from django.db import models

from apps.common.models import TimeStampedModel


class CreditAccount(TimeStampedModel):
    team = models.OneToOneField("accounts.Team", on_delete=models.CASCADE, related_name="credit_account")
    balance = models.DecimalField(max_digits=14, decimal_places=4, default=0)
    reserved_balance = models.DecimalField(max_digits=14, decimal_places=4, default=0)
    currency = models.CharField(max_length=16, default="CNY")

    def __str__(self) -> str:
        return f"{self.team} / {self.balance}"


class CreditLedger(TimeStampedModel):
    class Type(models.TextChoices):
        RECHARGE = "recharge", "Recharge"
        RESERVE = "reserve", "Reserve"
        RELEASE = "release", "Release"
        CHARGE = "charge", "Charge"
        ADJUSTMENT = "adjustment", "Adjustment"
        REFUND = "refund", "Refund"

    team = models.ForeignKey("accounts.Team", on_delete=models.CASCADE, related_name="credit_ledgers")
    user = models.ForeignKey("accounts.User", on_delete=models.SET_NULL, null=True, blank=True, related_name="credit_ledgers")
    project = models.ForeignKey(
        "projects.Project",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="credit_ledgers",
    )
    task = models.ForeignKey("ai.AITask", on_delete=models.SET_NULL, null=True, blank=True, related_name="credit_ledgers")
    ledger_type = models.CharField(max_length=32, choices=Type.choices)
    amount = models.DecimalField(max_digits=14, decimal_places=4)
    balance_after = models.DecimalField(max_digits=14, decimal_places=4)
    reason = models.CharField(max_length=255, blank=True)
    metadata = models.JSONField(default=dict, blank=True)

    class Meta:
        indexes = [
            # 团队流水倒序翻页 + 按类型过滤(账户消费页 / 消息中心 charge 通知)
            models.Index(fields=["team", "-created_at"]),
            models.Index(fields=["team", "ledger_type", "created_at"]),
            models.Index(fields=["project", "task"]),
        ]


class CreditReservation(TimeStampedModel):
    class Status(models.TextChoices):
        ACTIVE = "active", "Active"
        RELEASED = "released", "Released"
        CHARGED = "charged", "Charged"
        CANCELLED = "cancelled", "Cancelled"

    team = models.ForeignKey("accounts.Team", on_delete=models.CASCADE, related_name="credit_reservations")
    user = models.ForeignKey("accounts.User", on_delete=models.SET_NULL, null=True, blank=True, related_name="credit_reservations")
    project = models.ForeignKey(
        "projects.Project",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="credit_reservations",
    )
    task = models.OneToOneField("ai.AITask", on_delete=models.CASCADE, related_name="credit_reservation")
    amount = models.DecimalField(max_digits=14, decimal_places=4)
    status = models.CharField(max_length=32, choices=Status.choices, default=Status.ACTIVE)
    expires_at = models.DateTimeField(null=True, blank=True)


class BillingConfig(TimeStampedModel):
    """平台计费全局配置 · 单行单例(pk 恒定,经 pricing.get_billing_config() 缓存读取)。

    积分制核心参数:1 积分 = 1/points_per_yuan 元(默认 ¥0.1);用户侧余额/价格/流水全用积分,
    平台成本(base_cost)仍以 ¥ 记账。视频类用户价 = 火山成本价 × video_margin_multiplier 换积分
    (首发 ×1.5,商业决策;adminpanel 可调,改动即刻生效于下一次估价/结算)。
    """

    points_per_yuan = models.DecimalField(max_digits=8, decimal_places=2, default=10)
    video_margin_multiplier = models.DecimalField(max_digits=6, decimal_places=2, default=1.50)
    # 视频预留 buffer(收编 free_video.RESERVE_BUFFER):预留=预估积分×buffer,应对真实 tokens 略超预估
    video_reserve_buffer = models.DecimalField(max_digits=4, decimal_places=2, default=1.10)

    def __str__(self) -> str:
        return f"1¥={self.points_per_yuan}积分 · 视频毛利×{self.video_margin_multiplier}"


class QuotaPolicy(TimeStampedModel):
    team = models.ForeignKey("accounts.Team", on_delete=models.CASCADE, related_name="quota_policies")
    user = models.ForeignKey("accounts.User", on_delete=models.CASCADE, null=True, blank=True, related_name="quota_policies")
    project = models.ForeignKey(
        "projects.Project",
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name="quota_policies",
    )
    monthly_limit = models.DecimalField(max_digits=14, decimal_places=4, null=True, blank=True)
    project_limit = models.DecimalField(max_digits=14, decimal_places=4, null=True, blank=True)
    per_task_limit = models.DecimalField(max_digits=14, decimal_places=4, null=True, blank=True)
    is_active = models.BooleanField(default=True)