package model

import (
	"context"
	"time"

	"spark-server/internal/module/group/entity"
	"spark-server/internal/pkg/errs"
)

// Group maps table groups.
type Group struct {
	ID             int64     `gorm:"column:id;primaryKey;autoIncrement;comment:群号，表内自增，对外群 ID"`
	ConversationID int64     `gorm:"column:conversation_id;uniqueIndex;comment:对应 conversations.id（Snowflake），发消息与同步用"`
	Name           string    `gorm:"column:name;comment:群名称"`
	Avatar         string    `gorm:"column:avatar;comment:群头像对象存储 key，空表示未设置"`
	Announcement   string    `gorm:"column:announcement;comment:群公告，仅群主/管理员可改"`
	OwnerID        int64     `gorm:"column:owner_id;comment:群主 user_id"`
	MutedAll       int       `gorm:"column:muted_all;comment:0=未全员禁言 1=全员禁言（群主/管理员仍可发言）"`
	MemberCount    int       `gorm:"column:member_count;comment:当前成员数，含群主"`
	Status         int       `gorm:"column:status;comment:1=正常 2=已解散"`
	CreatedAt      time.Time `gorm:"column:created_at;comment:创建时间"`
	UpdatedAt      time.Time `gorm:"column:updated_at;comment:资料或成员变更时间"`
}

func (Group) TableName() string { return "groups" }

func (r *Group) entity() *entity.Group {
	if r == nil {
		return nil
	}
	g := &entity.Group{
		ID: r.ID, ConversationID: r.ConversationID, Name: r.Name, Avatar: r.Avatar, Announcement: r.Announcement, OwnerID: r.OwnerID,
		MemberCount: r.MemberCount, Status: entity.Status(r.Status),
		CreatedAtMS: r.CreatedAt.UnixMilli(), UpdatedAtMS: r.UpdatedAt.UnixMilli(),
	}
	g.MutedAll = r.MutedAll != 0
	return g
}

func groupRow(g *entity.Group) *Group {
	now := msTime(g.CreatedAtMS)
	updated := msTime(g.UpdatedAtMS)
	if g.UpdatedAtMS <= 0 {
		updated = now
	}
	row := &Group{
		ID: g.ID, ConversationID: g.ConversationID, Name: g.Name, Avatar: g.Avatar, Announcement: g.Announcement, OwnerID: g.OwnerID,
		MemberCount: g.MemberCount, Status: int(g.Status),
		CreatedAt: now, UpdatedAt: updated,
	}
	if g.MutedAll {
		row.MutedAll = 1
	}
	if row.Status == 0 {
		row.Status = int(entity.StatusActive)
	}
	return row
}

func (m *Repo) Get(ctx context.Context, id int64) (*entity.Group, error) {
	if id <= 0 {
		return nil, errs.ErrInvalidArgument
	}
	db, err := m.session(ctx)
	if err != nil {
		return nil, err
	}
	var row Group
	if err := db.Where("id = ?", id).Take(&row).Error; err != nil {
		return nil, mapDBErr(err)
	}
	return row.entity(), nil
}

func (m *Repo) GetByConversation(ctx context.Context, conversationID int64) (*entity.Group, error) {
	if conversationID <= 0 {
		return nil, errs.ErrInvalidArgument
	}
	db, err := m.session(ctx)
	if err != nil {
		return nil, err
	}
	var row Group
	if err := db.Where("conversation_id = ?", conversationID).Take(&row).Error; err != nil {
		return nil, mapDBErr(err)
	}
	return row.entity(), nil
}

func (m *Repo) ListByUser(ctx context.Context, userID int64, limit int) ([]*entity.Group, error) {
	if userID <= 0 {
		return nil, errs.ErrInvalidArgument
	}
	db, err := m.session(ctx)
	if err != nil {
		return nil, err
	}
	limit = entity.ClampLimit(limit)
	var rows []Group
	err = db.Table("groups AS g").Select("g.*").
		Joins("INNER JOIN group_members m ON m.group_id = g.id").
		Where("m.user_id = ? AND g.status = ?", userID, entity.StatusActive).
		Order("g.updated_at DESC").Limit(limit).Find(&rows).Error
	if err != nil {
		return nil, mapDBErr(err)
	}
	out := make([]*entity.Group, 0, len(rows))
	for i := range rows {
		out = append(out, rows[i].entity())
	}
	return out, nil
}

const purgeListCap = 10000

func (m *Repo) ListAllActiveByUser(ctx context.Context, userID int64) ([]*entity.Group, error) {
	if userID <= 0 {
		return nil, errs.ErrInvalidArgument
	}
	db, err := m.session(ctx)
	if err != nil {
		return nil, err
	}
	var rows []Group
	err = db.Table("groups AS g").Select("g.*").
		Joins("INNER JOIN group_members m ON m.group_id = g.id").
		Where("m.user_id = ? AND g.status = ?", userID, entity.StatusActive).
		Order("g.updated_at DESC").Limit(purgeListCap).Find(&rows).Error
	if err != nil {
		return nil, mapDBErr(err)
	}
	out := make([]*entity.Group, 0, len(rows))
	for i := range rows {
		out = append(out, rows[i].entity())
	}
	return out, nil
}

func (m *Repo) UpdateProfile(ctx context.Context, g *entity.Group) error {
	if g == nil || g.ID <= 0 {
		return errs.ErrInvalidArgument
	}
	db, err := m.session(ctx)
	if err != nil {
		return err
	}
	res := db.Model(&Group{}).Where("id = ? AND status = ?", g.ID, entity.StatusActive).Updates(map[string]any{
		"name":         g.Name,
		"avatar":       g.Avatar,
		"announcement": g.Announcement,
		"muted_all":    boolInt(g.MutedAll),
		"updated_at":   msTime(g.UpdatedAtMS),
	})
	if res.Error != nil {
		return mapDBErr(res.Error)
	}
	if res.RowsAffected == 0 {
		return errs.ErrNotFound
	}
	return nil
}

func (m *Repo) UpdateLastMsg(ctx context.Context, conversationID, msgID, atMS int64) error {
	db, err := m.session(ctx)
	if err != nil {
		return err
	}
	res := db.Table("conversations").Where("id = ?", conversationID).Updates(map[string]any{
		"last_msg_id": msgID,
		"last_msg_at": msTime(atMS),
	})
	if res.Error != nil {
		return mapDBErr(res.Error)
	}
	if res.RowsAffected == 0 {
		return errs.ErrNotFound
	}
	return nil
}

func msTime(ms int64) time.Time {
	if ms <= 0 {
		return time.Now()
	}
	return time.UnixMilli(ms)
}

func boolInt(v bool) int {
	if v {
		return 1
	}
	return 0
}