package usestrconv

import (
	"go/ast"

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

const LinterName = "useStrconv"

var LogsAnalyzer = &analysis.Analyzer{
	Name: LinterName,
	Doc:  LinterName + " linter recommends the utilization of `strconv` over `fmt` when performing string conversions of primitive data types.",
	Run:  run,
}

type Configuration struct {
	Enable bool `mapstructure:"enable"`
}

var Config = Configuration{
	Enable: true,
}
var modyficators = []string{"%d", "%f", "%t", "%x"}

func New(conf any) (*analysis.Analyzer, error) {
	configMap, ok := conf.(map[string]any)
	if !ok {
		Config.Enable = true
		return LogsAnalyzer, nil
	}

	var config Configuration
	config.Enable = true
	err := mapstructure.Decode(configMap, &config)
	if err != nil {
		return nil, err
	}

	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
			}

			expectedPackageAlias, err := astutils.GetAliasByPkgName(file, "fmt")
			if err != nil {
				return false
			}
			if expectedPackageAlias != astutils.GetPackageName(expr.Fun) {
				return true
			}

			isTarget, _ := astutils.IsTargetMethod(expr.Fun, []string{"Sprintf"})

			if !isTarget || !astutils.IsStringValue(expr.Args[0]) {
				return true
			}

			stringLiteral, ok := expr.Args[0].(*ast.BasicLit)

			if !ok {
				return true
			}

			modValue := unquote(stringLiteral.Value)
			for _, modificator := range modyficators {
				if modValue == modificator {
					pass.Report(analysis.Diagnostic{
						Pos:            expr.Pos(),
						End:            expr.End(),
						Category:       LinterName,
						Message:        `Usage of fmt.Sprintf(` + modificator + `) is not allowed`,
						SuggestedFixes: nil,
					})
					return false
				}
			}

			return true
		})
	}

	return nil, nil
}

func unquote(s string) string {
	if len(s) < 2 {
		return s
	}
	return s[1 : len(s)-1]
}