#!/usr/bin/env python3

import csv
import os
import time
from typing import List, Literal
import logging

from github import Github
from github.Commit import Commit
from github.CommitStatus import CommitStatus

from ci_config import CI_CONFIG, REQUIRED_CHECKS
from env_helper import GITHUB_REPOSITORY, GITHUB_RUN_URL
from pr_info import PRInfo, SKIP_MERGEABLE_CHECK_LABEL

RETRY = 5
CommitStatuses = List[CommitStatus]
MERGEABLE_NAME = "Mergeable Check"


def override_status(status: str, check_name: str, invert: bool = False) -> str:
    if CI_CONFIG["tests_config"].get(check_name, {}).get("force_tests", False):
        return "success"

    if invert:
        if status == "success":
            return "error"
        return "success"

    return status


def get_commit(gh: Github, commit_sha: str, retry_count: int = RETRY) -> Commit:
    for i in range(retry_count):
        try:
            repo = gh.get_repo(GITHUB_REPOSITORY)
            commit = repo.get_commit(commit_sha)
            break
        except Exception as ex:
            if i == retry_count - 1:
                raise ex
            time.sleep(i)

    return commit


def post_commit_status(
    gh: Github, sha: str, check_name: str, description: str, state: str, report_url: str
) -> None:
    for i in range(RETRY):
        try:
            commit = get_commit(gh, sha, 1)
            commit.create_status(
                context=check_name,
                description=description,
                state=state,
                target_url=report_url,
            )
            break
        except Exception as ex:
            if i == RETRY - 1:
                raise ex
            time.sleep(i)


def post_commit_status_to_file(
    file_path: str, description: str, state: str, report_url: str
) -> None:
    if os.path.exists(file_path):
        raise Exception(f'File "{file_path}" already exists!')
    with open(file_path, "w", encoding="utf-8") as f:
        out = csv.writer(f, delimiter="\t")
        out.writerow([state, report_url, description])


def get_commit_filtered_statuses(commit: Commit) -> CommitStatuses:
    """
    Squash statuses to latest state
    1. context="first", state="success", update_time=1
    2. context="second", state="success", update_time=2
    3. context="first", stat="failure", update_time=3
    =========>
    1. context="second", state="success"
    2. context="first", stat="failure"
    """
    filtered = {}
    for status in sorted(commit.get_statuses(), key=lambda x: x.updated_at):
        filtered[status.context] = status
    return list(filtered.values())


def remove_labels(gh: Github, pr_info: PRInfo, labels_names: List[str]) -> None:
    repo = gh.get_repo(GITHUB_REPOSITORY)
    pull_request = repo.get_pull(pr_info.number)
    for label in labels_names:
        pull_request.remove_from_labels(label)


def post_labels(gh: Github, pr_info: PRInfo, labels_names: List[str]) -> None:
    repo = gh.get_repo(GITHUB_REPOSITORY)
    pull_request = repo.get_pull(pr_info.number)
    for label in labels_names:
        pull_request.add_to_labels(label)


def format_description(description: str) -> str:
    if len(description) > 140:
        description = description[:137] + "..."
    return description


def set_mergeable_check(
    commit: Commit,
    description: str = "",
    state: Literal["success", "failure"] = "success",
) -> None:
    commit.create_status(
        context=MERGEABLE_NAME,
        description=description,
        state=state,
        target_url=GITHUB_RUN_URL,
    )


def update_mergeable_check(gh: Github, pr_info: PRInfo, check_name: str) -> None:
    not_run = (
        pr_info.labels.intersection({SKIP_MERGEABLE_CHECK_LABEL, "release"})
        or check_name not in REQUIRED_CHECKS
        or pr_info.release_pr
        or pr_info.number == 0
    )
    if not_run:
        # Let's avoid unnecessary work
        return

    logging.info("Update Mergeable Check by %s", check_name)

    commit = get_commit(gh, pr_info.sha)
    statuses = get_commit_filtered_statuses(commit)

    required_checks = [
        status for status in statuses if status.context in REQUIRED_CHECKS
    ]

    mergeable_status = None
    for status in statuses:
        if status.context == MERGEABLE_NAME:
            mergeable_status = status
            break

    success = []
    fail = []
    for status in required_checks:
        if status.state == "success":
            success.append(status.context)
        else:
            fail.append(status.context)

    if fail:
        description = "failed: " + ", ".join(fail)
        if success:
            description += "; succeeded: " + ", ".join(success)
        description = format_description(description)
        if mergeable_status is None or mergeable_status.description != description:
            set_mergeable_check(commit, description, "failure")
        return

    description = ", ".join(success)
    description = format_description(description)
    if mergeable_status is None or mergeable_status.description != description:
        set_mergeable_check(commit, description)