package repository

import (
	"database/sql"
	"errors"
	"strings"

	"github.com/wmms/wmms/internal/model"
	"github.com/wmms/wmms/pkg/database"
)

// ErrDuplicateCodeRule 表示该分类下已经有一条编码规则。code_rules 上有
// uk_code_rules_org_category(organization_id, category_id)，新建选到已占用的
// 分类、或者改分类改到已占用的分类，都会撞上它。
var ErrDuplicateCodeRule = errors.New("该分类已有编码规则")

// translateDuplicateCodeRule 把唯一键冲突翻译成可直接展示的中文错误，
// 其余错误原样返回。前端只有拿到中文消息才会照原样弹出，否则显示"请求失败"。
func translateDuplicateCodeRule(err error) error {
	if err != nil && strings.Contains(err.Error(), "Duplicate entry") {
		return ErrDuplicateCodeRule
	}
	return err
}

type MasterDataRepository struct{}

func NewMasterDataRepository() *MasterDataRepository { return &MasterDataRepository{} }

func (r *MasterDataRepository) ListCategories(organizationID int64) ([]model.MaterialCategory, error) {
	rows, err := database.DB.Query(`SELECT id, organization_id, code, name, description, parent_id, status FROM material_categories WHERE organization_id = ? ORDER BY code`, organizationID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	items := make([]model.MaterialCategory, 0)
	for rows.Next() {
		var item model.MaterialCategory
		if err := rows.Scan(&item.ID, &item.OrganizationID, &item.Code, &item.Name, &item.Description, &item.ParentID, &item.Status); err != nil {
			return nil, err
		}
		items = append(items, item)
	}
	return items, rows.Err()
}

func (r *MasterDataRepository) CreateCategory(item *model.MaterialCategory) error {
	result, err := database.DB.Exec(`INSERT INTO material_categories (organization_id, code, name, description, parent_id, status) VALUES (?, ?, ?, ?, ?, ?)`, item.OrganizationID, item.Code, item.Name, item.Description, item.ParentID, item.Status)
	if err != nil {
		return err
	}
	item.ID, err = result.LastInsertId()
	return err
}

func (r *MasterDataRepository) UpdateCategory(item *model.MaterialCategory) error {
	return execExpectingRow(`UPDATE material_categories SET name = ?, description = ?, parent_id = ?, status = ? WHERE id = ? AND organization_id = ?`, item.Name, item.Description, item.ParentID, item.Status, item.ID, item.OrganizationID)
}

func (r *MasterDataRepository) ListUnits(organizationID int64) ([]model.Unit, error) {
	rows, err := database.DB.Query(`SELECT id, organization_id, code, name, precision_scale, status FROM units WHERE organization_id = ? ORDER BY code`, organizationID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	items := make([]model.Unit, 0)
	for rows.Next() {
		var item model.Unit
		if err := rows.Scan(&item.ID, &item.OrganizationID, &item.Code, &item.Name, &item.PrecisionScale, &item.Status); err != nil {
			return nil, err
		}
		items = append(items, item)
	}
	return items, rows.Err()
}

func (r *MasterDataRepository) CreateUnit(item *model.Unit) error {
	result, err := database.DB.Exec(`INSERT INTO units (organization_id, code, name, precision_scale, status) VALUES (?, ?, ?, ?, ?)`, item.OrganizationID, item.Code, item.Name, item.PrecisionScale, item.Status)
	if err != nil {
		return err
	}
	item.ID, err = result.LastInsertId()
	return err
}

func (r *MasterDataRepository) UpdateUnit(item *model.Unit) error {
	return execExpectingRow(`UPDATE units SET name = ?, precision_scale = ?, status = ? WHERE id = ? AND organization_id = ?`, item.Name, item.PrecisionScale, item.Status, item.ID, item.OrganizationID)
}

func (r *MasterDataRepository) ListCodeRules(organizationID int64) ([]model.CodeRule, error) {
	rows, err := database.DB.Query(`SELECT cr.id, cr.organization_id, cr.category_id, c.code, c.name, cr.prefix, cr.sequence_length, cr.next_sequence, cr.status
		FROM code_rules cr JOIN material_categories c ON c.id = cr.category_id
		WHERE cr.organization_id = ? ORDER BY c.code`, organizationID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	items := make([]model.CodeRule, 0)
	for rows.Next() {
		var item model.CodeRule
		if err := rows.Scan(&item.ID, &item.OrganizationID, &item.CategoryID, &item.CategoryCode, &item.CategoryName, &item.Prefix, &item.SequenceLength, &item.NextSequence, &item.Status); err != nil {
			return nil, err
		}
		items = append(items, item)
	}
	return items, rows.Err()
}

func (r *MasterDataRepository) CreateCodeRule(item *model.CodeRule) error {
	result, err := database.DB.Exec(`INSERT INTO code_rules (organization_id, category_id, prefix, sequence_length, next_sequence, status) VALUES (?, ?, ?, ?, ?, ?)`, item.OrganizationID, item.CategoryID, item.Prefix, item.SequenceLength, item.NextSequence, item.Status)
	if err != nil {
		return translateDuplicateCodeRule(err)
	}
	item.ID, err = result.LastInsertId()
	return err
}

// UpdateCodeRule 更新编码规则。category_id 必须写进 SET：前端编辑弹窗里的
// 分类下拉没有禁用（与同页的编码输入框不同），而规则又只能改不能删，
// 漏掉这一列会让"改分类"提示成功却完全不落库。
func (r *MasterDataRepository) UpdateCodeRule(item *model.CodeRule) error {
	return translateDuplicateCodeRule(execExpectingRow(`UPDATE code_rules SET category_id = ?, prefix = ?, sequence_length = ?, next_sequence = ?, status = ? WHERE id = ? AND organization_id = ?`, item.CategoryID, item.Prefix, item.SequenceLength, item.NextSequence, item.Status, item.ID, item.OrganizationID))
}

// FindActiveCodeRule 取小类当前启用的编码规则，没有规则时返回 (nil, nil)。
// 只读，不加锁：占号发生在创建物料的事务里。
func (r *MasterDataRepository) FindActiveCodeRule(organizationID, categoryID int64) (*model.CodeRule, error) {
	query := `SELECT id, organization_id, category_id, prefix, sequence_length, next_sequence, status FROM code_rules WHERE organization_id = ? AND category_id = ? AND status = 'active'`
	rule := &model.CodeRule{}
	err := database.DB.QueryRow(query, organizationID, categoryID).Scan(&rule.ID, &rule.OrganizationID,
		&rule.CategoryID, &rule.Prefix, &rule.SequenceLength, &rule.NextSequence, &rule.Status)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	return rule, nil
}