from collections import Counter, defaultdict
from pathlib import Path
from typing import Iterable
import csv

from serato_doctor.models.reference import ReferenceResult


def write_missing_report(results: Iterable[ReferenceResult], out: Path) -> None:
    rows = [result.as_row() for result in results]
    missing = [r for r in rows if not r["exists_by_filename"]]

    crate_counts = Counter(r["crate"] for r in missing)
    filename_counts = Counter(r["filename"] for r in missing)

    with out.open("w", encoding="utf-8") as f:
        f.write("# Serato Doctor Missing Report\n\n")
        f.write(f"Total missing references: {len(missing)}\n\n")

        f.write("## Missing by crate\n\n")
        for crate, count in crate_counts.most_common():
            f.write(f"{count:5}  {crate}\n")

        f.write("\n## Most common missing filenames\n\n")
        for filename, count in filename_counts.most_common(100):
            f.write(f"{count:5}  {filename}\n")

        f.write("\n## Detail\n\n")
        by_crate = defaultdict(list)
        for r in missing:
            by_crate[r["crate"]].append(r["filename"])

        for crate, names in sorted(by_crate.items()):
            f.write(f"\n### {crate}\n")
            for name in sorted(set(names)):
                f.write(f"- {name}\n")


def write_csv(results: Iterable[ReferenceResult], out: Path) -> None:
    rows = [result.as_row() for result in results]
    with out.open("w", newline="", encoding="utf-8") as f:
        writer = csv.DictWriter(
            f,
            fieldnames=["crate", "serato_path", "filename", "exists_by_filename"],
        )
        writer.writeheader()
        writer.writerows(rows)