require('spec.helpers')

local config = require('pending.config')
local store = require('pending.store')

describe('diff', function()
  local tmpdir
  local diff = require('pending.diff')

  before_each(function()
    tmpdir = vim.fn.tempname()
    vim.fn.mkdir(tmpdir, 'p')
    vim.g.pending = { data_path = tmpdir .. '/tasks.json' }
    config.reset()
    store.unload()
    store.load()
  end)

  after_each(function()
    vim.fn.delete(tmpdir, 'rf')
    vim.g.pending = nil
    config.reset()
  end)

  describe('parse_buffer', function()
    it('parses headers and tasks', function()
      local lines = {
        'School',
        '/1/  Do homework',
        '/2/  [1] Read chapter 5',
        '',
        'Errands',
        '/3/  Buy groceries',
      }
      local result = diff.parse_buffer(lines)
      assert.are.equal(6, #result)
      assert.are.equal('header', result[1].type)
      assert.are.equal('School', result[1].category)
      assert.are.equal('task', result[2].type)
      assert.are.equal(1, result[2].id)
      assert.are.equal('Do homework', result[2].description)
      assert.are.equal('School', result[2].category)
      assert.are.equal('task', result[3].type)
      assert.are.equal(1, result[3].priority)
      assert.are.equal('blank', result[4].type)
      assert.are.equal('Errands', result[6].category)
    end)

    it('handles new tasks without ids', function()
      local lines = {
        'Inbox',
        '  New task here',
      }
      local result = diff.parse_buffer(lines)
      assert.are.equal(2, #result)
      assert.are.equal('task', result[2].type)
      assert.is_nil(result[2].id)
      assert.are.equal('New task here', result[2].description)
    end)
  end)

  describe('apply', function()
    it('creates new tasks from buffer lines', function()
      local lines = {
        'Inbox',
        '  First task',
        '  Second task',
      }
      diff.apply(lines)
      store.unload()
      store.load()
      local tasks = store.active_tasks()
      assert.are.equal(2, #tasks)
      assert.are.equal('First task', tasks[1].description)
      assert.are.equal('Second task', tasks[2].description)
    end)

    it('deletes tasks removed from buffer', function()
      store.add({ description = 'Keep me' })
      store.add({ description = 'Delete me' })
      store.save()
      local lines = {
        'Inbox',
        '/1/  Keep me',
      }
      diff.apply(lines)
      store.unload()
      store.load()
      local active = store.active_tasks()
      assert.are.equal(1, #active)
      assert.are.equal('Keep me', active[1].description)
      local deleted = store.get(2)
      assert.are.equal('deleted', deleted.status)
    end)

    it('updates modified tasks', function()
      store.add({ description = 'Original' })
      store.save()
      local lines = {
        'Inbox',
        '/1/  Renamed',
      }
      diff.apply(lines)
      store.unload()
      store.load()
      local task = store.get(1)
      assert.are.equal('Renamed', task.description)
    end)

    it('handles duplicate ids as copies', function()
      store.add({ description = 'Original' })
      store.save()
      local lines = {
        'Inbox',
        '/1/  Original',
        '/1/  Copy of original',
      }
      diff.apply(lines)
      store.unload()
      store.load()
      local tasks = store.active_tasks()
      assert.are.equal(2, #tasks)
    end)

    it('moves tasks between categories', function()
      store.add({ description = 'Moving task', category = 'Inbox' })
      store.save()
      local lines = {
        'Work',
        '/1/  Moving task',
      }
      diff.apply(lines)
      store.unload()
      store.load()
      local task = store.get(1)
      assert.are.equal('Work', task.category)
    end)

    it('does not update modified when task is unchanged', function()
      store.add({ description = 'Stable task', category = 'Inbox' })
      store.save()
      local lines = {
        'Inbox',
        '/1/  Stable task',
      }
      diff.apply(lines)
      store.unload()
      store.load()
      local modified_after_first = store.get(1).modified
      diff.apply(lines)
      store.unload()
      store.load()
      local task = store.get(1)
      assert.are.equal(modified_after_first, task.modified)
    end)

    it('clears due when removed from buffer line', function()
      store.add({ description = 'Pay bill', due = '2026-03-15' })
      store.save()
      local lines = {
        'Inbox',
        '/1/  Pay bill',
      }
      diff.apply(lines)
      store.unload()
      store.load()
      local task = store.get(1)
      assert.is_nil(task.due)
    end)

    it('clears priority when [N] is removed from buffer line', function()
      store.add({ description = 'Task name', priority = 1 })
      store.save()
      local lines = {
        'Inbox',
        '/1/  Task name',
      }
      diff.apply(lines)
      store.unload()
      store.load()
      local task = store.get(1)
      assert.are.equal(0, task.priority)
    end)
  end)
end)