"""CRUD routes for Ansible inventory: groups and targets."""
from __future__ import annotations
import uuid
import yaml

from quart import Blueprint, current_app, redirect, render_template, request, session, url_for
from sqlalchemy import select
from sqlalchemy.orm import selectinload

from steward.ansible import guards
from steward.ansible.inventory_gen import ansible_group_name
from steward.auth.middleware import require_role
from steward.core.audit import audit_request as _audit
from steward.models.ansible_inventory import AnsibleGroup, AnsibleTarget
from steward.models.ansible_schedule import AnsibleSchedule
from steward.models.hosts import Host
from steward.models.users import UserRole

inventory_bp = Blueprint("ansible_inventory", __name__, url_prefix="/ansible/inventory")


def _parse_ansible_vars(raw: str) -> dict:
    """Parse a YAML/JSON string into a dict. Raises ValueError on invalid input."""
    raw = raw.strip()
    if not raw:
        return {}
    try:
        parsed = yaml.safe_load(raw)
    except yaml.YAMLError as exc:
        raise ValueError(f"Invalid YAML: {exc}") from exc
    if parsed is None:
        return {}
    if not isinstance(parsed, dict):
        raise ValueError("ansible_vars must be a YAML mapping (key: value pairs)")
    return parsed


def _vars_refusal(new: dict, old: dict | None = None) -> str | None:
    """Why this editor may not make this vars change, or None (ansible/guards.py)."""
    return guards.check_vars_for_role(guards.changed_vars(new, old),
                                      UserRole(session.get("user_role", "viewer")))


def _add(kind: str, error: str, values: dict) -> dict:
    """An Add dialog to reopen on the Inventory page: which, why, what was typed."""
    return {"kind": kind, "error": error, "values": values}


async def _name_taken(model, name: str) -> bool:
    async with current_app.db_sessionmaker() as db:
        return (await db.execute(select(model.id).where(model.name == name))).first() is not None


# ---------------------------------------------------------------------------
# The Inventory tab (#5333): targets and groups on one page
# ---------------------------------------------------------------------------

async def _scope_users(db) -> dict[str, list[AnsibleSchedule]]:
    """{inventory scope: [schedule, …]}: which schedules run against a target
    or group, so its page can say what deleting it would leave pointing at
    nothing."""
    out: dict[str, list[AnsibleSchedule]] = {}
    for sch in (await db.execute(select(AnsibleSchedule).order_by(AnsibleSchedule.name))).scalars():
        out.setdefault(sch.inventory_scope, []).append(sch)
    return out


@inventory_bp.get("/")
@require_role(UserRole.viewer)
async def inventory(add: dict | None = None, status: int = 200):
    """Every target with its address, the Steward host it is linked to and
    its groups; then every group with its members. The row opens the target
    or group, where it is edited and deleted. `add` reopens an Add dialog
    with the error and what was typed (a failed create), or ?add=target|group
    opens one empty."""
    async with current_app.db_sessionmaker() as db:
        targets = (await db.execute(
            select(AnsibleTarget).options(selectinload(AnsibleTarget.groups))
            .order_by(AnsibleTarget.name))).scalars().all()
        groups = (await db.execute(
            select(AnsibleGroup).options(selectinload(AnsibleGroup.targets))
            .order_by(AnsibleGroup.name))).scalars().all()
        host_ids = [t.host_id for t in targets if t.host_id]
        hosts = {h.id: h for h in (await db.execute(
            select(Host).where(Host.id.in_(host_ids)))).scalars()} if host_ids else {}
        users = await _scope_users(db)
    if add is None and request.args.get("add") in ("target", "group"):
        add = {"kind": request.args["add"], "error": None, "values": {}}
    verdict = {
        "targets": len(targets), "groups": len(groups),
        "unlinked": sum(1 for t in targets if t.host_id not in hosts),
        "ungrouped": sum(1 for t in targets if not t.groups),
    }
    body = await render_template(
        "ansible/inventory/index.html", targets=targets, groups=groups, hosts=hosts,
        users=users, verdict=verdict, add=add)
    return body, status


# ---------------------------------------------------------------------------
# Groups
# ---------------------------------------------------------------------------

