import {
    type Grant,
    type GrantId,
    type PartitionId,
    type SharePermission,
    grantId as toGrantId,
    partitionId as toPartitionId,
    userId as toUserId,
    type UserId,
} from "@suaveplan/drive-sharing";
import { useCallback, useEffect, useRef, useState } from "react";
import {
    DRIVE_REACT_SHARING_CODES,
    DriveReactSharingError,
} from "../../error-codes.js";
import { getDriveReactSharingInstruments } from "../../otel/instruments.js";
import type {
    ShareRecipient,
    UseSharingOptions,
    UseSharingResult,
} from "../../types/sharing.types.js";

/** Permission tier ordering for `primaryPermission` resolution. */
const TIER_RANK: Record<SharePermission, number> = {
    read: 1,
    write: 2,
    delete: 3,
    share: 4,
    admin: 5,
};

function primaryOf(permissions: readonly SharePermission[]): SharePermission {
    let best: SharePermission = "read";
    let bestRank = 0;
    for (const p of permissions) {
        const rank = TIER_RANK[p];
        if (rank > bestRank) {
            best = p;
            bestRank = rank;
        }
    }
    return best;
}

function projectGrant(grant: Grant): ShareRecipient {
    return {
        grantId: grant.id,
        recipientId: grant.granteeId,
        permissions: grant.permissions,
        primaryPermission: primaryOf(grant.permissions),
        createdAt: grant.createdAt,
        ...(grant.expiresAt !== undefined
            ? { expiresAt: grant.expiresAt }
            : {}),
        revoked: grant.revoked,
    };
}

function loadRecipients(options: UseSharingOptions): readonly ShareRecipient[] {
    const pid = toPartitionId(options.partitionId) as PartitionId;
    return options.grants
        .list({ partitionId: pid, active: true })
        .map(projectGrant);
}

function wrap(
    code:
        | typeof DRIVE_REACT_SHARING_CODES.ADD_FAILED
        | typeof DRIVE_REACT_SHARING_CODES.REVOKE_FAILED
        | typeof DRIVE_REACT_SHARING_CODES.UPDATE_FAILED
        | typeof DRIVE_REACT_SHARING_CODES.REFRESH_FAILED,
    messageKey: string,
    cause: unknown
): DriveReactSharingError {
    return new DriveReactSharingError(code, messageKey, { cause });
}

function checkAborted(signal: AbortSignal | undefined): void {
    if (signal?.aborted === true) {
        throw new DriveReactSharingError(
            DRIVE_REACT_SHARING_CODES.ADD_FAILED,
            "drive-react-sharing.aborted"
        );
    }
}

/**
 * React hook binding a partition's share state to the live engine.
 *
 * Holds an in-memory `ShareRecipient[]` that mirrors active grants for the
 * supplied `partitionId`, plus async action callbacks (`addRecipient`,
 * `removeRecipient`, `updatePermission`, `refresh`) that delegate to
 * `@suaveplan/drive-sharing` and re-sync state on success. Every action
 * accepts an optional `AbortSignal`. Errors are surfaced both via
 * `result.error` and by re-throwing so callers can render inline.
 */
export function useSharing(options: UseSharingOptions): UseSharingResult {
    const optionsRef = useRef(options);
    optionsRef.current = options;

    const [recipients, setRecipients] = useState<readonly ShareRecipient[]>(
        () => options.initialRecipients ?? loadRecipients(options)
    );
    const [loading, setLoading] = useState(false);
    const [error, setError] = useState<DriveReactSharingError | null>(null);

    // Track mount status so async tasks do not setState after unmount.
    const mountedRef = useRef(true);
    useEffect(() => {
        mountedRef.current = true;
        return () => {
            mountedRef.current = false;
        };
    }, []);

    const safeSetRecipients = useCallback(
        (next: readonly ShareRecipient[]): void => {
            if (mountedRef.current) setRecipients(next);
        },
        []
    );
    const safeSetLoading = useCallback((next: boolean): void => {
        if (mountedRef.current) setLoading(next);
    }, []);
    const safeSetError = useCallback(
        (next: DriveReactSharingError | null): void => {
            if (mountedRef.current) setError(next);
        },
        []
    );

    const refresh = useCallback(
        async (signal?: AbortSignal): Promise<void> => {
            safeSetLoading(true);
            try {
                checkAborted(signal);
                const next = loadRecipients(optionsRef.current);
                safeSetRecipients(next);
                safeSetError(null);
            } catch (err) {
                const wrapped = wrap(
                    DRIVE_REACT_SHARING_CODES.REFRESH_FAILED,
                    "drive-react-sharing.refresh-failed",
                    err
                );
                safeSetError(wrapped);
                throw wrapped;
            } finally {
                safeSetLoading(false);
            }
        },
        [safeSetError, safeSetLoading, safeSetRecipients]
    );

