"""QC module.

Two clearly separated halves:

**تعریف (Definition)** — what must eventually be checked
  * `QCTemplate` + `QCQuestion`      : global, reusable, editable
  * `TaskQCDefinition`/`TaskQCQuestion`: a task-specific COPY the user customizes

**اجرا (Execution)** — the actual evaluation during the project
  * `TaskQCResult`  : append-only answers (pass / fail / na) + comment
  * `Defect`        : problems raised on a task, with corrective action

Applying a template to a task deep-copies its questions, so customizing a task
never mutates the global template.

Access split (app/authz.py):
  * `qc.define`  — templates + the per-task QC structure: project manager only
  * `qc.execute` — recording answers and defects, on assigned projects
  * `qc.view`    — reading status/readiness, on assigned projects
"""
import uuid
from dataclasses import dataclass
from datetime import datetime, timezone

from fastapi import APIRouter, Depends
from pydantic import BaseModel, field_validator
from sqlalchemy import delete, select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload

from app.authz import (
    AuthContext,
    Perm,
    require_permission,
    scoped_task,
)
from app.db import get_db
from app.errors import NotFoundError, ValidationError
from app.models import (
    Defect,
    QCAnswer,
    QCQuestion,
    QCQuestionPhase,
    QCTemplate,
    Task,
    TaskQCDefinition,
    TaskQCQuestion,
    TaskQCResult,
)
from app.qc_service import (
    PRE,
    build_state,
    definition_dict,
    load_definitions,
    question_dict,
    recompute_task_qc_status,
    state_dict,
    task_qc_state,
)
from app.serializers import _iso

router = APIRouter(prefix="/qc", tags=["qc"])

define_qc = require_permission(Perm.qc_define)
execute_qc = require_permission(Perm.qc_execute)
view_qc = require_permission(Perm.qc_view)

PHASE_LABELS = {PRE: "پیش از اجرا", "during": "هنگام اجرا", "after": "پس از اجرا"}


def _phase(value: str) -> QCQuestionPhase:
    try:
        return QCQuestionPhase(value)
    except ValueError as exc:
        raise ValidationError("مرحله باید pre، during یا after باشد", field="phase") from exc


def _answer(value: str) -> QCAnswer:
    try:
        return QCAnswer(value)
    except ValueError as exc:
        raise ValidationError("پاسخ باید pass، fail یا na باشد", field="answer") from exc


@dataclass
class QCTaskRef:
    """A task as the QC module sees it."""

    id: uuid.UUID
    subject: str
    progress: int
    status: str

    @property
    def key(self):
        return self.id


async def _qc_task(db: AsyncSession, ctx: AuthContext, task_ref: str | uuid.UUID) -> QCTaskRef:
    """Resolve the task a QC screen is about, enforcing the caller's scope."""
    native = await scoped_task(db, ctx, task_ref)
    return QCTaskRef(
        id=native.id,
        subject=native.title or "",
        progress=native.progress or 0,
        status=native.status or "",
    )


async def _ensure_definition_scope(db: AsyncSession, ctx: AuthContext, definition: TaskQCDefinition) -> None:
    native = await db.get(Task, definition.task_id)
    if native is not None:
        ctx.ensure_project(native.project_id)
        return
    raise NotFoundError("تعریف QC یافت نشد")


async def _definition(db: AsyncSession, definition_id: uuid.UUID) -> TaskQCDefinition:
    row = await db.scalar(
        select(TaskQCDefinition)
        .options(selectinload(TaskQCDefinition.questions).selectinload(TaskQCQuestion.results))
        .where(TaskQCDefinition.id == definition_id)
    )
    if row is None:
        raise NotFoundError("تعریف QC یافت نشد")
    return row


async def _scoped_definition(db: AsyncSession, ctx: AuthContext, definition_id: uuid.UUID) -> TaskQCDefinition:
    definition = await _definition(db, definition_id)
    await _ensure_definition_scope(db, ctx, definition)
    return definition


async def _question(db: AsyncSession, question_id: uuid.UUID) -> TaskQCQuestion:
    row = await db.scalar(
        select(TaskQCQuestion)
        .options(selectinload(TaskQCQuestion.results))
        .where(TaskQCQuestion.id == question_id)
    )
    if row is None:
        raise NotFoundError("سؤال QC یافت نشد")
    return row


async def _scoped_definition_question(
    db: AsyncSession, ctx: AuthContext, question_id: uuid.UUID
) -> tuple[TaskQCQuestion, TaskQCDefinition]:
    question = await _question(db, question_id)
    definition = await db.get(TaskQCDefinition, question.definition_id)
    if definition is None:
        raise NotFoundError("تعریف QC یافت نشد")
    await _ensure_definition_scope(db, ctx, definition)
    return question, definition


