from django.core.validators import MinValueValidator, MaxValueValidator
from django.db import models
from registered_user.models import RegisteredUser
from workout.models import Workout
from exercise.models import Exercise
from equipment.models import Equipment
from muscle.models import Muscle


INTENSITY_CHOICES = (
    ('low', 'Low'),
    ('medium', 'Medium'),
    ('high', 'High'),
)

GOAL_CHOICES = (
    ('strength', 'Strength'),
    ('hypertrophy', 'Hypertrophy'),
    ('endurance', 'Endurance'),
    ('weight_loss', 'Weight Loss'),
    ('general_fitness', 'General Fitness'),
)

FITNESS_LEVEL_CHOICES = (
    (1, 'Beginner'),
    (2, 'Intermediate'),
    (3, 'Advanced'),
    (4, 'Elite'),
)

PLAN_STATUS_CHOICES = (
    ('pending', 'Pending'),
    ('completed', 'Completed'),
    ('failed', 'Failed'),
)

WORKOUT_STATUS_CHOICES = (
    ('pending', 'Pending'),
    ('accepted', 'Accepted'),
    ('rejected', 'Rejected'),
    ('completed', 'Completed'),
)

SPLIT_TYPE_CHOICES = (
    ('push', 'Push'),
    ('pull', 'Pull'),
    ('legs', 'Legs'),
    ('upper', 'Upper'),
    ('lower', 'Lower'),
    ('full_body', 'Full Body'),
    ('core', 'Core'),
    ('cardio', 'Cardio'),
)

SECTION_TYPE_CHOICES = (
    ('warm_up', 'Warm Up'),
    ('working', 'Working'),
    ('cool_down', 'Cool Down'),
)

POSITION_CHOICES = (
    ('early', 'Early'),
    ('middle', 'Middle'),
    ('late', 'Late'),
)


# ============================================================
# Reference / Config Models
# ============================================================

class WorkoutType(models.Model):
    name = models.CharField(max_length=100, unique=True)
    display_name = models.CharField(max_length=100, blank=True, default='')
    description = models.TextField(blank=True, default='')
    typical_rest_between_sets = models.IntegerField(default=60, help_text='Seconds')
    typical_intensity = models.CharField(max_length=10, choices=INTENSITY_CHOICES, default='medium')
    rep_range_min = models.IntegerField(default=8)
    rep_range_max = models.IntegerField(default=12)
    round_range_min = models.IntegerField(default=3)
    round_range_max = models.IntegerField(default=4)
    duration_bias = models.FloatField(default=0.5, help_text='0.0=all rep-based, 1.0=all duration-based')
    superset_size_min = models.IntegerField(default=2)
    superset_size_max = models.IntegerField(default=4)

    def __str__(self):
        return self.name


# ============================================================
# User Preference Model
# ============================================================

class UserPreference(models.Model):
    registered_user = models.OneToOneField(
        RegisteredUser,
        on_delete=models.CASCADE,
        related_name='generator_preference'
    )
    available_equipment = models.ManyToManyField(Equipment, blank=True, related_name='user_preferences')
    target_muscle_groups = models.ManyToManyField(Muscle, blank=True, related_name='user_preferences')
    preferred_workout_types = models.ManyToManyField(WorkoutType, blank=True, related_name='user_preferences')
    fitness_level = models.IntegerField(choices=FITNESS_LEVEL_CHOICES, default=2)
    primary_goal = models.CharField(max_length=20, choices=GOAL_CHOICES, default='general_fitness')
    secondary_goal = models.CharField(max_length=20, choices=GOAL_CHOICES, blank=True, default='')
    days_per_week = models.IntegerField(default=4)
    preferred_workout_duration = models.IntegerField(
        default=45, help_text='Minutes',
        validators=[MinValueValidator(15), MaxValueValidator(120)],
    )
    preferred_days = models.JSONField(default=list, blank=True, help_text='List of weekday ints (0=Mon, 6=Sun)')
    injuries_limitations = models.TextField(blank=True, default='')
    injury_types = models.JSONField(
        default=list, blank=True,
        help_text='Structured injury types: knee, lower_back, upper_back, shoulder, hip, wrist, ankle, neck',
    )
    excluded_exercises = models.ManyToManyField(Exercise, blank=True, related_name='excluded_by_users')

    def __str__(self):
        return f"Preferences for {self.registered_user.first_name}"


