-- ════════════════════════════════════════════════════════════════════════════
-- COPY: duplicate dead properties along with files and folders
-- ════════════════════════════════════════════════════════════════════════════
-- RFC 4918 §8.8 — "If a property cannot be copied live, then its value
-- MUST be duplicated, exactly as it would be for a PROPPATCH SET
-- operation, in the copy." Dead properties are by definition not live
-- (the server stores them verbatim with no interpretation), so every
-- COPY MUST duplicate the source's dead properties onto the new
-- resource.
--
-- The pre-rekey path-based store handled this by accident in some
-- cases and missed it in others; the id-keyed store (migration
-- 20260830000001) makes the requirement explicit — dead properties
-- key on `folder_id` / `file_id`, so a copy that doesn't insert new
-- rows for the destination's ids loses the properties entirely.
--
-- This migration replaces `storage.copy_folder_tree` with a version
-- that:
--
--   1. Pre-allocates destination file ids in a new temp table
--      `_copy_file_map(old_id, new_id)` — analogous to the
--      pre-existing `_copy_map` that already does this for folders.
--      Previously, file ids were generated by the `gen_random_uuid()`
--      DEFAULT during the batch INSERT, leaving no way to relate src
--      and dst files afterward.
--   2. Switches the batch file INSERT to use the explicit
--      pre-allocated id, so src→dst is bidirectionally known by
--      `_copy_file_map`.
--   3. Adds two `INSERT INTO storage.webdav_dead_properties` SELECTs
--      at the end that duplicate dead-property rows for every copied
--      folder (via `_copy_map`) and every copied file (via
--      `_copy_file_map`). Each duplicated row carries the same
--      `(namespace, local_name, value)` triple as the source — the
--      definition of "duplicate" in RFC 4918 §8.8.
--
-- Idempotent via CREATE OR REPLACE FUNCTION. No callers change (the
-- function signature and return shape are unchanged).
--
-- COPY semantics out of scope for this migration:
--   * Cross-user permission handling on the copied resources is the
--     caller's responsibility (the `_with_perms` service variant
--     already enforces this on the source side). Dead properties
--     hitch a ride on the resource's ACL; nothing additional needed.
--   * Trash: trashed source rows are excluded by the existing
--     `NOT is_trashed` filter; dead-props on trashed rows live on
--     until the resource itself is hard-deleted, at which point
--     CASCADE handles them. Same model holds in the new COPY path.

CREATE OR REPLACE FUNCTION storage.copy_folder_tree(
    p_source_id UUID,
    p_target_parent_id UUID,       -- NULL = copy to root (keeps source drive)
    p_dest_name TEXT DEFAULT NULL   -- NULL = keep source folder name
) RETURNS TABLE(new_root_id TEXT, folders_copied BIGINT, files_copied BIGINT) AS $$
DECLARE
    v_root_lpath    ltree;
    v_root_depth    INT;
    v_max_depth     INT;
    v_level         INT;
    v_folders       BIGINT := 0;
    v_files         BIGINT := 0;
    v_inserted      BIGINT;
    v_new_root      UUID;
    v_dest_drive_id UUID;
BEGIN
    -- Validate source exists
    SELECT fo.lpath, nlevel(fo.lpath)
      INTO v_root_lpath, v_root_depth
      FROM storage.folders fo
     WHERE fo.id = p_source_id AND NOT fo.is_trashed;

    IF v_root_lpath IS NULL THEN
        RAISE EXCEPTION 'Source folder not found: %', p_source_id
            USING ERRCODE = 'P0002';  -- no_data_found
    END IF;

    -- Resolve the destination drive_id ONCE up front. The whole copied
    -- subtree lands in this drive; pulling it per-row from `fo.drive_id`
    -- (the previous body) was the cross-drive bug.
    --
    -- When p_target_parent_id is NULL the caller asked for "copy to
    -- root" — there is no global root in the multi-drive world, so we
    -- preserve the source's drive_id (legacy behaviour, defensive).
    -- Real API call sites always pass a concrete target folder.
    IF p_target_parent_id IS NULL THEN
        SELECT fo.drive_id INTO v_dest_drive_id
          FROM storage.folders fo
         WHERE fo.id = p_source_id;
    ELSE
        SELECT fo.drive_id INTO v_dest_drive_id
          FROM storage.folders fo
         WHERE fo.id = p_target_parent_id AND NOT fo.is_trashed;
        IF v_dest_drive_id IS NULL THEN
            RAISE EXCEPTION 'Target parent folder not found: %', p_target_parent_id
                USING ERRCODE = 'P0002';  -- no_data_found
        END IF;
    END IF;

    -- Temp mapping: every folder in the subtree → new UUID
    CREATE TEMP TABLE IF NOT EXISTS _copy_map(
        old_id UUID PRIMARY KEY,
        new_id UUID NOT NULL DEFAULT gen_random_uuid()
    ) ON COMMIT DROP;
    TRUNCATE _copy_map;

    INSERT INTO _copy_map(old_id)
    SELECT fo.id
      FROM storage.folders fo
     WHERE NOT fo.is_trashed
       AND fo.lpath <@ v_root_lpath;

