/*
 Copyright 2021 Qiniu Cloud (qiniu.com)
 Licensed 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 build

import (
	"crypto/sha256"
	"fmt"
	"path"
	"time"
)

// declareCoverVars attaches the required cover variables names
// to the files, to be used when annotating the files.
func declareCoverVars(p *Package) map[string]*FileVar {
	coverVars := make(map[string]*FileVar)
	coverIndex := 0
	// We create the cover counters as new top-level variables in the package.
	// We need to avoid collisions with user variables (GoCover_0 is unlikely but still)
	// and more importantly with dot imports of other covered packages,
	// so we append 12 hex digits from the SHA-256 of the import path.
	// The point is only to avoid accidents, not to defeat users determined to
	// break things.
	sum := sha256.Sum256([]byte(p.ImportPath))
	h := fmt.Sprintf("%x", sum[:6])
	for _, file := range p.GoFiles {
		// These names appear in the cmd/cover HTML interface.
		var longFile = path.Join(p.ImportPath, file)
		coverVars[file] = &FileVar{
			File: longFile,
			Var:  fmt.Sprintf("GoCover_%d_%x", coverIndex, h),
		}
		coverIndex++
	}

	for _, file := range p.CgoFiles {
		// These names appear in the cmd/cover HTML interface.
		var longFile = path.Join(p.ImportPath, file)
		coverVars[file] = &FileVar{
			File: longFile,
			Var:  fmt.Sprintf("GoCover_%d_%x", coverIndex, h),
		}
		coverIndex++
	}

	return coverVars
}

// PackageCover holds all the generate coverage variables of a package
type PackageCover struct {
	Package *Package
	Vars    map[string]*FileVar
}

// FileVar holds the name of the generated coverage variables targeting the named file.
type FileVar struct {
	File string // 这里其实不是文件名，是 importpath + filename
	Var  string
}

// Package map a package output by go list
// this is subset of package struct in: https://github.com/golang/go/blob/master/src/cmd/go/internal/load/pkg.go#L58
type Package struct {
	Dir        string `json:"Dir"`        // directory containing package sources
	ImportPath string `json:"ImportPath"` // import path of package in dir
	Name       string `json:"Name"`       // package name
	Target     string `json:",omitempty"` // installed target for this package (may be executable)
	Root       string `json:",omitempty"` // Go root, Go path dir, or module root dir containing this package

	Module   *ModulePublic `json:",omitempty"`         // info about package's module, if any
	Goroot   bool          `json:"Goroot,omitempty"`   // is this package in the Go root?
	Standard bool          `json:"Standard,omitempty"` // is this package part of the standard Go library?
	DepOnly  bool          `json:"DepOnly,omitempty"`  // package is only a dependency, not explicitly listed

	// Source files
	GoFiles  []string `json:"GoFiles,omitempty"`  // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
	CgoFiles []string `json:"CgoFiles,omitempty"` // .go source files that import "C"

	// Dependency information
	Deps      []string          `json:"Deps,omitempty"` // all (recursively) imported dependencies
	Imports   []string          `json:",omitempty"`     // import paths used by this package
	ImportMap map[string]string `json:",omitempty"`     // map from source import to ImportPath (identity entries omitted)

	// Error information
	Incomplete bool            `json:"Incomplete,omitempty"` // this package or a dependency has an error
	Error      *PackageError   `json:"Error,omitempty"`      // error loading package
	DepsErrors []*PackageError `json:"DepsErrors,omitempty"` // errors loading dependencies
}

// ModulePublic represents the package info of a module
type ModulePublic struct {
	Path      string        `json:",omitempty"` // module path
	Version   string        `json:",omitempty"` // module version
	Versions  []string      `json:",omitempty"` // available module versions
	Replace   *ModulePublic `json:",omitempty"` // replaced by this module
	Time      *time.Time    `json:",omitempty"` // time version was created
	Update    *ModulePublic `json:",omitempty"` // available update (with -u)
	Main      bool          `json:",omitempty"` // is this the main module?
	Indirect  bool          `json:",omitempty"` // module is only indirectly needed by main module
	Dir       string        `json:",omitempty"` // directory holding local copy of files, if any
	GoMod     string        `json:",omitempty"` // path to go.mod file describing module, if any
	GoVersion string        `json:",omitempty"` // go version used in module
	Error     *ModuleError  `json:",omitempty"` // error loading module
}

// ModuleError represents the error loading module
type ModuleError struct {
	Err string // error text
}

// PackageError is the error info for a package when list failed
type PackageError struct {
	ImportStack []string // shortest path from package named on command line to this one
	Pos         string   // position of error (if present, file:line:col)
	Err         string   // the error itself
}