import os
import re
from re import Pattern
from typing import Optional


BOT_COMMANDS_WIKI = "https://github.com/pytorch/pytorch/wiki/Bot-commands"

CIFLOW_LABEL = re.compile(r"^ciflow/.+")
CIFLOW_TRUNK_LABEL = re.compile(r"^ciflow/trunk")

OFFICE_HOURS_LINK = "https://github.com/pytorch/pytorch/wiki/Dev-Infra-Office-Hours"
CONTACT_US = f"Questions? Feedback? Please reach out to the [PyTorch DevX Team]({OFFICE_HOURS_LINK})"
ALTERNATIVES = f"Learn more about merging in the [wiki]({BOT_COMMANDS_WIKI})."


def has_label(labels: list[str], pattern: Pattern[str] = CIFLOW_LABEL) -> bool:
    return len(list(filter(pattern.match, labels))) > 0


class TryMergeExplainer:
    force: bool
    labels: list[str]
    pr_num: int
    org: str
    project: str
    ignore_current: bool

    has_trunk_label: bool
    has_ciflow_label: bool

    def __init__(
        self,
        force: bool,
        labels: list[str],
        pr_num: int,
        org: str,
        project: str,
        ignore_current: bool,
    ):
        self.force = force
        self.labels = labels
        self.pr_num = pr_num
        self.org = org
        self.project = project
        self.ignore_current = ignore_current

    def _get_flag_msg(
        self,
        ignore_current_checks: Optional[
            list[tuple[str, Optional[str], Optional[int]]]
        ] = None,
    ) -> str:
        if self.force:
            return (
                "Your change will be merged immediately since you used the force (-f) flag, "
                + "**bypassing any CI checks** (ETA: 1-5 minutes).  "
                + "Please use `-f` as last resort and instead consider `-i/--ignore-current` "
                + "to continue the merge ignoring current failures.  This will allow "
                + "currently pending tests to finish and report signal before the merge."
            )
        elif self.ignore_current and ignore_current_checks is not None:
            msg = f"Your change will be merged while ignoring the following {len(ignore_current_checks)} checks: "
            msg += ", ".join(f"[{x[0]}]({x[1]})" for x in ignore_current_checks)
            return msg
        else:
            return "Your change will be merged once all checks pass (ETA 0-4 Hours)."

    def get_merge_message(
        self,
        ignore_current_checks: Optional[
            list[tuple[str, Optional[str], Optional[int]]]
        ] = None,
    ) -> str:
        title = "### Merge started"
        main_message = self._get_flag_msg(ignore_current_checks)

        advanced_debugging = "\n".join(
            (
                "<details><summary>Advanced Debugging</summary>",
                "Check the merge workflow status ",
                f'<a href="{os.getenv("GH_RUN_URL")}">here</a>',
                "</details>",
            )
        )

        msg = title + "\n"
        msg += main_message + "\n\n"
        msg += ALTERNATIVES + "\n\n"
        msg += CONTACT_US
        msg += advanced_debugging
        return msg


def get_revert_message(org: str, project: str, pr_num: int) -> str:
    msg = (
        "@pytorchbot successfully started a revert job."
        + f" Check the current status [here]({os.getenv('GH_RUN_URL')}).\n"
    )
    msg += CONTACT_US
    return msg