import uuid
from datetime import date, datetime
from typing import Literal

from pydantic import BaseModel, ConfigDict, field_validator

from api.schemas.workstream_dependency import WorkstreamDepStub
from api.workplan_status import normalize_workstream_status

WorkstreamStatus = Literal[
    "proposed",
    "ready",
    "active",
    "blocked",
    "backlog",
    "finished",
    "archived",
]
ExecutionState = Literal["manual", "queued", "scheduled", "launching", "paused", "completed", "cancelled"]
LaunchMode = Literal["manual", "queued", "scheduled", "immediate"]
ConcurrencyMode = Literal["sequential", "parallel"]


class WorkstreamStatusMixin(BaseModel):
    @field_validator("status", mode="before", check_fields=False)
    @classmethod
    def _normalise_status(cls, value):
        return normalize_workstream_status(value)


class WorkstreamCreate(WorkstreamStatusMixin):
    topic_id: uuid.UUID
    slug: str
    title: str
    description: str | None = None
    status: WorkstreamStatus = "active"
    owner: str | None = None
    due_date: date | None = None
    planning_priority: str | None = None
    planning_order: int | None = None
    execution_state: ExecutionState = "manual"
    launch_mode: LaunchMode = "manual"
    concurrency_mode: ConcurrencyMode = "sequential"
    queue_rank: int | None = None
    execution_group: str | None = None
    scheduled_for: datetime | None = None
    repo_id: uuid.UUID | None = None  # GEMS primary: the owning repository
    repo_goal_id: uuid.UUID | None = None


class WorkstreamUpdate(WorkstreamStatusMixin):
    title: str | None = None
    description: str | None = None
    status: WorkstreamStatus | None = None
    owner: str | None = None
    due_date: date | None = None
    planning_priority: str | None = None
    planning_order: int | None = None
    execution_state: ExecutionState | None = None
    launch_mode: LaunchMode | None = None
    concurrency_mode: ConcurrencyMode | None = None
    queue_rank: int | None = None
    execution_group: str | None = None
    scheduled_for: datetime | None = None
    repo_id: uuid.UUID | None = None
    repo_goal_id: uuid.UUID | None = None


class WorkstreamRead(WorkstreamStatusMixin):
    model_config = ConfigDict(from_attributes=True)
    id: uuid.UUID
    topic_id: uuid.UUID
    repo_id: uuid.UUID | None = None
    repo_goal_id: uuid.UUID | None = None
    slug: str
    title: str
    description: str | None = None
    status: WorkstreamStatus
    owner: str | None = None
    due_date: date | None = None
    planning_priority: str | None = None
    planning_order: int | None = None
    execution_state: ExecutionState = "manual"
    launch_mode: LaunchMode = "manual"
    concurrency_mode: ConcurrencyMode = "sequential"
    queue_rank: int | None = None
    execution_group: str | None = None
    scheduled_for: datetime | None = None
    created_at: datetime
    updated_at: datetime


class WorkstreamWithTaskCounts(WorkstreamRead):
    tasks_total: int = 0
    tasks_wait: int = 0
    tasks_todo: int = 0
    tasks_progress: int = 0
    tasks_done: int = 0
    tasks_cancel: int = 0


class WorkstreamWithDeps(WorkstreamWithTaskCounts):
    """WorkstreamWithTaskCounts enriched with dependency graph edges."""
    depends_on: list[WorkstreamDepStub] = []
    blocks: list[WorkstreamDepStub] = []
    blocked_reasons: list[dict] = []