"""matching/ranking.py — the shared tier-1 ranker.

Two things are being protected here:

  1. Find Talent's numbers did not change when relevance_score moved out of
     talent/plugins.py. The scoring tiers were tuned against live LinkedIn
     pools, so a silent shift would be a regression nobody would notice until
     the ordering looked wrong.
  2. A banked CV maps onto the same profile shape and therefore scores the
     same as the equivalent sourced profile.
"""

import pytest

from matching.ranking import bank_row_as_profile, rank_bank_row, rank_profile
from talent.plugins import relevance_score

JOB = {
    "title": "Backend Engineer",
    "requirements": ["Python", "FastAPI", "PostgreSQL"],
    "optional_skills": ["Docker"],
}


class FakeBankRow:
    """The columns bank_row_as_profile reads. Not a SQLModel — this test must
    not need a database to check arithmetic."""

    def __init__(self, *, current_position="", current_company="", skills=None, full_text=""):
        self.current_position = current_position
        self.current_company = current_company
        self.skills = skills or []
        self.full_text = full_text


# --------------------------------------------------------------------------
# Find Talent parity
# --------------------------------------------------------------------------

def test_relevance_score_is_the_shared_ranker():
    """talent/plugins.py re-exports rather than reimplements."""
    assert relevance_score is rank_profile


@pytest.mark.parametrize(
    "profile",
    [
        {"current_title": "Backend Engineer", "headline": "", "skills": [], "summary": None},
        {"current_title": "", "headline": "Backend Engineer | Python", "skills": [], "summary": None},
        {"current_title": "", "headline": "", "skills": ["Python", "FastAPI"], "summary": None},
        {"current_title": "Senior Backend Engineer", "headline": "", "skills": ["Python"], "summary": None},
        {"current_title": None, "headline": None, "skills": None, "summary": None},
    ],
)
def test_find_talent_call_shape_still_works(profile):
    """The old call site passes exactly this shape, including Nones."""
    score = relevance_score(JOB, profile)
    assert isinstance(score, int)
    assert 0 <= score <= 100


def test_title_containment_beats_headline_phrase():
    """The tuned tier order: title containment 55 > headline phrase 45 > overlap.

    This is the rule the live pool forced (a keyword-stuffed headline must not
    outrank someone whose title IS the job title), so it is the one most worth
    pinning.
    """
    own_title = rank_profile(JOB, {"current_title": "Senior Backend Engineer", "headline": "", "skills": [], "summary": None})
    stuffed = rank_profile(JOB, {"current_title": "", "headline": "Backend Engineer | AI | ML", "skills": [], "summary": None})
    assert own_title > stuffed


def test_unrelated_profile_scores_low():
    score = rank_profile(JOB, {
        "current_title": "Pastry Chef",
        "headline": "Baking and patisserie",
        "skills": ["Sourdough"],
        "summary": None,
    })
    assert score < 20


def test_empty_job_does_not_crash_or_credit():
    assert rank_profile({}, {"current_title": "Backend Engineer", "skills": ["Python"]}) == 0


# --------------------------------------------------------------------------
# Banked CVs score identically to the equivalent sourced profile
# --------------------------------------------------------------------------

def test_bank_row_scores_the_same_as_the_equivalent_profile():
    row = FakeBankRow(
        current_position="Backend Engineer",
        current_company="Acme",
        skills=["Python", "FastAPI", "PostgreSQL"],
        full_text="Built services at Acme.",
    )
    equivalent = {
        "current_title": "Backend Engineer",
        "headline": "Acme",
        "skills": ["Python", "FastAPI", "PostgreSQL"],
        "summary": "Built services at Acme.",
    }
    assert rank_bank_row(JOB, row) == rank_profile(JOB, equivalent)


def test_bank_mapping_uses_company_as_the_headline():
    """A resume has no headline; the employer is the nearest equivalent."""
    profile = bank_row_as_profile(FakeBankRow(current_position="Engineer", current_company="Acme"))
    assert profile["current_title"] == "Engineer"
    assert profile["headline"] == "Acme"


def test_bank_mapping_truncates_full_text():
    """Feeding a whole resume to the token overlap would flatten every score."""
    from matching.ranking import RESUME_EXCERPT_CHARS

    profile = bank_row_as_profile(FakeBankRow(full_text="x" * (RESUME_EXCERPT_CHARS + 500)))
    assert len(profile["summary"]) == RESUME_EXCERPT_CHARS


def test_bank_mapping_survives_missing_columns():
    """A CV banked before extraction existed has no skills and no title."""
    profile = bank_row_as_profile(FakeBankRow())
    assert profile == {"current_title": "", "headline": "", "skills": [], "summary": ""}
    assert rank_bank_row(JOB, FakeBankRow()) == 0


def test_skills_only_bank_row_still_ranks():
    """Extraction is what makes an untitled CV rankable at all."""
    row = FakeBankRow(skills=["Python", "FastAPI", "PostgreSQL", "Docker"])
    assert rank_bank_row(JOB, row) > 0