"""Regression tests for SFTP and S3 environment variable resolution.

Bug 2 (introduced commit ffa216d, fixed INT-2649):
  The Jenkins parameter was renamed from TRANSFER_FILES to SFTP_TRANSFER_ENABLED
  but config.py and feed_file_exporter.py still read only TRANSFER_FILES.
  Result: selecting "Transfer Files = Yes" in Jenkins had no effect — SFTP
  transfer was silently disabled on every production run.

  Fix: config.SFTP_TRANSFER_ENABLED now reads SFTP_TRANSFER_ENABLED first
  (Jenkins) and falls back to TRANSFER_FILES (CLI / legacy) for backwards compat.

Bug 3 (introduced commits 351445a / d2ea76c, fixed INT-2649):
  S3 config was originally split into separate S3_* and SAP_S3_* blocks,
  which has been corrected to a single S3_* namespace.
  This falsely implied two independent S3 subsystems. There is ONE S3
  transfer capability; whether a given PROCESS_MODE may use it is determined
  by the whitelist guard in feed_file_exporter.py.

  S3 transfer via S3_TRANSFER_ENABLED is whitelist-gated: only SAP_SETTLEMENT
  is currently authorised. Any other mode that sets S3_TRANSFER_ENABLED will
  receive a logged warning and be skipped gracefully (no crash, no transfer).
"""

import sys


def _reload_config(monkeypatch, **env_overrides):
    """Reload config module with a controlled environment.

    Removes the cached module so that os.environ changes take effect, applies
    overrides (None means delete the variable), and returns the fresh module.
    """
    monkeypatch.delitem(sys.modules, 'config', raising=False)
    for key, value in env_overrides.items():
        if value is None:
            monkeypatch.delenv(key, raising=False)
        else:
            monkeypatch.setenv(key, value)
    import config as cfg  # noqa: PLC0415 — intentional deferred import
    return cfg


# ── Bug 2: SFTP env var rename backwards-compat ───────────────────────────────

def test_sftp_enabled_via_new_jenkins_env_var(monkeypatch):
    """SFTP_TRANSFER_ENABLED=True (the Jenkins param) activates SFTP transfer."""
    cfg = _reload_config(
        monkeypatch,
        SFTP_TRANSFER_ENABLED='True',
        TRANSFER_FILES=None,
    )
    assert cfg.SFTP_TRANSFER_ENABLED == 1


def test_sftp_enabled_via_legacy_env_var(monkeypatch):
    """TRANSFER_FILES=True (CLI --enable-sftp path) still activates SFTP.

    Backwards-compatibility: the CLI sets TRANSFER_FILES; must not break.
    """
    cfg = _reload_config(
        monkeypatch,
        TRANSFER_FILES='True',
        SFTP_TRANSFER_ENABLED=None,
    )
    assert cfg.SFTP_TRANSFER_ENABLED == 1


def test_sftp_disabled_when_neither_env_var_set(monkeypatch):
    """SFTP is disabled (default False) when neither env var is present."""
    cfg = _reload_config(
        monkeypatch,
        SFTP_TRANSFER_ENABLED=None,
        TRANSFER_FILES=None,
    )
    assert cfg.SFTP_TRANSFER_ENABLED == 0


def test_sftp_disabled_explicitly_via_new_env_var(monkeypatch):
    """SFTP_TRANSFER_ENABLED=False explicitly disables SFTP."""
    cfg = _reload_config(
        monkeypatch,
        SFTP_TRANSFER_ENABLED='False',
        TRANSFER_FILES=None,
    )
    assert cfg.SFTP_TRANSFER_ENABLED == 0


def test_sftp_disabled_explicitly_via_legacy_env_var(monkeypatch):
    """TRANSFER_FILES=No explicitly disables SFTP (Jenkins Yes/No string)."""
    cfg = _reload_config(
        monkeypatch,
        TRANSFER_FILES='No',
        SFTP_TRANSFER_ENABLED=None,
    )
    assert cfg.SFTP_TRANSFER_ENABLED == 0


# ── Bug 3: S3 config reads correct env vars ──────────────────────────────────
# S3_TRANSFER_ENABLED is whitelist-gated to certain modes only.
# These tests confirm the config-level read is correct; whitelist enforcement
# at runtime is tested in test_s3_whitelist.py.

def test_s3_transfer_enabled_via_env_var(monkeypatch):
    """S3_TRANSFER_ENABLED=True is read correctly by config."""
    cfg = _reload_config(monkeypatch, S3_TRANSFER_ENABLED='True')
    assert cfg.S3_TRANSFER_ENABLED == 1


def test_s3_transfer_disabled_by_default(monkeypatch):
    """S3 transfer is disabled by default (no env var set)."""
    cfg = _reload_config(monkeypatch, S3_TRANSFER_ENABLED=None)
    assert cfg.S3_TRANSFER_ENABLED == 0


def test_s3_gzip_enabled_via_env_var(monkeypatch):
    """S3_GZIP_ENABLED=True enables gzip before S3 transfer."""
    cfg = _reload_config(monkeypatch, S3_GZIP_ENABLED='True')
    assert cfg.S3_GZIP_ENABLED == 1


def test_s3_gzip_defaults_to_enabled(monkeypatch):
    """S3 gzip defaults to enabled."""
    cfg = _reload_config(monkeypatch, S3_GZIP_ENABLED=None)
    assert cfg.S3_GZIP_ENABLED == 1


