from django.db import models


class Fertilizer(models.Model):
    name = models.CharField(max_length=100, unique=True, verbose_name='肥料名')
    maker = models.CharField(max_length=100, blank=True, null=True, verbose_name='メーカー')
    capacity_kg = models.DecimalField(
        max_digits=8, decimal_places=3, blank=True, null=True, verbose_name='1袋重量(kg)'
    )
    nitrogen_pct = models.DecimalField(
        max_digits=5, decimal_places=2, blank=True, null=True, verbose_name='窒素含有率(%)'
    )
    phosphorus_pct = models.DecimalField(
        max_digits=5, decimal_places=2, blank=True, null=True, verbose_name='リン酸含有率(%)'
    )
    potassium_pct = models.DecimalField(
        max_digits=5, decimal_places=2, blank=True, null=True, verbose_name='カリ含有率(%)'
    )
    notes = models.TextField(blank=True, null=True, verbose_name='備考')
    material = models.OneToOneField(
        'materials.Material',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='legacy_fertilizer',
        verbose_name='資材マスタ',
    )

    class Meta:
        verbose_name = '肥料マスタ'
        verbose_name_plural = '肥料マスタ'
        ordering = ['name']

    def __str__(self):
        return self.name


class FertilizationPlan(models.Model):
    name = models.CharField(max_length=200, verbose_name='計画名')
    year = models.IntegerField(verbose_name='年度')
    variety = models.ForeignKey(
        'plans.Variety', on_delete=models.PROTECT,
        related_name='fertilization_plans', verbose_name='品種'
    )
    calc_settings = models.JSONField(default=list, blank=True, verbose_name='計算設定')
    is_confirmed = models.BooleanField(default=False, verbose_name='散布確定済み')
    confirmed_at = models.DateTimeField(null=True, blank=True, verbose_name='散布確定日時')
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        verbose_name = '施肥計画'
        verbose_name_plural = '施肥計画'
        ordering = ['-year', 'variety']

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


class FertilizationEntry(models.Model):
    """圃場 × 肥料 × 袋数 の中間テーブル"""
    plan = models.ForeignKey(
        FertilizationPlan, on_delete=models.CASCADE, related_name='entries'
    )
    field = models.ForeignKey(
        'fields.Field', on_delete=models.CASCADE, verbose_name='圃場'
    )
    fertilizer = models.ForeignKey(
        Fertilizer, on_delete=models.PROTECT, verbose_name='肥料'
    )
    bags = models.DecimalField(max_digits=8, decimal_places=2, verbose_name='袋数')
    actual_bags = models.DecimalField(
        max_digits=10,
        decimal_places=4,
        null=True,
        blank=True,
        verbose_name='実績袋数',
    )

    class Meta:
        verbose_name = '施肥エントリ'
        verbose_name_plural = '施肥エントリ'
        unique_together = [['plan', 'field', 'fertilizer']]
        ordering = ['field', 'fertilizer']

    def __str__(self):
        return f"{self.plan} / {self.field} / {self.fertilizer}: {self.bags}袋"


class DeliveryPlan(models.Model):
    """運搬計画：施肥計画の肥料を軽トラで運ぶ単位で計画・記録する"""
    year = models.IntegerField(verbose_name='年度')
    name = models.CharField(max_length=200, verbose_name='計画名')
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        verbose_name = '運搬計画'
        verbose_name_plural = '運搬計画'
        ordering = ['-year', 'name']

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


class DeliveryGroup(models.Model):
    """配送先グループ：まとめて運ぶ圃場のグループ"""
    delivery_plan = models.ForeignKey(
        DeliveryPlan, on_delete=models.CASCADE,
        related_name='groups', verbose_name='運搬計画'
    )
    name = models.CharField(max_length=100, verbose_name='グループ名')
    order = models.PositiveIntegerField(default=0, verbose_name='表示順')

    class Meta:
        verbose_name = '配送先グループ'
        verbose_name_plural = '配送先グループ'
        unique_together = [['delivery_plan', 'name']]
        ordering = ['order', 'id']

    def __str__(self):
        return f"{self.delivery_plan} / {self.name}"


