package httpapi

import (
	"net/http"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/sundynix/pets-be/internal/model"
	"gorm.io/gorm"
)

func (a *API) meetupView(m model.Meetup) gin.H {
	var count int64
	a.db.Model(&model.MeetupParticipant{}).Where("meetup_id = ?", m.ID).Count(&count)
	return gin.H{"id": m.ID, "host_user_id": m.HostUserID, "title": m.Title, "description": m.Description, "place_name": m.PlaceName, "latitude": m.Latitude, "longitude": m.Longitude, "starts_at": m.StartsAt, "max_people": m.MaxPeople, "status": m.Status, "participants": count, "cover_file_id": m.CoverFileID, "cover_url": a.fileURL(m.CoverFileID)}
}
func (a *API) listMeetups(c *gin.Context) {
	var rows []model.Meetup
	if a.db.Where("starts_at > ? AND status = ?", time.Now().Add(-time.Hour), "open").Order("starts_at ASC").Limit(100).Find(&rows).Error != nil {
		fail(c, 500, "读取约遛失败")
		return
	}
	items := make([]gin.H, 0, len(rows))
	for _, m := range rows {
		items = append(items, a.meetupView(m))
	}
	ok(c, items)
}
func (a *API) getMeetup(c *gin.Context) {
	var m model.Meetup
	if !validID(c.Param("id")) || a.db.First(&m, "id = ?", c.Param("id")).Error != nil {
		fail(c, 404, "约遛不存在")
		return
	}
	view := a.meetupView(m)
	var joins []model.MeetupParticipant
	a.db.Where("meetup_id = ?", m.ID).Find(&joins)
	people := make([]gin.H, 0, len(joins))
	for _, j := range joins {
		var pets []model.MeetupPet
		a.db.Where("participant_id = ?", j.ID).Find(&pets)
		ids := []string{}
		for _, p := range pets {
			ids = append(ids, p.PetID)
		}
		people = append(people, gin.H{"user_id": j.UserID, "pet_ids": ids})
	}
	view["people"] = people
	ok(c, view)
}

type meetupInput struct {
	Title       string    `json:"title" binding:"required"`
	Description string    `json:"description"`
	PlaceName   string    `json:"place_name" binding:"required"`
	Latitude    float64   `json:"latitude"`
	Longitude   float64   `json:"longitude"`
	StartsAt    time.Time `json:"starts_at" binding:"required"`
	MaxPeople   int       `json:"max_people"`
	PetIDs      []string  `json:"pet_ids" binding:"required"`
	CoverFileID *string   `json:"cover_file_id"`
}

