package build

import (
	"fmt"
	"strings"

	"git.secnex.io/secnex/pgson/schema"
	"git.secnex.io/secnex/pgson/sql"
)

func AlterTable(s *schema.Table) (*string, error) {
	if err := sql.ValidateIdent(s.Name); err != nil {
		return nil, err
	}

	var ddlParts, comments []string

	for _, f := range s.Schema {
		if err := sql.ValidateIdent(f.Name); err != nil {
			return nil, err
		}

		pgType, err := sql.ValidateType(f.Type)
		if err != nil {
			return nil, err
		}

		colParts := []string{sql.QuoteIdent(f.Name), pgType}
		if f.Nullable != nil && !*f.Nullable {
			colParts = append(colParts, "NOT NULL")
		}

		if f.Unique != nil && *f.Unique {
			colParts = append(colParts, "UNIQUE")
		}

		if f.Default != nil && *f.Default != "" {
			def, err := sql.ValidateDefault(*f.Default)
			if err != nil {
				return nil, err
			}
			colParts = append(colParts, "DEFAULT "+def)
		}

		if f.References != nil {
			if err := sql.ValidateIdent(f.References.Table); err != nil {
				return nil, err
			}
			if err := sql.ValidateIdent(f.References.Column); err != nil {
				return nil, err
			}
			onDelete, err := sql.ValidateAction(f.References.OnDelete)
			if err != nil {
				return nil, err
			}
			onUpdate, err := sql.ValidateAction(f.References.OnUpdate)
			if err != nil {
				return nil, err
			}
			fk := fmt.Sprintf("REFERENCES %s(%s) ON DELETE %s ON UPDATE %s", sql.QuoteIdent(f.References.Table), sql.QuoteIdent(f.References.Column), onDelete, onUpdate)
			colParts = append(colParts, fk)
		}

		ddlParts = append(ddlParts, strings.Join(colParts, " "))

		if f.Comment != nil {
			comments = append(comments, fmt.Sprintf("COMMENT ON COLUMN %s.%s IS '%s'", sql.QuoteIdent(s.Name), sql.QuoteIdent(f.Name), *f.Comment))
		}
	}

	ddl := fmt.Sprintf(sql.DDL_ALTER_TABLE, sql.QuoteIdent(s.Name), strings.Join(ddlParts, " "))

	return &ddl, nil
}

func AddColumn(s *schema.Table, f *schema.Field) (*string, error) {
	if err := sql.ValidateIdent(s.Name); err != nil {
		return nil, err
	}
	if err := sql.ValidateIdent(f.Name); err != nil {
		return nil, err
	}
	ddl := fmt.Sprintf(sql.DDL_ADD_COLUMN, sql.QuoteIdent(s.Name), sql.QuoteIdent(f.Name))
	return &ddl, nil
}

func DropColumn(s *schema.Table, f *schema.Field) (*string, error) {
	if err := sql.ValidateIdent(s.Name); err != nil {
		return nil, err
	}
	if err := sql.ValidateIdent(f.Name); err != nil {
		return nil, err
	}
	ddl := fmt.Sprintf(sql.DDL_DROP_COLUMN, sql.QuoteIdent(s.Name), sql.QuoteIdent(f.Name))

	return &ddl, nil
}

func AlterColumn(s *schema.Table, f *schema.Field) (*string, error) {
	if err := sql.ValidateIdent(s.Name); err != nil {
		return nil, err
	}

	pgType, err := sql.ValidateType(f.Type)
	if err != nil {
		return nil, err
	}

	colParts := []string{sql.QuoteIdent(f.Name), pgType}
	if f.Nullable != nil && !*f.Nullable {
		colParts = append(colParts, "NOT NULL")
	}

	ddl := fmt.Sprintf(sql.DDL_ALTER_COLUMN, sql.QuoteIdent(s.Name), sql.QuoteIdent(f.Name), strings.Join(colParts, " "))
	if f.Default != nil && *f.Default != "" {
		def, err := sql.ValidateDefault(*f.Default)
		if err != nil {
			return nil, err
		}
		colParts = append(colParts, "DEFAULT "+def)
	}

	return &ddl, nil
}

func AddForeignKey(s *schema.Table, f *schema.Field) (*string, error) {
	if err := sql.ValidateIdent(s.Name); err != nil {
		return nil, err
	}
	if err := sql.ValidateIdent(f.Name); err != nil {
		return nil, err
	}
	ddl := fmt.Sprintf(sql.DDL_ADD_FOREIGN_KEY, sql.QuoteIdent(s.Name), sql.QuoteIdent(f.Name))

	return &ddl, nil
}

func DropForeignKey(s *schema.Table, f *schema.Field) (*string, error) {
	if err := sql.ValidateIdent(s.Name); err != nil {
		return nil, err
	}
	if err := sql.ValidateIdent(f.Name); err != nil {
		return nil, err
	}
	ddl := fmt.Sprintf(sql.DDL_DROP_FOREIGN_KEY, sql.QuoteIdent(s.Name), sql.QuoteIdent(f.Name))

	return &ddl, nil
}

func AddConstraint(s *schema.Table, f *schema.Field) (*string, error) {
	if err := sql.ValidateIdent(s.Name); err != nil {
		return nil, err
	}
	if err := sql.ValidateIdent(f.Name); err != nil {
		return nil, err
	}
	ddl := fmt.Sprintf(sql.DDL_ADD_CONSTRAINT, sql.QuoteIdent(s.Name), sql.QuoteIdent(f.Name))

	return &ddl, nil
}

func DropConstraint(s *schema.Table, f *schema.Field) (*string, error) {
	if err := sql.ValidateIdent(s.Name); err != nil {
		return nil, err
	}
	if err := sql.ValidateIdent(f.Name); err != nil {
		return nil, err
	}
	ddl := fmt.Sprintf(sql.DDL_DROP_CONSTRAINT, sql.QuoteIdent(s.Name), sql.QuoteIdent(f.Name))

	return &ddl, nil
}