# ============================================================
# Generated Plan / Workout Models
# ============================================================

class GeneratedWeeklyPlan(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    registered_user = models.ForeignKey(
        RegisteredUser,
        on_delete=models.CASCADE,
        related_name='generated_plans'
    )
    week_start_date = models.DateField()
    week_end_date = models.DateField()
    status = models.CharField(max_length=10, choices=PLAN_STATUS_CHOICES, default='pending')
    preferences_snapshot = models.JSONField(default=dict, blank=True)
    generation_time_ms = models.IntegerField(null=True, blank=True)

    # Periodization fields
    week_number = models.IntegerField(default=1, help_text='Position in training cycle (1-based)')
    is_deload = models.BooleanField(default=False, help_text='Whether this is a recovery/deload week')
    cycle_id = models.CharField(max_length=64, null=True, blank=True, help_text='Groups weeks into training cycles')

    class Meta:
        ordering = ['-created_at']

    def __str__(self):
        return f"Plan {self.id} for {self.registered_user.first_name} ({self.week_start_date})"


class GeneratedWorkout(models.Model):
    plan = models.ForeignKey(
        GeneratedWeeklyPlan,
        on_delete=models.CASCADE,
        related_name='generated_workouts'
    )
    workout = models.OneToOneField(
        Workout,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='generated_from'
    )
    workout_type = models.ForeignKey(
        WorkoutType,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='generated_workouts'
    )
    scheduled_date = models.DateField()
    day_of_week = models.IntegerField(help_text='0=Monday, 6=Sunday')
    is_rest_day = models.BooleanField(default=False)
    status = models.CharField(max_length=10, choices=WORKOUT_STATUS_CHOICES, default='pending')
    focus_area = models.CharField(max_length=255, blank=True, default='')
    target_muscles = models.JSONField(default=list, blank=True)
    user_rating = models.IntegerField(null=True, blank=True)
    user_feedback = models.TextField(blank=True, default='')

    class Meta:
        ordering = ['scheduled_date']

    def __str__(self):
        if self.is_rest_day:
            return f"Rest Day - {self.scheduled_date}"
        return f"{self.focus_area} - {self.scheduled_date}"


# ============================================================
# ML Pattern Models (populated by analyze_workouts command)
# ============================================================

class MuscleGroupSplit(models.Model):
    muscle_names = models.JSONField(default=list, help_text='List of muscle group names')
    frequency = models.IntegerField(default=0, help_text='How often this combo appeared')
    label = models.CharField(max_length=100, blank=True, default='')
    typical_exercise_count = models.IntegerField(default=6)
    split_type = models.CharField(max_length=20, choices=SPLIT_TYPE_CHOICES, default='full_body')

    def __str__(self):
        return f"{self.label} ({self.split_type}) - freq: {self.frequency}"


class WeeklySplitPattern(models.Model):
    days_per_week = models.IntegerField()
    pattern = models.JSONField(default=list, help_text='Ordered list of MuscleGroupSplit IDs')
    pattern_labels = models.JSONField(default=list, help_text='Ordered list of split labels')
    frequency = models.IntegerField(default=0)
    rest_day_positions = models.JSONField(default=list, help_text='Day indices that are rest days')

    def __str__(self):
        return f"{self.days_per_week}-day split (freq: {self.frequency}): {self.pattern_labels}"


class WorkoutStructureRule(models.Model):
    workout_type = models.ForeignKey(
        WorkoutType,
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name='structure_rules'
    )
    section_type = models.CharField(max_length=10, choices=SECTION_TYPE_CHOICES)
    movement_patterns = models.JSONField(default=list)
    typical_rounds = models.IntegerField(default=3)
    typical_exercises_per_superset = models.IntegerField(default=3)
    typical_rep_range_min = models.IntegerField(default=8)
    typical_rep_range_max = models.IntegerField(default=12)
    typical_duration_range_min = models.IntegerField(default=30, help_text='Seconds')
    typical_duration_range_max = models.IntegerField(default=45, help_text='Seconds')
    goal_type = models.CharField(max_length=20, choices=GOAL_CHOICES, default='general_fitness')

    def __str__(self):
        wt = self.workout_type.name if self.workout_type else 'Any'
        return f"{wt} - {self.section_type} ({self.goal_type})"


class MovementPatternOrder(models.Model):
    position = models.CharField(max_length=10, choices=POSITION_CHOICES)
    movement_pattern = models.CharField(max_length=100)
    frequency = models.IntegerField(default=0)
    section_type = models.CharField(max_length=10, choices=SECTION_TYPE_CHOICES, default='working')

    class Meta:
        ordering = ['position', '-frequency']

    def __str__(self):
        return f"{self.movement_pattern} @ {self.position} (freq: {self.frequency})"