class DeliveryGroupField(models.Model):
    """圃場のグループへの割り当て（1圃場=1グループ/1運搬計画）"""
    delivery_plan = models.ForeignKey(
        DeliveryPlan, on_delete=models.CASCADE, verbose_name='運搬計画'
    )
    group = models.ForeignKey(
        DeliveryGroup, on_delete=models.CASCADE,
        related_name='field_assignments', verbose_name='グループ'
    )
    field = models.ForeignKey(
        'fields.Field', on_delete=models.PROTECT, verbose_name='圃場'
    )

    class Meta:
        verbose_name = 'グループ圃場割り当て'
        verbose_name_plural = 'グループ圃場割り当て'
        unique_together = [['delivery_plan', 'field']]
        ordering = ['field__display_order', 'field__id']

    def __str__(self):
        return f"{self.group.name} / {self.field.name}"


class DeliveryTrip(models.Model):
    """運搬回：軽トラ1回分の積載"""
    delivery_plan = models.ForeignKey(
        DeliveryPlan, on_delete=models.CASCADE,
        related_name='trips', verbose_name='運搬計画'
    )
    order = models.PositiveIntegerField(default=0, verbose_name='何回目')
    name = models.CharField(max_length=100, blank=True, verbose_name='名前')
    date = models.DateField(null=True, blank=True, verbose_name='運搬日')

    class Meta:
        verbose_name = '運搬回'
        verbose_name_plural = '運搬回'
        ordering = ['order', 'id']

    def __str__(self):
        return f"{self.delivery_plan} / {self.order + 1}回目"


class DeliveryTripItem(models.Model):
    """運搬明細：圃場×肥料単位の袋数"""
    trip = models.ForeignKey(
        DeliveryTrip, on_delete=models.CASCADE,
        related_name='items', verbose_name='運搬回'
    )
    field = models.ForeignKey(
        'fields.Field', on_delete=models.PROTECT, verbose_name='圃場'
    )
    fertilizer = models.ForeignKey(
        Fertilizer, on_delete=models.PROTECT, verbose_name='肥料'
    )
    bags = models.DecimalField(max_digits=10, decimal_places=4, verbose_name='袋数')

    class Meta:
        verbose_name = '運搬明細'
        verbose_name_plural = '運搬明細'
        unique_together = [['trip', 'field', 'fertilizer']]
        ordering = ['field__display_order', 'field__id', 'fertilizer__name']

    def __str__(self):
        return f"{self.trip} / {self.field.name} / {self.fertilizer.name}: {self.bags}袋"


class SpreadingSession(models.Model):
    """散布日単位の実績"""
    year = models.IntegerField(verbose_name='年度')
    date = models.DateField(verbose_name='散布日')
    name = models.CharField(max_length=100, blank=True, verbose_name='名前')
    notes = models.TextField(blank=True, default='', verbose_name='備考')
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        verbose_name = '散布実績'
        verbose_name_plural = '散布実績'
        ordering = ['-date', '-id']

    def __str__(self):
        label = self.name.strip() or f'{self.date}'
        return f'{self.year} {label}'


class SpreadingSessionItem(models.Model):
    """散布実績明細：圃場×肥料ごとの実績"""
    session = models.ForeignKey(
        SpreadingSession,
        on_delete=models.CASCADE,
        related_name='items',
        verbose_name='散布実績',
    )
    field = models.ForeignKey(
        'fields.Field', on_delete=models.PROTECT, verbose_name='圃場'
    )
    fertilizer = models.ForeignKey(
        Fertilizer, on_delete=models.PROTECT, verbose_name='肥料'
    )
    actual_bags = models.DecimalField(max_digits=10, decimal_places=4, verbose_name='実散布袋数')
    planned_bags_snapshot = models.DecimalField(
        max_digits=10,
        decimal_places=4,
        verbose_name='計画袋数スナップショット',
    )
    delivered_bags_snapshot = models.DecimalField(
        max_digits=10,
        decimal_places=4,
        verbose_name='運搬済み袋数スナップショット',
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        verbose_name = '散布実績明細'
        verbose_name_plural = '散布実績明細'
        unique_together = [['session', 'field', 'fertilizer']]
        ordering = ['field__display_order', 'field__id', 'fertilizer__name']

    def __str__(self):
        return (
            f'{self.session} / {self.field.name} / '
            f'{self.fertilizer.name}: {self.actual_bags}袋'
        )