const std = @import("std");

const Db = @import("Db.zig");
const Item = @import("Item.zig");
const Tag = @import("Tag.zig");
const json = @import("json.zig");
const util = @import("util.zig");

pub fn process(jobj: *json.Obj, db: *Db) !void {
    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
    defer arena.deinit();
    const allocator = arena.allocator();

    var jret = json.Obj.newObject();
    defer jret.deinit();

    // Test the action to carry and pass the object
    if (jobj.objectGet("add") catch null) |*jaction| {
        var ret = try add(jaction, db, allocator);
        jret.objectAdd("added", &ret);
    }

    if (jobj.objectGet("query") catch null) |*jaction| {
        var ret = try query(jaction, db, allocator);
        jret.objectAdd("queried", &ret);
    }

    if (jobj.objectGet("delete") catch null) |*jaction| {
        var ret = try delete(jaction, db, allocator);
        jret.objectAdd("deleted", &ret);
    }

    std.debug.print("{s}\n", .{jret.toString()});
}

pub fn add(jobj: *json.Obj, db: *Db, allocator: std.mem.Allocator) !json.Obj {
    // TODO: Maybe return error when no items in the array?

    // Freed by the caller
    var jret = json.Obj.newArray();

    var iter = jobj.arrayGetIterator();
    while (iter.next()) |*jtags| {
        var item = Item{
            .id = null,
            .tags = try Item.tagsFromJson(jtags, allocator),
        };
        item.deinit();

        // Insert new items into the DB
        try item.persist(db, allocator);

        // Add item to new json array (Makes a deep copy, freed with jret.deinit())
        jret.arrayAdd(&item.toJson());
    }

    return jret;
}

pub fn query(jobj: *json.Obj, db: *Db, allocator: std.mem.Allocator) !json.Obj {
    // TODO: Have into account limits so it is scalable
    // TODO: Do not fetch EVERY id at once, iterate where possible
    const query_str = jobj.getString();
    var jret = json.Obj.newArray();

    var ids = std.ArrayList([]u8).init(allocator);
    defer {
        for (ids.items) |item| {
            Db.free(item.ptr);
        }
        ids.deinit();
    }

    if (query_str.len > 0) {
        // Get all the items under the individual tags
        var tag_iter = std.mem.split(u8, query_str, " ");
        while (tag_iter.next()) |tag| {
            // Get the tag selector: "tag:<tag>"
            const tag_sel = try std.mem.concat(allocator, u8, &[_][]const u8{ "tag:", tag });
            defer allocator.free(tag_sel);

            // Get the items that have that tag: "<item1> <item2> <item3>"
            try ids.append(db.get(tag_sel) orelse return jret);

            // This has been deferred before.
            //defer Db.free(tag_str.ptr);
        }
    } else {
        try ids.append(db.get("item") orelse return jret);
    }

    var id_iter = util.intersection(ids.items);
    while (id_iter.next()) |item_id| {
        var item = (try Item.getById(item_id, db, allocator)) orelse continue;
        defer item.deinit();

        jret.arrayAdd(&item.toJson());
    }

    return jret;
}

pub fn delete(jobj: *json.Obj, db: *Db, allocator: std.mem.Allocator) !json.Obj {
    var jret = json.Obj.newArray();

    // Go over each tag
    var id_iter = jobj.arrayGetIterator();
    while (id_iter.next()) |*jid| {
        const id = jid.getString();

        // TODO: Return some kind of error or somethign telling that some were not found
        var item = (try Item.getById(id, db, allocator)) orelse continue;
        defer item.deinit();

        jret.arrayAdd(&item.toJson());

        try item.delete(db);
    }

    return jret;
}