package parse import ( "fmt" "strings" "time" "git.sr.ht/~rjarry/aerc/lib/log" ) const dateFmt = "2006-01-02" // ParseDateRange parses a date range into a start and end date. Dates are // expected to be in the YYYY-MM-DD format. // // Start and end dates are connected by the range operator ".." where end date // is not included in the date range. // // ParseDateRange can also parse open-ended ranges, i.e. start.. or ..end are // allowed. // // Relative date terms (such as "1 week 1 day" or "1w 1d") can be used, too. func DateRange(s string) (start, end time.Time, err error) { s = cleanInput(s) s = ensureRangeOp(s) i := strings.Index(s, "..") switch { case i < 0: // single date start, err = translate(s) if err != nil { err = fmt.Errorf("failed to parse date: %w", err) return } end = start.AddDate(0, 0, 1) case i == 0: // end date only if len(s) < 2 { err = fmt.Errorf("no date found") return } end, err = translate(s[2:]) if err != nil { err = fmt.Errorf("failed to parse date: %w", err) return } case i > 0: // start date first start, err = translate(s[:i]) if err != nil { err = fmt.Errorf("failed to parse date: %w", err) return } if len(s[i:]) <= 2 { return } // and end dates if available end, err = translate(s[(i + 2):]) if err != nil { err = fmt.Errorf("failed to parse date: %w", err) return } } return } type dictFunc = func(bool) time.Time // dict is a dictionary to translate words to dates. Map key must be at least 3 // characters for matching purposes. var dict map[string]dictFunc = map[string]dictFunc{ "today": func(_ bool) time.Time { return time.Now() }, "yesterday": func(_ bool) time.Time { return time.Now().AddDate(0, 0, -1) }, "week": func(this bool) time.Time { diff := 0 if !this { diff = -7 } return time.Now().AddDate(0, 0, daydiff(time.Monday)+diff) }, "month": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(0, diff, -t.Day()+1) }, "year": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, 0, -t.YearDay()+1) }, "monday": func(this bool) time.Time { diff := 0 if !this { diff = -7 } return time.Now().AddDate(0, 0, daydiff(time.Monday)+diff) }, "tuesday": func(this bool) time.Time { diff := 0 if !this { diff = -7 } return time.Now().AddDate(0, 0, daydiff(time.Tuesday)+diff) }, "wednesday": func(this bool) time.Time { diff := 0 if !this { diff = -7 } return time.Now().AddDate(0, 0, daydiff(time.Wednesday)+diff) }, "thursday": func(this bool) time.Time { diff := 0 if !this { diff = -7 } return time.Now().AddDate(0, 0, daydiff(time.Thursday)+diff) }, "friday": func(this bool) time.Time { diff := 0 if !this { diff = -7 } return time.Now().AddDate(0, 0, daydiff(time.Friday)+diff) }, "saturday": func(this bool) time.Time { diff := 0 if !this { diff = -7 } return time.Now().AddDate(0, 0, daydiff(time.Saturday)+diff) }, "sunday": func(this bool) time.Time { diff := 0 if !this { diff = -7 } return time.Now().AddDate(0, 0, daydiff(time.Sunday)+diff) }, "january": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.January), -t.Day()+1) }, "february": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.February), -t.Day()+1) }, "march": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.March), -t.Day()+1) }, "april": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.April), -t.Day()+1) }, "may": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.May), -t.Day()+1) }, "june": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.June), -t.Day()+1) }, "july": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.July), -t.Day()+1) }, "august": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.August), -t.Day()+1) }, "september": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.September), -t.Day()+1) }, "october": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.October), -t.Day()+1) }, "november": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.November), -t.Day()+1) }, "december": func(this bool) time.Time { diff := 0 