# =============================================================================
# Global QC templates
# =============================================================================


def _template_dict(template: QCTemplate) -> dict:
    return {
        "id": str(template.id),
        "name": template.name,
        "activity_type": template.activity_type,
        "description": template.description,
        "questions": [
            {
                "id": str(q.id),
                "phase": q.phase.value,
                "text": q.text,
                "sort_order": q.sort_order,
                "required": q.required,
            }
            for q in template.questions
        ],
    }


async def _template(db: AsyncSession, template_id: uuid.UUID) -> QCTemplate:
    row = await db.scalar(
        select(QCTemplate)
        .options(selectinload(QCTemplate.questions))
        .where(QCTemplate.id == template_id)
    )
    if row is None:
        raise NotFoundError("قالب QC یافت نشد")
    return row


@router.get("/templates")
async def list_templates(activity_type: str | None = None, _: AuthContext = Depends(view_qc), db: AsyncSession = Depends(get_db)):
    stmt = select(QCTemplate).options(selectinload(QCTemplate.questions)).order_by(QCTemplate.name)
    if activity_type:
        stmt = stmt.where(QCTemplate.activity_type == activity_type)
    templates = (await db.execute(stmt)).scalars().all()
    return {"data": [_template_dict(t) for t in templates]}


@router.get("/templates/{template_id}")
async def get_template(template_id: uuid.UUID, _: AuthContext = Depends(view_qc), db: AsyncSession = Depends(get_db)):
    return {"data": _template_dict(await _template(db, template_id))}


class QuestionIn(BaseModel):
    phase: str
    text: str
    required: bool = True
    sort_order: int = 0


class TemplateIn(BaseModel):
    name: str
    activity_type: str = ""
    description: str = ""
    questions: list[QuestionIn] = []

    @field_validator("name")
    @classmethod
    def _name_not_empty(cls, v: str) -> str:
        if not v.strip():
            raise ValueError("نام قالب الزامی است")
        return v.strip()


@router.post("/templates")
async def create_template(payload: TemplateIn, _: AuthContext = Depends(define_qc), db: AsyncSession = Depends(get_db)):
    template = QCTemplate(
        name=payload.name,
        activity_type=payload.activity_type,
        description=payload.description,
    )
    db.add(template)
    await db.flush()

    for index, q in enumerate(payload.questions):
        db.add(
            QCQuestion(
                template_id=template.id,
                phase=_phase(q.phase),
                text=q.text.strip(),
                sort_order=q.sort_order if q.sort_order else index,
                required=q.required,
            )
        )
    await db.commit()
    return {"data": _template_dict(await _template(db, template.id))}


class TemplatePatch(BaseModel):
    name: str | None = None
    activity_type: str | None = None
    description: str | None = None


@router.patch("/templates/{template_id}")
async def patch_template(
    template_id: uuid.UUID, payload: TemplatePatch, _: AuthContext = Depends(define_qc), db: AsyncSession = Depends(get_db)
):
    template = await _template(db, template_id)
    if payload.name is not None:
        if not payload.name.strip():
            raise ValidationError("نام قالب نمی‌تواند خالی باشد", field="name")
        template.name = payload.name.strip()
    if payload.activity_type is not None:
        template.activity_type = payload.activity_type
    if payload.description is not None:
        template.description = payload.description
    await db.commit()
    return {"data": _template_dict(template)}


@router.delete("/templates/{template_id}")
async def delete_template(template_id: uuid.UUID, _: AuthContext = Depends(define_qc), db: AsyncSession = Depends(get_db)):
    template = await _template(db, template_id)
    await db.delete(template)
    await db.commit()
    return {"data": {"deleted": True}}


@router.post("/templates/{template_id}/questions")
async def add_template_question(
    template_id: uuid.UUID, payload: QuestionIn, _: AuthContext = Depends(define_qc), db: AsyncSession = Depends(get_db)
):
    template = await _template(db, template_id)
    question = QCQuestion(
        template_id=template.id,
        phase=_phase(payload.phase),
        text=payload.text.strip(),
        sort_order=payload.sort_order,
        required=payload.required,
    )
    db.add(question)
    await db.commit()
    return {"data": _template_dict(await _template(db, template_id))}


class QuestionPatch(BaseModel):
    text: str | None = None
    phase: str | None = None
    required: bool | None = None
    sort_order: int | None = None