@inventory_bp.post("/groups")
@require_role(UserRole.operator)
async def groups_create():
    form = await request.form
    name = form.get("name", "").strip()
    values = {"name": name}
    if not name:
        return await inventory(_add("group", "A group needs a name.", values), 400)
    try:
        ansible_vars = _parse_ansible_vars(form.get("ansible_vars", ""))
    except ValueError as exc:
        return await inventory(_add("group", str(exc), values), 400)

    err = _vars_refusal(ansible_vars)
    if err:
        return await inventory(_add("group", err, values), 400)
    if await _name_taken(AnsibleGroup, name):
        return await inventory(_add("group", f"There is already a group named {name}.", values), 400)

    group = AnsibleGroup(id=str(uuid.uuid4()), name=name, ansible_vars=ansible_vars)
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            db.add(group)
    await _audit("ansible.group.created", "ansible_group", group.id,
                 {"name": name, "vars": sorted(ansible_vars)})
    return redirect(url_for("ansible_inventory.group_detail", group_id=group.id))


@inventory_bp.get("/groups/<group_id>")
@require_role(UserRole.viewer)
async def group_detail(group_id: str):
    async with current_app.db_sessionmaker() as db:
        result = await db.execute(
            select(AnsibleGroup)
            .where(AnsibleGroup.id == group_id)
            .options(selectinload(AnsibleGroup.targets))
        )
        group = result.scalar_one_or_none()
        if group is None:
            return "Group not found", 404
        all_targets = (
            await db.execute(select(AnsibleTarget).order_by(AnsibleTarget.name))
        ).scalars().all()
        used = (await _scope_users(db)).get(f"steward:group:{group.id}", [])
    member_ids = {t.id for t in group.targets}
    ansible_vars_yaml = yaml.dump(group.ansible_vars) if group.ansible_vars else ""
    return await render_template(
        "ansible/inventory/group_detail.html",
        group=group,
        ansible_name=ansible_group_name(group.name),
        used=used,
        all_targets=all_targets,
        member_ids=member_ids,
        ansible_vars_yaml=ansible_vars_yaml,
    )


@inventory_bp.post("/groups/<group_id>")
@require_role(UserRole.operator)
async def group_update(group_id: str):
    form = await request.form
    try:
        ansible_vars = _parse_ansible_vars(form.get("ansible_vars", ""))
    except ValueError as exc:
        return str(exc), 400

    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            result = await db.execute(
                select(AnsibleGroup)
                .where(AnsibleGroup.id == group_id)
                .options(selectinload(AnsibleGroup.targets))
            )
            group = result.scalar_one_or_none()
            if group is None:
                return "Group not found", 404
            err = _vars_refusal(ansible_vars, group.ansible_vars)
            if err:
                return err, 400

            name = form.get("name", group.name).strip()
            if name:
                group.name = name
            group.ansible_vars = ansible_vars

            new_ids = set(form.getlist("target_ids"))
            all_targets = (
                await db.execute(select(AnsibleTarget))
            ).scalars().all()
            target_map = {t.id: t for t in all_targets}
            group.targets = [target_map[tid] for tid in new_ids if tid in target_map]
            detail = {"name": group.name, "vars": sorted(ansible_vars),
                      "targets": sorted(t.name for t in group.targets)}

    await _audit("ansible.group.updated", "ansible_group", group_id, detail)
    return redirect(url_for("ansible_inventory.group_detail", group_id=group_id))


@inventory_bp.post("/groups/<group_id>/delete")
@require_role(UserRole.operator)
async def group_delete(group_id: str):
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            result = await db.execute(
                select(AnsibleGroup).where(AnsibleGroup.id == group_id)
            )
            group = result.scalar_one_or_none()
            if group is None:
                return redirect(url_for("ansible_inventory.inventory"))
            name = group.name
            await db.delete(group)
    await _audit("ansible.group.deleted", "ansible_group", group_id, {"name": name})
    return redirect(url_for("ansible_inventory.inventory"))


# ---------------------------------------------------------------------------
# Targets
# ---------------------------------------------------------------------------

