import uuid

from django.conf import settings
from django.db import models


class ToolProviderType(models.TextChoices):
    NATIVE = "native", "原生工具"
    MCP_HTTP = "mcp_http", "HTTP MCP"


class ToolRiskLevel(models.TextChoices):
    READ_ONLY = "read_only", "只读"
    LOW_WRITE = "low_write", "低风险写"
    HIGH_RISK = "high_risk", "高风险"


class ToolProvider(models.Model):
    name = models.CharField(max_length=120, unique=True)
    provider_type = models.CharField(
        max_length=24,
        choices=ToolProviderType.choices,
        default=ToolProviderType.MCP_HTTP,
    )
    base_url = models.URLField(max_length=500, blank=True)
    token_encrypted = models.TextField(blank=True)
    enabled = models.BooleanField(default=True)
    timeout_seconds = models.PositiveIntegerField(default=30)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="created_tool_providers",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["name"]


class UnifiedTool(models.Model):
    code = models.CharField(max_length=160, unique=True)
    provider = models.ForeignKey(
        ToolProvider,
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="tools",
    )
    external_name = models.CharField(max_length=200, blank=True)
    name = models.CharField(max_length=160)
    description = models.TextField(blank=True)
    input_schema = models.JSONField(default=dict)
    risk_level = models.CharField(
        max_length=24,
        choices=ToolRiskLevel.choices,
        default=ToolRiskLevel.READ_ONLY,
    )
    enabled = models.BooleanField(default=True)
    synced_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 = ["code"]


class ToolAuthorization(models.Model):
    tool = models.ForeignKey(
        UnifiedTool,
        on_delete=models.CASCADE,
        related_name="authorizations",
    )
    principal_type = models.CharField(max_length=24)
    principal_id = models.PositiveBigIntegerField()
    allowed = models.BooleanField(default=True)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="created_tool_authorizations",
    )
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=["tool", "principal_type", "principal_id"],
                name="unique_tool_authorization_principal",
            )
        ]


class ToolCallStatus(models.TextChoices):
    PENDING_CONFIRMATION = "pending_confirmation", "待确认"
    RUNNING = "running", "执行中"
    SUCCEEDED = "succeeded", "成功"
    FAILED = "failed", "失败"
    REJECTED = "rejected", "已拒绝"


class ToolCall(models.Model):
    public_id = models.UUIDField(default=uuid.uuid4, unique=True, editable=False)
    tool = models.ForeignKey(UnifiedTool, on_delete=models.PROTECT, related_name="calls")
    agent_run = models.ForeignKey(
        "agents.AgentRun",
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="tool_calls",
    )
    requested_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="requested_tool_calls",
    )
    status = models.CharField(max_length=32, choices=ToolCallStatus.choices)
    input_payload = models.JSONField(default=dict)
    output_payload = models.JSONField(null=True, blank=True)
    authorization_snapshot = models.JSONField(default=dict)
    risk_snapshot = models.JSONField(default=dict)
    idempotency_key = models.CharField(max_length=160, blank=True)
    error_code = models.CharField(max_length=80, blank=True)
    error_message = models.TextField(blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    started_at = models.DateTimeField(null=True, blank=True)
    finished_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        ordering = ["-created_at"]
        constraints = [
            models.UniqueConstraint(
                fields=["tool", "idempotency_key"],
                condition=models.Q(idempotency_key__gt=""),
                name="unique_tool_call_idempotency_key",
            )
        ]


class ToolConfirmation(models.Model):
    call = models.OneToOneField(
        ToolCall,
        on_delete=models.CASCADE,
        related_name="confirmation",
    )
    status = models.CharField(max_length=24, default="pending")
    reason = models.TextField(blank=True)
    decided_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="decided_tool_confirmations",
    )
    decided_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)