@router.patch("/questions/{question_id}")
async def patch_question(
    question_id: uuid.UUID, payload: QuestionPatch, _: AuthContext = Depends(define_qc), db: AsyncSession = Depends(get_db)
):
    question = await db.get(QCQuestion, question_id)
    if question is None:
        raise NotFoundError("سؤال QC یافت نشد")
    if payload.text is not None:
        if not payload.text.strip():
            raise ValidationError("متن سؤال نمی‌تواند خالی باشد", field="text")
        question.text = payload.text.strip()
    if payload.phase is not None:
        question.phase = _phase(payload.phase)
    if payload.required is not None:
        question.required = payload.required
    if payload.sort_order is not None:
        question.sort_order = payload.sort_order
    await db.commit()
    return {"data": {"id": str(question.id)}}


@router.delete("/questions/{question_id}")
async def delete_question(question_id: uuid.UUID, _: AuthContext = Depends(define_qc), db: AsyncSession = Depends(get_db)):
    question = await db.get(QCQuestion, question_id)
    if question is None:
        raise NotFoundError("سؤال QC یافت نشد")
    await db.delete(question)
    await db.commit()
    return {"data": {"deleted": True}}


# =============================================================================
# Task QC Definitions
# =============================================================================


class DefinitionIn(BaseModel):
    name: str = ""
    template_id: str | None = None


@router.get("/tasks/{task_ref}")
async def task_qc(
    task_ref: str, ctx: AuthContext = Depends(view_qc), db: AsyncSession = Depends(get_db)
):
    """Everything the QC screen needs: definitions + questions + results + readiness."""
    task = await _qc_task(db, ctx, task_ref)
    definitions = await load_definitions(db, task.key)
    state = build_state(definitions)
    return {
        "data": {
            "task": {
                "id": str(task.id),
                "subject": task.subject,
                "percentage_done": task.progress,
                "status": task.status,
            },
            "definitions": [definition_dict(d, state) for d in definitions],
            "readiness": state_dict(state, progress=task.progress),
        }
    }


@router.post("/tasks/{task_ref}/definition")
async def create_definition(
    task_ref: str,
    payload: DefinitionIn,
    ctx: AuthContext = Depends(define_qc),
    db: AsyncSession = Depends(get_db),
):
    task = await _qc_task(db, ctx, task_ref)
    template: QCTemplate | None = None
    if payload.template_id:
        try:
            template_uuid = uuid.UUID(payload.template_id)
        except ValueError as exc:
            raise ValidationError("شناسه قالب نامعتبر است", field="template_id") from exc
        template = await _template(db, template_uuid)

    definition = TaskQCDefinition(
        task_id=task.id,
        name=payload.name.strip() or (template.name if template else "QC تسک"),
        source_template_id=template.id if template else None,
    )
    db.add(definition)
    await db.flush()

    if template:
        for index, question in enumerate(template.questions):
            db.add(
                TaskQCQuestion(
                    definition_id=definition.id,
                    phase=question.phase,
                    text=question.text,
                    sort_order=index,
                    required=question.required,
                )
            )
    await db.commit()
    await recompute_task_qc_status(db, task.key)
    await db.commit()
    return {"data": {"id": str(definition.id)}}


class DefinitionPatch(BaseModel):
    name: str


@router.patch("/definitions/{definition_id}")
async def patch_definition(
    definition_id: uuid.UUID,
    payload: DefinitionPatch,
    ctx: AuthContext = Depends(define_qc),
    db: AsyncSession = Depends(get_db),
):
    definition = await _scoped_definition(db, ctx, definition_id)
    if not payload.name.strip():
        raise ValidationError("نام تعریف الزامی است", field="name")
    definition.name = payload.name.strip()
    await db.commit()
    return {"data": {"id": str(definition.id), "name": definition.name}}


@router.delete("/definitions/{definition_id}")
async def delete_definition(
    definition_id: uuid.UUID, ctx: AuthContext = Depends(define_qc), db: AsyncSession = Depends(get_db)
):
    definition = await _scoped_definition(db, ctx, definition_id)
    task_key = definition.task_id
    await db.delete(definition)
    await db.commit()
    await recompute_task_qc_status(db, task_key)
    await db.commit()
    return {"data": {"deleted": True}}


class TaskQuestionIn(BaseModel):
    text: str
    phase: str
    required: bool = True
    sort_order: int = 0


