require('spec.helpers')

local commands = require('diffs.commands')

describe('commands', function()
  describe('setup', function()
    it('registers Gdiff, Gvdiff, and Ghdiff commands', function()
      commands.setup()
      local cmds = vim.api.nvim_get_commands({})
      assert.is_not_nil(cmds.Gdiff)
      assert.is_not_nil(cmds.Gvdiff)
      assert.is_not_nil(cmds.Ghdiff)
    end)
  end)

  describe('unified diff generation', function()
    local old_lines = { 'local M = {}', 'return M' }
    local new_lines = { 'local M = {}', 'local x = 1', 'return M' }
    local diff_fn = vim.text and vim.text.diff or vim.diff

    it('generates valid unified diff', function()
      local old_content = table.concat(old_lines, '\n')
      local new_content = table.concat(new_lines, '\n')
      local diff_output = diff_fn(old_content, new_content, {
        result_type = 'unified',
        ctxlen = 3,
      })
      assert.is_not_nil(diff_output)
      assert.is_true(diff_output:find('@@ ') ~= nil)
      assert.is_true(diff_output:find('+local x = 1') ~= nil)
    end)

    it('returns empty for identical content', function()
      local content = table.concat(old_lines, '\n')
      local diff_output = diff_fn(content, content, {
        result_type = 'unified',
        ctxlen = 3,
      })
      assert.are.equal('', diff_output)
    end)
  end)

  describe('find_hunk_line', function()
    it('finds matching @@ header and returns target line', function()
      local diff_lines = {
        'diff --git a/file.lua b/file.lua',
        '--- a/file.lua',
        '+++ b/file.lua',
        '@@ -1,3 +1,4 @@',
        ' local M = {}',
        '+local new = true',
        ' return M',
      }
      local hunk_position = {
        hunk_header = '@@ -1,3 +1,4 @@',
        offset = 2,
      }
      local target_line = commands.find_hunk_line(diff_lines, hunk_position)
      assert.equals(6, target_line)
    end)

    it('returns nil when hunk header not found', function()
      local diff_lines = {
        'diff --git a/file.lua b/file.lua',
        '@@ -1,3 +1,4 @@',
        ' local M = {}',
      }
      local hunk_position = {
        hunk_header = '@@ -99,3 +99,4 @@',
        offset = 1,
      }
      local target_line = commands.find_hunk_line(diff_lines, hunk_position)
      assert.is_nil(target_line)
    end)

    it('handles multiple hunks and finds correct one', function()
      local diff_lines = {
        'diff --git a/file.lua b/file.lua',
        '--- a/file.lua',
        '+++ b/file.lua',
        '@@ -1,3 +1,4 @@',
        ' local M = {}',
        '+local x = 1',
        ' ',
        '@@ -10,3 +11,4 @@',
        ' function M.foo()',
        '+  print("hello")',
        ' end',
      }
      local hunk_position = {
        hunk_header = '@@ -10,3 +11,4 @@',
        offset = 2,
      }
      local target_line = commands.find_hunk_line(diff_lines, hunk_position)
      assert.equals(10, target_line)
    end)
  end)
end)