use std::process::{Command, Output};

fn cli(args: &[&str]) -> Output {
    Command::new(env!("CARGO_BIN_EXE_deckcraft-cli")).args(args).output().unwrap()
}

fn stdout(o: &Output) -> String {
    assert!(o.status.success(), "exit {:?}\nstderr: {}", o.status, String::from_utf8_lossy(&o.stderr));
    String::from_utf8_lossy(&o.stdout).into_owned()
}

fn stderr(o: &Output) -> String {
    assert!(!o.status.success(), "exit {:?}\nstdout: {}", o.status, String::from_utf8_lossy(&o.stdout));
    String::from_utf8_lossy(&o.stderr).into_owned()
}

const SUBCOMMANDS: [&str; 11] = ["info", "render", "render-transition", "convert", "run", "commands", "describe", "app", "mcp", "bench", "links"];

fn words(s: &str) -> String {
    s.split_whitespace().collect::<Vec<_>>().join(" ")
}

#[test]
fn an_unknown_subcommand_is_named_before_the_overview() {
    for args in [vec!["frobnicate"], vec!["help", "frobnicate"], vec!["--info", "--help"]] {
        let err = stderr(&cli(&args));
        assert!(err.contains("unknown subcommand `") && err.contains("\n\ndeckcraft-cli works on"), "{args:?}: {err}");
    }
}

#[test]
fn no_subcommand_shows_the_overview_and_fails() {
    assert!(stderr(&cli(&[])).starts_with("deckcraft-cli works on"));
}

#[test]
fn help_lists_every_subcommand_with_a_run_example() {
    for flag in ["help", "--help", "-h"] {
        let out = stdout(&cli(&[flag]));
        for sub in SUBCOMMANDS {
            assert!(out.contains(&format!("\n  {sub} ")), "{flag} lacks {sub}: {out}");
        }
        assert!(out.contains("deckcraft-cli run --cmd 'slide.new={\"title\":\"Q3 results\"}' --save q3.deckcraft"), "{out}");
    }
}

#[test]
fn every_subcommand_answers_help_and_does_nothing_else() {
    let dir = std::env::temp_dir().join(format!("dc-cli-help-{}", std::process::id()));
    std::fs::create_dir_all(&dir).unwrap();
    for sub in SUBCOMMANDS {
        for args in [vec![sub, "--help"], vec![sub, "-h", "out.png"], vec!["help", sub]] {
            let o = Command::new(env!("CARGO_BIN_EXE_deckcraft-cli")).current_dir(&dir).args(&args).output().unwrap();
            assert!(stdout(&o).starts_with(&format!("usage: deckcraft-cli {sub}")), "{args:?}");
        }
    }
    assert_eq!(std::fs::read_dir(&dir).unwrap().count(), 0, "help wrote nothing");
    std::fs::remove_dir_all(&dir).unwrap();
    for args in [["help", "version"], ["--version", "--help"]] {
        assert!(stdout(&cli(&args)).starts_with("usage: deckcraft-cli --version"), "{args:?}");
    }
    for args in [["help", "help"], ["help", "--help"]] {
        assert!(stdout(&cli(&args)).starts_with("deckcraft-cli works on"), "{args:?}");
    }
}

#[test]
fn run_help_says_what_the_ids_do_not() {
    let out = words(&stdout(&cli(&["run", "--help"])));
    for fact in [
        "COMMAND is a command id, then `=`, then the command's parameters as one JSON object.",
        "points on a 960×540 slide",
        "Slide indices start at 0.",
        "Shape ids are looked up on the current slide only.",
        "A command that adds a shape (shape.insert, insert.textBox, insert.table…) selects it.",
        "format.* acts on the selected text or shapes",
    ] {
        assert!(out.contains(fact), "{fact}: {out}");
    }
}

#[test]
fn describe_spells_out_a_command() {
    assert_eq!(
        stdout(&cli(&["describe", "shape.insert"])),
        "shape.insert: Shapes, in Insert ▸ Illustrations.

Parameters:
  preset          rect|roundRect|ellipse|triangle|rightArrow|star5|… (see shape.presets)
  rect            [x,y,w,h] pt
  text, optional  string

Run it with: deckcraft-cli run --cmd 'shape.insert={…}'
"
    );
    assert_eq!(
        stdout(&cli(&["describe", "format.size"])),
        "format.size: Font Size, in Home ▸ Font.

Parameters:
  size  pt
Acts on the selected text or shapes.

Run it with: deckcraft-cli run --cmd 'format.size={…}'
"
    );
    assert!(stdout(&cli(&["describe", "edit.copy"])).contains("Answers with {text, html?}.\n\nRun it with: deckcraft-cli run --cmd edit.copy\n"));
    assert!(stdout(&cli(&["describe", "text.set"])).contains("Note: replaces the whole text, keeping the first run's formatting\n"));
    assert_eq!(
        stdout(&cli(&["describe", "shape.setDefault"])),
        "shape.setDefault: Set as Default Shape.\n\nTakes no parameters.\nActs on the selected shapes.\n\nRun it with: deckcraft-cli run --cmd shape.setDefault\n"
    );
}

#[test]
fn describe_shows_alternative_sets_of_parameters() {
    assert!(stdout(&cli(&["describe", "slide.go"])).contains("Parameters:\n  either:\n    index\n  or:\n    id\n"));
    let remove = stdout(&cli(&["describe", "animation.remove"]));
    assert!(remove.contains("  or:\n    ids, optional  (all of the shapes' animations)\n"), "{remove}");
    assert!(remove.ends_with("Run it with: deckcraft-cli run --cmd animation.remove\n") && !remove.contains("Note:"), "{remove}");
    assert!(stdout(&cli(&["describe", "shape.move"])).contains(
        "  either:
    dx, optional   pt (relative)
    dy, optional   pt (relative)
    ids, optional
  or:
    x, optional    pt (absolute)
    y, optional    pt (absolute)
    ids, optional
"
    ));
}

#[test]
fn commands_lists_one_line_per_command() {
    assert_eq!(stdout(&cli(&["commands", "format.size"])), "format.size — Font Size: {size: pt}\n");
    assert_eq!(stdout(&cli(&["commands", "slide.next"])), "slide.next — Next Slide\n");
    assert_eq!(stdout(&cli(&["commands", "shape.presets"])), "shape.presets — Shape Gallery → [{name, label, category}]\n");
}