package mysqldriver

import (
	"context"
	"database/sql"
	"git.aiterp.net/stufflog/server/internal/generate"
	"git.aiterp.net/stufflog/server/internal/slerrors"
	"git.aiterp.net/stufflog/server/models"
	sq "github.com/Masterminds/squirrel"
	"github.com/jmoiron/sqlx"
)

type itemRepository struct {
	db *sqlx.DB
}

func (r *itemRepository) Find(ctx context.Context, id string) (*models.Item, error) {
	item := models.Item{}
	err := r.db.GetContext(ctx, &item, "SELECT * FROM item WHERE item_id=?", id)
	if err != nil {
		if err == sql.ErrNoRows {
			return nil, slerrors.NotFound("Project")
		}

		return nil, err
	}

	err = r.db.SelectContext(ctx, &item.Tags, "SELECT tag FROM item_tag WHERE item_id=? ORDER BY tag", id)
	if err != nil {
		return nil, err
	}

	return &item, nil
}

func (r *itemRepository) List(ctx context.Context, filter models.ItemFilter) ([]*models.Item, error) {
	q := sq.Select("item.*").From("item").OrderBy("name")
	if len(filter.ItemIDs) > 0 {
		q = q.Where(sq.Eq{"item_id": filter.ItemIDs})
	}
	if len(filter.Tags) > 0 {
		q = q.LeftJoin("item_tag ON item_tag.item_id = item.item_id").
			Where(sq.Eq{"item_tag.tag": filter.Tags}).
			GroupBy("item.item_id")
	}

	query, args, err := q.ToSql()
	if err != nil {
		return nil, err
	}

	results := make([]*models.Item, 0, 16)
	err = r.db.SelectContext(ctx, &results, query, args...)
	if err != nil {
		if err == sql.ErrNoRows {
			return []*models.Item{}, nil
		}

		return nil, err
	}

	err = r.fillTags(ctx, results)
	if err != nil {
		return nil, err
	}

	return results, nil
}

func (r *itemRepository) Insert(ctx context.Context, item models.Item) (*models.Item, error) {
	item.ID = generate.ItemID()

	tx, err := r.db.BeginTxx(ctx, nil)
	if err != nil {
		return nil, err
	}

	_, err = tx.NamedExecContext(ctx, `
		INSERT INTO item (item_id, name, description, image_url)
		VALUES (:item_id, :name, :description, :image_url)
	`, item)
	if err != nil {
		_ = tx.Rollback()
		return nil, err
	}

	if len(item.Tags) > 0 {
		q := sq.Insert("item_tag").Columns("item_id", "tag")
		for _, tag := range item.Tags {
			q = q.Values(item.ID, tag)
		}

		tagQuery, args, err := q.ToSql()
		if err != nil {
			_ = tx.Rollback()
			return nil, err
		}

		_, err = r.db.ExecContext(ctx, tagQuery, args...)
		if err != nil {
			_ = tx.Rollback()
			return nil, err
		}
	}

	err = tx.Commit()
	if err != nil {
		return nil, err
	}

	return &item, nil
}

func (r *itemRepository) Save(ctx context.Context, item models.Item) error {
	tx, err := r.db.BeginTxx(ctx, nil)
	if err != nil {
		return err
	}

	_, err = tx.NamedExecContext(ctx, `
		UPDATE item 
		SET name=:name, description=:description, image_url=:image_url
		WHERE item_id=:item_id
	`, item)
	if err != nil {
		_ = tx.Rollback()
		return err
	}

	_, err = r.db.ExecContext(ctx, "DELETE FROM item_tag WHERE item_id=?", item.ID)
	if err != nil && err != sql.ErrNoRows {
		_ = tx.Rollback()
		return err
	}

	if len(item.Tags) > 0 {
		q := sq.Insert("item_tag").Columns("item_id", "tag")
		for _, tag := range item.Tags {
			q = q.Values(item.ID, tag)
		}

		tagQuery, args, err := q.ToSql()
		if err != nil {
			_ = tx.Rollback()
			return err
		}

		_, err = r.db.ExecContext(ctx, tagQuery, args...)
		if err != nil {
			_ = tx.Rollback()
			return err
		}
	}

	err = tx.Commit()
	if err != nil {
		return err
	}

	return nil
}

func (r *itemRepository) Delete(ctx context.Context, item models.Item) error {
	_, err := r.db.ExecContext(ctx, "DELETE FROM item WHERE item_id=?", item.ID)
	if err != nil {
		return err
	}

	_, err = r.db.ExecContext(ctx, "DELETE FROM item_tag WHERE item_id=?", item.ID)
	if err != nil {
		return err
	}

	return err
}

func (r *itemRepository) GetTags(ctx context.Context) ([]string, error) {
	tags := make([]string, 0, 16)
	err := r.db.SelectContext(ctx, &tags, "SELECT DISTINCT(tag) FROM item_tag")
	if err != nil {
		return nil, err
	}

	return tags, nil
}

func (r *itemRepository) fillTags(ctx context.Context, items []*models.Item) error {
	ids := make([]string, len(items))
	idMap := make(map[string]int, len(items))
	for i, item := range items {
		ids[i] = item.ID
		idMap[item.ID] = i
	}

	query, args, err := sq.Select("*").From("item_tag").Where(sq.Eq{"item_id": ids}).ToSql()
	if err != nil {
		return err
	}

	results := make([]struct {
		ItemID string `db:"item_id"`
		Tag    string `db:"tag"`
	}, 0, len(items)*4)
	err = r.db.SelectContext(ctx, &results, query, args...)
	if err != nil {
		return err
	}

	for _, result := range results {
		item := items[idMap[result.ItemID]]
		item.Tags = append(item.Tags, result.Tag)
	}

	return nil
}