api/cmd/rpdata-logpaste/post.go

package main

import (
	"bufio"
	"errors"
	"io"
	"strconv"
	"strings"
	"time"
)

// ErrNotPost is returned by parsePost if the line is empty or not a post.
var ErrNotPost = errors.New("not a post")

// ErrTooShort is returned by parsePost if the line too short to be a post.
var ErrTooShort = errors.New("post too short")

// ErrInvalidTimestamp is returned by parsePost if the line is empty or not a post.
var ErrInvalidTimestamp = errors.New("invalid timestamp")

// A Post is a part of a log.
type Post struct {
	Time time.Time
	Kind string
	Nick string
	Text string
}

func parsePosts(reader io.Reader, date time.Time) ([]Post, error) {
	prev := Post{}
	posts := make([]Post, 0, 8)
	bufReader := bufio.NewReader(reader)

	for {
		line, err := bufReader.ReadString('\n')
		if err != nil && err != io.EOF {
			return nil, err
		}

		if len(line) > 8 {
			post, err := parsePost(strings.Trim(line, "  \n\r"), date, prev)
			if err != nil {
				return nil, err
			}

			posts = append(posts, post)
			prev = post
		}

		if err == io.EOF {
			break
		}
	}

	return posts, nil
}

func parsePost(line string, date time.Time, prev Post) (Post, error) {
	// Do basic validation
	line = strings.Trim(line, "  \t\n\r")
	if len(line) == 0 || !strings.HasPrefix(line, "[") {
		return Post{}, ErrNotPost
	}

	// Parse timestamp
	tsEndIndex := strings.IndexByte(line, ']')
	if tsEndIndex == -1 || len(line) < tsEndIndex+5 {
		return Post{}, ErrNotPost
	}
	tsStr := line[1:tsEndIndex]
	tsSplit := strings.Split(tsStr, ":")
	tsUnits := make([]int, len(tsSplit))
	if len(tsSplit) < 2 {
		return Post{}, ErrNotPost
	}
	for i := range tsSplit {
		n, err := strconv.Atoi(tsSplit[i])
		if err != nil {
			return Post{}, ErrNotPost
		}

		tsUnits[i] = n
	}
	if len(tsUnits) == 2 {
		tsUnits = append(tsUnits, 0)
	}

	ts := time.Date(date.Year(), date.Month(), date.Day(), tsUnits[0], tsUnits[1], tsUnits[2], 0, date.Location())
	if !prev.Time.IsZero() && prev.Time.After(ts) {
		ts = ts.AddDate(0, 0, 1)
	}

	if line[tsEndIndex+2] == '*' {
		split := strings.SplitN(line[tsEndIndex+4:], " ", 2)

		post := Post{
			Time: ts,
			Kind: "action",
			Nick: strings.TrimLeft(split[0], "+@!~"),
			Text: split[1],
		}

		if post.Nick[0] == '=' {
			post.Kind = "scene"
		}

		return post, nil
	} else if line[tsEndIndex+2] == '<' {
		split := strings.SplitN(line[tsEndIndex+2:], " ", 2)

		post := Post{
			Time: ts,
			Kind: "text",
			Nick: strings.TrimLeft(split[0][1:len(split[0])-1], "+@!~"),
			Text: split[1],
		}

		if post.Nick[0] == '=' {
			post.Kind = "scene"
		}

		return post, nil
	} else {
		return Post{}, ErrNotPost
	}
}