package noliteral

import (
	"go/ast"

	astutils "git.frostfs.info/TrueCloudLab/linters/pkg/ast-utils"
	"github.com/mitchellh/mapstructure"
	"golang.org/x/tools/go/analysis"
)

const LinterName = "noliteral"

var LogsAnalyzer = &analysis.Analyzer{
	Name: LinterName,
	Doc:  LinterName + " is a helper tool that ensures logging messages in Go code are structured and not written as simple text.",
	Run:  run,
}

type Configuration struct {
	TargetMethods    []string `mapstructure:"target-methods"`
	DisablePackages  []string `mapstructure:"disable-packages"`
	ConstantsPackage string   `mapstructure:"constants-package"`
	Enable           bool     `mapstructure:"enable"`
}

var Config = Configuration{
	TargetMethods: []string{"Debug", "Info", "Warn", "Error"},
}

func New(conf any) (*analysis.Analyzer, error) {
	var config Configuration
	config.Enable = true

	err := mapstructure.Decode(conf, &config)
	if err != nil {
		Config.Enable = true
		return LogsAnalyzer, nil
	}

	Config.TargetMethods = append(Config.TargetMethods, config.TargetMethods...)
	Config.ConstantsPackage = config.ConstantsPackage
	Config.DisablePackages = config.DisablePackages
	Config.Enable = config.Enable

	return LogsAnalyzer, nil
}

func run(pass *analysis.Pass) (interface{}, error) {
	if !Config.Enable {
		return nil, nil
	}
	for _, file := range pass.Files {
		ast.Inspect(file, func(n ast.Node) bool {
			expr, ok := n.(*ast.CallExpr)
			if !ok {
				return true
			}

			isLog, _ := astutils.IsTargetMethod(expr.Fun, Config.TargetMethods)
			if !isLog || len(expr.Args) == 0 || astutils.HasNoLintComment(pass, expr.Pos()) {
				return true
			}

			if !astutils.IsStringValue(expr.Args[0]) {
				alias, _ := astutils.GetAliasByPkgName(file, Config.ConstantsPackage)
				if Config.ConstantsPackage == "" || astutils.GetPackageName(expr.Args[0]) == alias || astutils.GetPackageName(expr.Args[0]) == "" {
					return true
				}

				for _, pkgName := range Config.DisablePackages {
					if pkgName == astutils.GetPackageName(expr.Args[0]) {
						return true
					}
				}

				pass.Report(analysis.Diagnostic{
					Pos:            expr.Pos(),
					End:            expr.End(),
					Category:       LinterName,
					Message:        "Wrong package for constants",
					SuggestedFixes: nil,
				})
				return true
			}

			pass.Report(analysis.Diagnostic{
				Pos:            expr.Pos(),
				End:            expr.End(),
				Category:       LinterName,
				Message:        "Literals are not allowed in the body of the logger",
				SuggestedFixes: nil,
			})

			return false
		})
	}

	return nil, nil
}