import re

from .glean import GLEAN_DISTRIBUTION_TYPES

GLAM_PRODUCT_MAPPINGS = {
    "org.mozilla.fenix": ("fenix", ""),
    "org.mozilla.firefox_beta": ("fenix", "beta"),
    "org.mozilla.firefox": ("fenix", "release"),
    "firefox.desktop": ("fog", ""),
}

# supported glam metric types, from:
# https://github.com/mozilla/bigquery-etl/blob/c48ab6649448cdf41191f6c24cb00fe46ca2323d/bigquery_etl/glam/clients_daily_histogram_aggregates.py#L39
# https://github.com/mozilla/bigquery-etl/blob/c48ab6649448cdf41191f6c24cb00fe46ca2323d/bigquery_etl/glam/clients_daily_scalar_aggregates.py#L95
SUPPORTED_GLAM_METRIC_TYPES = GLEAN_DISTRIBUTION_TYPES | {
    "boolean",
    "counter",
    "labeled_counter",
    "quantity",
    "timespan",
}

# ETL specific snakecase taken from:
# https://github.com/mozilla/bigquery-etl/blob/master/bigquery_etl/util/common.py
#
# Search for all camelCase situations in reverse with arbitrary lookaheads.
REV_WORD_BOUND_PAT = re.compile(
    r"""
    \b                                  # standard word boundary
    |(?<=[a-z][A-Z])(?=\d*[A-Z])        # A7Aa -> A7|Aa boundary
    |(?<=[a-z][A-Z])(?=\d*[a-z])        # a7Aa -> a7|Aa boundary
    |(?<=[A-Z])(?=\d*[a-z])             # a7A -> a7|A boundary
    """,
    re.VERBOSE,
)


def etl_snake_case(line: str) -> str:
    """Convert a string into a snake_cased string."""
    # replace non-alphanumeric characters with spaces in the reversed line
    subbed = re.sub(r"[^\w]|_", " ", line[::-1])
    # apply the regex on the reversed string
    words = REV_WORD_BOUND_PAT.split(subbed)
    # filter spaces between words and snake_case and reverse again
    return "_".join([w.lower() for w in words if w.strip()])[::-1]


def get_glam_metadata_for_metric(app, metric, ping_name):
    # GLAM data is per application and per ping (well,
    # only the metrics ping right now), when it exists
    metric_type = metric.definition["type"]
    if not GLAM_PRODUCT_MAPPINGS.get(app.app_id):
        return {"glam_unsupported_reason": "This application is not supported by GLAM."}
    elif metric.bq_prefix in ["client_info", "ping_info"]:
        return {"glam_unsupported_reason": "Internal Glean metrics are not supported by GLAM."}
    elif metric_type not in SUPPORTED_GLAM_METRIC_TYPES:
        return {
            "glam_unsupported_reason": "Currently GLAM does not support "
            f"`{metric_type}` metrics."
        }
    elif ping_name != "metrics":
        return {
            "glam_unsupported_reason": (
                f"Metrics sent in the `{ping_name}` ping are not supported "
                "by GLAM "
                "([mozilla/glam#1652](https://github.com/mozilla/glam/issues/1652))."
            )
        }

    (glam_product, glam_app_id) = GLAM_PRODUCT_MAPPINGS[app.app_id]
    glam_metric_id = etl_snake_case(metric.identifier)
    return {
        "glam_url": (
            "https://glam.telemetry.mozilla.org/"
            + f"{glam_product}/probe/{glam_metric_id}/explore"
            + f"?app_id={glam_app_id}"
        )
    }