"""Tests for the evolution tables SQL migration (WP-04).

Unit tests read the SQL migration file and verify that all required DDL
statements are present — no database connection needed.

Integration tests (marked with pytest.mark.integration) execute the
migration against a live PostgreSQL instance and verify structure via
information_schema and pg_indexes.  They are skipped automatically when
POSTGRES_HOST is not set, and are designed to be idempotent so they can
be run against the dev database without damage.

To run integration tests locally:
    POSTGRES_HOST=localhost POSTGRES_USER=pd_admin POSTGRES_PASSWORD=... \\
        pytest tests/test_evolution_migration.py -m integration
"""

import os
import re

import pytest

# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

MIGRATION_PATH = os.path.join(
    os.path.dirname(__file__),
    "..",
    "migrations",
    "2026-03-12_add_evolution_tables.sql",
)


def _load_sql():
    """Return the migration file text, lowercased and with SQL comments stripped.

    Single-line comments (-- ...) are removed before pattern matching so that
    the verification regexes do not accidentally match against comment text.
    """
    with open(MIGRATION_PATH) as fh:
        content = fh.read()
    content = re.sub(r"--[^\n]*", "", content)
    return content.lower()


# ---------------------------------------------------------------------------
# Unit tests — SQL file content, no DB required
# ---------------------------------------------------------------------------


def test_migration_file_exists():
    """The migration file must exist at the expected path."""
    assert os.path.isfile(MIGRATION_PATH), f"Migration file not found: {MIGRATION_PATH}"


def test_migration_wrapped_in_transaction():
    """Migration must be wrapped in BEGIN / COMMIT for atomicity."""
    sql = _load_sql()
    assert "begin;" in sql
    assert "commit;" in sql


def test_all_five_tables_created():
    """Each of the five new tables must have a CREATE TABLE IF NOT EXISTS statement."""
    sql = _load_sql()
    expected = [
        "player_season_stats",
        "evolution_track",
        "evolution_card_state",
        "evolution_tier_boost",
        "evolution_cosmetic",
    ]
    for table in expected:
        pattern = rf"create table if not exists {table}"
        assert re.search(
            pattern, sql
        ), f"Missing CREATE TABLE IF NOT EXISTS for {table}"


def test_player_season_stats_columns():
    """player_season_stats must contain all required batting, pitching and meta columns."""
    sql = _load_sql()
    required_columns = [
        "player_id",
        "team_id",
        "season",
        "games_batting",
        "pa",
        "ab",
        "hits",
        "hr",
        "doubles",
        "triples",
        "bb",
        "hbp",
        "so",
        "rbi",
        "runs",
        "sb",
        "cs",
        "games_pitching",
        "outs",
        r"\bk\b",  # pitcher Ks — match as whole word to avoid false positives
        "bb_allowed",
        "hits_allowed",
        "hr_allowed",
        "wins",
        "losses",
        "saves",
        "holds",
        "blown_saves",
        "last_game_id",
        "last_updated_at",
    ]
    # Extract just the player_season_stats block for targeted matching
    match = re.search(
        r"create table if not exists player_season_stats\s*\((.+?)\);",
        sql,
        re.DOTALL,
    )
    assert match, "Could not locate player_season_stats table body"
    block = match.group(1)
    for col in required_columns:
        assert re.search(
            col, block
        ), f"Missing column pattern '{col}' in player_season_stats"


def test_evolution_track_columns():
    """evolution_track must have name, card_type, formula, and t1–t4 threshold columns."""
    sql = _load_sql()
    match = re.search(
        r"create table if not exists evolution_track\s*\((.+?)\);",
        sql,
        re.DOTALL,
    )
    assert match, "Could not locate evolution_track table body"
    block = match.group(1)
    for col in [
        "name",
        "card_type",
        "formula",
        "t1_threshold",
        "t2_threshold",
        "t3_threshold",
        "t4_threshold",
    ]:
        assert col in block, f"Missing column '{col}' in evolution_track"


def test_evolution_card_state_columns():
    """evolution_card_state must have player_id, team_id, track_id, tier, value, and flags."""
    sql = _load_sql()
    match = re.search(
        r"create table if not exists evolution_card_state\s*\((.+?)\);",
        sql,
        re.DOTALL,
    )
    assert match, "Could not locate evolution_card_state table body"
    block = match.group(1)
    for col in [
        "player_id",
        "team_id",
        "track_id",
        "current_tier",
        "current_value",
        "fully_evolved",
        "last_evaluated_at",
    ]:
        assert col in block, f"Missing column '{col}' in evolution_card_state"


