#!/usr/bin/env python3

from __future__ import annotations

import json
import os
from pathlib import Path


def read_lcov_summary(lcov_path: Path) -> tuple[int, int, int, int]:
    line_found = 0
    line_hit = 0
    function_found = 0
    function_hit = 0

    with lcov_path.open("r", encoding="utf-8") as fh:
        for raw_line in fh:
            line = raw_line.strip()
            try:
                if line.startswith("LF:"):
                    line_found += int(line[3:])
                elif line.startswith("LH:"):
                    line_hit += int(line[3:])
                elif line.startswith("FNF:"):
                    function_found += int(line[4:])
                elif line.startswith("FNH:"):
                    function_hit += int(line[4:])
            except ValueError:
                continue

    return line_found, line_hit, function_found, function_hit


def rate(hit: int, found: int) -> float:
    return round((hit / found) * 100, 2) if found else 0.0


def main() -> None:
    stage_dir = Path(os.environ["COVERAGE_STAGE_DIR"])
    lcov_path = Path(os.environ["COVERAGE_OUTPUT_DIR"]) / "lcov.info"
    line_found, line_hit, function_found, function_hit = read_lcov_summary(lcov_path)

    manifest = {
        "schema_version": 1,
        "generated_at": os.environ["COVERAGE_RUN_TIMESTAMP"],
        "generated_date": os.environ["COVERAGE_RUN_DATE"],
        "repository": os.environ["GITHUB_REPOSITORY"],
        "branch": os.environ["COVERAGE_BRANCH_NAME"],
        "branch_slug": os.environ["COVERAGE_BRANCH_SLUG"],
        "sha": os.environ["GITHUB_SHA"],
        "short_sha": os.environ["COVERAGE_SHORT_SHA"],
        "run_id": os.environ["GITHUB_RUN_ID"],
        "run_number": os.environ["GITHUB_RUN_NUMBER"],
        "run_attempt": os.environ["GITHUB_RUN_ATTEMPT"],
        "event_name": os.environ["GITHUB_EVENT_NAME"],
        "bucket": os.environ["COVERAGE_BUCKET"],
        "object_prefix": os.environ["COVERAGE_OBJECT_PREFIX"],
        "archive_name": os.environ["COVERAGE_ARCHIVE_NAME"],
        "manifest_name": os.environ["COVERAGE_MANIFEST_NAME"],
        "archive_key": os.environ["COVERAGE_ARCHIVE_KEY"],
        "manifest_key": os.environ["COVERAGE_MANIFEST_KEY"],
        "report_dir": os.environ["COVERAGE_SHORT_SHA"],
        "report_index": f"{os.environ['COVERAGE_SHORT_SHA']}/html/index.html",
        "lcov_path": f"{os.environ['COVERAGE_SHORT_SHA']}/lcov.info",
        "summary": {
            "lines": {
                "found": line_found,
                "hit": line_hit,
                "rate": rate(line_hit, line_found),
            },
            "functions": {
                "found": function_found,
                "hit": function_hit,
                "rate": rate(function_hit, function_found),
            },
        },
    }

    manifest_path = stage_dir / os.environ["COVERAGE_MANIFEST_NAME"]
    manifest_path.write_text(json.dumps(manifest, indent=2) + "\n", encoding="utf-8")


if __name__ == "__main__":
    main()