use std::{cell::RefCell, ops::Range, rc::Rc, sync::Arc};

use crate::{
    insert::NormalBefore,
    motion::Motion,
    state::{Mode, Operator, RecordedSelection, ReplayableAction},
    visual::visual_motion,
    Vim,
};
use gpui::{actions, Action, ViewContext, WindowContext};
use util::ResultExt;
use workspace::Workspace;

actions!(vim, [Repeat, EndRepeat, ToggleRecord, ReplayLastRecording]);

fn should_replay(action: &Box<dyn Action>) -> bool {
    // skip so that we don't leave the character palette open
    if editor::actions::ShowCharacterPalette.partial_eq(&**action) {
        return false;
    }
    true
}

fn repeatable_insert(action: &ReplayableAction) -> Option<Box<dyn Action>> {
    match action {
        ReplayableAction::Action(action) => {
            if super::InsertBefore.partial_eq(&**action)
                || super::InsertAfter.partial_eq(&**action)
                || super::InsertFirstNonWhitespace.partial_eq(&**action)
                || super::InsertEndOfLine.partial_eq(&**action)
            {
                Some(super::InsertBefore.boxed_clone())
            } else if super::InsertLineAbove.partial_eq(&**action)
                || super::InsertLineBelow.partial_eq(&**action)
            {
                Some(super::InsertLineBelow.boxed_clone())
            } else if crate::replace::ToggleReplace.partial_eq(&**action) {
                Some(crate::replace::ToggleReplace.boxed_clone())
            } else {
                None
            }
        }
        ReplayableAction::Insertion { .. } => None,
    }
}

pub(crate) fn register(workspace: &mut Workspace, _: &mut ViewContext<Workspace>) {
    workspace.register_action(|_: &mut Workspace, _: &EndRepeat, cx| {
        Vim::update(cx, |vim, cx| {
            vim.workspace_state.dot_replaying = false;
            vim.switch_mode(Mode::Normal, false, cx)
        });
    });

    workspace.register_action(|_: &mut Workspace, _: &Repeat, cx| repeat(cx, false));
    workspace.register_action(|_: &mut Workspace, _: &ToggleRecord, cx| {
        Vim::update(cx, |vim, cx| {
            if let Some(char) = vim.workspace_state.recording_register.take() {
                vim.workspace_state.last_recorded_register = Some(char)
            } else {
                vim.push_operator(Operator::RecordRegister, cx);
            }
        })
    });

    workspace.register_action(|_: &mut Workspace, _: &ReplayLastRecording, cx| {
        let Some(register) = Vim::read(cx).workspace_state.last_recorded_register else {
            return;
        };
        replay_register(register, cx)
    });
}

pub struct ReplayerState {
    actions: Vec<ReplayableAction>,
    running: bool,
    ix: usize,
}

#[derive(Clone)]
pub struct Replayer(Rc<RefCell<ReplayerState>>);

impl Replayer {
    pub fn new() -> Self {
        Self(Rc::new(RefCell::new(ReplayerState {
            actions: vec![],
            running: false,
            ix: 0,
        })))
    }

    pub fn replay(&mut self, actions: Vec<ReplayableAction>, cx: &mut WindowContext) {
        let mut lock = self.0.borrow_mut();
        let range = lock.ix..lock.ix;
        lock.actions.splice(range, actions);
        if lock.running {
            return;
        }
        lock.running = true;
        let this = self.clone();
        cx.defer(move |cx| this.next(cx))
    }

    pub fn stop(self) {
        self.0.borrow_mut().actions.clear()
    }

    pub fn next(self, cx: &mut WindowContext) {
        let mut lock = self.0.borrow_mut();
        let action = if lock.ix < 10000 {
            lock.actions.get(lock.ix).cloned()
        } else {
            log::error!("Aborting replay after 10000 actions");
            None
        };
        lock.ix += 1;
        drop(lock);
        let Some(action) = action else {
            Vim::update(cx, |vim, _| vim.workspace_state.replayer.take());
            return;
        };
        match action {
            ReplayableAction::Action(action) => {
                if should_replay(&action) {
                    cx.dispatch_action(action.boxed_clone());
                    cx.defer(move |cx| observe_action(action.boxed_clone(), cx));
                }
            }
            ReplayableAction::Insertion {
                text,
                utf16_range_to_replace,
            } => {
                if let Some(editor) = Vim::read(cx).active_editor.clone() {
                    editor
                        .update(cx, |editor, cx| {
                            editor.replay_insert_event(&text, utf16_range_to_replace.clone(), cx)
                        })
                        .log_err();
                }
            }
        }
        cx.defer(move |cx| self.next(cx));
    }
}

pub(crate) fn record_register(register: char, cx: &mut WindowContext) {
    Vim::update(cx, |vim, cx| {
        vim.workspace_state.recording_register = Some(register);
        vim.workspace_state.recordings.remove(&register);
        vim.workspace_state.ignore_current_insertion = true;
        vim.clear_operator(cx)
    })
}

pub(crate) fn replay_register(mut register: char, cx: &mut WindowContext) {
    Vim::update(cx, |vim, cx| {
        let mut count = vim.take_count(cx).unwrap_or(1);
        vim.clear_operator(cx);

