elliotchance/gedcom

package html

import (
    "io"
    "time"

    "github.com/elliotchance/gedcom/v39"
)

type Age struct {
    start, end gedcom.Age
}

func NewAge(start, end gedcom.Age) *Age {
    return &Age{
        start: start,
        end:   end,
    }
}

func (c *Age) string(age gedcom.Age) string {
    if !age.IsKnown {
        return ""
    }

    // Ages can be after death, such as a burial or probate. It does not make
    // sense to show these ages.
    if age.Constraint == gedcom.AgeConstraintAfterDeath {
        return ""
    }

    return age.String()
}

func (c *Age) WriteHTMLTo(w io.Writer) (int64, error) {
    start := c.string(c.start)
    end := c.string(c.end)

    switch {
    case start == "" && end == "":
        return writeNothing()

    case end == "":
        return writeSprintf(w, `after %s`, start)

    case start == end:
        return writeString(w, start)

    case start == "":
        return writeSprintf(w, `until %s`, end)

    case start != end:
        // If there is less than a year between the two dates (which is very
        // common because many dates only contain a year) we collapse it into a
        // single minimum value.
        //
        // The 1.05 is to account for slight rounding errors and leap years.
        //
        // We only need to check one direction because Age() and AgeAt()
        // guarantee that the end is greater than or equal to the start.
        yearAndABit := float64(gedcom.Year) * 1.05

        if c.end.Age-c.start.Age < time.Duration(yearAndABit) {
            return writeString(w, start)
        }

        return writeSprintf(w, `from %s to %s`, start, end)
    }

    return writeNothing()
}