package main

import (
	"c65gm/internal/preproc"
	"flag"
	"fmt"
	"os"
	"strings"
)

// c65cm - A 6502 Cross-Compiler for the ACME Cross-Assembler
// Copyright (C) 1999, 2025 Mattias Hansson
// Distributed under GPL. External library github.com/armon/go-radix under MIT.

// Package-level shared state accessible by other compilation units
var (
/*
	VarList         *VarList
	WhileStack      *LabelStack
	WendStack       *LabelStack
	IfStack         *LabelStack
	GeneralStack    *LabelStack
	FuncList        *FunctionHandler
	ConstStrHandler *ConstantStringHandler
	Pragmas         []string
*/

)

type ShowMode int

const (
	ShowNone ShowMode = iota
	ShowLineCount
	ShowLineView
)

func main() {
	fmt.Println("c65cm - A 6502 Cross-Compiler for the ACME Cross-Assembler.")
	fmt.Println("Copyright (C) 1999, 2025 Mattias Hansson. v0.7")
	fmt.Println("Distributed under GPL. External library github.com/armon/go-radix under MIT.")
	fmt.Println()

	inFile := flag.String("in", "", "input source file (required)")
	outFile := flag.String("out", "", "output assembly file (required)")
	view := flag.String("view", "lines", "output mode: none, count, lines")
	flag.Parse()

	if *inFile == "" || *outFile == "" {
		fmt.Fprintln(os.Stderr, "Error: -in and -out are required")
		flag.Usage()
		os.Exit(1)
	}

	var showMode ShowMode
	switch strings.ToLower(*view) {
	case "none":
		showMode = ShowNone
	case "count":
		showMode = ShowLineCount
	case "lines":
		showMode = ShowLineView
	default:
		fmt.Fprintf(os.Stderr, "Error: invalid view mode: %s\n", *view)
		os.Exit(1)
	}

	if err := run(*inFile, *outFile, showMode); err != nil {
		if _, ok := err.(preproc.HaltError); ok {
			os.Exit(0)
		}
		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
		os.Exit(1)
	}
}

func run(inFile, outFile string, showMode ShowMode) error {
	initSharedObjects()
	return compile(inFile, outFile, showMode)
}

func initSharedObjects() {
	/*
		VarList = NewVarList()
		WhileStack = NewLabelStack("whilelbl")
		WendStack = NewLabelStack("wendlbl")
		IfStack = NewLabelStack("iflbl")
		GeneralStack = NewLabelStack("General")
		FuncList = NewFunctionHandler()
		ConstStrHandler = NewConstantStringHandler()
		Pragmas = make([]string, 0)
	*/
}

func compile(inFile, outFile string, showMode ShowMode) error {
	lines, err := preproc.PreProcess(inFile)
	if err != nil {
		return fmt.Errorf("preprocessor failed: %w", err)
	}

	asmSource := make([]string, 0, len(lines)*2)
	lineCount := 0

	for i := 0; i < len(lines); {
		line := lines[i]
		lineCount++

		displayProgress(showMode, lineCount, line.Text)

		// Handle inline ASM blocks
		if isAsmStart(line) {
			asmSource = append(asmSource, ";"+line.Text)
			i++

			for i < len(lines) && !isAsmEnd(lines[i]) {
				lineCount++
				displayProgress(showMode, lineCount, lines[i].Text)

				if lines[i].Text != "" {
					//processed := LocalVarsInAsmLine(lines[i].Text)
					processed := lines[i].Text
					asmSource = append(asmSource, processed)
				}
				i++
			}

			i++ // Skip ENDASM line
			continue
		}

		if isAsmEnd(line) {
			i++
			continue
		}

		text := stripComments(line.Text)
		if text == "" {
			i++
			continue
		}

		/*
			if !InterpretLine(text, &asmSource) {
				return fmt.Errorf("line not recognized: %s", text)
			}
		*/

		i++
	}

	/*
		VarList.WriteDownTypesToAsm(&asmSource)
		ConstStrHandler.GenerateConstStrDecls(&asmSource)
		VarList.WriteAbsVars(&asmSource)
		VarList.WriteConstants(&asmSource)
	*/

	if err := writeLines(outFile, asmSource); err != nil {
		return fmt.Errorf("failed to write output: %w", err)
	}

	if showMode != ShowNone {
		fmt.Println("\ndone.")
	}

	return nil
}

func displayProgress(mode ShowMode, lineCount int, text string) {
	switch mode {
	case ShowLineCount:
		fmt.Printf("\rCompiling line: %d", lineCount)
	case ShowLineView:
		fmt.Println(text)
	}
}

func isAsmStart(line preproc.Line) bool {
	//return len(line.Tokens) == 1 && strings.ToUpper(line.Tokens[0]) == "ASM"
	return false
}

func isAsmEnd(line preproc.Line) bool {
	//return len(line.Tokens) == 1 && strings.ToUpper(line.Tokens[0]) == "ENDASM"
	return false
}

func stripComments(s string) string {
	if strings.HasPrefix(s, "//") {
		return ""
	}
	if idx := strings.Index(s, "//"); idx >= 0 {
		return strings.TrimSpace(s[:idx])
	}
	return s
}

func writeLines(filename string, lines []string) error {
	f, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer f.Close()

	for _, line := range lines {
		if _, err := fmt.Fprintln(f, line); err != nil {
			return err
		}
	}
	return nil
}