// Referenced from https://github.com/yuriisk/clang-tidy-converter/blob/master/clang_tidy_converter/parser/clang_tidy_parser.py
package clang_tidy

import (
	"os"
	"path/filepath"
	"regexp"
	"strconv"
)

type Level int

const (
	UNKNOWN Level = iota
	NOTE
	REMARK
	WARNING
	ERROR
	FATAL
)

type ClangMessage struct {
	filepath       string
	line           int
	column         int
	level          Level
	message        string
	diagnosticName string
	detailsLines   []string
	children       []ClangMessage
}

func newClangMessage(filepath string, line int, column int, level Level, message string, diagnosticName string, detailsLines []string, children []ClangMessage) *ClangMessage {
	if detailsLines == nil {
		detailsLines = make([]string, 0)
	}
	if children == nil {
		children = make([]ClangMessage, 0)
	}

	return &ClangMessage{
		filepath:       filepath,
		line:           line,
		column:         column,
		level:          level,
		message:        message,
		diagnosticName: diagnosticName,
		detailsLines:   detailsLines,
		children:       children,
	}
}

func LevelFromString(levelString string) Level {
	switch levelString {
	case "note":
		return NOTE
	case "remark":
		return REMARK
	case "warning":
		return WARNING
	case "error":
		return ERROR
	case "fatal":
		return FATAL
	default:
		return UNKNOWN
	}
}

func is_ignored(line string) bool {
	IGNORE_REGEX := regexp.MustCompile("^error:.*$")
	return IGNORE_REGEX.MatchString(line)
}

func parse_message(line string) ClangMessage {
	MESSAGE_REGEX := regexp.MustCompile(`^(?P<filepath>.+):(?P<line>\d+):(?P<column>\d+): (?P<level>\S+): (?P<message>.*?)(?: \[(?P<diagnostic_name>.*)\])?\n$`)
	regex_res := MESSAGE_REGEX.FindStringSubmatch(line)
	if len(regex_res) == 0 {
		return *newClangMessage("", 0, 0, UNKNOWN, "", "", nil, nil)
	} else {
		filepath := regex_res[1]
		line, _ := strconv.Atoi(regex_res[2])
		column, _ := strconv.Atoi(regex_res[3])
		level := LevelFromString(regex_res[4])
		message := regex_res[5]
		diagnostic_name := regex_res[6]

		return ClangMessage{
			filepath:       filepath,
			line:           line,
			column:         column,
			level:          level,
			message:        message,
			diagnosticName: diagnostic_name,
			detailsLines:   make([]string, 0),
			children:       make([]ClangMessage, 0),
		}
	}
}

func group_messages(messages []ClangMessage) []ClangMessage {
	grouped_messages := make([]ClangMessage, 0)
	for _, message := range messages {
		if message.level == NOTE {
			grouped_messages[len(grouped_messages)-1].children = append(grouped_messages[len(grouped_messages)-1].children, message)
		} else {
			grouped_messages = append(grouped_messages, message)
		}
	}
	return grouped_messages
}

func convert_paths_to_relative(messages *[]ClangMessage) {
	currentDir, _ := os.Getwd()
	for i := range *messages {
		(*messages)[i].filepath, _ = filepath.Rel(currentDir, (*messages)[i].filepath)
	}
}

func parse_lines(lines []string) []ClangMessage {
	messages := make([]ClangMessage, 0)
	for _, line := range lines {
		if is_ignored(string(line)) {
			continue
		}
		message := parse_message(string(line))
		if message.level == UNKNOWN && len(messages) > 0 {
			messages[len(messages)-1].detailsLines = append(messages[len(messages)-1].detailsLines, string(line))
		} else {
			messages = append(messages, message)
		}
	}
	convert_paths_to_relative(&messages)
	return group_messages(messages)
}