from pydantic import BaseModel
from typing import Optional, List
from datetime import datetime, time
from enum import Enum


class TaskTypeEnum(str, Enum):
    ISSUE = "issue"
    MAINTENANCE = "maintenance"
    RESEARCH = "research"
    REVIEW = "review"
    STORY = "story"
    TEST = "test"
    RESOLUTION = "resolution"
    # P7.1: 'task' type removed — defect subtype migrated to issue/defect


class TaskStatusEnum(str, Enum):
    OPEN = "open"
    PENDING = "pending"
    UNDERGOING = "undergoing"
    COMPLETED = "completed"
    CLOSED = "closed"


class TaskPriorityEnum(str, Enum):
    LOW = "low"
    MEDIUM = "medium"
    HIGH = "high"
    CRITICAL = "critical"


# Task schemas
class TaskBase(BaseModel):
    title: str
    description: Optional[str] = None
    task_type: TaskTypeEnum = TaskTypeEnum.ISSUE
    task_subtype: Optional[str] = None
    priority: TaskPriorityEnum = TaskPriorityEnum.MEDIUM
    tags: Optional[str] = None
    estimated_effort: Optional[int] = None
    estimated_working_time: Optional[str] = None


class TaskCreate(TaskBase):
    project_code: Optional[str] = None
    milestone_code: Optional[str] = None
    reporter_id: Optional[int] = None
    assignee_id: Optional[int] = None
    type: Optional[TaskTypeEnum] = None
    # Resolution specific
    resolution_summary: Optional[str] = None
    positions: Optional[str] = None
    pending_matters: Optional[str] = None


class TaskUpdate(BaseModel):
    title: Optional[str] = None
    description: Optional[str] = None
    task_type: Optional[TaskTypeEnum] = None
    type: Optional[TaskTypeEnum] = None
    task_subtype: Optional[str] = None
    status: Optional[TaskStatusEnum] = None
    priority: Optional[TaskPriorityEnum] = None
    assignee_id: Optional[int] = None
    taken_by: Optional[str] = None
    tags: Optional[str] = None
    estimated_effort: Optional[int] = None
    # Resolution specific
    resolution_summary: Optional[str] = None
    positions: Optional[str] = None
    pending_matters: Optional[str] = None


class TaskResponse(TaskBase):
    status: TaskStatusEnum
    task_code: Optional[str] = None
    code: Optional[str] = None
    type: Optional[str] = None
    due_date: Optional[datetime] = None
    project_code: Optional[str] = None
    milestone_code: Optional[str] = None
    reporter_id: int
    assignee_id: Optional[int] = None
    taken_by: Optional[str] = None
    created_by_id: Optional[int] = None
    estimated_working_time: Optional[time] = None
    resolution_summary: Optional[str] = None
    positions: Optional[str] = None
    pending_matters: Optional[str] = None
    # BE-PR-008: Proposal Accept tracking
    source_proposal_code: Optional[str] = None
    source_essential_code: Optional[str] = None
    created_at: datetime
    updated_at: Optional[datetime] = None
    
    class Config:
        from_attributes = True


# Comment schemas
class CommentBase(BaseModel):
    content: str


class CommentCreate(CommentBase):
    task_id: int
    author_id: int


class CommentUpdate(BaseModel):
    content: Optional[str] = None


class CommentResponse(CommentBase):
    id: int
    task_id: int
    author_id: int
    created_at: datetime
    updated_at: Optional[datetime] = None
    
    class Config:
        from_attributes = True


# Project schemas
class ProjectBase(BaseModel):
    name: str
    owner_name: Optional[str] = None
    description: Optional[str] = None
    repo: Optional[str] = None
    sub_projects: Optional[list[str]] = None
    related_projects: Optional[list[str]] = None


class ProjectCreate(ProjectBase):
    owner_id: int


class ProjectUpdate(BaseModel):
    description: Optional[str] = None
    owner_name: Optional[str] = None
    repo: Optional[str] = None
    sub_projects: Optional[list[str]] = None
    related_projects: Optional[list[str]] = None


