from __future__ import annotations

import json
from copy import deepcopy
from pathlib import Path
from typing import Any
from uuid import uuid4

DEFAULT_STATE = {
    'users': {
        'john': {
            'id': 'john',
            'display_name': 'John',
            'is_stub': False,
            'measurement_system': 'imperial',
            'height_inches': 68.5,
            'goal_weight_lbs': None,
            'notes': 'Seeded with John default height assumption from current intake.',
        },
        'manndra': {
            'id': 'manndra',
            'display_name': 'Manndra',
            'is_stub': True,
            'measurement_system': 'imperial',
            'height_inches': None,
            'goal_weight_lbs': None,
            'notes': 'Stubbed for future shared use.',
        },
    },
    'exercise_templates': [],
    'routines': [],
    'weight_entries': [],
    'measurement_entries': [],
    'workout_sessions': [],
}


class JSONStore:
    def __init__(self, state_dir: Path) -> None:
        self.state_dir = Path(state_dir)
        self.state_path = self.state_dir / 'state.json'
        self.state_dir.mkdir(parents=True, exist_ok=True)
        if not self.state_path.exists():
            self._write(deepcopy(DEFAULT_STATE))

    def _read(self) -> dict[str, Any]:
        return json.loads(self.state_path.read_text())

    def _write(self, payload: dict[str, Any]) -> None:
        self.state_path.write_text(json.dumps(payload, indent=2, sort_keys=True))

    def update_profile(self, user_id: str, changes: dict[str, Any]) -> dict[str, Any]:
        state = self._read()
        user = state['users'].get(user_id)
        if user is None:
            raise KeyError(user_id)
        for key, value in changes.items():
            if value is not None:
                user[key] = value
        state['users'][user_id] = user
        self._write(state)
        return user

    def add_weight_entry(self, user_id: str, entry: dict[str, Any]) -> dict[str, Any]:
        state = self._read()
        user = self._user_or_raise(state, user_id)
        saved = {
            'id': uuid4().hex,
            'user_id': user_id,
            'recorded_at': entry['recorded_at'],
            'weight_lbs': entry['weight_lbs'],
            'body_fat_percent': entry.get('body_fat_percent'),
            'notes': entry.get('notes'),
            'bmi': _calculate_bmi(entry['weight_lbs'], user.get('height_inches')),
        }
        state['weight_entries'].append(saved)
        self._write(state)
        return saved

    def weight_history(self, user_id: str) -> list[dict[str, Any]]:
        state = self._read()
        self._user_or_raise(state, user_id)
        return _history_for_user(state['weight_entries'], user_id, 'recorded_at')

    def add_measurement_entry(self, user_id: str, entry: dict[str, Any]) -> dict[str, Any]:
        state = self._read()
        self._user_or_raise(state, user_id)
        saved = {
            'id': uuid4().hex,
            'user_id': user_id,
            'recorded_at': entry['recorded_at'],
            'waist_inches': entry.get('waist_inches'),
            'hip_inches': entry.get('hip_inches'),
            'chest_inches': entry.get('chest_inches'),
            'neck_inches': entry.get('neck_inches'),
            'notes': entry.get('notes'),
        }
        state['measurement_entries'].append(saved)
        self._write(state)
        return saved

    def measurement_history(self, user_id: str) -> list[dict[str, Any]]:
        state = self._read()
        self._user_or_raise(state, user_id)
        return _history_for_user(state['measurement_entries'], user_id, 'recorded_at')

    def add_exercise_template(self, payload: dict[str, Any]) -> dict[str, Any]:
        state = self._read()
        saved = {
            'id': uuid4().hex,
            'name': payload['name'],
            'primary_muscle': payload.get('primary_muscle'),
            'equipment': payload.get('equipment'),
            'notes': payload.get('notes'),
        }
        state['exercise_templates'].append(saved)
        self._write(state)
        return saved

    def list_exercise_templates(self) -> list[dict[str, Any]]:
        state = self._read()
        return sorted(state['exercise_templates'], key=lambda item: item['name'].lower())

    def add_routine(self, payload: dict[str, Any]) -> dict[str, Any]:
        state = self._read()
        self._user_or_raise(state, payload['user_id'])
        saved = {
            'id': uuid4().hex,
            'user_id': payload['user_id'],
            'name': payload['name'],
            'notes': payload.get('notes'),
            'exercises': [dict(exercise) for exercise in payload['exercises']],
        }
        state['routines'].append(saved)
        self._write(state)
        return saved

    def list_routines(self) -> list[dict[str, Any]]:
        state = self._read()
        return sorted(state['routines'], key=lambda item: item['name'].lower())

    def add_workout(self, payload: dict[str, Any]) -> dict[str, Any]:
        state = self._read()
        self._user_or_raise(state, payload['user_id'])

        set_count = 0
        total_volume_lbs = 0.0
        exercises: list[dict[str, Any]] = []
        for exercise in payload['exercises']:
            normalized_sets = []
            for item in exercise['sets']:
                set_count += 1
                total_volume_lbs += item['reps'] * item['weight_lbs']
                normalized_sets.append(dict(item))
            exercises.append({
                'exercise_name': exercise['exercise_name'],
                'notes': exercise.get('notes'),
                'sets': normalized_sets,
            })

