypoints)
			if err != nil {
				return err
			}
			if len(waypoints) > 0 {
				return tx.Create(&waypoints).Error
			}
		}
		return nil
	})
	if err != nil {
		logger.ERROR("更新航线失败", err)
		return nil, common.ErrInternal
	}

	common.DB.First(&route, id)
	waypoints, _ := s.waypoints(id)
	return &vo.RouteVO{Route: &route, Waypoints: waypoints}, nil
}

// Delete 删除航线（含航点）
func (s *RouteService) Delete(userID int64, isAdmin bool, id int64) *common.BusiError {
	err := common.DB.Transaction(func(tx *gorm.DB) error {
		res := tx.Scopes(withUserFilter(userID, isAdmin)).Delete(&model.Route{}, id)
		if res.Error != nil {
			return res.Error
		}
		if res.RowsAffected == 0 {
			return gorm.ErrRecordNotFound
		}
		return tx.Where("route_id = ?", id).Delete(&model.RouteWaypoint{}).Error
	})
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return common.ErrRouteNotFound
		}
		logger.ERROR("删除航线失败", err)
		return common.ErrInternal
	}
	return nil
}

func (s *RouteService) waypoints(routeID int64) ([]model.RouteWaypoint, error) {
	var waypoints []model.RouteWaypoint
	err := common.DB.Where("route_id = ?", routeID).Order("seq ASC").Find(&waypoints).Error
	return waypoints, err
}

// buildWaypoints 将航点请求转换为模型，Seq 从 1 递增
func buildWaypoints(routeID int64, reqs []vo.RouteWaypointReq) ([]model.RouteWaypoint, error) {
	out := make([]model.RouteWaypoint, 0, len(reqs))
	now := time.Now()
	for i, w := range reqs {
		id, err := tool.NextID()
		if err != nil {
			return nil, err
		}
		out = append(out, model.RouteWaypoint{
			ID:        id,
			RouteID:   routeID,
			Seq:       i + 1,
			Longitude: w.Longitude,
			Latitude:  w.Latitude,
			Altitude:  w.Altitude,
			Speed:     w.Speed,
			Yaw:       w.Yaw,
			HoldSec:   w.HoldSec,
			CreatedAt: now,
		})
	}
	return out, nil
}