class ProjectResponse(BaseModel):
    id: int
    name: str
    owner_name: Optional[str] = None
    project_code: Optional[str] = None
    description: Optional[str] = None
    repo: Optional[str] = None
    sub_projects: Optional[list[str]] = None
    related_projects: Optional[list[str]] = None
    owner_id: int
    created_at: datetime

    class Config:
        from_attributes = True


# User schemas
class UserBase(BaseModel):
    username: str
    email: str
    full_name: Optional[str] = None


class UserCreate(UserBase):
    password: Optional[str] = None
    role_id: Optional[int] = None
    discord_user_id: Optional[str] = None
    # Agent binding (both must be provided or both omitted)
    agent_id: Optional[str] = None
    claw_identifier: Optional[str] = None


class UserUpdate(BaseModel):
    full_name: Optional[str] = None
    email: Optional[str] = None
    password: Optional[str] = None
    role_id: Optional[int] = None
    is_active: Optional[bool] = None
    discord_user_id: Optional[str] = None


class UserResponse(UserBase):
    id: int
    is_active: bool
    is_admin: bool
    role_id: Optional[int] = None
    role_name: Optional[str] = None
    agent_id: Optional[str] = None
    discord_user_id: Optional[str] = None
    created_at: datetime
    
    class Config:
        from_attributes = True


# Project Member schemas
class ProjectMemberBase(BaseModel):
    user_id: int
    role: str = "dev"


class ProjectMemberCreate(ProjectMemberBase):
    pass


class ProjectMemberResponse(BaseModel):
    id: int
    user_id: int
    username: Optional[str] = None
    full_name: Optional[str] = None
    project_id: int
    role: str = "dev"
    
    class Config:
        from_attributes = True


class MilestoneStatusEnum(str, Enum):
    OPEN = "open"
    FREEZE = "freeze"
    UNDERGOING = "undergoing"
    COMPLETED = "completed"
    CLOSED = "closed"


# Milestone schemas
class MilestoneBase(BaseModel):
    title: str
    description: Optional[str] = None
    status: Optional[MilestoneStatusEnum] = MilestoneStatusEnum.OPEN
    due_date: Optional[datetime] = None
    planned_release_date: Optional[datetime] = None
    depend_on_milestones: Optional[List[str]] = None
    depend_on_tasks: Optional[List[int]] = None


class MilestoneCreate(MilestoneBase):
    project_id: Optional[int] = None
    pass


class MilestoneUpdate(BaseModel):
    title: Optional[str] = None
    description: Optional[str] = None
    status: Optional[MilestoneStatusEnum] = None
    due_date: Optional[datetime] = None
    planned_release_date: Optional[datetime] = None
    depend_on_milestones: Optional[List[str]] = None
    depend_on_tasks: Optional[List[int]] = None


class MilestoneResponse(MilestoneBase):
    milestone_code: Optional[str] = None
    code: Optional[str] = None
    project_code: Optional[str] = None
    created_by_id: Optional[int] = None
    started_at: Optional[datetime] = None
    created_at: datetime
    updated_at: Optional[datetime] = None

    class Config:
        from_attributes = True


# Proposal schemas (renamed from Propose)

class ProposalStatusEnum(str, Enum):
    OPEN = "open"
    ACCEPTED = "accepted"
    REJECTED = "rejected"


class ProposalBase(BaseModel):
    title: str
    description: Optional[str] = None


class ProposalCreate(ProposalBase):
    pass


class ProposalUpdate(BaseModel):
    title: Optional[str] = None
    description: Optional[str] = None


