package ast

import (
	"config-lsp/common"
	commonparser "config-lsp/common/parser"
	"config-lsp/handlers/fstab/ast/parser"
	"config-lsp/utils"
	"regexp"

	"github.com/antlr4-go/antlr/v4"
	"github.com/emirpasic/gods/maps/treemap"

	gods "github.com/emirpasic/gods/utils"
)

func NewFstabConfig() *FstabConfig {
	config := &FstabConfig{}
	config.Clear()

	return config
}

func (c *FstabConfig) Clear() {
	c.Entries = treemap.NewWith(gods.UInt32Comparator)
	c.CommentLines = map[uint32]struct{}{}
}

var commentPattern = regexp.MustCompile(`^\s*#`)
var emptyPattern = regexp.MustCompile(`^\s*$`)

func (c *FstabConfig) Parse(input string) []common.LSPError {
	errors := make([]common.LSPError, 0)
	lines := utils.SplitIntoLines(input)
	context := createListenerContext()

	for rawLineNumber, line := range lines {
		lineNumber := uint32(rawLineNumber)
		context.line = lineNumber

		if emptyPattern.MatchString(line) {
			continue
		}

		if commentPattern.MatchString(line) {
			c.CommentLines[lineNumber] = struct{}{}
			continue
		}

		errors = append(
			errors,
			c.parseStatement(context, line)...,
		)
	}

	return errors
}

// TODO: Handle leading comments
func (c *FstabConfig) parseStatement(
	context *fstabListenerContext,
	input string,
) []common.LSPError {
	stream := antlr.NewInputStream(input)

	lexerErrorListener := createErrorListener(context.line)
	lexer := parser.NewFstabLexer(stream)
	lexer.RemoveErrorListeners()
	lexer.AddErrorListener(&lexerErrorListener)

	tokenStream := antlr.NewCommonTokenStream(lexer, antlr.TokenDefaultChannel)

	parserErrorListener := createErrorListener(context.line)
	antlrParser := parser.NewFstabParser(tokenStream)
	antlrParser.RemoveErrorListeners()
	antlrParser.AddErrorListener(&parserErrorListener)

	listener := createListener(c, context)
	antlr.ParseTreeWalkerDefault.Walk(
		&listener,
		antlrParser.Entry(),
	)

	errors := lexerErrorListener.Errors
	errors = append(errors, parserErrorListener.Errors...)
	errors = append(errors, listener.Errors...)

	return errors
}

// func (c *FstabConfig) parseStatement(
// 	line uint32,
// 	input string,
// ) []common.LSPError {
// 	fields := whitespacePattern.FindAllStringIndex(input, -1)
//
// 	if len(fields) == 0 {
// 		return []common.LSPError{
// 			{
// 				Range: common.LocationRange{
// 					Start: common.Location{
// 						Line:      line,
// 						Character: 0,
// 					},
// 					End: common.Location{
// 						Line:      line,
// 						Character: 0,
// 					},
// 				},
// 			},
// 		}
// 	}
//
// 	var spec *FstabField
// 	var mountPoint *FstabField
// 	var filesystemType *FstabField
// 	var options *FstabField
// 	var freq *FstabField
// 	var pass *FstabField
//
// 	switch len(fields) {
// 	case 6:
// 		pass = parseField(line, input, fields[5])
// 		fallthrough
// 	case 5:
// 		freq = parseField(line, input, fields[4])
// 		fallthrough
// 	case 4:
// 		options = parseField(line, input, fields[3])
// 		fallthrough
// 	case 3:
// 		filesystemType = parseField(line, input, fields[2])
// 		fallthrough
// 	case 2:
// 		mountPoint = parseField(line, input, fields[1])
// 		fallthrough
// 	case 1:
// 		spec = parseField(line, input, fields[0])
// 	}
//
// 	fstabLine := &FstabEntry{
// 		Fields: FstabFields{
// 			LocationRange: common.LocationRange{
// 				Start: common.Location{
// 					Line:      line,
// 					Character: 0,
// 				},
// 				End: common.Location{
// 					Line:      line,
// 					Character: uint32(len(input)),
// 				},
// 			},
// 			Spec:           spec,
// 			MountPoint:     mountPoint,
// 			FilesystemType: filesystemType,
// 			Options:        options,
// 			Freq:           freq,
// 			Pass:           pass,
// 		},
// 	}
//
// 	c.Entries.Put(line, fstabLine)
//
// 	return nil
// }

func parseField(
	line uint32,
	input string,
	field []int,
) *FstabField {
	start := uint32(field[0])
	end := uint32(field[1])
	value := input[start:end]

	return &FstabField{
		LocationRange: common.LocationRange{
			Start: common.Location{
				Line:      line,
				Character: start,
			},
			End: common.Location{
				Line:      line,
				Character: end,
			},
		},
		Value: commonparser.ParseRawString(value, commonparser.ParseFeatures{
			ParseEscapedCharacters: true,
			ParseDoubleQuotes:      true,
			Replacements: &map[string]string{
				`\\040`: " ",
			},
		}),
	}
}