@inventory_bp.post("/targets")
@require_role(UserRole.operator)
async def targets_create():
    form = await request.form
    name = form.get("name", "").strip()
    address = form.get("address", "").strip()
    values = {"name": name, "address": address}
    if not name or not address:
        return await inventory(_add("target", "A target needs a name and an address.", values), 400)
    try:
        ansible_vars = _parse_ansible_vars(form.get("ansible_vars", ""))
    except ValueError as exc:
        return await inventory(_add("target", str(exc), values), 400)

    err = _vars_refusal(ansible_vars)
    if err:
        return await inventory(_add("target", err, values), 400)
    if await _name_taken(AnsibleTarget, name):
        return await inventory(_add("target", f"There is already a target named {name}.", values), 400)

    target = AnsibleTarget(
        id=str(uuid.uuid4()), name=name, address=address, ansible_vars=ansible_vars
    )
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            db.add(target)
    await _audit("ansible.target.created", "ansible_target", target.id,
                 {"name": name, "address": address, "vars": sorted(ansible_vars)})
    return redirect(url_for("ansible_inventory.target_detail", target_id=target.id))


@inventory_bp.get("/targets/<target_id>")
@require_role(UserRole.viewer)
async def target_detail(target_id: str):
    async with current_app.db_sessionmaker() as db:
        result = await db.execute(
            select(AnsibleTarget)
            .where(AnsibleTarget.id == target_id)
            .options(selectinload(AnsibleTarget.groups))
        )
        target = result.scalar_one_or_none()
        if target is None:
            return "Target not found", 404
        all_groups = (
            await db.execute(select(AnsibleGroup).order_by(AnsibleGroup.name))
        ).scalars().all()
        host = await db.get(Host, target.host_id) if target.host_id else None
        used = (await _scope_users(db)).get(f"steward:target:{target.id}", [])
    member_group_ids = {g.id for g in target.groups}
    ansible_vars_yaml = yaml.dump(target.ansible_vars) if target.ansible_vars else ""
    return await render_template(
        "ansible/inventory/target_detail.html",
        target=target,
        host=host,
        used=used,
        all_groups=all_groups,
        member_group_ids=member_group_ids,
        ansible_vars_yaml=ansible_vars_yaml,
    )


@inventory_bp.post("/targets/<target_id>")
@require_role(UserRole.operator)
async def target_update(target_id: str):
    form = await request.form
    try:
        ansible_vars = _parse_ansible_vars(form.get("ansible_vars", ""))
    except ValueError as exc:
        return str(exc), 400

    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            result = await db.execute(
                select(AnsibleTarget)
                .where(AnsibleTarget.id == target_id)
                .options(selectinload(AnsibleTarget.groups))
            )
            target = result.scalar_one_or_none()
            if target is None:
                return "Target not found", 404
            err = _vars_refusal(ansible_vars, target.ansible_vars)
            if err:
                return err, 400

            name = form.get("name", target.name).strip()
            address = form.get("address", target.address).strip()
            if name:
                target.name = name
            if address:
                target.address = address
            target.ansible_vars = ansible_vars

            new_group_ids = set(form.getlist("group_ids"))
            all_groups_result = await db.execute(select(AnsibleGroup))
            group_map = {g.id: g for g in all_groups_result.scalars().all()}
            target.groups = [group_map[gid] for gid in new_group_ids if gid in group_map]
            detail = {"name": target.name, "address": target.address, "vars": sorted(ansible_vars),
                      "groups": sorted(g.name for g in target.groups)}

    await _audit("ansible.target.updated", "ansible_target", target_id, detail)
    return redirect(url_for("ansible_inventory.target_detail", target_id=target_id))


@inventory_bp.post("/targets/<target_id>/delete")
@require_role(UserRole.operator)
async def target_delete(target_id: str):
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            result = await db.execute(
                select(AnsibleTarget).where(AnsibleTarget.id == target_id)
            )
            target = result.scalar_one_or_none()
            if target is None:
                return redirect(url_for("ansible_inventory.inventory"))
            name = target.name
            await db.delete(target)
    await _audit("ansible.target.deleted", "ansible_target", target_id, {"name": name})
    return redirect(url_for("ansible_inventory.inventory"))