"""Goal and budget schemas for AGI executive layer."""

from datetime import datetime, timezone
from enum import Enum
from typing import Any

from pydantic import BaseModel, Field, field_validator


def _utc_now() -> datetime:
    return datetime.now(timezone.utc)


class GoalStatus(str, Enum):
    """Goal lifecycle status."""

    ACTIVE = "active"
    ACHIEVED = "achieved"
    ABANDONED = "abandoned"
    BLOCKED = "blocked"
    SUSPENDED = "suspended"


class GoalBudget(BaseModel):
    """Time and compute budget for a goal/task."""

    time_seconds: float | None = Field(default=None, ge=0, description="Max wall-clock seconds")
    compute_budget: float | None = Field(default=None, ge=0, description="Max compute units (e.g. token budget)")
    started_at: datetime | None = Field(default=None, description="When execution started")


class Blocker(BaseModel):
    """Reason a task or goal is stuck."""

    blocker_id: str = Field(..., min_length=1)
    task_id: str = Field(..., min_length=1)
    reason: str = Field(default="")
    dependency_step_id: str | None = Field(default=None)
    reported_at: datetime = Field(default_factory=_utc_now)


class Checkpoint(BaseModel):
    """Resumable point in task execution."""

    checkpoint_id: str = Field(..., min_length=1)
    task_id: str = Field(..., min_length=1)
    step_ids_completed: list[str] = Field(default_factory=list)
    state_snapshot: dict[str, Any] = Field(default_factory=dict)
    created_at: datetime = Field(default_factory=_utc_now)


class Goal(BaseModel):
    """Explicit goal with objectives, priorities, constraints, and budget."""

    goal_id: str = Field(..., min_length=1)
    objective: str = Field(..., min_length=1)
    constraints: list[str] = Field(default_factory=list)
    priority: int = Field(default=0, ge=0, le=10)
    status: GoalStatus = Field(default=GoalStatus.ACTIVE)
    budget: GoalBudget | None = Field(default=None)
    metadata: dict[str, Any] = Field(default_factory=dict)
    created_at: datetime = Field(default_factory=_utc_now)
    updated_at: datetime | None = Field(default=None)

    @field_validator("goal_id", "objective")
    @classmethod
    def validate_non_whitespace(cls, v: str) -> str:
        if not v.strip():
            raise ValueError("Field cannot be empty or whitespace")
        return v