package query

import (
	"fmt"
	"strings"

	"github.com/jinzhu/gorm"
	"github.com/photoprism/photoprism/pkg/txt"

	"github.com/photoprism/photoprism/internal/entity"
)

// Subjects returns subjects from the index.
func Subjects(limit, offset int) (result entity.Subjects, err error) {
	stmt := Db()

	stmt = stmt.Order("subject_name").Limit(limit).Offset(offset)
	err = stmt.Find(&result).Error

	return result, err
}

// SubjectMap returns a map of subjects indexed by UID.
func SubjectMap() (result map[string]entity.Subject, err error) {
	result = make(map[string]entity.Subject)

	var subj entity.Subjects

	stmt := Db().Where("subject_src <> ?", entity.SrcDefault)

	if err = stmt.Find(&subj).Error; err != nil {
		return result, err
	}

	for _, s := range subj {
		result[s.SubjectUID] = s
	}

	return result, err
}

// RemoveDanglingMarkerSubjects permanently deletes dangling marker subjects from the index.
func RemoveDanglingMarkerSubjects() (removed int64, err error) {
	res := UnscopedDb().
		Where("subject_src = ?", entity.SrcMarker).
		Where(fmt.Sprintf("subject_uid NOT IN (SELECT subject_uid FROM %s)", entity.Face{}.TableName())).
		Where(fmt.Sprintf("subject_uid NOT IN (SELECT subject_uid FROM %s)", entity.Marker{}.TableName())).
		Delete(&entity.Subject{})

	return res.RowsAffected, res.Error
}

// CreateMarkerSubjects adds and references known marker subjects.
func CreateMarkerSubjects() (affected int64, err error) {
	var markers entity.Markers

	if err := Db().
		Where("subject_uid = '' AND marker_name <> ''").
		Where("marker_invalid = 0 AND marker_type = ?", entity.MarkerFace).
		Order("marker_name").
		Find(&markers).Error; err != nil {
		return affected, err
	} else if len(markers) == 0 {
		return affected, nil
	}

	var name string
	var subj *entity.Subject

	for _, m := range markers {
		if name == m.MarkerName && subj != nil {
			// Do nothing.
		} else if subj = entity.NewSubject(m.MarkerName, entity.SubjectPerson, entity.SrcMarker); subj == nil {
			log.Errorf("faces: subject should not be nil - bug?")
			continue
		} else if subj = entity.FirstOrCreateSubject(subj); subj == nil {
			log.Errorf("faces: failed adding subject %s", txt.Quote(m.MarkerName))
			continue
		} else {
			affected++
		}

		name = m.MarkerName

		if err := m.Updates(entity.Values{"SubjectUID": subj.SubjectUID}); err != nil {
			return affected, err
		}

		if m.FaceID == "" {
			continue
		} else if err := Db().Model(&entity.Face{}).Where("id = ? AND subject_uid = ''", m.FaceID).Update("SubjectUID", subj.SubjectUID).Error; err != nil {
			return affected, err
		}
	}

	return affected, err
}

// SearchSubjectUIDs finds subject UIDs matching the search string, and removes names from the remaining query.
func SearchSubjectUIDs(s string) (result []string, names []string, remaining string) {
	if s == "" {
		return result, names, s
	}

	type Matches struct {
		SubjectUID  string
		SubjectName string
	}

	var matches []Matches

	stmt := Db().Model(entity.Subject{})
	stmt = stmt.Where("subject_src <> ?", entity.SrcDefault)

	if where := LikeAllNames("subject_name", s); len(where) == 0 {
		return result, names, s
	} else {
		stmt = stmt.Where("?", gorm.Expr(strings.Join(where, " OR ")))
	}

	if err := stmt.Scan(&matches).Error; err != nil {
		log.Errorf("search: %s while finding subjects", err)
	} else if len(matches) == 0 {
		return result, names, s
	}

	for _, m := range matches {
		result = append(result, m.SubjectUID)
		names = append(names, m.SubjectName)

		for _, n := range strings.Split(strings.ToLower(m.SubjectName), " ") {
			s = strings.ReplaceAll(s, n, "")
		}
	}

	s = strings.Trim(s, "&| ")

	return result, names, s
}