Hacked together task system whilst we wait for the proper version

[OmegaLambda1998]

Hey, just wanted to share a hacky little way I took advantage of the templating system to get tasks working in a way that works for me.

The basic idea is to have a tasks directory which contains markdown files with the following frontmatter

desc: "desc"
due: "YYYY-MM-DD"
priority: "0-10"
status: "x| |!|..."

desc: A short description of the task
due: An (optional) due date for the task (due: [] means no due date)
priority: An (optional) task priority (priority: [] means no priority). High values are less prioritised.
status: The character you'd put in a checkbox to indicate the state of the task ( for "not started", ~ for "ongoing", x for completed, etc...)

I then have a bunch of functions to filter and sort these tasks. In particular my basic sorting is by priority, then due date. Based on this I have a daily note which, when it is created, generates various lists of tasks (due today, due this week, high priority but not due for a while, low priority and not due for a while).

I've got some ideas to extend this slightly such that the creation date of the task is included in the metadata, allowing due: tomorrow to be calculated relative to the creation date of the task. But I don't want to invest too heavily in this with the proper task system coming along.

--- Tasks ---

---@param task obsidian.Note
---@return number priority
local function task_priority(task)
    local md = task.metadata or {}
    local priority = md.priority
    if type(priority) ~= "number" then
        return math.huge
    end
    local due = md.due
    if type(due) ~= "string" then
        return priority + 0.99
    end
    local date_pattern = "(%d+)-(%d+)-(%d+)"
    local year, month, day = due:match(date_pattern)
    local timestamp = os.time(
        {
            year = year,
            month = month,
            day = day,
        }
    )
    local today = os.time()
    local offset = (timestamp - today) / (7 * 24 * 60 * 60)
    if offset >= 1 then
        offset = 0.99
    elseif offset <= -1 then
        offset = -0.99
    end
    return priority + offset
end

---@param filter? fun(task: obsidian.Note): boolean
---@param comp? fun(a: obsidian.Note, b: obsidian.Note): boolean
---@return obsidian.Note[]
local function get_tasks(filter, comp)
    local obs = require("obsidian").get_client()
    ---@type obsidian.Note[]
    local tasks = vim.tbl_filter(
        function(note)
            return note.path.filename:match("Numenor/Notes/Tasks") --- REPLACE WITH YOUR PATH
        end, obs:find_notes("task_")
    )

    if filter == nil then
        ---@param _ obsidian.Note
        ---@return boolean
        filter = function(_)
            return true
        end
    end

    if comp == nil then
        ---@param a obsidian.Note
        ---@param b obsidian.Note
        ---@return boolean
        comp = function(a, b)
            return task_priority(a) < task_priority(b)
        end
    end

    local notes = vim.tbl_filter(filter, tasks)
    table.sort(notes, comp)
    return notes
end

---@param task obsidian.Note
---@return string
local function task_str(task)
    local md = task.metadata or {}
    local status = md.status or " "
    local desc = md.desc or "MISSING"
    local path = task.path or "MISSING"
    local str = "- [%s] [%s](%s)"
    str = str:format(status, desc, path)
    local priority = md.priority
    if type(priority) == "number" then
        str = str .. (" - Priority: %s"):format(priority)
    end
    local due = md.due
    if type(due) == "string" then
        str = str .. (" - Due: %s"):format(due)
    end
    return str
end

---@param tasks obsidian.Note[]
---@return string
local function tasks_str(tasks)
    return table.concat(vim.tbl_map(task_str, tasks), "\n")
end

subs.tasks_all = function()
    local tasks = get_tasks()
    return tasks_str(tasks)
end

local function task_completed(task)
    local md = task.metadata or {}
    return md.status == "x"
end
subs.tasks_completed = function()
    local tasks = get_tasks(task_completed)
    return tasks_str(tasks)
end

local function task_uncompleted(task)
    return not task_completed(task)
end
subs.tasks_uncompleted = function()
    local tasks = get_tasks(task_uncompleted)
    return tasks_str(tasks)
end

local function task_due(task)
    local md = task.metadata or {}
    if type(md.due) ~= "string" then
        return false
    end
    local p_orig = md.priority
    if type(p_orig) ~= "number" then
        p_orig = math.huge
    end
    local p_due = task_priority(task)
    return p_due < p_orig
end
subs.tasks_due = function()
    local tasks = get_tasks(
        function(task)
            return task_uncompleted(task) and task_due(task)
        end
    )
    return tasks_str(tasks)
end

local function task_due_weekly(task)
    local md = task.metadata or {}
    if type(md.due) ~= "string" then
        return false
    end
    local p_orig = md.priority
    if type(p_orig) ~= "number" then
        p_orig = math.huge
    end
    local p_due = task_priority(task)
    return p_due < (p_orig + 0.9)
end
subs.tasks_due_weekly = function()
    local tasks = get_tasks(
        function(task)
            return task_uncompleted(task) and (not task_due(task)) and
                       task_due_weekly(task)
        end
    )
    return tasks_str(tasks)
end

local function task_high_priority(task)
    local md = task.metadata or {}
    local priority = md.priority
    if type(priority) ~= "number" then
        priority = math.huge
    end
    return priority < 1
end
subs.tasks_high_priority = function()
    local tasks = get_tasks(
        function(task)
            return task_uncompleted(task) and (not task_due(task)) and
                       (not task_due_weekly(task)) and task_high_priority(task)
        end
    )
    return tasks_str(tasks)
end

subs.tasks_low_priority = function()
    local tasks = get_tasks(
        function(task)
            return task_uncompleted(task) and (not task_due(task)) and
                       (not task_due_weekly(task)) and
                       (not task_high_priority(task))
        end
    )
    return tasks_str(tasks)
end