"""Handle the management of resources."""
import json
import sqlite3
from uuid import UUID, uuid4
from functools import reduce, partial
from typing import Dict, Sequence, Optional

from ...db import sqlite3 as db
from ...dictify import dictify
from ...authentication.users import User
from ...db.sqlite3 import with_db_connection

from .checks import authorised_for

from ..checks import authorised_p
from ..errors import NotFoundError, AuthorisationError
from ..groups.models import (
    Group, GroupRole, user_group, group_by_id, is_group_leader)

class MissingGroupError(AuthorisationError):
    """Raised for any resource operation without a group."""


def __assign_resource_owner_role__(cursor, resource, user):
    """Assign `user` the 'Resource Owner' role for `resource`."""
    cursor.execute(
        "SELECT gr.* FROM group_roles AS gr INNER JOIN roles AS r "
        "ON gr.role_id=r.role_id WHERE r.role_name='resource-owner' "
        "AND gr.group_id=?",
        (str(resource.group.group_id),))
    role = cursor.fetchone()
    if not role:
        cursor.execute("SELECT * FROM roles WHERE role_name='resource-owner'")
        role = cursor.fetchone()
        cursor.execute(
            "INSERT INTO group_roles VALUES "
            "(:group_role_id, :group_id, :role_id)",
            {"group_role_id": str(uuid4()),
             "group_id": str(resource.group.group_id),
             "role_id": role["role_id"]})

    cursor.execute(
            "INSERT INTO group_user_roles_on_resources "
            "VALUES ("
            ":group_id, :user_id, :role_id, :resource_id"
            ")",
            {"group_id": str(resource.group.group_id),
             "user_id": str(user.user_id),
             "role_id": role["role_id"],
             "resource_id": str(resource.resource_id)})

@authorised_p(("group:resource:create-resource",),
              error_description="Insufficient privileges to create a resource",
              oauth2_scope="profile resource")
def create_resource(
        conn: db.DbConnection, resource_name: str,
        resource_category: ResourceCategory, user: User,
        public: bool) -> Resource:
    """Create a resource item."""
    with db.cursor(conn) as cursor:
        group = user_group(conn, user).maybe(
            False, lambda grp: grp)# type: ignore[misc, arg-type]
        if not group:
            raise MissingGroupError(
                "User with no group cannot create a resource.")
        resource = Resource(
            group, uuid4(), resource_name, resource_category, public)
        cursor.execute(
            "INSERT INTO resources VALUES (?, ?, ?, ?, ?)",
            (str(resource.group.group_id), str(resource.resource_id),
             resource_name,
             str(resource.resource_category.resource_category_id),
             1 if resource.public else 0))
        __assign_resource_owner_role__(cursor, resource, user)

    return resource

def resource_category_by_id(
        conn: db.DbConnection, category_id: UUID) -> ResourceCategory:
    """Retrieve a resource category by its ID."""
    with db.cursor(conn) as cursor:
        cursor.execute(
            "SELECT * FROM resource_categories WHERE "
            "resource_category_id=?",
            (str(category_id),))
        results = cursor.fetchone()
        if results:
            return ResourceCategory(
                UUID(results["resource_category_id"]),
                results["resource_category_key"],
                results["resource_category_description"])

    raise NotFoundError(
        f"Could not find a ResourceCategory with ID '{category_id}'")

def resource_categories(conn: db.DbConnection) -> Sequence[ResourceCategory]:
    """Retrieve all available resource categories"""
    with db.cursor(conn) as cursor:
        cursor.execute("SELECT * FROM resource_categories")
        return tuple(
            ResourceCategory(UUID(row[0]), row[1], row[2])
            for row in cursor.fetchall())
    return tuple()

def public_resources(conn: db.DbConnection) -> Sequence[Resource]:
    """List all resources marked as public"""
    categories = {
        str(cat.resource_category_id): cat for cat in resource_categories(conn)
    }
    with db.cursor(conn) as cursor:
        cursor.execute("SELECT * FROM resources WHERE public=1")
        results = cursor.fetchall()
        group_uuids = tuple(row[0] for row in results)
        query = ("SELECT * FROM groups WHERE group_id IN "
                 f"({', '.join(['?'] * len(group_uuids))})")
        cursor.execute(query, group_uuids)
        groups = {
            row[0]: Group(
                UUID(row[0]), row[1], json.loads(row[2] or "{}"))
            for row in cursor.fetchall()
        }
        return tuple(
            Resource(groups[row[0]], UUID(row[1]), row[2], categories[row[3]],
                     bool(row[4]))
            for row in results)