@router.post("/definitions/{definition_id}/questions")
async def add_task_question(
    definition_id: uuid.UUID,
    payload: TaskQuestionIn,
    ctx: AuthContext = Depends(define_qc),
    db: AsyncSession = Depends(get_db),
):
    definition = await _scoped_definition(db, ctx, definition_id)
    question = TaskQCQuestion(
        definition_id=definition.id,
        phase=_phase(payload.phase),
        text=payload.text.strip(),
        sort_order=payload.sort_order,
        required=payload.required,
    )
    db.add(question)
    definition.updated_at = datetime.now(timezone.utc)
    await db.commit()
    await recompute_task_qc_status(db, definition.task_id)
    await db.commit()
    return {"data": {"id": str(question.id)}}


@router.patch("/task-questions/{question_id}")
async def patch_task_question(
    question_id: uuid.UUID,
    payload: QuestionPatch,
    ctx: AuthContext = Depends(define_qc),
    db: AsyncSession = Depends(get_db),
):
    question, definition = await _scoped_definition_question(db, ctx, question_id)
    values = payload.model_dump(exclude_unset=True)
    if "text" in values:
        if not values["text"].strip():
            raise ValidationError("متن سؤال نمی‌تواند خالی باشد", field="text")
        question.text = values["text"].strip()
        values.pop("text")
    if "phase" in values:
        question.phase = _phase(values.pop("phase"))
    for key, value in values.items():
        setattr(question, key, value)
    definition.updated_at = datetime.now(timezone.utc)
    await db.commit()
    await recompute_task_qc_status(db, definition.task_id)
    await db.commit()
    return {"data": {"id": str(question.id)}}


@router.delete("/task-questions/{question_id}")
async def delete_task_question(
    question_id: uuid.UUID, ctx: AuthContext = Depends(define_qc), db: AsyncSession = Depends(get_db)
):
    question, definition = await _scoped_definition_question(db, ctx, question_id)
    task_key = definition.task_id
    await db.delete(question)
    await db.commit()
    await recompute_task_qc_status(db, task_key)
    await db.commit()
    return {"data": {"deleted": True}}


# =============================================================================
# Execution / evaluation
# =============================================================================


class ResultIn(BaseModel):
    answer: str | None = None
    comment: str = ""
    photo_id: str | None = None


@router.put("/task-questions/{question_id}/result")
async def evaluate_question(
    question_id: uuid.UUID,
    payload: ResultIn,
    ctx: AuthContext = Depends(execute_qc),
    db: AsyncSession = Depends(get_db),
):
    question, definition = await _scoped_definition_question(db, ctx, question_id)

    # اگر پاسخ خالی یا null باشد، انتخاب قبلی لغو شده و سؤال به حالت بدون پاسخ برمی‌گردد
    if not payload.answer or payload.answer.strip().lower() in ("none", "null", "cancel", "clear", "pending"):
        await db.execute(delete(TaskQCResult).where(TaskQCResult.question_id == question.id))
        await db.commit()
        status = await recompute_task_qc_status(db, definition.task_id)
        await db.commit()
        state = await task_qc_state(db, definition.task_id)
        return {
            "data": {
                "question_id": str(question.id),
                "answer": None,
                "task_qc_status": status,
                "readiness": state_dict(state, progress=await _progress(db, definition.task_id)),
            }
        }

    user = ctx.user
    answer = _answer(payload.answer)

    existing_latest = await db.scalar(
        select(TaskQCResult)
        .where(TaskQCResult.question_id == question.id)
        .order_by(TaskQCResult.evaluated_at.desc(), TaskQCResult.id.desc())
    )
    photo_path = payload.photo_id
    if photo_path is None and existing_latest and existing_latest.answer == answer:
        photo_path = existing_latest.photo_path
    elif photo_path == "":
        photo_path = None

    db.add(
        TaskQCResult(
            question_id=question.id,
            answer=answer,
            comment=payload.comment.strip(),
            photo_path=photo_path,
            evaluated_by=user.display_name or user.username,
        )
    )
    await db.commit()

    status = await recompute_task_qc_status(db, definition.task_id)
    await db.commit()
    state = await task_qc_state(db, definition.task_id)
    return {
        "data": {
            "question_id": str(question.id),
            "answer": answer.value,
            "photo_url": f"/api/v1/files/{photo_path}" if photo_path else None,
            "task_qc_status": status,
            "readiness": state_dict(state, progress=await _progress(db, definition.task_id)),
        }
    }


