import uuid
from datetime import date
from typing import Literal

from pydantic import BaseModel, Field
from sqlalchemy import delete, or_, select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.milestone import Milestone
from app.models.site import Site
from app.models.study import Study
from app.models.study_center_confirm import StudyCenterConfirm
from app.models.user import User
from app.schemas.study_setup_config import StudySetupConfigData

PROJECT_MILESTONE_TYPE = "SETUP_PROJECT_MILESTONE"
SITE_MILESTONE_TYPE = "SETUP_SITE_MILESTONE"
MILESTONE_STATUS_MAP = {
    "未开始": "NOT_STARTED",
    "进行中": "IN_PROGRESS",
    "已完成": "DONE",
    "延期": "BLOCKED",
}


def _map_milestone_status(raw_status: str | None) -> str | None:
    normalized = (raw_status or "").strip()
    if not normalized:
        return "NOT_STARTED"
    return MILESTONE_STATUS_MAP.get(normalized)


class SetupProjectionSkippedItem(BaseModel):
    site_id: str
    reason: str


class SetupProjectionResult(BaseModel):
    status: Literal["success", "partial_success", "failed"]
    study_updated: bool = False
    site_updated_count: int = 0
    site_skipped_count: int = 0
    warnings: list[str] = Field(default_factory=list)
    skipped_items: list[SetupProjectionSkippedItem] = Field(default_factory=list)


def _parse_date(value: str) -> date | None:
    if not value:
        return None
    try:
        return date.fromisoformat(value)
    except ValueError:
        return None


def _normalize_text(value: str | None) -> str | None:
    if value is None:
        return None
    normalized = value.strip()
    return normalized or None


async def _build_owner_lookup(
    db: AsyncSession,
    *,
    setup_data: StudySetupConfigData,
    result: SetupProjectionResult,
) -> dict[str, uuid.UUID]:
    owners: set[str] = set()
    for row in setup_data.projectMilestones:
        owner = _normalize_text(row.owner)
        if owner:
            owners.add(owner)
    for row in setup_data.siteMilestones:
        owner = _normalize_text(row.owner)
        if owner:
            owners.add(owner)

    if not owners:
        return {}

    users_result = await db.execute(
        select(User.id, User.full_name, User.email).where(
            or_(User.full_name.in_(owners), User.email.in_(owners))
        )
    )
    rows = users_result.all()

    owner_candidates: dict[str, set[uuid.UUID]] = {}
    for user_id, full_name, email in rows:
        full_name_key = _normalize_text(full_name)
        email_key = _normalize_text(email)
        if full_name_key and full_name_key in owners:
            owner_candidates.setdefault(full_name_key, set()).add(user_id)
        if email_key and email_key in owners:
            owner_candidates.setdefault(email_key, set()).add(user_id)

    resolved: dict[str, uuid.UUID] = {}
    for owner in sorted(owners):
        candidates = owner_candidates.get(owner, set())
        if len(candidates) == 1:
            resolved[owner] = next(iter(candidates))
        elif len(candidates) > 1:
            result.warnings.append(f"milestone_owner_ambiguous:{owner}")
    return resolved


