package tequat

import (
    "strings"
)

// Normalised is pure.
func (tqa TQA) Normalised() TQA {
    atoms := []Atom(tqa)

    // search for a signature block and move it to the end
    if true {
        var signatureblock *SignatureBlock
        // [2023-02-15, jfrech] TODO Think about recognising the non-space terminated mark. (Maybe only when it is the very last non-quote non-attachment atom?)
        for _, mark := range []string{"-- ", "--"} {
            for j := len(atoms)-1; signatureblock == nil && j >= 0; j-- {
                if text, ok := atoms[j].(Text); ok {
                    if strings.HasPrefix(text.Raw, mark + "\n") {
                        atoms = append(atoms[:j], atoms[j+1:]...)
                        signatureblock = &SignatureBlock{text.Raw[len(mark + "\n"):]}
                    } else if k := strings.Index(text.Raw, "\n" + mark + "\n"); k != -1 {
                        atoms[j] = Text{text.Raw[:k+1]}
                        signatureblock = &SignatureBlock{text.Raw[k+1+len(mark + "\n"):]}
                    }
                }
            }
        }
        if signatureblock != nil {
            atoms = append(atoms, *signatureblock)
        }
    }

    // TODO combine text atoms

    return TQA(atoms)
}