package schema

import (
	"strings"

	"git.offline-twitter.com/offline-labs/gas-stack/pkg/textutils"
)

// Column represents a single column in a table.
type Column struct {
	// TableName is the name of the SQLite table this column belongs to.
	TableName string `db:"table_name"`

	// Name is the SQLite column name.
	Name string `db:"column_name"`

	// Type is the SQLite type this column contains.
	Type string `db:"column_type"`

	IsNotNull              bool   `db:"notnull"`
	HasDefaultValue        bool   `db:"has_default_value"`
	DefaultValue           string `db:"dflt_value"`
	IsPrimaryKey           bool   `db:"is_primary_key"`
	PrimaryKeyRank         uint   `db:"primary_key_rank"`
	IsForeignKey           bool   `db:"is_foreign_key"`
	ForeignKeyTargetTable  string `db:"fk_target_table"`
	ForeignKeyTargetColumn string `db:"fk_target_column"`
}

// IsNullableForeignKey is a helper function.
func (c Column) IsNullableForeignKey() bool {
	return !c.IsNotNull && !c.IsPrimaryKey && c.IsForeignKey
}

func (c Column) IsNonCodeTableForeignKey() bool {
	return c.IsForeignKey && strings.HasSuffix(c.Name, "_id")
}

func (c Column) GoFieldName() string {
	if c.Name == "rowid" {
		return "ID"
	}
	if c.IsNonCodeTableForeignKey() {
		return textutils.SnakeToCamel(strings.TrimSuffix(c.Name, "_id")) + "ID"
	}
	return textutils.SnakeToCamel(c.Name)
}

// GoVarName returns the name of a local variable for this column, e.g., when used as a function parameter.
func (c Column) GoVarName() string {
	if c.Name == "rowid" {
		return strings.ToLower(c.TableName)[0:1] + "ID"
		// TODO: Or should it just be "id"??
	}
	// For foreign keys, use first letter of the target type and "ID".  "UserID" => "uID"
	if c.IsNonCodeTableForeignKey() {
		return strings.ToLower(c.ForeignKeyTargetTable)[0:1] + "ID"
	}

	// Otherwise, just use the whole name
	return c.LongGoVarName()
}

// LongGoVarName returns a lowercased version of the field name (Pascal => Camel).
func (c Column) LongGoVarName() string {
	return textutils.CamelToPascal(c.GoFieldName())
}