---@diagnostic disable: duplicate-set-field, need-check-nil, param-type-mismatch, assign-type-mismatch, redundant-parameter
local diff = require 'bugabinga.pivi.diff'
local entry = require 'bugabinga.pivi.entry'
local follow = require 'bugabinga.pivi.follow'
local transcript = require 'bugabinga.pivi.transcript'
local fake = dofile 'tests/helpers/pivi_fake.lua'

local temp_file = function( lines )
  local path = vim.fs.normalize( vim.fn.tempname() .. '.lua' )
  vim.fn.writefile( lines, path )
  return path
end

-- A change as the edit tool formats it: every changed line carries its number.
local CHANGE = table.concat( {
  ' 1 one',
  '-2 two',
  '+2 TWO',
  ' 3 three',
}, '\n' )

local recorded = function( bufnr, path, change )
  local id = entry.open( bufnr, 'tool', {
    tool = 'edit',
    args = { path = path, },
    result = { details = { diff = change, firstChangedLine = 2, }, },
  } )
  entry.line( bufnr, id, 'edit  ' .. vim.fs.basename( path ) )
  for _, line in ipairs( vim.split( change, '\n', { plain = true, } ) ) do
    entry.line( bufnr, id, line )
  end
  entry.close( bufnr, id )
  return id
end

describe( 'pivi diff', function()
  local bufnr, win

  before_each( function()
    bufnr = transcript.ensure 'comparing'
    transcript.clear( bufnr )
    win = transcript.show( bufnr )
    vim.api.nvim_set_current_win( win )
  end )

  after_each( function()
    diff.close()
    follow.reset()
    transcript.forget_all()
    fake.close_extra_windows()
    vim.cmd 'silent! %bwipeout!'
  end )

  describe( 'reading a reported change', function()
    it( 'separates what was added from what was removed', function()
      local removed, added = diff.parse( CHANGE )

      assert.same( { { line = 2, text = 'two', }, }, removed )
      assert.same( { { line = 2, text = 'TWO', }, }, added )
    end )

    it( 'ignores context lines', function()
      local removed, added = diff.parse ' 1 untouched'
      assert.same( {}, removed )
      assert.same( {}, added )
    end )

    it( 'rebuilds the content that existed before the change', function()
      local original, faithful = diff.before( { 'one', 'TWO', 'three', }, CHANGE )

      assert.same( { 'one', 'two', 'three', }, original )
      assert.is_true( faithful )
    end )

    it( 'rebuilds a change that only added lines', function()
      local original = diff.before( { 'one', 'two', }, '+2 two' )
      assert.same( { 'one', }, original )
    end )

    it( 'rebuilds a change that only removed lines', function()
      local original = diff.before( { 'one', }, '-2 two' )
      assert.same( { 'one', 'two', }, original )
    end )

    it( 'says so when the content no longer matches the change', function()
      local _, faithful = diff.before( { 'one', 'something else', 'three', }, CHANGE )
      assert.is_false( faithful )
    end )
  end )

  describe( 'comparing', function()
    it( 'opens the change as an editor comparison', function()
      local path = temp_file { 'one', 'TWO', 'three', }
      local id = recorded( bufnr, path, CHANGE )
      local first = select( 1, entry.range( bufnr, id ) )

      local changed, original, faithful = diff.open( bufnr, first )

      assert.is_number( changed )
      assert.is_number( original )
      assert.is_true( faithful )

      assert.is_true( vim.wo[changed].diff )
      assert.is_true( vim.wo[original].diff )
      assert.same( { 'one', 'two', 'three', }, vim.api.nvim_buf_get_lines( vim.api.nvim_win_get_buf( original ), 0, -1, false ) )
    end )

    it( 'keeps the working window and leaves the transcript untouched', function()
      local path = temp_file { 'one', 'TWO', 'three', }
      local id = recorded( bufnr, path, CHANGE )
      local first = select( 1, entry.range( bufnr, id ) )
      local before_text = transcript.lines( bufnr )

      diff.open( bufnr, first )

      assert.equal( win, vim.api.nvim_get_current_win() )
      assert.same( before_text, transcript.lines( bufnr ) )
    end )

    it( 'states that the file has moved on', function()
      local path = temp_file { 'one', 'something else', 'three', }
      local id = recorded( bufnr, path, CHANGE )
      local first = select( 1, entry.range( bufnr, id ) )

      local _, original, faithful = diff.open( bufnr, first )

      assert.is_false( faithful )
      assert.is_true( vim.api.nvim_buf_get_name( vim.api.nvim_win_get_buf( original ) ):find( 'moved on', 1, true ) ~= nil )
    end )

    it( 'compares nothing for an entry that reports no change', function()
      local id = entry.open( bufnr, 'tool', { tool = 'read', args = { path = temp_file { 'one', }, }, } )
      entry.line( bufnr, id, 'read  a.lua' )
      entry.close( bufnr, id )

      assert.is_nil( diff.open( bufnr, select( 1, entry.range( bufnr, id ) ) ) )
    end )

    it( 'compares nothing outside a tool entry', function()
      local id = entry.open( bufnr, 'answer' )
      entry.line( bufnr, id, 'just words' )
      entry.close( bufnr, id )

      assert.is_nil( diff.open( bufnr, select( 1, entry.range( bufnr, id ) ) ) )
    end )

    it( 'can be left again', function()
      local path = temp_file { 'one', 'TWO', 'three', }
      local id = recorded( bufnr, path, CHANGE )
      local _, original = diff.open( bufnr, select( 1, entry.range( bufnr, id ) ) )

      diff.close()

      assert.is_false( vim.api.nvim_win_is_valid( original ) )
      assert.equal( win, vim.api.nvim_get_current_win() )
    end )

    it( 'publishes comparison as an intent', function()
      local published
      for _, mapping in ipairs( vim.api.nvim_buf_get_keymap( bufnr, 'n' ) ) do
        if mapping.lhs == '<Plug>(pivi-compare-change)' then published = mapping end
      end

      assert.is_table( published )
    end )
  end )
end )