def test_s3_config_vars_read_from_env(monkeypatch):
    """S3_BUCKET, S3_FOLDER, S3_REGION are read from environment correctly."""
    cfg = _reload_config(
        monkeypatch,
        S3_TARGET_ENV='prod',
        S3_ROLE_ARN='arn:aws:iam::123456789012:role/custom-role',
        S3_BUCKET='my-prod-bucket',
        S3_FOLDER='stars/monthly',
        S3_REGION='eu-west-1',
    )
    assert cfg.S3_TARGET_ENV == 'prod'
    assert cfg.S3_ROLE_ARN == 'arn:aws:iam::123456789012:role/custom-role'
    assert cfg.S3_BUCKET == 'my-prod-bucket'
    assert cfg.S3_FOLDER == 'stars/monthly'
    assert cfg.S3_REGION == 'eu-west-1'


def test_s3_retries_and_backoff_from_env(monkeypatch):
    """S3_RETRIES and S3_RETRY_BACKOFF_SEC are read from environment."""
    cfg = _reload_config(
        monkeypatch,
        S3_RETRIES='5',
        S3_RETRY_BACKOFF_SEC='3.5',
    )
    assert cfg.S3_RETRIES == 5
    assert cfg.S3_RETRY_BACKOFF_SEC == 3.5


def test_s3_continue_on_error_from_env(monkeypatch):
    """S3_CONTINUE_ON_ERROR=True sets the config flag correctly."""
    cfg = _reload_config(monkeypatch, S3_CONTINUE_ON_ERROR='True')
    assert cfg.S3_CONTINUE_ON_ERROR == 1


def test_s3_bucket_and_folder_defaults(monkeypatch):
    """S3 bucket and folder defaults match the production values."""
    cfg = _reload_config(
        monkeypatch,
        S3_TARGET_ENV=None,
        S3_ROLE_ARN=None,
        S3_BUCKET=None,
        S3_FOLDER=None,
    )
    assert cfg.S3_TARGET_ENV == 'qa'
    assert cfg.S3_ROLE_ARN == (
        'arn:aws:iam::989790945997:role/'
        'qa-sme-feed-file-exporter-jenkins-role'
    )
    assert cfg.S3_BUCKET == 'prod-abacus-sap'
    assert cfg.S3_FOLDER == 'bw_settlement_files'


def test_s3_role_arn_defaults_from_prod_target_env(monkeypatch):
    """prod target env derives the prod Jenkins assume-role ARN."""
    cfg = _reload_config(
        monkeypatch,
        S3_TARGET_ENV='prod',
        S3_ROLE_ARN=None,
    )
    assert cfg.S3_TARGET_ENV == 'prod'
    assert cfg.S3_ROLE_ARN == (
        'arn:aws:iam::989790945997:role/'
        'prod-sme-feed-file-exporter-jenkins-role'
    )


def test_s3_target_env_invalid_value_falls_back_to_qa(monkeypatch):
    """Unexpected target env values fall back to the safe QA role."""
    cfg = _reload_config(
        monkeypatch,
        S3_TARGET_ENV='staging',
        S3_ROLE_ARN=None,
    )
    assert cfg.S3_TARGET_ENV == 'qa'
    assert cfg.S3_ROLE_ARN == (
        'arn:aws:iam::989790945997:role/'
        'qa-sme-feed-file-exporter-jenkins-role'
    )


def test_s3_bucket_and_folder_read_from_env(monkeypatch):
    """S3 target can be overridden via environment."""
    cfg = _reload_config(
        monkeypatch,
        S3_BUCKET='qa-abacus-sap',
        S3_FOLDER='bw_settlement_files',
    )
    assert cfg.S3_BUCKET == 'qa-abacus-sap'
    assert cfg.S3_FOLDER == 'bw_settlement_files'


def test_s3_transfer_mode_defaults_to_individual_files(monkeypatch):
    """S3 uploads individual files by default."""
    cfg = _reload_config(monkeypatch, S3_TRANSFER_MODE=None)
    assert cfg.S3_TRANSFER_MODE == 'Individual Files'


def test_s3_allowed_modes_defaults_to_sap_settlement(monkeypatch):
    """S3_ALLOWED_MODES defaults to {SAP_SETTLEMENT} when env var absent."""
    cfg = _reload_config(monkeypatch, S3_ALLOWED_MODES=None)
    assert cfg.S3_ALLOWED_MODES == frozenset({'SAP_SETTLEMENT'})


def test_s3_allowed_modes_parsed_from_env(monkeypatch):
    """S3_ALLOWED_MODES parses a comma-separated list into a frozenset."""
    cfg = _reload_config(monkeypatch, S3_ALLOWED_MODES='SAP_SETTLEMENT,US,GB')
    assert cfg.S3_ALLOWED_MODES == frozenset({'SAP_SETTLEMENT', 'US', 'GB'})


def test_s3_allowed_modes_strips_whitespace(monkeypatch):
    """Surrounding whitespace in S3_ALLOWED_MODES entries is stripped."""
    cfg = _reload_config(monkeypatch, S3_ALLOWED_MODES=' SAP_SETTLEMENT , US ')
    assert cfg.S3_ALLOWED_MODES == frozenset({'SAP_SETTLEMENT', 'US'})