        if register == '@' {
            let Some(last) = vim.workspace_state.last_replayed_register else {
                return;
            };
            register = last;
        }
        let Some(actions) = vim.workspace_state.recordings.get(&register) else {
            return;
        };

        let mut repeated_actions = vec![];
        while count > 0 {
            repeated_actions.extend(actions.iter().cloned());
            count -= 1
        }

        vim.workspace_state.last_replayed_register = Some(register);

        vim.workspace_state
            .replayer
            .get_or_insert_with(|| Replayer::new())
            .replay(repeated_actions, cx);
    });
}

pub(crate) fn repeat(cx: &mut WindowContext, from_insert_mode: bool) {
    let Some((mut actions, selection)) = Vim::update(cx, |vim, cx| {
        let actions = vim.workspace_state.recorded_actions.clone();
        if actions.is_empty() {
            return None;
        }

        let count = vim.take_count(cx);

        let selection = vim.workspace_state.recorded_selection.clone();
        match selection {
            RecordedSelection::SingleLine { .. } | RecordedSelection::Visual { .. } => {
                vim.workspace_state.recorded_count = None;
                vim.switch_mode(Mode::Visual, false, cx)
            }
            RecordedSelection::VisualLine { .. } => {
                vim.workspace_state.recorded_count = None;
                vim.switch_mode(Mode::VisualLine, false, cx)
            }
            RecordedSelection::VisualBlock { .. } => {
                vim.workspace_state.recorded_count = None;
                vim.switch_mode(Mode::VisualBlock, false, cx)
            }
            RecordedSelection::None => {
                if let Some(count) = count {
                    vim.workspace_state.recorded_count = Some(count);
                }
            }
        }

        if vim.workspace_state.replayer.is_none() {
            if let Some(recording_register) = vim.workspace_state.recording_register {
                vim.workspace_state
                    .recordings
                    .entry(recording_register)
                    .or_default()
                    .push(ReplayableAction::Action(Repeat.boxed_clone()));
            }
        }

        Some((actions, selection))
    }) else {
        return;
    };

    match selection {
        RecordedSelection::SingleLine { cols } => {
            if cols > 1 {
                visual_motion(Motion::Right, Some(cols as usize - 1), cx)
            }
        }
        RecordedSelection::Visual { rows, cols } => {
            visual_motion(
                Motion::Down {
                    display_lines: false,
                },
                Some(rows as usize),
                cx,
            );
            visual_motion(
                Motion::StartOfLine {
                    display_lines: false,
                },
                None,
                cx,
            );
            if cols > 1 {
                visual_motion(Motion::Right, Some(cols as usize - 1), cx)
            }
        }
        RecordedSelection::VisualBlock { rows, cols } => {
            visual_motion(
                Motion::Down {
                    display_lines: false,
                },
                Some(rows as usize),
                cx,
            );
            if cols > 1 {
                visual_motion(Motion::Right, Some(cols as usize - 1), cx);
            }
        }
        RecordedSelection::VisualLine { rows } => {
            visual_motion(
                Motion::Down {
                    display_lines: false,
                },
                Some(rows as usize),
                cx,
            );
        }
        RecordedSelection::None => {}
    }

    // insert internally uses repeat to handle counts
    // vim doesn't treat 3a1 as though you literally repeated a1
    // 3 times, instead it inserts the content thrice at the insert position.
    if let Some(to_repeat) = repeatable_insert(&actions[0]) {
        if let Some(ReplayableAction::Action(action)) = actions.last() {
            if NormalBefore.partial_eq(&**action) {
                actions.pop();
            }
        }

        let mut new_actions = actions.clone();
        actions[0] = ReplayableAction::Action(to_repeat.boxed_clone());

        let mut count = Vim::read(cx).workspace_state.recorded_count.unwrap_or(1);

        // if we came from insert mode we're just doing repetitions 2 onwards.
        if from_insert_mode {
            count -= 1;
            new_actions[0] = actions[0].clone();
        }

        for _ in 1..count {
            new_actions.append(actions.clone().as_mut());
        }
        new_actions.push(ReplayableAction::Action(NormalBefore.boxed_clone()));
        actions = new_actions;
    }

    actions.push(ReplayableAction::Action(EndRepeat.boxed_clone()));

    Vim::update(cx, |vim, cx| {
        vim.workspace_state.dot_replaying = true;

        vim.workspace_state
            .replayer
            .get_or_insert_with(|| Replayer::new())
            .replay(actions, cx);
    })
}

pub(crate) fn observe_action(action: Box<dyn Action>, cx: &mut WindowContext) {
    Vim::update(cx, |vim, _| {
        if vim.workspace_state.dot_recording {
            vim.workspace_state
                .recorded_actions
                .push(ReplayableAction::Action(action.boxed_clone()));

            if vim.workspace_state.stop_recording_after_next_action {
                vim.workspace_state.dot_recording = false;
                vim.workspace_state.stop_recording_after_next_action = false;
            }
        }
        if vim.workspace_state.replayer.is_none() {
            if let Some(recording_register) = vim.workspace_state.recording_register {
                vim.workspace_state
                    .recordings
                    .entry(recording_register)
                    .or_default()
                    .push(ReplayableAction::Action(action));
            }
        }
    })
}

