from typing import Any

from fastapi import HTTPException, Request, status
from passlib.context import CryptContext

from app.db.database import get_connection
from app.db.migrations import run_migrations

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")


def _table_columns(con, table_name: str) -> set[str]:
    rows = con.execute(f"PRAGMA table_info({table_name})").fetchall()
    return {row["name"] for row in rows}


def _user_select_columns(con) -> str:
    columns = _table_columns(con, "users")
    enabled_select = "COALESCE(is_enabled, 1) AS is_enabled" if "is_enabled" in columns else "1 AS is_enabled"
    optional_columns = []
    for column in (
        "last_login_at",
        "auth_provider",
        "provider_subject",
        "avatar_url",
        "gitea_user_id",
        "gitea_sync_status",
        "gitea_sync_error",
        "gitea_synced_at",
    ):
        if column in columns:
            optional_columns.append(column)
        else:
            optional_columns.append(f"NULL AS {column}")
    return (
        "id, username, display_name, email, password_hash, role, "
        f"is_active, {enabled_select}, created_at, updated_at, "
        + ", ".join(optional_columns)
    )


def mark_last_login(user_id: int) -> None:
    run_migrations()
    con = get_connection()
    columns = _table_columns(con, "users")
    if "last_login_at" in columns:
        con.execute(
            """
            UPDATE users
            SET last_login_at = CURRENT_TIMESTAMP,
                updated_at = CURRENT_TIMESTAMP
            WHERE id = ?
            """,
            (user_id,),
        )
        con.commit()
    con.close()


def hash_password(password: str) -> str:
    return pwd_context.hash(password)


def verify_password(plain_password: str, password_hash: str) -> bool:
    if not password_hash:
        return False

    return pwd_context.verify(plain_password, password_hash)


def get_user_by_username(username: str) -> dict[str, Any] | None:
    run_migrations()
    con = get_connection()

    row = con.execute(
        f"""
        SELECT {_user_select_columns(con)}
        FROM users
        WHERE username = ?
        """,
        (username,),
    ).fetchone()

    con.close()
    return dict(row) if row else None


def find_or_create_oauth_user(username: str, display_name: str, email: str) -> dict[str, Any]:
    username = username.strip()
    display_name = (display_name or username).strip() or username
    email = (email or "").strip()

    run_migrations()
    con = get_connection()
    row = con.execute(
        f"""
        SELECT {_user_select_columns(con)}
        FROM users
        WHERE username = ?
        """,
        (username,),
    ).fetchone()

    if row:
        con.execute(
            """
            UPDATE users
            SET display_name = ?,
                email = ?,
                updated_at = CURRENT_TIMESTAMP
            WHERE id = ?
            """,
            (display_name, email, row["id"]),
        )
    else:
        con.execute(
            """
            INSERT INTO users (
                username,
                display_name,
                email,
                password_hash,
                role,
                is_active,
                created_at,
                updated_at
            )
            VALUES (?, ?, ?, '', 'developer', 1, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
            """,
            (username, display_name, email),
        )

    con.commit()
    user_id = row["id"] if row else con.execute("SELECT last_insert_rowid() AS id").fetchone()["id"]
    user = con.execute(
        f"""
        SELECT {_user_select_columns(con)}
        FROM users
        WHERE id = ?
        """,
        (user_id,),
    ).fetchone()

    con.close()
    return dict(user)


def find_or_create_google_user(email: str, display_name: str, provider_subject: str, avatar_url: str = "") -> tuple[dict[str, Any], bool]:
    email = email.strip().lower()
    display_name = (display_name or email).strip() or email
    provider_subject = (provider_subject or "").strip()
    avatar_url = (avatar_url or "").strip()

    run_migrations()
    con = get_connection()
    columns = _table_columns(con, "users")
    params: list[Any] = [email, email]
    provider_clause = ""
    if provider_subject:
        provider_clause = " OR (auth_provider = 'google' AND provider_subject = ?)"
        params.append(provider_subject)

    row = con.execute(
        f"""
        SELECT {_user_select_columns(con)}
        FROM users
        WHERE LOWER(COALESCE(email, '')) = ?
           OR LOWER(COALESCE(username, '')) = ?
           {provider_clause}
        ORDER BY
            CASE
                WHEN LOWER(COALESCE(email, '')) = ? THEN 0
                WHEN LOWER(COALESCE(username, '')) = ? THEN 1
                ELSE 2
            END,
            id
        LIMIT 1
        """,
        (*params, email, email),
    ).fetchone()

    if row:
        updates = [
            "display_name = ?",
            "email = ?",
            "auth_provider = 'google'",
            "provider_subject = ?",
            "updated_at = CURRENT_TIMESTAMP",
        ]
        values: list[Any] = [display_name, email, provider_subject]
        if "avatar_url" in columns:
            updates.append("avatar_url = ?")
            values.append(avatar_url)
        values.append(row["id"])
        con.execute(f"UPDATE users SET {', '.join(updates)} WHERE id = ?", values)
        created = False
        user_id = row["id"]
    else:
        role = "admin" if con.execute("SELECT COUNT(*) AS count FROM users").fetchone()["count"] == 0 else "viewer"
        insert_columns = [
            "username",
            "display_name",
            "email",
            "password_hash",
            "role",
            "is_active",
            "is_enabled",
            "auth_provider",
            "provider_subject",
            "created_at",
            "updated_at",
        ]
        values = [email, display_name, email, "", role, 1, 1, "google", provider_subject]
        placeholders = ["?", "?", "?", "?", "?", "?", "?", "?", "?", "CURRENT_TIMESTAMP", "CURRENT_TIMESTAMP"]
        if "avatar_url" in columns:
            insert_columns.append("avatar_url")
            values.append(avatar_url)
            placeholders.append("?")
        con.execute(
            f"""
            INSERT INTO users ({', '.join(insert_columns)})
            VALUES ({', '.join(placeholders)})
            """,
            values,
        )
        created = True
        user_id = con.execute("SELECT last_insert_rowid() AS id").fetchone()["id"]

    con.commit()
    user = con.execute(
        f"""
        SELECT {_user_select_columns(con)}
        FROM users
        WHERE id = ?
        """,
        (user_id,),
    ).fetchone()

    con.close()
    return dict(user), created


def get_user_by_id(user_id: int) -> dict[str, Any] | None:
    run_migrations()
    con = get_connection()

    row = con.execute(
        f"""
        SELECT {_user_select_columns(con)}
        FROM users
        WHERE id = ?
        """,
        (user_id,),
    ).fetchone()

    con.close()
    return dict(row) if row else None


def authenticate_user(username: str, password: str) -> dict[str, Any] | None:
    user = get_user_by_username(username.strip())

    if not user or not user.get("is_active") or not user.get("is_enabled", 1):
        return None

    if not verify_password(password, user.get("password_hash") or ""):
        return None

    mark_last_login(int(user["id"]))
    return user


def current_user(request: Request) -> dict[str, Any] | None:
    user_id = request.session.get("user_id")
    if not user_id:
        return None

    try:
        user_id = int(user_id)
    except (TypeError, ValueError):
        request.session.pop("user_id", None)
        return None

    user = get_user_by_id(user_id)
    if not user or not user.get("is_active") or not user.get("is_enabled", 1):
        request.session.pop("user_id", None)
        return None

    return user


def require_user(request: Request) -> dict[str, Any]:
    user = current_user(request)
    if user:
        return user

    raise HTTPException(
        status_code=status.HTTP_303_SEE_OTHER,
        headers={"Location": "/portal/login"},
    )