def group_leader_resources(
        conn: db.DbConnection, user: User, group: Group,
        res_categories: Dict[UUID, ResourceCategory]) -> Sequence[Resource]:
    """Return all the resources available to the group leader"""
    if is_group_leader(conn, user, group):
        with db.cursor(conn) as cursor:
            cursor.execute("SELECT * FROM resources WHERE group_id=?",
                           (str(group.group_id),))
            return tuple(
                Resource(group, UUID(row[1]), row[2],
                         res_categories[UUID(row[3])], bool(row[4]))
                for row in cursor.fetchall())
    return tuple()

def user_resources(conn: db.DbConnection, user: User) -> Sequence[Resource]:
    """List the resources available to the user"""
    categories = { # Repeated in `public_resources` function
        cat.resource_category_id: cat for cat in resource_categories(conn)
    }
    with db.cursor(conn) as cursor:
        def __all_resources__(group) -> Sequence[Resource]:
            gl_resources = group_leader_resources(conn, user, group, categories)

            cursor.execute(
                ("SELECT resources.* FROM group_user_roles_on_resources "
                 "LEFT JOIN resources "
                 "ON group_user_roles_on_resources.resource_id=resources.resource_id "
                 "WHERE group_user_roles_on_resources.group_id = ? "
                 "AND group_user_roles_on_resources.user_id = ?"),
                (str(group.group_id), str(user.user_id)))
            rows = cursor.fetchall()
            private_res = tuple(
                Resource(group, UUID(row[1]), row[2], categories[UUID(row[3])],
                         bool(row[4]))
                for row in rows)
            return tuple({
                res.resource_id: res
                for res in
                (private_res + gl_resources + public_resources(conn))# type: ignore[operator]
            }.values())

        # Fix the typing here
        return user_group(conn, user).map(__all_resources__).maybe(# type: ignore[arg-type,misc]
            public_resources(conn), lambda res: res)# type: ignore[arg-type,return-value]

def resource_data(conn, resource, offset: int = 0, limit: Optional[int] = None) -> tuple[dict, ...]:
    """
    Retrieve the data for `resource`, optionally limiting the number of items.
    """
    resource_data_function = {
        "mrna": mrna_resource_data,
        "genotype": genotype_resource_data,
        "phenotype": phenotype_resource_data
    }
    with db.cursor(conn) as cursor:
        return tuple(
            dict(data_row) for data_row in
            resource_data_function[
                resource.resource_category.resource_category_key](
                    cursor, resource.resource_id, offset, limit))

def attach_resource_data(cursor: db.DbCursor, resource: Resource) -> Resource:
    """Attach the linked data to the resource"""
    resource_data_function = {
        "mrna": mrna_resource_data,
        "genotype": genotype_resource_data,
        "phenotype": phenotype_resource_data
    }
    category = resource.resource_category
    data_rows = tuple(
        dict(data_row) for data_row in
        resource_data_function[category.resource_category_key](
            cursor, resource.resource_id))
    return Resource(
        resource.group, resource.resource_id, resource.resource_name,
        resource.resource_category, resource.public, data_rows)

def mrna_resource_data(cursor: db.DbCursor,
                       resource_id: UUID,
                       offset: int = 0,
                       limit: Optional[int] = None) -> Sequence[sqlite3.Row]:
    """Fetch data linked to a mRNA resource"""
    cursor.execute(
        (("SELECT * FROM mrna_resources AS mr "
          "INNER JOIN linked_mrna_data AS lmr "
          "ON mr.data_link_id=lmr.data_link_id "
          "WHERE mr.resource_id=?") + (
              f" LIMIT {limit} OFFSET {offset}" if bool(limit) else "")),
        (str(resource_id),))
    return cursor.fetchall()

