package shared

import (
	"fmt"
	"os"
	"strings"
)

type Error struct {
	message string
	loc     Location
}

func NewError(loc Location, message string, a ...any) Error {
	return Error{
		message: fmt.Sprintf(message, a...),
		loc:     loc,
	}
}

func (err Error) Error() string {
	f, e := os.ReadFile(err.loc.FilePath)
	if e != nil {
		return err.message
	}

	line := strings.Split(string(f), "\n")[err.loc.LC.Line-1]
	pointer := ""
	if err.loc.LC.Col == 1 {
		pointer = "^" + strings.Repeat("~", len(line)-1)
	} else {
		pointer = strings.Repeat("~", max(0, err.loc.LC.Col-2)) + "^" + strings.Repeat("~", len(line)-err.loc.LC.Col+1)
	}

	return fmt.Sprintf("%s:%d:%d\n%s\n%s\n\n%s", err.loc.FilePath, err.loc.LC.Line, err.loc.LC.Col, line, pointer, err.message)
}

type LineCol struct {
	Line int
	Col  int
}

type Location struct {
	LC       LineCol
	FilePath string
}

type Pair[T1 any, T2 any] struct {
	L T1
	R T2
}