class ProposalResponse(ProposalBase):
    proposal_code: Optional[str] = None  # preferred name
    propose_code: Optional[str] = None   # backward compat alias (same value)
    status: ProposalStatusEnum
    project_code: Optional[str] = None
    created_by_id: Optional[int] = None
    created_by_username: Optional[str] = None
    feat_task_id: Optional[str] = None   # DEPRECATED (BE-PR-010): legacy field, read-only. Use generated_tasks instead.
    created_at: datetime
    updated_at: Optional[datetime] = None

    class Config:
        from_attributes = True


# ---------------------------------------------------------------------------
# Essential schemas (under Proposal)
# ---------------------------------------------------------------------------

class EssentialTypeEnum(str, Enum):
    FEATURE = "feature"
    IMPROVEMENT = "improvement"
    REFACTOR = "refactor"


class EssentialBase(BaseModel):
    title: str
    type: EssentialTypeEnum
    description: Optional[str] = None


class EssentialCreate(EssentialBase):
    """Create a new Essential under a Proposal.

    ``proposal_id`` is inferred from the URL path, not the body.
    """
    pass


class EssentialUpdate(BaseModel):
    title: Optional[str] = None
    type: Optional[EssentialTypeEnum] = None
    description: Optional[str] = None


class EssentialResponse(EssentialBase):
    essential_code: str
    proposal_code: Optional[str] = None
    created_by_id: Optional[int] = None
    created_at: datetime
    updated_at: Optional[datetime] = None

    class Config:
        from_attributes = True


class GeneratedTaskBrief(BaseModel):
    """Brief info about a story task generated from Proposal Accept."""
    task_code: Optional[str] = None
    task_type: str
    task_subtype: Optional[str] = None
    title: str
    status: Optional[str] = None
    source_essential_code: Optional[str] = None


class ProposalDetailResponse(ProposalResponse):
    """Extended Proposal response that embeds its Essential list and generated tasks."""

    essentials: List[EssentialResponse] = []
    generated_tasks: List[GeneratedTaskBrief] = []

    class Config:
        from_attributes = True


class GeneratedTaskSummary(BaseModel):
    """Brief summary of a task generated from a Proposal Essential."""
    task_code: str
    task_type: str
    task_subtype: str
    title: str
    essential_code: str


class ProposalAcceptResponse(ProposalResponse):
    """Response for Proposal Accept — includes the generated story tasks."""

    essentials: List[EssentialResponse] = []
    generated_tasks: List[GeneratedTaskSummary] = []

    class Config:
        from_attributes = True


# ---------------------------------------------------------------------------
# Agent schemas (BE-CAL-003)
# ---------------------------------------------------------------------------

class AgentStatusEnum(str, Enum):
    IDLE = "idle"
    ON_CALL = "on_call"
    BUSY = "busy"
    EXHAUSTED = "exhausted"
    OFFLINE = "offline"


class ExhaustReasonEnum(str, Enum):
    RATE_LIMIT = "rate_limit"
    BILLING = "billing"


class AgentResponse(BaseModel):
    """Read-only representation of an Agent."""
    id: int
    user_id: int
    agent_id: str
    claw_identifier: str
    status: AgentStatusEnum
    last_heartbeat: Optional[datetime] = None
    exhausted_at: Optional[datetime] = None
    recovery_at: Optional[datetime] = None
    exhaust_reason: Optional[ExhaustReasonEnum] = None
    created_at: datetime

    class Config:
        from_attributes = True


class AgentStatusUpdate(BaseModel):
    """Payload for updating an agent's runtime status."""
    status: AgentStatusEnum
    exhaust_reason: Optional[ExhaustReasonEnum] = None
    recovery_at: Optional[datetime] = None


# Backward-compatible aliases
ProposeStatusEnum = ProposalStatusEnum
ProposeBase = ProposalBase
ProposeCreate = ProposalCreate
ProposeUpdate = ProposalUpdate
ProposeResponse = ProposalResponse


# Paginated response
from typing import Generic, TypeVar
T = TypeVar("T")

class PaginatedResponse(BaseModel, Generic[T]):
    items: List[T]
    total: int
    page: int
    page_size: int
    total_pages: int