def genotype_resource_data(
        cursor: db.DbCursor,
        resource_id: UUID,
        offset: int = 0,
        limit: Optional[int] = None) -> Sequence[sqlite3.Row]:
    """Fetch data linked to a Genotype resource"""
    cursor.execute(
        (("SELECT * FROM genotype_resources AS gr "
          "INNER JOIN linked_genotype_data AS lgd "
          "ON gr.data_link_id=lgd.data_link_id "
          "WHERE gr.resource_id=?") + (
              f" LIMIT {limit} OFFSET {offset}" if bool(limit) else "")),
        (str(resource_id),))
    return cursor.fetchall()

def phenotype_resource_data(
        cursor: db.DbCursor,
        resource_id: UUID,
        offset: int = 0,
        limit: Optional[int] = None) -> Sequence[sqlite3.Row]:
    """Fetch data linked to a Phenotype resource"""
    cursor.execute(
        ("SELECT * FROM phenotype_resources AS pr "
         "INNER JOIN linked_phenotype_data AS lpd "
         "ON pr.data_link_id=lpd.data_link_id "
         "WHERE pr.resource_id=?") + (
             f" LIMIT {limit} OFFSET {offset}" if bool(limit) else ""),
        (str(resource_id),))
    return cursor.fetchall()

def resource_by_id(
        conn: db.DbConnection, user: User, resource_id: UUID) -> Resource:
    """Retrieve a resource by its ID."""
    if not authorised_for(
            conn, user, ("group:resource:view-resource",),
            (resource_id,))[resource_id]:
        raise AuthorisationError(
            "You are not authorised to access resource with id "
            f"'{resource_id}'.")

    with db.cursor(conn) as cursor:
        cursor.execute("SELECT * FROM resources WHERE resource_id=:id",
                       {"id": str(resource_id)})
        row = cursor.fetchone()
        if row:
            return Resource(
                group_by_id(conn, UUID(row["group_id"])),
                UUID(row["resource_id"]), row["resource_name"],
                resource_category_by_id(conn, row["resource_category_id"]),
                bool(int(row["public"])))

    raise NotFoundError(f"Could not find a resource with id '{resource_id}'")

def __link_mrna_data_to_resource__(
        conn: db.DbConnection, resource: Resource, data_link_id: UUID) -> dict:
    """Link mRNA Assay data with a resource."""
    with db.cursor(conn) as cursor:
        params = {
            "group_id": str(resource.group.group_id),
            "resource_id": str(resource.resource_id),
            "data_link_id": str(data_link_id)
        }
        cursor.execute(
            "INSERT INTO mrna_resources VALUES"
            "(:group_id, :resource_id, :data_link_id)",
            params)
        return params

def __link_geno_data_to_resource__(
        conn: db.DbConnection, resource: Resource, data_link_id: UUID) -> dict:
    """Link Genotype data with a resource."""
    with db.cursor(conn) as cursor:
        params = {
            "group_id": str(resource.group.group_id),
            "resource_id": str(resource.resource_id),
            "data_link_id": str(data_link_id)
        }
        cursor.execute(
            "INSERT INTO genotype_resources VALUES"
            "(:group_id, :resource_id, :data_link_id)",
            params)
        return params

def __link_pheno_data_to_resource__(
        conn: db.DbConnection, resource: Resource, data_link_id: UUID) -> dict:
    """Link Phenotype data with a resource."""
    with db.cursor(conn) as cursor:
        params = {
            "group_id": str(resource.group.group_id),
            "resource_id": str(resource.resource_id),
            "data_link_id": str(data_link_id)
        }
        cursor.execute(
            "INSERT INTO phenotype_resources VALUES"
            "(:group_id, :resource_id, :data_link_id)",
            params)
        return params

def link_data_to_resource(
        conn: db.DbConnection, user: User, resource_id: UUID, dataset_type: str,
        data_link_id: UUID) -> dict:
    """Link data to resource."""
    if not authorised_for(
            conn, user, ("group:resource:edit-resource",),
            (resource_id,))[resource_id]:
        raise AuthorisationError(
            "You are not authorised to link data to resource with id "
            f"{resource_id}")

    resource = with_db_connection(partial(
        resource_by_id, user=user, resource_id=resource_id))
    return {
        "mrna": __link_mrna_data_to_resource__,
        "genotype": __link_geno_data_to_resource__,
        "phenotype": __link_pheno_data_to_resource__,
    }[dataset_type.lower()](conn, resource, data_link_id)