func (a *API) createMeetup(c *gin.Context) {
	var in meetupInput
	if c.ShouldBindJSON(&in) != nil || strings.TrimSpace(in.Title) == "" || strings.TrimSpace(in.PlaceName) == "" || !in.StartsAt.After(time.Now()) || len(in.PetIDs) == 0 {
		fail(c, 400, "约遛资料无效")
		return
	}
	if in.MaxPeople == 0 {
		in.MaxPeople = 8
	}
	if in.MaxPeople < 2 || in.MaxPeople > 100 {
		fail(c, 400, "人数应为 2 到 100")
		return
	}
	for _, id := range in.PetIDs {
		if _, err := a.ownedPet(actor(c), id); err != nil {
			fail(c, 400, "宠物无效")
			return
		}
	}
	if in.CoverFileID != nil && !a.fileExists(*in.CoverFileID) {
		fail(c, 400, "封面文件无效")
		return
	}
	m := model.Meetup{HostUserID: actor(c), Title: strings.TrimSpace(in.Title), Description: strings.TrimSpace(in.Description), PlaceName: strings.TrimSpace(in.PlaceName), Latitude: in.Latitude, Longitude: in.Longitude, StartsAt: in.StartsAt, MaxPeople: in.MaxPeople, Status: "open", CoverFileID: in.CoverFileID}
	err := a.db.Transaction(func(tx *gorm.DB) error {
		if e := tx.Create(&m).Error; e != nil {
			return e
		}
		j := model.MeetupParticipant{MeetupID: m.ID, UserID: actor(c)}
		if e := tx.Create(&j).Error; e != nil {
			return e
		}
		for _, id := range in.PetIDs {
			if e := tx.Create(&model.MeetupPet{ParticipantID: j.ID, PetID: id}).Error; e != nil {
				return e
			}
		}
		return nil
	})
	if err != nil {
		fail(c, 500, "发布失败")
		return
	}
	created(c, a.meetupView(m))
}
func (a *API) joinMeetup(c *gin.Context) {
	var in struct {
		PetIDs []string `json:"pet_ids" binding:"required"`
	}
	if c.ShouldBindJSON(&in) != nil || len(in.PetIDs) == 0 {
		fail(c, 400, "请选择宠物")
		return
	}
	for _, id := range in.PetIDs {
		if _, err := a.ownedPet(actor(c), id); err != nil {
			fail(c, 400, "宠物无效")
			return
		}
	}
	var m model.Meetup
	if !validID(c.Param("id")) || a.db.First(&m, "id = ?", c.Param("id")).Error != nil {
		fail(c, 404, "约遛不存在")
		return
	}
	if m.Status != "open" || !m.StartsAt.After(time.Now()) {
		fail(c, 409, "约遛已关闭")
		return
	}
	var count int64
	a.db.Model(&model.MeetupParticipant{}).Where("meetup_id = ?", m.ID).Count(&count)
	if count >= int64(m.MaxPeople) {
		fail(c, 409, "人数已满")
		return
	}
	var existing int64
	a.db.Model(&model.MeetupParticipant{}).Where("meetup_id = ? AND user_id = ?", m.ID, actor(c)).Count(&existing)
	if existing > 0 {
		fail(c, 409, "已经参加")
		return
	}
	j := model.MeetupParticipant{MeetupID: m.ID, UserID: actor(c)}
	err := a.db.Transaction(func(tx *gorm.DB) error {
		if e := tx.Create(&j).Error; e != nil {
			return e
		}
		for _, id := range in.PetIDs {
			if e := tx.Create(&model.MeetupPet{ParticipantID: j.ID, PetID: id}).Error; e != nil {
				return e
			}
		}
		return nil
	})
	if err != nil {
		fail(c, 500, "报名失败")
		return
	}
	ok(c, a.meetupView(m))
}
func (a *API) leaveMeetup(c *gin.Context) {
	var j model.MeetupParticipant
	if !validID(c.Param("id")) || a.db.Where("meetup_id = ? AND user_id = ?", c.Param("id"), actor(c)).First(&j).Error != nil {
		fail(c, 404, "未参加")
		return
	}
	var m model.Meetup
	a.db.First(&m, "id = ?", j.MeetupID)
	if m.HostUserID == actor(c) {
		fail(c, http.StatusConflict, "发起人请取消约遛")
		return
	}
	if a.db.Transaction(func(tx *gorm.DB) error {
		if e := tx.Where("participant_id = ?", j.ID).Delete(&model.MeetupPet{}).Error; e != nil {
			return e
		}
		return tx.Delete(&j).Error
	}) != nil {
		fail(c, 500, "退出失败")
		return
	}
	ok(c, gin.H{"left": true})
}
func (a *API) cancelMeetup(c *gin.Context) {
	if !validID(c.Param("id")) {
		fail(c, 400, "ID 无效")
		return
	}
	result := a.db.Model(&model.Meetup{}).Where("id = ? AND host_user_id = ? AND status = ?", c.Param("id"), actor(c), "open").Update("status", "cancelled")
	if result.Error != nil || result.RowsAffected == 0 {
		fail(c, 404, "约遛不存在或已关闭")
		return
	}
	ok(c, gin.H{"status": "cancelled"})
}