def test_phase2_stubs_have_card_state_fk():
    """evolution_tier_boost and evolution_cosmetic must reference evolution_card_state."""
    sql = _load_sql()
    for table in ["evolution_tier_boost", "evolution_cosmetic"]:
        match = re.search(
            rf"create table if not exists {table}\s*\((.+?)\);",
            sql,
            re.DOTALL,
        )
        assert match, f"Could not locate {table} table body"
        block = match.group(1)
        assert "card_state_id" in block, f"Missing card_state_id FK in {table}"
        assert (
            "evolution_card_state" in block
        ), f"Missing FK reference to evolution_card_state in {table}"


def test_indexes_use_if_not_exists():
    """All CREATE INDEX statements must use IF NOT EXISTS for idempotency."""
    sql = _load_sql()
    raw_indexes = re.findall(r"create(?:\s+unique)?\s+index\s+(?!if not exists)", sql)
    assert not raw_indexes, (
        f"Found CREATE INDEX without IF NOT EXISTS — migration is not idempotent. "
        f"Matches: {raw_indexes}"
    )


def test_required_indexes_present():
    """The migration must create all required indexes."""
    sql = _load_sql()
    expected_indexes = [
        "player_season_stats_player_team_season_uniq",
        "player_season_stats_team_season_idx",
        "player_season_stats_player_season_idx",
        "evolution_card_state_player_team_uniq",
    ]
    for idx in expected_indexes:
        assert idx in sql, f"Missing index '{idx}' in migration"


def test_player_season_stats_unique_index_covers_correct_columns():
    """The UNIQUE index on player_season_stats must cover (player_id, team_id, season)."""
    sql = _load_sql()
    match = re.search(
        r"player_season_stats_player_team_season_uniq[^\n]*\n\s+on player_season_stats\s*\(([^)]+)\)",
        sql,
    )
    assert match, "Could not locate UNIQUE index definition for player_season_stats"
    cols = match.group(1)
    for col in ["player_id", "team_id", "season"]:
        assert (
            col in cols
        ), f"Column '{col}' missing from UNIQUE index on player_season_stats"


def test_evolution_card_state_unique_index_covers_correct_columns():
    """The UNIQUE index on evolution_card_state must cover (player_id, team_id)."""
    sql = _load_sql()
    match = re.search(
        r"evolution_card_state_player_team_uniq[^\n]*\n\s+on evolution_card_state\s*\(([^)]+)\)",
        sql,
    )
    assert match, "Could not locate UNIQUE index definition for evolution_card_state"
    cols = match.group(1)
    for col in ["player_id", "team_id"]:
        assert (
            col in cols
        ), f"Column '{col}' missing from UNIQUE index on evolution_card_state"


def test_card_variant_column_added():
    """card.variant must be added as INTEGER NULL DEFAULT NULL."""
    sql = _load_sql()
    assert "alter table card" in sql
    assert "add column if not exists variant" in sql
    match = re.search(
        r"add column if not exists variant\s+(\w+)\s+null\s+default null", sql
    )
    assert match, "card.variant must be INTEGER NULL DEFAULT NULL"
    assert (
        match.group(1) == "integer"
    ), f"card.variant type must be INTEGER, got {match.group(1)}"


def test_battingcard_image_url_column_added():
    """battingcard.image_url must be added as VARCHAR(500) NULL."""
    sql = _load_sql()
    assert "alter table battingcard" in sql
    match = re.search(
        r"alter table battingcard\s+add column if not exists image_url\s+varchar\(500\)\s+null",
        sql,
    )
    assert match, "battingcard.image_url must be VARCHAR(500) NULL with IF NOT EXISTS"


def test_pitchingcard_image_url_column_added():
    """pitchingcard.image_url must be added as VARCHAR(500) NULL."""
    sql = _load_sql()
    assert "alter table pitchingcard" in sql
    match = re.search(
        r"alter table pitchingcard\s+add column if not exists image_url\s+varchar\(500\)\s+null",
        sql,
    )
    assert match, "pitchingcard.image_url must be VARCHAR(500) NULL with IF NOT EXISTS"


def test_add_column_uses_if_not_exists():
    """All ALTER TABLE ADD COLUMN statements must use IF NOT EXISTS for idempotency."""
    sql = _load_sql()
    # Find any ADD COLUMN that is NOT followed by IF NOT EXISTS
    bad_adds = re.findall(r"add column(?!\s+if not exists)", sql)
    assert not bad_adds, (
        f"Found ADD COLUMN without IF NOT EXISTS — migration is not idempotent. "
        f"Count: {len(bad_adds)}"
    )


def test_rollback_section_present():
    """Migration must include rollback DROP statements for documentation."""
    with open(MIGRATION_PATH) as fh:
        raw = fh.read().lower()
    assert "rollback" in raw
    assert "drop table if exists" in raw