def __unlink_mrna_data_to_resource__(
        conn: db.DbConnection, resource: Resource, data_link_id: UUID) -> dict:
    """Unlink data from mRNA Assay resources"""
    with db.cursor(conn) as cursor:
        cursor.execute("DELETE FROM mrna_resources "
                       "WHERE resource_id=? AND data_link_id=?",
                       (str(resource.resource_id), str(data_link_id)))
        return {
            "resource_id": str(resource.resource_id),
            "dataset_type": resource.resource_category.resource_category_key,
            "data_link_id": data_link_id
        }

def __unlink_geno_data_to_resource__(
        conn: db.DbConnection, resource: Resource, data_link_id: UUID) -> dict:
    """Unlink data from Genotype resources"""
    with db.cursor(conn) as cursor:
        cursor.execute("DELETE FROM genotype_resources "
                       "WHERE resource_id=? AND data_link_id=?",
                       (str(resource.resource_id), str(data_link_id)))
        return {
            "resource_id": str(resource.resource_id),
            "dataset_type": resource.resource_category.resource_category_key,
            "data_link_id": data_link_id
        }

def __unlink_pheno_data_to_resource__(
        conn: db.DbConnection, resource: Resource, data_link_id: UUID) -> dict:
    """Unlink data from Phenotype resources"""
    with db.cursor(conn) as cursor:
        cursor.execute("DELETE FROM phenotype_resources "
                       "WHERE resource_id=? AND data_link_id=?",
                       (str(resource.resource_id), str(data_link_id)))
        return {
            "resource_id": str(resource.resource_id),
            "dataset_type": resource.resource_category.resource_category_key,
            "data_link_id": str(data_link_id)
        }

def unlink_data_from_resource(
        conn: db.DbConnection, user: User, resource_id: UUID, data_link_id: UUID):
    """Unlink data from resource."""
    if not authorised_for(
            conn, user, ("group:resource:edit-resource",),
            (resource_id,))[resource_id]:
        raise AuthorisationError(
            "You are not authorised to link data to resource with id "
            f"{resource_id}")

    resource = with_db_connection(partial(
        resource_by_id, user=user, resource_id=resource_id))
    dataset_type = resource.resource_category.resource_category_key
    return {
        "mrna": __unlink_mrna_data_to_resource__,
        "genotype": __unlink_geno_data_to_resource__,
        "phenotype": __unlink_pheno_data_to_resource__,
    }[dataset_type.lower()](conn, resource, data_link_id)

def organise_resources_by_category(resources: Sequence[Resource]) -> dict[
        ResourceCategory, tuple[Resource]]:
    """Organise the `resources` by their categories."""
    def __organise__(accumulator, resource):
        category = resource.resource_category
        return {
            **accumulator,
            category: accumulator.get(category, tuple()) + (resource,)
        }
    return reduce(__organise__, resources, {})

def __attach_data__(
        data_rows: Sequence[sqlite3.Row],
        resources: Sequence[Resource]) -> Sequence[Resource]:
    def __organise__(acc, row):
        resource_id = UUID(row["resource_id"])
        return {
            **acc,
            resource_id: acc.get(resource_id, tuple()) + (dict(row),)
        }
    organised: dict[UUID, tuple[dict, ...]] = reduce(__organise__, data_rows, {})
    return tuple(
        Resource(
            resource.group, resource.resource_id, resource.resource_name,
            resource.resource_category, resource.public,
            organised.get(resource.resource_id, tuple()))
        for resource in resources)

def attach_mrna_resources_data(
        cursor, resources: Sequence[Resource]) -> Sequence[Resource]:
    """Attach linked data to mRNA Assay resources"""
    placeholders = ", ".join(["?"] * len(resources))
    cursor.execute(
        "SELECT * FROM mrna_resources AS mr INNER JOIN linked_mrna_data AS lmd"
        " ON mr.data_link_id=lmd.data_link_id "
        f"WHERE mr.resource_id IN ({placeholders})",
        tuple(str(resource.resource_id) for resource in resources))
    return __attach_data__(cursor.fetchall(), resources)

def attach_genotype_resources_data(
        cursor, resources: Sequence[Resource]) -> Sequence[Resource]:
    """Attach linked data to Genotype resources"""
    placeholders = ", ".join(["?"] * len(resources))
    cursor.execute(
        "SELECT * FROM genotype_resources AS gr "
        "INNER JOIN linked_genotype_data AS lgd "
        "ON gr.data_link_id=lgd.data_link_id "
        f"WHERE gr.resource_id IN ({placeholders})",
        tuple(str(resource.resource_id) for resource in resources))
    return __attach_data__(cursor.fetchall(), resources)

