package lox

import (
	"bufio"
	"fmt"
	"golox/interpreter"
	"golox/parser"
	"golox/scanner"
	"golox/token"
	"os"
)

type Lox struct {
	hadError        bool
	hadRuntimeError bool
	interpreter     *interpreter.Interpreter
}

func New() *Lox {
	l := &Lox{
		hadError:        false,
		hadRuntimeError: false,
	}

	l.interpreter = interpreter.New(l)

	return l
}

func (l *Lox) RunFile(path string) {
	bytes, err := os.ReadFile(path)
	if err != nil {
		fmt.Println("Error reading file", path)
		os.Exit(74)
	}

	l.run(string(bytes))

	if l.hadError {
		os.Exit(65)
	}

	if l.hadRuntimeError {
		os.Exit(70)
	}
}

func (l *Lox) RunPrompt() {
	reader := bufio.NewReader(os.Stdin)

	for {
		fmt.Print("> ")

		line, err := reader.ReadString('\n')
		if err != nil {
			fmt.Println(err)
			os.Exit(74)
		}

		if line == "\n" {
			break
		}

		l.run(line)
		l.hadError = false
	}
}

func (l *Lox) Error(line int, message string) {
	l.hadError = true
	l.report(line, "", message)
}

func (l *Lox) ErrorAtToken(t token.Token, message string) {
	l.hadError = true
	if t.Type == token.EOF {
		l.report(t.Line, " at end", message)
	} else {
		l.report(t.Line, " at '"+t.Lexeme+"'", message)
	}
}

func (l *Lox) RuntimeError(message string) {
	l.hadRuntimeError = true
	fmt.Println(message)
}

func (l *Lox) report(line int, where string, message string) {
	fmt.Printf("[line %d] Error %s: %s\n", line, where, message)
}

func (l *Lox) run(source string) {
	scanner := scanner.New(source, l)
	tokens := scanner.ScanTokens()
	parser := parser.New(tokens, l)
	stmts := parser.Parse()

	// Stop if there was a syntax error.
	if l.hadError {
		return
	}

	l.interpreter.Interpret(stmts)
}