if !this { diff = -1 } t := time.Now() return t.AddDate(diff, monthdiff(time.December), -t.Day()+1) }, } func daydiff(d time.Weekday) int { daydiff := d - time.Now().Weekday() if daydiff > 0 { return int(daydiff) - 7 } return int(daydiff) } func monthdiff(d time.Month) int { monthdiff := d - time.Now().Month() if monthdiff > 0 { return int(monthdiff) - 12 } return int(monthdiff) } // translate translates regular time words into date strings func translate(s string) (time.Time, error) { if s == "" { return time.Now(), fmt.Errorf("empty string") } log.Tracef("input: %s", s) s0 := s // if next characters is integer, then parse a relative date if '0' <= s[0] && s[0] <= '9' && hasUnit(s) { relDate, err := RelativeDate(s) if err != nil { log.Errorf("could not parse relative date from '%s': %v", s0, err) } else { log.Tracef("relative date: translated to %v from %s", relDate, s0) return bod(relDate.Apply(time.Now())), nil } } // consult dictionary for terms translation s, this, hasPrefix := handlePrefix(s) for term, dateFn := range dict { if term == "month" && !hasPrefix { continue } if strings.Contains(term, s) { log.Tracef("dictionary: translated to %s from %s", term, s0) return bod(dateFn(this)), nil } } // this is a regular date, parse it in the normal format log.Infof("parse: translates %s to regular format", s0) return time.Parse(dateFmt, s) } // bod returns the begin of the day func bod(t time.Time) time.Time { y, m, d := t.Date() return time.Date(y, m, d, 0, 0, 0, 0, t.Location()) } func handlePrefix(s string) (string, bool, bool) { var hasPrefix bool this := true if strings.HasPrefix(s, "this") { hasPrefix = true s = strings.TrimPrefix(s, "this") } if strings.HasPrefix(s, "last") { hasPrefix = true this = false s = strings.TrimPrefix(s, "last") } return s, this, hasPrefix } func cleanInput(s string) string { s = strings.ToLower(s) s = strings.ReplaceAll(s, " ", "") s = strings.ReplaceAll(s, "_", "") return s } // RelDate is the relative date in the past, e.g. yesterday would be // represented as RelDate{0,0,1}. type RelDate struct { Year uint Month uint Day uint } func (d RelDate) Apply(t time.Time) time.Time { return t.AddDate(-int(d.Year), -int(d.Month), -int(d.Day)) } // ParseRelativeDate parses a string of relative terms into a DateAdd. // // Syntax: N (year|month|week|day) .. // // The following are valid inputs: // 5weeks1day // 5w1d // // Adapted from the Go stdlib in src/time/format.go func RelativeDate(s string) (RelDate, error) { s0 := s s = cleanInput(s) var da RelDate for s != "" { var n uint var err error // expect an integer if !('0' <= s[0] && s[0] <= '9') { return da, fmt.Errorf("not a valid relative term: %s", s0) } // consume integer n, s, err = leadingInt(s) if err != nil { return da, fmt.Errorf("cannot read integer in %s", s0) } // consume the units i := 0 for ; i < len(s); i++ { c := s[i] if '0' <= c && c <= '9' { break } } if i == 0 { return da, fmt.Errorf("missing unit in %s", s0) } u := s[:i] s = s[i:] switch u[0] { case 'y': da.Year += n case 'm': da.Month += n case 'w': da.Day += 7 * n case 'd': da.Day += n default: return da, fmt.Errorf("unknown unit %s in %s", u, s0) } } return da, nil } func hasUnit(s string) (has bool) { for _, u := range "ymwd" { if strings.Contains(s, string(u)) { return true } } return false } // leadingInt parses and returns the leading integer in s. // // Adapted from the Go stdlib in src/time/format.go func leadingInt(s string) (x uint, rem string, err error) { i := 0 for ; i < len(s); i++ { c := s[i] if c < '0' || c > '9' { break } x = x*10 + uint(c) - '0' } return x, s[i:], nil } func ensureRangeOp(s string) string { if strings.Contains(s, "..") { return s } s0 := s for _, m := range []string{"this", "last"} { for _, u := range []string{"year", "month", "week"} { term := m + u if strings.Contains(s, term) { if m == "last" { return s0 + "..this" + u } else { return s0 + ".." } } } } return s0 }