    const addRecipient = useCallback(
        async (
            recipientId: string,
            permission: SharePermission,
            signal?: AbortSignal
        ): Promise<void> => {
            if (recipientId.trim() === "") {
                const e = new DriveReactSharingError(
                    DRIVE_REACT_SHARING_CODES.INVALID_RECIPIENT,
                    "drive-react-sharing.invalid-recipient"
                );
                safeSetError(e);
                throw e;
            }
            safeSetLoading(true);
            try {
                checkAborted(signal);
                const opts = optionsRef.current;
                opts.grants.create({
                    grantorId: opts.grantorId,
                    granteeId: toUserId(recipientId) as UserId,
                    partitionId: toPartitionId(opts.partitionId) as PartitionId,
                    permissions: [permission],
                });
                getDriveReactSharingInstruments().recipientsAddedTotal.add(1, {
                    permission,
                });
                safeSetRecipients(loadRecipients(opts));
                safeSetError(null);
            } catch (err) {
                const wrapped = wrap(
                    DRIVE_REACT_SHARING_CODES.ADD_FAILED,
                    "drive-react-sharing.add-failed",
                    err
                );
                safeSetError(wrapped);
                throw wrapped;
            } finally {
                safeSetLoading(false);
            }
        },
        [safeSetError, safeSetLoading, safeSetRecipients]
    );

    const removeRecipient = useCallback(
        async (grantId: string, signal?: AbortSignal): Promise<void> => {
            const opts = optionsRef.current;
            const existing = opts.grants.get(toGrantId(grantId) as GrantId);
            if (existing === undefined) {
                const e = new DriveReactSharingError(
                    DRIVE_REACT_SHARING_CODES.GRANT_NOT_FOUND,
                    "drive-react-sharing.grant-not-found"
                );
                safeSetError(e);
                throw e;
            }
            safeSetLoading(true);
            try {
                checkAborted(signal);
                opts.grants.revoke(toGrantId(grantId) as GrantId);
                getDriveReactSharingInstruments().recipientsRemovedTotal.add(1);
                safeSetRecipients(loadRecipients(opts));
                safeSetError(null);
            } catch (err) {
                const wrapped = wrap(
                    DRIVE_REACT_SHARING_CODES.REVOKE_FAILED,
                    "drive-react-sharing.revoke-failed",
                    err
                );
                safeSetError(wrapped);
                throw wrapped;
            } finally {
                safeSetLoading(false);
            }
        },
        [safeSetError, safeSetLoading, safeSetRecipients]
    );

    const updatePermission = useCallback(
        async (
            grantId: string,
            permission: SharePermission,
            signal?: AbortSignal
        ): Promise<void> => {
            const opts = optionsRef.current;
            const existing = opts.grants.get(toGrantId(grantId) as GrantId);
            if (existing === undefined) {
                const e = new DriveReactSharingError(
                    DRIVE_REACT_SHARING_CODES.GRANT_NOT_FOUND,
                    "drive-react-sharing.grant-not-found"
                );
                safeSetError(e);
                throw e;
            }
            safeSetLoading(true);
            try {
                checkAborted(signal);
                // Revoke + recreate is the engine-supported way to swap
                // permissions atomically; GrantManager has no mutate API.
                opts.grants.revoke(existing.id);
                opts.grants.create({
                    grantorId: existing.grantorId,
                    granteeId: existing.granteeId,
                    partitionId: existing.partitionId,
                    permissions: [permission],
                    ...(existing.expiresAt !== undefined
                        ? { expiresAt: existing.expiresAt }
                        : {}),
                });
                getDriveReactSharingInstruments().permissionsUpdatedTotal.add(
                    1,
                    { permission }
                );
                safeSetRecipients(loadRecipients(opts));
                safeSetError(null);
            } catch (err) {
                const wrapped = wrap(
                    DRIVE_REACT_SHARING_CODES.UPDATE_FAILED,
                    "drive-react-sharing.update-failed",
                    err
                );
                safeSetError(wrapped);
                throw wrapped;
            } finally {
                safeSetLoading(false);
            }
        },
        [safeSetError, safeSetLoading, safeSetRecipients]
    );

    return {
        recipients,
        loading,
        error,
        addRecipient,
        removeRecipient,
        updatePermission,
        refresh,
    };
}