        saved = {
            'id': uuid4().hex,
            'user_id': payload['user_id'],
            'performed_at': payload['performed_at'],
            'routine_name': payload['routine_name'],
            'notes': payload.get('notes'),
            'exercise_count': len(exercises),
            'set_count': set_count,
            'total_volume_lbs': int(total_volume_lbs) if total_volume_lbs.is_integer() else total_volume_lbs,
            'exercises': exercises,
        }
        state['workout_sessions'].append(saved)
        self._write(state)
        return saved

    def workout_history(self, user_id: str) -> list[dict[str, Any]]:
        state = self._read()
        self._user_or_raise(state, user_id)
        return _history_for_user(state['workout_sessions'], user_id, 'performed_at')

    def exercise_progression(self, user_id: str) -> list[dict[str, Any]]:
        state = self._read()
        self._user_or_raise(state, user_id)
        progression: dict[str, dict[str, Any]] = {}
        for workout in _history_for_user(state['workout_sessions'], user_id, 'performed_at'):
            for exercise in workout['exercises']:
                name = exercise['exercise_name']
                stats = progression.setdefault(
                    name,
                    {
                        'exercise_name': name,
                        'sessions': 0,
                        'set_count': 0,
                        'max_weight_lbs': 0.0,
                        'best_set_estimated_1rm': 0.0,
                        'last_performed_at': workout['performed_at'],
                    },
                )
                stats['sessions'] += 1
                if workout['performed_at'] > stats['last_performed_at']:
                    stats['last_performed_at'] = workout['performed_at']
                for item in exercise['sets']:
                    stats['set_count'] += 1
                    stats['max_weight_lbs'] = max(stats['max_weight_lbs'], item['weight_lbs'])
                    stats['best_set_estimated_1rm'] = max(
                        stats['best_set_estimated_1rm'],
                        _estimated_1rm(item['weight_lbs'], item['reps']),
                    )
        results = []
        for item in progression.values():
            results.append(
                {
                    **item,
                    'max_weight_lbs': _normalize_number(item['max_weight_lbs']),
                    'best_set_estimated_1rm': _normalize_number(item['best_set_estimated_1rm']),
                }
            )
        return sorted(results, key=lambda item: item['exercise_name'].lower())

    def dashboard_summary(self) -> dict[str, Any]:
        state = self._read()
        users = []
        weight_entries = state['weight_entries']
        measurement_entries = state['measurement_entries']
        for user in state['users'].values():
            latest_weight = _latest_entry_for_user(weight_entries, user['id'])
            latest_measurements = _latest_entry_for_user(measurement_entries, user['id'])
            users.append({
                'id': user['id'],
                'display_name': user['display_name'],
                'is_stub': user['is_stub'],
                'measurement_system': user.get('measurement_system', 'imperial'),
                'height_inches': user['height_inches'],
                'goal_weight_lbs': user['goal_weight_lbs'],
                'current_weight_lbs': latest_weight['weight_lbs'] if latest_weight else None,
                'current_bmi': latest_weight['bmi'] if latest_weight else None,
                'last_weight_recorded_at': latest_weight['recorded_at'] if latest_weight else None,
                'latest_measurements': _trim_measurement_entry(latest_measurements),
            })

        recent_workouts = sorted(
            state['workout_sessions'],
            key=lambda item: item['performed_at'],
            reverse=True,
        )[:5]
        return {
            'users': users,
            'recent_workouts': recent_workouts,
            'exercise_templates': self.list_exercise_templates()[:5],
            'routines': self.list_routines()[:5],
            'counts': {
                'exercise_templates': len(state['exercise_templates']),
                'measurement_entries': len(state['measurement_entries']),
                'routines': len(state['routines']),
                'weight_entries': len(state['weight_entries']),
                'workout_sessions': len(state['workout_sessions']),
            },
        }

    def _user_or_raise(self, state: dict[str, Any], user_id: str) -> dict[str, Any]:
        user = state['users'].get(user_id)
        if user is None:
            raise KeyError(user_id)
        return user


def _latest_entry_for_user(entries: list[dict[str, Any]], user_id: str) -> dict[str, Any] | None:
    matches = [entry for entry in entries if entry['user_id'] == user_id]
    if not matches:
        return None
    return max(matches, key=lambda item: item['recorded_at'])


def _history_for_user(entries: list[dict[str, Any]], user_id: str, sort_key: str) -> list[dict[str, Any]]:
    matches = [entry for entry in entries if entry['user_id'] == user_id]
    return sorted(matches, key=lambda item: item[sort_key], reverse=True)


def _trim_measurement_entry(entry: dict[str, Any] | None) -> dict[str, Any] | None:
    if entry is None:
        return None
    return {
        'recorded_at': entry['recorded_at'],
        'waist_inches': entry['waist_inches'],
        'hip_inches': entry['hip_inches'],
        'chest_inches': entry['chest_inches'],
        'neck_inches': entry['neck_inches'],
    }


def _normalize_number(value: float) -> int | float:
    return int(value) if float(value).is_integer() else round(value, 1)


def _estimated_1rm(weight_lbs: float, reps: int) -> float:
    return weight_lbs * (1 + reps / 30)


def _calculate_bmi(weight_lbs: float, height_inches: float | None) -> float | None:
    if not height_inches:
        return None
    return 703 * weight_lbs / (height_inches * height_inches)