async def _replace_project_milestones(
    db: AsyncSession,
    *,
    study_id: uuid.UUID,
    setup_data: StudySetupConfigData,
    owner_lookup: dict[str, uuid.UUID],
    result: SetupProjectionResult,
) -> None:
    await db.execute(
        delete(Milestone).where(
            Milestone.study_id == study_id,
            Milestone.type == PROJECT_MILESTONE_TYPE,
        )
    )
    for row in setup_data.projectMilestones:
        start_text = (row.startDate or row.planDate or "").strip()
        if not any([(row.name or "").strip(), (row.owner or "").strip(), (row.remark or "").strip(), start_text]):
            continue
        name = (row.name or "").strip()
        if not name:
            result.warnings.append(f"project_milestone_name_empty:{row.id}")
            continue
        planned_date = _parse_date(start_text)
        if start_text and not planned_date:
            result.warnings.append(f"project_milestone_plan_date_invalid:{row.id}")
        raw_status = (row.status or "").strip()
        mapped_status = MILESTONE_STATUS_MAP.get(raw_status, "NOT_STARTED")
        if raw_status and raw_status not in MILESTONE_STATUS_MAP:
            result.warnings.append(f"project_milestone_status_unknown:{row.id}")
        owner_name = _normalize_text(row.owner)
        owner_id = owner_lookup.get(owner_name, None) if owner_name else None
        db.add(
            Milestone(
                study_id=study_id,
                type=PROJECT_MILESTONE_TYPE,
                name=name,
                planned_date=planned_date,
                adjusted_start_date=_parse_date((getattr(row, "adjustedStartDate", "") or "").strip()),
                adjusted_end_date=_parse_date((getattr(row, "adjustedEndDate", "") or "").strip()),
                actual_start_date=_parse_date((getattr(row, "actualStartDate", "") or "").strip()),
                actual_end_date=_parse_date((getattr(row, "actualEndDate", "") or "").strip()),
                actual_date=_parse_date((getattr(row, "actualEndDate", "") or "").strip()),
                status=mapped_status,
                owner_id=owner_id,
                owner_name=owner_name,
                notes=_normalize_text(row.remark),
            )
        )


async def _replace_site_milestones(
    db: AsyncSession,
    *,
    study_id: uuid.UUID,
    setup_data: StudySetupConfigData,
    owner_lookup: dict[str, uuid.UUID],
    result: SetupProjectionResult,
) -> None:
    await db.execute(
        delete(Milestone).where(
            Milestone.study_id == study_id,
            Milestone.type == SITE_MILESTONE_TYPE,
        )
    )
    for row in setup_data.siteMilestones:
        if not any(
            [
                (row.milestone or "").strip(),
                (row.owner or "").strip(),
                (row.remark or "").strip(),
                (row.planDate or "").strip(),
            ]
        ):
            continue
        milestone_name = (row.milestone or "").strip()
        if not milestone_name:
            result.warnings.append(f"site_milestone_name_empty:{row.id}")
            continue
        planned_date = _parse_date(row.planDate)
        if row.planDate and not planned_date:
            result.warnings.append(f"site_milestone_plan_date_invalid:{row.id}")
        mapped_status = _map_milestone_status(row.status)
        if mapped_status is None:
            result.warnings.append(f"site_milestone_status_unknown:{row.id}")
            mapped_status = "NOT_STARTED"
        owner_name = _normalize_text(row.owner)
        owner_id = owner_lookup.get(owner_name, None) if owner_name else None
        db.add(
            Milestone(
                study_id=study_id,
                type=SITE_MILESTONE_TYPE,
                name=milestone_name,
                planned_date=planned_date,
                status=mapped_status,
                owner_id=owner_id,
                owner_name=owner_name,
                notes=_normalize_text(row.remark),
            )
        )



async def _replace_center_confirms(
    db: AsyncSession,
    *,
    study_id: uuid.UUID,
    setup_data: StudySetupConfigData,
    site_map: dict[str, Site],
    result: SetupProjectionResult,
) -> None:
    await db.execute(delete(StudyCenterConfirm).where(StudyCenterConfirm.study_id == study_id))
    for row in setup_data.centerConfirm:
        site_id = (row.siteId or "").strip()
        confirmer = _normalize_text(row.confirmer)
        note = _normalize_text(row.note)
        raw_confirm_date = row.confirmDate or ""
        parsed_confirm_date = _parse_date(raw_confirm_date)
        if not any([site_id, confirmer, note, raw_confirm_date]):
            continue
        if not site_id:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id="", reason="center_confirm_site_id_empty"))
            continue
        site = site_map.get(site_id)
        if not site:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id=site_id, reason="center_confirm_site_not_found"))
            continue
        if not site.is_active:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id=site_id, reason="center_confirm_site_inactive"))
            continue
        if raw_confirm_date and not parsed_confirm_date:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id=site_id, reason="center_confirm_date_invalid"))
            result.warnings.append(f"center_confirm_date_invalid:{site_id}")
            continue
        db.add(
            StudyCenterConfirm(
                study_id=study_id,
                site_id=site.id,
                source_setup_item_id=_normalize_text(row.id),
                confirmer=confirmer,
                confirm_status=_normalize_text(row.confirmStatus) or "待确认",
                confirm_date=parsed_confirm_date,
                note=note,
            )
        )


