"""
Citation formatters: APA 7th edition and AMA style.
Standard in nursing education programs.
"""


# ---------------------------------------------------------------------------
# APA 7th Edition
# ---------------------------------------------------------------------------

def format_apa7(article: dict) -> str:
    """
    APA 7th edition journal article format:
    Author, F. M., & Author, F. M. (Year). Title of article.
    *Journal Name*, *Volume*(Issue), Pages. https://doi.org/xxxxx
    """
    authors_str = _apa_authors(article.get("authors", []))
    year    = article.get("year") or "n.d."
    title   = _clean_title(article.get("title", ""))
    journal = article.get("journal", "")
    volume  = article.get("volume", "")
    issue   = article.get("issue", "")
    pages   = article.get("pages", "")
    doi     = _clean_doi(article.get("doi", ""))
    url     = article.get("url", "")

    citation = f"{authors_str} ({year}). {title}."

    if journal:
        citation += f" *{journal}*"
        if volume:
            citation += f", *{volume}*"
            if issue:
                citation += f"({issue})"
        if pages:
            citation += f", {pages}"
        citation += "."

    if doi:
        citation += f" https://doi.org/{doi}"
    elif url:
        citation += f" {url}"

    return citation


def _apa_authors(authors: list[str]) -> str:
    if not authors:
        return "Unknown Author"

    formatted = [_apa_single(a) for a in authors[:20]]

    # APA 7: 21+ authors → first 19, ellipsis, last author
    if len(authors) > 20:
        last = _apa_single(authors[-1])
        return ", ".join(formatted[:19]) + ", . . . " + last

    if len(formatted) == 1:
        return formatted[0]
    if len(formatted) == 2:
        return f"{formatted[0]}, & {formatted[1]}"
    return ", ".join(formatted[:-1]) + f", & {formatted[-1]}"


def _apa_single(name: str) -> str:
    name = name.strip()
    if name.lower() in ("et al.", "et al"):
        return "et al."
    if "," in name:
        # "Last, First M." → keep as-is, just ensure initials
        last, *rest = name.split(",", 1)
        initials = _initials(" ".join(rest))
        return f"{last.strip()}, {initials}"
    parts = name.split()
    if len(parts) >= 2:
        last = parts[-1]
        initials = _initials(" ".join(parts[:-1]))
        return f"{last}, {initials}"
    return name


# ---------------------------------------------------------------------------
# AMA Style
# ---------------------------------------------------------------------------

def format_ama(article: dict) -> str:
    """
    AMA citation format (used in some nursing / medical journals):
    Last FM, Last FM. Title. Journal. Year;Vol(Issue):Pages. doi:xxxxx
    """
    authors_str = _ama_authors(article.get("authors", []))
    year    = article.get("year", "")
    title   = _clean_title(article.get("title", ""))
    journal = article.get("journal", "")
    volume  = article.get("volume", "")
    issue   = article.get("issue", "")
    pages   = article.get("pages", "")
    doi     = _clean_doi(article.get("doi", ""))

    citation = f"{authors_str}. {title}. *{journal}*."

    if year:
        citation += f" {year}"
    if volume:
        citation += f";{volume}"
        if issue:
            citation += f"({issue})"
    if pages:
        citation += f":{pages}"
    citation += "."

    if doi:
        citation += f" doi:{doi}"

    return citation


def _ama_authors(authors: list[str]) -> str:
    if not authors:
        return "Unknown Author"

    formatted = [_ama_single(a) for a in authors[:6]]
    if len(authors) > 6:
        formatted.append("et al")

    return ", ".join(formatted)


def _ama_single(name: str) -> str:
    name = name.strip()
    if name.lower() in ("et al.", "et al", "et al."):
        return "et al"
    if "," in name:
        last, *rest = name.split(",", 1)
        initials = "".join(p[0].upper() for p in " ".join(rest).split() if p)
        return f"{last.strip()} {initials}"
    parts = name.split()
    if len(parts) >= 2:
        last = parts[-1]
        initials = "".join(p[0].upper() for p in parts[:-1] if p)
        return f"{last} {initials}"
    return name


# ---------------------------------------------------------------------------
# Shared helpers
# ---------------------------------------------------------------------------

def _initials(first_middle: str) -> str:
    """Convert first/middle name string to initials: "John Paul" → "J. P." """
    parts = first_middle.strip().split()
    return " ".join(p[0].upper() + "." for p in parts if p)


def _clean_title(title: str) -> str:
    return title.strip().rstrip(".")


def _clean_doi(doi: str) -> str:
    doi = doi.strip()
    for prefix in ("https://doi.org/", "http://doi.org/", "doi:", "doi: "):
        if doi.lower().startswith(prefix):
            doi = doi[len(prefix):]
    return doi