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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
use crate::colors;use dissimilar::{diff as difference, Chunk};use std::fmt::Write as _;
/// Print diff of the same file_path, before and after formatting.////// Diff format is loosely based on GitHub diff formatting.pub fn diff(orig_text: &str, edit_text: &str) -> String {  if orig_text == edit_text {    return String::new();  }
  // normalize newlines as it adds too much noise if they differ  let orig_text = orig_text.replace("\r\n", "\n");  let edit_text = edit_text.replace("\r\n", "\n");
  if orig_text == edit_text {    return " | Text differed by line endings.\n".to_string();  }
  DiffBuilder::build(&orig_text, &edit_text)}
struct DiffBuilder {  output: String,  line_number_width: usize,  orig_line: usize,  edit_line: usize,  orig: String,  edit: String,  has_changes: bool,}
impl DiffBuilder {  pub fn build(orig_text: &str, edit_text: &str) -> String {    let mut diff_builder = DiffBuilder {      output: String::new(),      orig_line: 1,      edit_line: 1,      orig: String::new(),      edit: String::new(),      has_changes: false,      line_number_width: {        let line_count = std::cmp::max(          orig_text.split('\n').count(),          edit_text.split('\n').count(),        );        line_count.to_string().chars().count()      },    };
    let chunks = difference(orig_text, edit_text);    diff_builder.handle_chunks(chunks);    diff_builder.output  }
  fn handle_chunks<'a>(&'a mut self, chunks: Vec<Chunk<'a>>) {    for chunk in chunks {      match chunk {        Chunk::Delete(s) => {          let split = s.split('\n').enumerate();          for (i, s) in split {            if i > 0 {              self.orig.push('\n');            }            self.orig.push_str(&fmt_rem_text_highlight(s));          }          self.has_changes = true        }        Chunk::Insert(s) => {          let split = s.split('\n').enumerate();          for (i, s) in split {            if i > 0 {              self.edit.push('\n');            }            self.edit.push_str(&fmt_add_text_highlight(s));          }          self.has_changes = true        }        Chunk::Equal(s) => {          let split = s.split('\n').enumerate();          for (i, s) in split {            if i > 0 {              self.flush_changes();            }            self.orig.push_str(&fmt_rem_text(s));            self.edit.push_str(&fmt_add_text(s));          }        }      }    }
    self.flush_changes();  }
  fn flush_changes(&mut self) {    if self.has_changes {      self.write_line_diff();
      self.orig_line += self.orig.split('\n').count();      self.edit_line += self.edit.split('\n').count();      self.has_changes = false;    } else {      self.orig_line += 1;      self.edit_line += 1;    }
    self.orig.clear();    self.edit.clear();  }
  fn write_line_diff(&mut self) {    let split = self.orig.split('\n').enumerate();    for (i, s) in split {      write!(        self.output,        "{:width$}{} ",        self.orig_line + i,        colors::gray(" |"),        width = self.line_number_width      )      .unwrap();      self.output.push_str(&fmt_rem());      self.output.push_str(s);      self.output.push('\n');    }
    let split = self.edit.split('\n').enumerate();    for (i, s) in split {      write!(        self.output,        "{:width$}{} ",        self.edit_line + i,        colors::gray(" |"),        width = self.line_number_width      )      .unwrap();      self.output.push_str(&fmt_add());      self.output.push_str(s);      self.output.push('\n');    }  }}
fn fmt_add() -> String {  colors::green_bold("+").to_string()}
fn fmt_add_text(x: &str) -> String {  colors::green(x).to_string()}
fn fmt_add_text_highlight(x: &str) -> String {  colors::black_on_green(x).to_string()}
fn fmt_rem() -> String {  colors::red_bold("-").to_string()}
fn fmt_rem_text(x: &str) -> String {  colors::red(x).to_string()}
fn fmt_rem_text_highlight(x: &str) -> String {  colors::white_on_red(x).to_string()}
#[cfg(test)]mod tests {  use super::*;
  #[test]  fn test_diff() {    run_test(      "console.log('Hello World')",      "console.log(\"Hello World\");",      concat!(        "1 | -console.log('Hello World')\n",        "1 | +console.log(\"Hello World\");\n",      ),    );
    run_test(      "\n\n\n\nconsole.log(\n'Hello World'\n)",      "console.log(\n\"Hello World\"\n);",      concat!(        "1 | -\n",        "2 | -\n",        "3 | -\n",        "4 | -\n",        "5 | -console.log(\n",        "1 | +console.log(\n",        "6 | -'Hello World'\n",        "2 | +\"Hello World\"\n",        "7 | -)\n3 | +);\n",      ),    );  }
  #[test]  fn test_eof_newline_missing() {    run_test(      "test\nsome line text test",      "test\nsome line text test\n",      concat!(        "2 | -some line text test\n",        "2 | +some line text test\n",        "3 | +\n",      ),    );  }
  #[test]  fn test_newlines_differing() {    run_test("test\n", "test\r\n", " | Text differed by line endings.\n");  }
  fn run_test(diff_text1: &str, diff_text2: &str, expected_output: &str) {    assert_eq!(      test_util::strip_ansi_codes(&diff(diff_text1, diff_text2,)),      expected_output,    );  }}