async def apply_setup_projection_on_publish(
    db: AsyncSession,
    *,
    study_id: uuid.UUID,
    setup_data: StudySetupConfigData,
    operator_id: uuid.UUID | None,
) -> SetupProjectionResult:
    _ = operator_id
    result = SetupProjectionResult(status="success")

    study_result = await db.execute(select(Study).where(Study.id == study_id))
    study = study_result.scalar_one_or_none()
    if not study:
        return SetupProjectionResult(
            status="failed",
            warnings=["study_not_found"],
            site_skipped_count=0,
        )

    if study.is_locked:
        result.status = "partial_success"
        result.warnings.append("study_locked_skipped")
        result.skipped_items.append(SetupProjectionSkippedItem(site_id=str(study_id), reason="study_locked"))
        result.site_skipped_count = 1
        return result

    plan = setup_data.enrollmentPlan
    new_monthly_goal_note = _normalize_text(plan.monthlyGoalNote)
    new_stage_breakdown = _normalize_text(plan.stageBreakdown)
    study_changed = (
        study.planned_enrollment_count != plan.totalTarget
        or study.enrollment_monthly_goal_note != new_monthly_goal_note
        or study.enrollment_stage_breakdown != new_stage_breakdown
    )
    study.planned_enrollment_count = plan.totalTarget
    study.enrollment_monthly_goal_note = new_monthly_goal_note
    study.enrollment_stage_breakdown = new_stage_breakdown
    result.study_updated = study_changed

    site_result = await db.execute(select(Site).where(Site.study_id == study_id))
    site_map = {str(site.id): site for site in site_result.scalars().all()}

    deduped_plans: dict[str, tuple[int, str, str, str]] = {}
    duplicate_ids: set[str] = set()
    for row in setup_data.siteEnrollmentPlans:
        site_id = (row.siteId or "").strip()
        if not site_id:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id="", reason="site_id_empty"))
            continue
        if site_id in deduped_plans:
            duplicate_ids.add(site_id)
        deduped_plans[site_id] = (
            row.target,
            row.startDate or "",
            row.endDate or "",
            row.note or "",
        )

    for site_id in sorted(duplicate_ids):
        result.warnings.append(f"duplicate_site_enrollment_plan:{site_id}")

    for site_id, (target, raw_start_date, raw_end_date, raw_note) in deduped_plans.items():
        site = site_map.get(site_id)
        if not site:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id=site_id, reason="site_not_found"))
            continue
        if not site.is_active:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id=site_id, reason="site_inactive"))
            continue
        if target < 0:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id=site_id, reason="target_invalid"))
            result.warnings.append(f"target_invalid:{site_id}")
            continue
        start_date = _parse_date(raw_start_date)
        end_date = _parse_date(raw_end_date)
        if raw_start_date and not start_date:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id=site_id, reason="site_plan_start_date_invalid"))
            result.warnings.append(f"site_plan_start_date_invalid:{site_id}")
            continue
        if raw_end_date and not end_date:
            result.skipped_items.append(SetupProjectionSkippedItem(site_id=site_id, reason="site_plan_end_date_invalid"))
            result.warnings.append(f"site_plan_end_date_invalid:{site_id}")
            continue
        site.enrollment_target = target
        site.enrollment_plan_start_date = start_date
        site.enrollment_plan_end_date = end_date
        site.enrollment_plan_note = _normalize_text(raw_note)
        result.site_updated_count += 1

    owner_lookup = await _build_owner_lookup(db, setup_data=setup_data, result=result)
    await _replace_project_milestones(
        db,
        study_id=study_id,
        setup_data=setup_data,
        owner_lookup=owner_lookup,
        result=result,
    )
    await _replace_site_milestones(
        db,
        study_id=study_id,
        setup_data=setup_data,
        owner_lookup=owner_lookup,
        result=result,
    )
    await _replace_center_confirms(db, study_id=study_id, setup_data=setup_data, site_map=site_map, result=result)

    result.site_skipped_count = len(result.skipped_items)
    if result.site_skipped_count > 0 and result.status != "failed":
        result.status = "partial_success"
    return result