// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package fuchsia

import (
	"encoding/json"
	"os"
)

// PackageManifest is a JSON structure that's produced by a Fuchsia build and
// describes which packages were built and where they're located.
type PackageManifest struct {
	Available  []string `json:"available"`
	Monolith   []string `json:"monolith"`
	Preinstall []string `json:"preinstall"`
	Packages   []PackageDescriptor
}

// PackageDescriptor provides information about a package.
type PackageDescriptor struct {
	// BuildDir is a relative path in the Fuchsia build directory to the location
	// of the built package.
	BuildDir string `json:"build_dir"`

	// Dir is the GN-relative location of the package (part of the build target
	// name).
	Dir string `json:"dir"`

	// Name is the basename of the package.
	Name string `json:"name"`
}

// LoadPackageManifest loads a PackageManifest specified in JSON at a given
// filepath.
func LoadPackageManifest(pkgManifestPath string) (*PackageManifest, error) {
	manifestFile, err := os.Open(pkgManifestPath)
	if err != nil {
		return nil, err
	}
	defer manifestFile.Close()
	var manifest PackageManifest
	err = json.NewDecoder(manifestFile).Decode(&manifest)
	return &manifest, err
}