@router.delete("/task-questions/{question_id}/result")
async def delete_question_result(
    question_id: uuid.UUID,
    ctx: AuthContext = Depends(execute_qc),
    db: AsyncSession = Depends(get_db),
):
    question, definition = await _scoped_definition_question(db, ctx, question_id)
    await db.execute(delete(TaskQCResult).where(TaskQCResult.question_id == question.id))
    await db.commit()
    status = await recompute_task_qc_status(db, definition.task_id)
    await db.commit()
    state = await task_qc_state(db, definition.task_id)
    return {
        "data": {
            "question_id": str(question.id),
            "answer": None,
            "task_qc_status": status,
            "readiness": state_dict(state, progress=await _progress(db, definition.task_id)),
        }
    }


async def _progress(db: AsyncSession, task_id: uuid.UUID) -> int:
    task = await db.scalar(select(Task).where(Task.id == task_id))
    return (task.progress or 0) if task else 0


# =============================================================================
# Defects
# =============================================================================


def _defect_dict(defect: Defect) -> dict:
    return {
        "id": str(defect.id),
        "task_id": str(defect.task_id),
        "question_id": str(defect.question_id) if defect.question_id else None,
        "title": defect.title,
        "description": defect.description,
        "severity": defect.severity,
        "status": defect.status,
        "corrective_action": defect.corrective_action,
        "resolution_notes": defect.resolution_notes,
        "photo_url": f"/api/v1/files/{defect.photo_path}" if defect.photo_path else None,
        "created_at": _iso(defect.created_at),
        "resolved_at": _iso(defect.resolved_at),
    }


class DefectIn(BaseModel):
    task_ref: str
    question_id: str | None = None
    title: str
    description: str = ""
    severity: str = "medium"
    corrective_action: str = ""
    photo_id: str | None = None

    @field_validator("title")
    @classmethod
    def _title(cls, v: str) -> str:
        if not v.strip():
            raise ValueError("عنوان عیب الزامی است")
        return v.strip()


@router.post("/defects")
async def create_defect(
    payload: DefectIn, ctx: AuthContext = Depends(execute_qc), db: AsyncSession = Depends(get_db)
):
    task = await _qc_task(db, ctx, payload.task_ref)
    question_id = None
    if payload.question_id:
        try:
            question_id = uuid.UUID(payload.question_id)
        except ValueError as exc:
            raise ValidationError("شناسه سؤال نامعتبر است", field="question_id") from exc
    defect = Defect(
        task_id=task.id,
        question_id=question_id,
        title=payload.title,
        description=payload.description,
        severity=payload.severity if payload.severity in ("low", "medium", "high") else "medium",
        corrective_action=payload.corrective_action,
        photo_path=payload.photo_id,
    )
    db.add(defect)
    await db.commit()
    return {"data": _defect_dict(defect)}


class ResolveIn(BaseModel):
    resolution_notes: str = ""


@router.post("/defects/{defect_id}/resolve")
async def resolve_defect(
    defect_id: uuid.UUID,
    payload: ResolveIn,
    ctx: AuthContext = Depends(execute_qc),
    db: AsyncSession = Depends(get_db),
):
    defect = await db.get(Defect, defect_id)
    if defect is None:
        raise NotFoundError("عیب یافت نشد")
    await scoped_task(db, ctx, defect.task_id)
    if defect.status == "resolved":
        raise ValidationError("این عیب قبلاً رفع شده است")
    defect.status = "resolved"
    defect.resolution_notes = payload.resolution_notes.strip()
    defect.resolved_at = datetime.now(timezone.utc)
    await db.commit()
    return {"data": _defect_dict(defect)}


@router.get("/defects")
async def list_defects(
    task_id: uuid.UUID | None = None,
    status: str | None = None,
    ctx: AuthContext = Depends(view_qc),
    db: AsyncSession = Depends(get_db),
):
    query = select(Defect).join(Task, Task.id == Defect.task_id)
    if task_id:
        query = query.where(Defect.task_id == task_id)
    if status:
        query = query.where(Defect.status == status)
    query = ctx.scope(query, Task.project_id)
    query = query.order_by(Defect.created_at.desc()).limit(150)
    rows = (await db.execute(query)).scalars().all()

    items = []
    for d in rows:
        task = await db.get(Task, d.task_id)
        di = _defect_dict(d)
        di["task_title"] = task.title if task else ""
        items.append(di)
    return {"data": items}


async def defects_for_task(db: AsyncSession, task_id: uuid.UUID) -> list[Defect]:
    rows = (
        await db.execute(select(Defect).where(Defect.task_id == task_id).order_by(Defect.created_at.desc()))
    ).scalars().all()
    return list(rows)