"""
Analytics models - KPIs, metrics, and dashboards

This module implements analytics capabilities:
- KPI definitions and tracking
- Metric aggregation
- Dashboard data
- Trend analysis
"""
from django.db import models

from apps.core.models import TimeStampedModel, UUIDModel


class KPI(UUIDModel, TimeStampedModel):
    """
    KPI (Key Performance Indicator) definition.
    
    Defines metrics to track across the system.
    """
    name = models.CharField(max_length=200, unique=True)
    name_ar = models.CharField(max_length=200, blank=True)
    description = models.TextField(blank=True)
    
    # Category
    category = models.CharField(
        max_length=100,
        choices=[
            ('patient_satisfaction', 'Patient Satisfaction'),
            ('complaint_management', 'Complaint Management'),
            ('action_management', 'Action Management'),
            ('sla_compliance', 'SLA Compliance'),
            ('survey_response', 'Survey Response'),
            ('operational', 'Operational'),
        ],
        db_index=True
    )
    
    # Measurement
    unit = models.CharField(
        max_length=50,
        help_text="Unit of measurement (%, count, hours, etc.)"
    )
    calculation_method = models.TextField(
        help_text="Description of how this KPI is calculated"
    )
    
    # Thresholds
    target_value = models.DecimalField(
        max_digits=10,
        decimal_places=2,
        null=True,
        blank=True,
        help_text="Target value for this KPI"
    )
    warning_threshold = models.DecimalField(
        max_digits=10,
        decimal_places=2,
        null=True,
        blank=True,
        help_text="Warning threshold"
    )
    critical_threshold = models.DecimalField(
        max_digits=10,
        decimal_places=2,
        null=True,
        blank=True,
        help_text="Critical threshold"
    )
    
    # Configuration
    is_active = models.BooleanField(default=True)
    
    class Meta:
        ordering = ['category', 'name']
        verbose_name = 'KPI'
        verbose_name_plural = 'KPIs'
    
    def __str__(self):
        return self.name


class KPIValue(UUIDModel, TimeStampedModel):
    """
    KPI value - actual measurement at a point in time.
    """
    kpi = models.ForeignKey(
        KPI,
        on_delete=models.CASCADE,
        related_name='values'
    )
    
    # Scope
    hospital = models.ForeignKey(
        'organizations.Hospital',
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name='kpi_values'
    )
    department = models.ForeignKey(
        'organizations.Department',
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name='kpi_values'
    )
    
    # Value
    value = models.DecimalField(
        max_digits=10,
        decimal_places=2
    )
    
    # Time period
    period_start = models.DateTimeField(db_index=True)
    period_end = models.DateTimeField(db_index=True)
    period_type = models.CharField(
        max_length=20,
        choices=[
            ('hourly', 'Hourly'),
            ('daily', 'Daily'),
            ('weekly', 'Weekly'),
            ('monthly', 'Monthly'),
            ('quarterly', 'Quarterly'),
            ('yearly', 'Yearly'),
        ],
        default='daily'
    )
    
    # Status
    status = models.CharField(
        max_length=20,
        choices=[
            ('on_target', 'On Target'),
            ('warning', 'Warning'),
            ('critical', 'Critical'),
        ],
        db_index=True
    )
    
    # Metadata
    metadata = models.JSONField(
        default=dict,
        blank=True,
        help_text="Additional calculation details"
    )
    
    class Meta:
        ordering = ['-period_end']
        indexes = [
            models.Index(fields=['kpi', '-period_end']),
            models.Index(fields=['hospital', 'kpi', '-period_end']),
        ]
    
    def __str__(self):
        scope = self.hospital.name if self.hospital else "Global"
        return f"{self.kpi.name} - {scope} - {self.period_end.strftime('%Y-%m-%d')}: {self.value}"