# ---------------------------------------------------------------------------
# Integration tests — require live PostgreSQL
# ---------------------------------------------------------------------------

_pg_available = bool(os.environ.get("POSTGRES_HOST"))

pytestmark_integration = pytest.mark.skipif(
    not _pg_available,
    reason="POSTGRES_HOST not set — skipping integration tests",
)


@pytestmark_integration
def test_integration_fresh_migration_creates_all_tables(pg_conn):
    """Running the migration on a clean schema creates all 5 expected tables."""
    cur = pg_conn.cursor()
    cur.execute("""
        SELECT table_name FROM information_schema.tables
        WHERE table_schema = 'public'
          AND table_name IN (
            'player_season_stats', 'evolution_track', 'evolution_card_state',
            'evolution_tier_boost', 'evolution_cosmetic'
          )
        """)
    found = {row[0] for row in cur.fetchall()}
    cur.close()
    expected = {
        "player_season_stats",
        "evolution_track",
        "evolution_card_state",
        "evolution_tier_boost",
        "evolution_cosmetic",
    }
    assert found == expected, f"Missing tables: {expected - found}"


@pytestmark_integration
def test_integration_idempotent_rerun(pg_conn):
    """Running the migration a second time must not raise any errors."""
    with open(MIGRATION_PATH) as fh:
        sql = fh.read()
    cur = pg_conn.cursor()
    cur.execute(sql)
    pg_conn.commit()
    cur.close()
    # If we reach here, the second run succeeded


@pytestmark_integration
def test_integration_required_indexes_exist(pg_conn):
    """All required indexes must be present in pg_indexes after migration."""
    cur = pg_conn.cursor()
    cur.execute("""
        SELECT indexname FROM pg_indexes
        WHERE tablename IN ('player_season_stats', 'evolution_card_state')
        """)
    found = {row[0] for row in cur.fetchall()}
    cur.close()
    expected = {
        "player_season_stats_player_team_season_uniq",
        "player_season_stats_team_season_idx",
        "player_season_stats_player_season_idx",
        "evolution_card_state_player_team_uniq",
    }
    assert expected.issubset(found), f"Missing indexes: {expected - found}"


@pytestmark_integration
def test_integration_fk_constraints_exist(pg_conn):
    """Foreign key constraints from evolution_card_state to player and team must exist."""
    cur = pg_conn.cursor()
    cur.execute("""
        SELECT tc.constraint_name, tc.table_name, kcu.column_name,
               ccu.table_name AS foreign_table
        FROM information_schema.table_constraints AS tc
        JOIN information_schema.key_column_usage AS kcu
          ON tc.constraint_name = kcu.constraint_name
        JOIN information_schema.constraint_column_usage AS ccu
          ON ccu.constraint_name = tc.constraint_name
        WHERE tc.constraint_type = 'FOREIGN KEY'
          AND tc.table_name = 'evolution_card_state'
        """)
    fks = {(row[2], row[3]) for row in cur.fetchall()}
    cur.close()
    assert (
        "player_id",
        "player",
    ) in fks, "FK from evolution_card_state.player_id to player missing"
    assert (
        "team_id",
        "team",
    ) in fks, "FK from evolution_card_state.team_id to team missing"
    assert (
        "track_id",
        "evolution_track",
    ) in fks, "FK from evolution_card_state.track_id to evolution_track missing"


@pytestmark_integration
def test_integration_existing_data_preserved(pg_conn):
    """Adding columns to card/battingcard/pitchingcard must not destroy existing rows."""
    cur = pg_conn.cursor()
    # Row counts should be non-negative and unchanged after migration
    for table in ("card", "battingcard", "pitchingcard"):
        cur.execute(f"SELECT COUNT(*) FROM {table}")
        count = cur.fetchone()[0]
        assert count >= 0, f"Unexpected row count for {table}: {count}"
    cur.close()


@pytestmark_integration
def test_integration_new_columns_nullable(pg_conn):
    """card.variant and battingcard/pitchingcard.image_url must be nullable."""
    cur = pg_conn.cursor()
    cur.execute("""
        SELECT table_name, column_name, is_nullable, column_default
        FROM information_schema.columns
        WHERE (table_name = 'card' AND column_name = 'variant')
           OR (table_name IN ('battingcard', 'pitchingcard') AND column_name = 'image_url')
        ORDER BY table_name, column_name
        """)
    rows = cur.fetchall()
    cur.close()
    assert len(rows) == 3, f"Expected 3 new columns, found {len(rows)}"
    for table_name, col_name, is_nullable, col_default in rows:
        assert is_nullable == "YES", f"{table_name}.{col_name} must be nullable"