from dataclasses import dataclass
from typing import Any, Dict, List, Optional

from src.analyzers.git_repository import GitRepository
from src.models.data_structures import VelocityAnalysis, Author


@dataclass
class VelocityAnalyzer:
    """Analyzes team velocity."""

    repo: GitRepository
    days: int

    def analyze(self) -> Optional[VelocityAnalysis]:
        """Analyze team velocity."""
        commits = self.repo.get_commits()

        if not commits:
            return None

        authors = self.repo.get_authors()
        authors.sort(key=lambda a: a.commit_count, reverse=True)
        top_contributors = authors[:10]

        commits_per_day = len(commits) / max(1, self.days)
        commits_per_week = commits_per_day * 7
        commits_per_month = commits_per_day * 30

        commits_by_day: Dict[str, int] = {}
        commits_by_hour: Dict[str, int] = {}

        for commit in commits:
            day_key = commit.timestamp.strftime("%A")
            hour_key = commit.timestamp.strftime("%H:00")

            commits_by_day[day_key] = commits_by_day.get(day_key, 0) + 1
            commits_by_hour[hour_key] = commits_by_hour.get(hour_key, 0) + 1

        most_active_day = max(commits_by_day, key=commits_by_day.get) if commits_by_day else "N/A"
        most_active_hour = max(commits_by_hour, key=commits_by_hour.get) if commits_by_hour else "N/A"

        if len(commits) >= 2:
            recent_commits = commits[:10]
            older_commits = commits[10:20]

            recent_avg = sum(1 for _ in recent_commits) / max(1, len(recent_commits))
            older_avg = sum(1 for _ in older_commits) / max(1, len(older_commits))

            if recent_avg > older_avg * 1.1:
                velocity_trend = "increasing"
            elif recent_avg < older_avg * 0.9:
                velocity_trend = "decreasing"
            else:
                velocity_trend = "stable"
        else:
            velocity_trend = "stable"

        return VelocityAnalysis(
            commits_per_day=commits_per_day,
            commits_per_week=commits_per_week,
            commits_per_month=commits_per_month,
            velocity_trend=velocity_trend,
            top_contributors=top_contributors,
            most_active_day=most_active_day,
            most_active_hour=most_active_hour,
        )