from pathlib import Path

import pandas as pd
import pytest

import reference_parser as rp


MEDLINE_SAMPLE = """PMID- 12345
TI  - A study about something
AB  - This is the abstract
      continued on next line
AU  - Smith J
AU  - Doe J
FAU - Smith, John
FAU - Doe, Jane
JT  - Journal of Testing
TA  - J Test
DP  - 2020 Jan
AID - 10.1000/xyz123 [doi]
LA  - eng
PT  - Journal Article
MH  - Testing
OT  - keyword1

PMID- 67890
TI  - Second study
AB  - Another abstract
JT  - Journal Two
DP  - 2019
"""

RIS_SAMPLE = """TY  - JOUR
TI  - RIS Study Title
AU  - Author, A
AU  - Author, B
AB  - RIS abstract text
JO  - RIS Journal
PY  - 2021
DO  - 10.2000/ABC
KW  - kw1
KW  - kw2
ER  -

TY  - JOUR
TI  - RIS Study Two
AB  - Another RIS abstract
JO  - RIS Journal Two
PY  - 2018
DO  - https://doi.org/10.3000/def
ER  -
"""


# ---------- MEDLINE parsing ----------


def test_parse_medline_text_splits_records_and_joins_continuations():
    records = rp.parse_medline_text(MEDLINE_SAMPLE)
    assert len(records) == 2
    assert records[0]["AB"] == "This is the abstract continued on next line"
    assert records[0]["AU"] == ["Smith J", "Doe J"]


def test_normalize_medline_records_extracts_expected_fields():
    records = rp.parse_medline_text(MEDLINE_SAMPLE)
    rows = rp.normalize_medline_records(records, Path("dummy.txt"))
    assert len(rows) == 2

    first = rows[0]
    assert first["PMID"] == "12345"
    assert first["Title"] == "A study about something"
    assert first["Authors"] == "Smith J; Doe J"
    assert first["FullAuthors"] == "Smith, John; Doe, Jane"
    assert first["Journal"] == "Journal of Testing"
    assert first["Year"] == "2020"
    assert first["DOI"] == "10.1000/xyz123"
    assert first["URL"] == "https://pubmed.ncbi.nlm.nih.gov/12345/"
    assert first["SourceFormat"] == "MEDLINE"

    second = rows[1]
    assert second["PMID"] == "67890"
    assert second["DOI"] == ""


# ---------- RIS parsing ----------


def test_parse_ris_text_splits_on_er_tag():
    records = rp.parse_ris_text(RIS_SAMPLE)
    assert len(records) == 2
    assert records[0]["TI"] == ["RIS Study Title"]
    assert records[0]["AU"] == ["Author, A", "Author, B"]


def test_normalize_ris_records_builds_doi_url():
    records = rp.parse_ris_text(RIS_SAMPLE)
    rows = rp.normalize_ris_records(records, Path("dummy.ris"))
    assert len(rows) == 2

    first = rows[0]
    assert first["Title"] == "RIS Study Title"
    assert first["Authors"] == "Author, A; Author, B"
    assert first["DOI"] == "10.2000/ABC"
    assert first["URL"] == "https://doi.org/10.2000/ABC"
    assert first["Keywords"] == "kw1; kw2"
    assert first["SourceFormat"] == "RIS"

    second = rows[1]
    # Already a full URL DOI value: used as-is, not double-wrapped.
    assert second["URL"] == "https://doi.org/10.3000/def"


# ---------- Dedup key ----------


def test_build_dedup_key_prefers_doi_over_pmid_and_title():
    row = pd.Series({"DOI": "10.1/ABC", "PMID": "111", "Title": "X", "Year": "2020"})
    assert rp.build_dedup_key(row) == "doi:10.1/abc"


def test_build_dedup_key_strips_doi_url_prefix():
    row = pd.Series({"DOI": "https://doi.org/10.1/ABC", "PMID": "", "Title": "", "Year": ""})
    assert rp.build_dedup_key(row) == "doi:10.1/abc"


def test_build_dedup_key_falls_back_to_pmid():
    row = pd.Series({"DOI": "", "PMID": "999", "Title": "X", "Year": "2020"})
    assert rp.build_dedup_key(row) == "pmid:999"


def test_build_dedup_key_falls_back_to_title_year():
    row = pd.Series({"DOI": "", "PMID": "", "Title": "  Some   Title  ", "Year": "2020"})
    assert rp.build_dedup_key(row) == "title_year:some title_2020"


# ---------- End-to-end process_paths ----------


def test_process_paths_dedups_same_doi_across_formats(tmp_path: Path):
    medline_path = tmp_path / "pubmed.txt"
    medline_path.write_text(
        "PMID- 1\nTI  - Shared Study\nAB  - abs\nAID - 10.9/shared [doi]\nDP  - 2020\n",
        encoding="utf-8",
    )
    ris_path = tmp_path / "scopus.ris"
    ris_path.write_text(
        "TY  - JOUR\nTI  - Shared Study (Scopus copy)\nDO  - https://doi.org/10.9/SHARED\nPY  - 2020\nER  -\n",
        encoding="utf-8",
    )

    df = rp.process_paths([medline_path, ris_path])
    assert len(df) == 1
    assert "DedupKey" not in df.columns
    assert "SourceFormat" not in df.columns


def test_process_paths_keeps_distinct_records(tmp_path: Path):
    medline_path = tmp_path / "pubmed.txt"
    medline_path.write_text(
        "PMID- 1\nTI  - Study One\nAB  - abs1\nDP  - 2020\n\n"
        "PMID- 2\nTI  - Study Two\nAB  - abs2\nDP  - 2021\n",
        encoding="utf-8",
    )

    df = rp.process_paths([medline_path])
    assert len(df) == 2


def test_process_paths_returns_empty_df_for_missing_file(tmp_path: Path):
    df = rp.process_paths([tmp_path / "does_not_exist.txt"])
    assert df.empty


def test_process_paths_writes_excel_when_output_path_given(tmp_path: Path):
    medline_path = tmp_path / "pubmed.txt"
    medline_path.write_text("PMID- 1\nTI  - Study One\nAB  - abs1\nDP  - 2020\n", encoding="utf-8")
    output_path = tmp_path / "out.xlsx"

    df = rp.parse_references([medline_path], output_path)
    assert output_path.exists()
    reloaded = pd.read_excel(output_path, engine="openpyxl")
    assert len(reloaded) == len(df) == 1