// Licensed to Pulumi Corporation ("Pulumi") under one or more
// contributor license agreements.  See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// Pulumi licenses this file to You under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License.  You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package diag

import (
	"fmt"
)

// ID is a unique diagnostics identifier.
type ID int

// Diag is an instance of an error or warning generated by the compiler.
type Diag struct {
	ID      ID        // a unique identifier for this diagnostic.
	Message string    // a human-friendly message for this diagnostic.
	Doc     *Document // the document in which this diagnostic occurred.
	Loc     *Location // the document location at which this diagnostic occurred.
}

// Message returns an anonymous diagnostic message without any source or ID information.
func Message(msg string, args ...interface{}) *Diag {
	return &Diag{Message: fmt.Sprintf(msg, args...)}
}

// Diagable can be used to determine a diagnostic's position.
type Diagable interface {
	Where() (*Document, *Location)
}

// At adds a position to an existing diagnostic, retaining its ID and message.
func (diag *Diag) At(d Diagable) *Diag {
	var doc *Document
	var loc *Location
	if d != nil {
		doc, loc = d.Where()
	}
	return &Diag{
		ID:      diag.ID,
		Message: diag.Message,
		Doc:     doc,
		Loc:     loc,
	}
}

// AtFile adds a file to an existing diagnostic, retaining its ID and message.
func (diag *Diag) AtFile(file string) *Diag {
	return &Diag{
		ID:      diag.ID,
		Message: diag.Message,
		Doc:     NewDocument(file),
	}
}