def attach_phenotype_resources_data(
        cursor, resources: Sequence[Resource]) -> Sequence[Resource]:
    """Attach linked data to Phenotype resources"""
    placeholders = ", ".join(["?"] * len(resources))
    cursor.execute(
        "SELECT * FROM phenotype_resources AS pr "
        "INNER JOIN linked_phenotype_data AS lpd "
        "ON pr.data_link_id=lpd.data_link_id "
        f"WHERE pr.resource_id IN ({placeholders})",
        tuple(str(resource.resource_id) for resource in resources))
    return __attach_data__(cursor.fetchall(), resources)

def attach_resources_data(
        conn: db.DbConnection, resources: Sequence[Resource]) -> Sequence[
            Resource]:
    """Attach linked data for each resource in `resources`"""
    resource_data_function = {
        "mrna": attach_mrna_resources_data,
        "genotype": attach_genotype_resources_data,
        "phenotype": attach_phenotype_resources_data
    }
    organised = organise_resources_by_category(resources)
    with db.cursor(conn) as cursor:
        return tuple(
            resource for categories in
            (resource_data_function[category.resource_category_key](
                cursor, rscs)
             for category, rscs in organised.items())
            for resource in categories)

@authorised_p(
    ("group:user:assign-role",),
    "You cannot assign roles to users for this group.",
    oauth2_scope="profile group role resource")
def assign_resource_user(
        conn: db.DbConnection, resource: Resource, user: User,
        role: GroupRole) -> dict:
    """Assign `role` to `user` for the specific `resource`."""
    with db.cursor(conn) as cursor:
        cursor.execute(
            "INSERT INTO "
            "group_user_roles_on_resources(group_id, user_id, role_id, "
            "resource_id) "
            "VALUES (?, ?, ?, ?) "
            "ON CONFLICT (group_id, user_id, role_id, resource_id) "
            "DO NOTHING",
            (str(resource.group.group_id), str(user.user_id),
             str(role.role.role_id), str(resource.resource_id)))
        return {
            "resource": dictify(resource),
            "user": dictify(user),
            "role": dictify(role),
            "description": (
                f"The user '{user.name}'({user.email}) was assigned the "
                f"'{role.role.role_name}' role on resource with ID "
                f"'{resource.resource_id}'.")}

@authorised_p(
    ("group:user:assign-role",),
    "You cannot assign roles to users for this group.",
    oauth2_scope="profile group role resource")
def unassign_resource_user(
        conn: db.DbConnection, resource: Resource, user: User,
        role: GroupRole) -> dict:
    """Assign `role` to `user` for the specific `resource`."""
    with db.cursor(conn) as cursor:
        cursor.execute(
            "DELETE FROM group_user_roles_on_resources "
            "WHERE group_id=? AND user_id=? AND role_id=? AND resource_id=?",
            (str(resource.group.group_id), str(user.user_id),
             str(role.role.role_id), str(resource.resource_id)))
        return {
            "resource": dictify(resource),
            "user": dictify(user),
            "role": dictify(role),
            "description": (
                f"The user '{user.name}'({user.email}) had the "
                f"'{role.role.role_name}' role on resource with ID "
                f"'{resource.resource_id}' taken away.")}

def save_resource(
        conn: db.DbConnection, user: User, resource: Resource) -> Resource:
    """Update an existing resource."""
    resource_id = resource.resource_id
    authorised = authorised_for(
        conn, user, ("group:resource:edit-resource",), (resource_id,))
    if authorised[resource_id]:
        with db.cursor(conn) as cursor:
            cursor.execute(
                "UPDATE resources SET "
                "resource_name=:resource_name, "
                "public=:public "
                "WHERE group_id=:group_id "
                "AND resource_id=:resource_id",
                {
                    "resource_name": resource.resource_name,
                    "public": 1 if resource.public else 0,
                    "group_id": str(resource.group.group_id),
                    "resource_id": str(resource.resource_id)
                })
            return resource

    raise AuthorisationError(
        "You do not have the appropriate privileges to edit this resource.")