From a0cbca6db5793d6f9c0a929a0a0512c86e036fa0 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Tue, 24 Feb 2026 15:09:22 -0500
Subject: [PATCH] feat(views): add category and priority view renderers

Problem: need to render task lists grouped by category or sorted
by priority with concealed IDs and metadata.

Solution: add category_view and priority_view functions that
produce buffer lines with hidden /id/ prefixes, priority flags,
and line metadata for extmark placement.
---
 lua/todo/views.lua | 181 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 181 insertions(+)
 create mode 100644 lua/todo/views.lua

diff --git a/lua/todo/views.lua b/lua/todo/views.lua
new file mode 100644
index 0000000..5330d86
--- /dev/null
+++ b/lua/todo/views.lua
@@ -0,0 +1,181 @@
+local config = require('todo.config')
+
+---@class todo.LineMeta
+---@field type 'task'|'header'|'blank'
+---@field id? integer
+---@field due? string
+---@field raw_due? string
+---@field status? string
+---@field category? string
+
+---@class todo.views
+local M = {}
+
+---@param due? string
+---@return string?
+local function format_due(due)
+  if not due then
+    return nil
+  end
+  local y, m, d = due:match('^(%d%d%d%d)-(%d%d)-(%d%d)$')
+  if not y then
+    return due
+  end
+  local t = os.time({ year = tonumber(y), month = tonumber(m), day = tonumber(d) })
+  return os.date(config.get().date_format, t)
+end
+
+---@param tasks todo.Task[]
+local function sort_tasks(tasks)
+  table.sort(tasks, function(a, b)
+    if a.priority ~= b.priority then
+      return a.priority > b.priority
+    end
+    if a.order ~= b.order then
+      return a.order < b.order
+    end
+    return a.id < b.id
+  end)
+end
+
+---@param tasks todo.Task[]
+local function sort_tasks_priority(tasks)
+  table.sort(tasks, function(a, b)
+    if a.priority ~= b.priority then
+      return a.priority > b.priority
+    end
+    local a_due = a.due or ''
+    local b_due = b.due or ''
+    if a_due ~= b_due then
+      if a_due == '' then
+        return false
+      end
+      if b_due == '' then
+        return true
+      end
+      return a_due < b_due
+    end
+    if a.order ~= b.order then
+      return a.order < b.order
+    end
+    return a.id < b.id
+  end)
+end
+
+---@param tasks todo.Task[]
+---@return string[] lines
+---@return todo.LineMeta[] meta
+function M.category_view(tasks)
+  local by_cat = {}
+  local cat_order = {}
+  local cat_seen = {}
+  local done_by_cat = {}
+
+  for _, task in ipairs(tasks) do
+    local cat = task.category or config.get().default_category
+    if not cat_seen[cat] then
+      cat_seen[cat] = true
+      table.insert(cat_order, cat)
+      by_cat[cat] = {}
+      done_by_cat[cat] = {}
+    end
+    if task.status == 'done' then
+      table.insert(done_by_cat[cat], task)
+    else
+      table.insert(by_cat[cat], task)
+    end
+  end
+
+  for _, cat in ipairs(cat_order) do
+    sort_tasks(by_cat[cat])
+    sort_tasks(done_by_cat[cat])
+  end
+
+  local lines = {}
+  local meta = {}
+
+  for i, cat in ipairs(cat_order) do
+    if i > 1 then
+      table.insert(lines, '')
+      table.insert(meta, { type = 'blank' })
+    end
+    table.insert(lines, cat)
+    table.insert(meta, { type = 'header', category = cat })
+
+    local all = {}
+    for _, t in ipairs(by_cat[cat]) do
+      table.insert(all, t)
+    end
+    for _, t in ipairs(done_by_cat[cat]) do
+      table.insert(all, t)
+    end
+
+    for _, task in ipairs(all) do
+      local prefix = '/' .. task.id .. '/'
+      local indent = '  '
+      local prio = task.priority == 1 and '! ' or ''
+      local line = prefix .. indent .. prio .. task.description
+      table.insert(lines, line)
+      table.insert(meta, {
+        type = 'task',
+        id = task.id,
+        due = format_due(task.due),
+        raw_due = task.due,
+        status = task.status,
+        category = cat,
+      })
+    end
+  end
+
+  return lines, meta
+end
+
+---@param tasks todo.Task[]
+---@return string[] lines
+---@return todo.LineMeta[] meta
+function M.priority_view(tasks)
+  local pending = {}
+  local done = {}
+
+  for _, task in ipairs(tasks) do
+    if task.status == 'done' then
+      table.insert(done, task)
+    else
+      table.insert(pending, task)
+    end
+  end
+
+  sort_tasks_priority(pending)
+  sort_tasks_priority(done)
+
+  local lines = {}
+  local meta = {}
+
+  local all = {}
+  for _, t in ipairs(pending) do
+    table.insert(all, t)
+  end
+  for _, t in ipairs(done) do
+    table.insert(all, t)
+  end
+
+  for _, task in ipairs(all) do
+    local prefix = '/' .. task.id .. '/'
+    local indent = '  '
+    local prio = task.priority == 1 and '! ' or ''
+    local line = prefix .. indent .. prio .. task.description
+    table.insert(lines, line)
+    table.insert(meta, {
+      type = 'task',
+      id = task.id,
+      due = format_due(task.due),
+      raw_due = task.due,
+      status = task.status,
+      category = task.category,
+    })
+  end
+
+  return lines, meta
+end
+
+return M