from __future__ import annotations

from datetime import datetime
from typing import Any, Literal

from pydantic import BaseModel, Field, model_validator


class WorkAssignmentPayload(BaseModel):
    kind: Literal[
        "account",
        "group",
        "role",
        "function",
        "function_assignment",
        "anyone",
    ]
    id: str = Field(min_length=1, max_length=255)
    label: str | None = Field(default=None, max_length=500)


class WorkSourcePayload(BaseModel):
    module_id: str = Field(min_length=1, max_length=100)
    resource_type: str = Field(min_length=1, max_length=100)
    resource_id: str = Field(min_length=1, max_length=255)
    revision: str | None = Field(default=None, max_length=255)
    url: str | None = Field(default=None, max_length=1500)
    label: str | None = Field(default=None, max_length=500)


class WorkItemResponse(BaseModel):
    id: str
    provider_id: str
    owner_module: str
    tenant_id: str
    title: str
    status: str
    priority: str
    summary: str | None = None
    required_action: str | None = None
    action_url: str | None = None
    due_at: datetime | None = None
    deferred_until: datetime | None = None
    assignments: list[WorkAssignmentPayload] = Field(default_factory=list)
    sources: list[WorkSourcePayload] = Field(default_factory=list)
    provenance: dict[str, Any] = Field(default_factory=dict)
    metadata: dict[str, Any] = Field(default_factory=dict)
    revision: str
    etag: str | None = None
    created_at: datetime | None = None
    updated_at: datetime | None = None


class WorkProviderDiagnostic(BaseModel):
    provider_id: str
    owner_module: str
    code: str
    message: str


class WorkItemListResponse(BaseModel):
    items: list[WorkItemResponse]
    total: int
    truncated: bool = False
    diagnostics: list[WorkProviderDiagnostic] = Field(default_factory=list)


class WorkSummaryResponse(BaseModel):
    total: int
    open: int
    in_progress: int
    deferred: int
    blocked: int
    overdue: int
    urgent: int
    truncated: bool = False
    diagnostics: list[WorkProviderDiagnostic] = Field(default_factory=list)


class TaskCreatePayload(BaseModel):
    title: str = Field(min_length=1, max_length=500)
    summary: str | None = Field(default=None, max_length=4000)
    priority: Literal["low", "normal", "high", "urgent"] = "normal"
    due_at: datetime | None = None
    required_action: str | None = Field(default=None, max_length=500)
    action_url: str | None = Field(default=None, max_length=1500)
    assignments: list[WorkAssignmentPayload] = Field(min_length=1, max_length=100)
    sources: list[WorkSourcePayload] = Field(default_factory=list, max_length=100)
    provenance: dict[str, Any] = Field(default_factory=dict)
    metadata: dict[str, Any] = Field(default_factory=dict)
    idempotency_key: str = Field(min_length=1, max_length=255)


class TaskActionPayload(BaseModel):
    action: Literal["start", "complete", "defer", "reopen", "cancel"]
    expected_revision: int = Field(ge=1)
    deferred_until: datetime | None = None
    comment: str | None = Field(default=None, max_length=4000)

    @model_validator(mode="after")
    def validate_action(self) -> "TaskActionPayload":
        if self.action == "defer" and self.deferred_until is None:
            raise ValueError("Deferring a task requires a date and time.")
        if self.action != "defer" and self.deferred_until is not None:
            raise ValueError("Only a defer action accepts deferred_until.")
        return self


__all__ = [
    "TaskActionPayload",
    "TaskCreatePayload",
    "WorkAssignmentPayload",
    "WorkItemListResponse",
    "WorkItemResponse",
    "WorkProviderDiagnostic",
    "WorkSourcePayload",
    "WorkSummaryResponse",
]