from django.db import models
from django.contrib.auth.models import User


class Screener(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name="screeners")
    name = models.CharField(max_length=255)
    filters = models.JSONField(default=dict, blank=True)
    columns = models.JSONField(default=list, blank=True)
    selected_symbols = models.JSONField(default=list, blank=True)
    cached_results = models.JSONField(null=True, blank=True, default=None)
    last_run_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-updated_at"]

    @staticmethod
    def _normalize_unique_symbols(values):
        if not isinstance(values, list):
            return []
        normalized = []
        seen = set()
        for raw in values:
            symbol = str(raw or "").strip().upper()
            if not symbol or symbol in seen:
                continue
            seen.add(symbol)
            normalized.append(symbol)
        return normalized

    def save(self, *args, **kwargs):
        # Enforce a canonical selected symbol list on every save path.
        self.selected_symbols = self._normalize_unique_symbols(self.selected_symbols)
        super().save(*args, **kwargs)

    def __str__(self):
        return f"{self.user.username}: {self.name}"


class ScreenerSymbolCache(models.Model):
    symbol = models.CharField(max_length=32, unique=True)
    data = models.JSONField(default=dict, blank=True)
    last_fetched_at = models.DateTimeField()
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-last_fetched_at"]

    def __str__(self):
        return self.symbol