    -- Remember new root ID
    SELECT cm.new_id INTO v_new_root
      FROM _copy_map cm WHERE cm.old_id = p_source_id;

    -- Max depth for level iteration
    SELECT MAX(nlevel(fo.lpath))
      INTO v_max_depth
      FROM storage.folders fo
      JOIN _copy_map cm ON fo.id = cm.old_id;

    -- ── Insert folders level by level ──
    -- Each level is a separate INSERT so the BEFORE INSERT trigger
    -- (trg_folders_path) can resolve the parent's path/lpath from rows
    -- inserted in the previous level. drive_id is the destination's
    -- (resolved once above); user_id + provenance preserved from source.
    FOR v_level IN v_root_depth .. v_max_depth LOOP
        INSERT INTO storage.folders(
            id, name, parent_id, user_id,
            drive_id, created_by, updated_by
        )
        SELECT cm.new_id,
               CASE WHEN fo.id = p_source_id AND p_dest_name IS NOT NULL
                    THEN p_dest_name ELSE fo.name END,
               CASE WHEN fo.id = p_source_id THEN p_target_parent_id
                    ELSE pm.new_id END,
               fo.user_id,
               v_dest_drive_id,
               fo.created_by,
               fo.updated_by
          FROM storage.folders fo
          JOIN _copy_map cm ON fo.id = cm.old_id
          LEFT JOIN _copy_map pm ON fo.parent_id = pm.old_id
         WHERE NOT fo.is_trashed
           AND nlevel(fo.lpath) = v_level;

        GET DIAGNOSTICS v_inserted = ROW_COUNT;
        v_folders := v_folders + v_inserted;
    END LOOP;

    -- ── NEW: temp mapping for files src→dst ───────────────────────────
    -- Pre-allocate destination ids so we can:
    --   (a) reference each dst file by id in the dead-property INSERT
    --       below — a batched INSERT...RETURNING couldn't tell us which
    --       new id corresponded to which source id, so the mapping
    --       has to be stamped at planning time, not after the fact;
    --   (b) batch the file INSERT with explicit ids exactly the same
    --       way folders are batched.
    CREATE TEMP TABLE IF NOT EXISTS _copy_file_map(
        old_id UUID PRIMARY KEY,
        new_id UUID NOT NULL DEFAULT gen_random_uuid()
    ) ON COMMIT DROP;
    TRUNCATE _copy_file_map;

    INSERT INTO _copy_file_map(old_id)
    SELECT f.id
      FROM storage.files f
      JOIN _copy_map cm ON f.folder_id = cm.old_id
     WHERE NOT f.is_trashed;

    -- ── Batch copy all files (zero-copy: same blob_hash) ──
    -- drive_id from destination; everything else (user_id, created_by,
    -- updated_by) preserved from source so authorship survives the copy.
    -- `id` is the pre-allocated dst id from _copy_file_map.
    INSERT INTO storage.files(
        id, name, folder_id, user_id, blob_hash, size, mime_type,
        media_sort_date, drive_id, created_by, updated_by
    )
    SELECT fm.new_id, f.name, cm.new_id, f.user_id, f.blob_hash, f.size,
           f.mime_type, f.media_sort_date, v_dest_drive_id, f.created_by,
           f.updated_by
      FROM storage.files f
      JOIN _copy_map      cm ON f.folder_id = cm.old_id
      JOIN _copy_file_map fm ON fm.old_id   = f.id
     WHERE NOT f.is_trashed;

    GET DIAGNOSTICS v_files = ROW_COUNT;

    -- ── Batch increment blob ref_counts ──
    IF v_files > 0 THEN
        UPDATE storage.blobs b
           SET ref_count = ref_count + hc.cnt
          FROM (
              SELECT f.blob_hash, COUNT(*)::int AS cnt
                FROM storage.files f
                JOIN _copy_map cm ON f.folder_id = cm.new_id
               WHERE NOT f.is_trashed
               GROUP BY f.blob_hash
          ) hc
         WHERE b.hash = hc.blob_hash;
    END IF;

    -- ── NEW: duplicate dead properties for every copied folder ────────
    -- RFC 4918 §8.8 — dead properties MUST be duplicated. The id-keyed
    -- store (migration 20260830000001) keys on `folder_id`, so we
    -- emit a new row per source dead-property pointing at the
    -- destination folder id. `(namespace, local_name, value)` is
    -- preserved verbatim — that's the "duplicate" definition.
    INSERT INTO storage.webdav_dead_properties
        (folder_id, namespace, local_name, value)
    SELECT cm.new_id, dp.namespace, dp.local_name, dp.value
      FROM storage.webdav_dead_properties dp
      JOIN _copy_map cm ON dp.folder_id = cm.old_id;

    -- ── NEW: duplicate dead properties for every copied file ──────────
    INSERT INTO storage.webdav_dead_properties
        (file_id, namespace, local_name, value)
    SELECT fm.new_id, dp.namespace, dp.local_name, dp.value
      FROM storage.webdav_dead_properties dp
      JOIN _copy_file_map fm ON dp.file_id = fm.old_id;

    RETURN QUERY SELECT v_new_root::text, v_folders, v_files;
END;
$$ LANGUAGE plpgsql;