pub(crate) fn observe_insertion(
    text: &Arc<str>,
    range_to_replace: Option<Range<isize>>,
    cx: &mut WindowContext,
) {
    Vim::update(cx, |vim, _| {
        if vim.workspace_state.ignore_current_insertion {
            vim.workspace_state.ignore_current_insertion = false;
            return;
        }
        if vim.workspace_state.dot_recording {
            vim.workspace_state
                .recorded_actions
                .push(ReplayableAction::Insertion {
                    text: text.clone(),
                    utf16_range_to_replace: range_to_replace.clone(),
                });
            if vim.workspace_state.stop_recording_after_next_action {
                vim.workspace_state.dot_recording = false;
                vim.workspace_state.stop_recording_after_next_action = false;
            }
        }
        if let Some(recording_register) = vim.workspace_state.recording_register {
            vim.workspace_state
                .recordings
                .entry(recording_register)
                .or_default()
                .push(ReplayableAction::Insertion {
                    text: text.clone(),
                    utf16_range_to_replace: range_to_replace,
                });
        }
    });
}

#[cfg(test)]
mod test {
    use editor::test::editor_lsp_test_context::EditorLspTestContext;
    use futures::StreamExt;
    use indoc::indoc;

    use gpui::ViewInputHandler;

    use crate::{
        state::Mode,
        test::{NeovimBackedTestContext, VimTestContext},
    };

    #[gpui::test]
    async fn test_dot_repeat(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        // "o"
        cx.set_shared_state("ˇhello").await;
        cx.simulate_shared_keystrokes("o w o r l d escape").await;
        cx.shared_state().await.assert_eq("hello\nworlˇd");
        cx.simulate_shared_keystrokes(".").await;
        cx.shared_state().await.assert_eq("hello\nworld\nworlˇd");

        // "d"
        cx.simulate_shared_keystrokes("^ d f o").await;
        cx.simulate_shared_keystrokes("g g .").await;
        cx.shared_state().await.assert_eq("ˇ\nworld\nrld");

        // "p" (note that it pastes the current clipboard)
        cx.simulate_shared_keystrokes("j y y p").await;
        cx.simulate_shared_keystrokes("shift-g y y .").await;
        cx.shared_state()
            .await
            .assert_eq("\nworld\nworld\nrld\nˇrld");

        // "~" (note that counts apply to the action taken, not . itself)
        cx.set_shared_state("ˇthe quick brown fox").await;
        cx.simulate_shared_keystrokes("2 ~ .").await;
        cx.set_shared_state("THE ˇquick brown fox").await;
        cx.simulate_shared_keystrokes("3 .").await;
        cx.set_shared_state("THE QUIˇck brown fox").await;
        cx.run_until_parked();
        cx.simulate_shared_keystrokes(".").await;
        cx.shared_state().await.assert_eq("THE QUICK ˇbrown fox");
    }

    #[gpui::test]
    async fn test_repeat_ime(cx: &mut gpui::TestAppContext) {
        let mut cx = VimTestContext::new(cx, true).await;

        cx.set_state("hˇllo", Mode::Normal);
        cx.simulate_keystrokes("i");

        // simulate brazilian input for ä.
        cx.update_editor(|editor, cx| {
            editor.replace_and_mark_text_in_range(None, "\"", Some(1..1), cx);
            editor.replace_text_in_range(None, "ä", cx);
        });
        cx.simulate_keystrokes("escape");
        cx.assert_state("hˇällo", Mode::Normal);
        cx.simulate_keystrokes(".");
        cx.assert_state("hˇäällo", Mode::Normal);
    }

    #[gpui::test]
    async fn test_repeat_completion(cx: &mut gpui::TestAppContext) {
        VimTestContext::init(cx);
        let cx = EditorLspTestContext::new_rust(
            lsp::ServerCapabilities {
                completion_provider: Some(lsp::CompletionOptions {
                    trigger_characters: Some(vec![".".to_string(), ":".to_string()]),
                    resolve_provider: Some(true),
                    ..Default::default()
                }),
                ..Default::default()
            },
            cx,
        )
        .await;
        let mut cx = VimTestContext::new_with_lsp(cx, true);

        cx.set_state(
            indoc! {"
            onˇe
            two
            three
        "},
            Mode::Normal,
        );

        let mut request =
            cx.handle_request::<lsp::request::Completion, _, _>(move |_, params, _| async move {
                let position = params.text_document_position.position;
                Ok(Some(lsp::CompletionResponse::Array(vec![
                    lsp::CompletionItem {
                        label: "first".to_string(),
                        text_edit: Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
                            range: lsp::Range::new(position, position),
                            new_text: "first".to_string(),
                        })),
                        ..Default::default()
                    },
                    lsp::CompletionItem {
                        label: "second".to_string(),
                        text_edit: Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
                            range: lsp::Range::new(position, position),
                            new_text: "second".to_string(),
                        })),
                        ..Default::default()
                    },
                ])))
            });
        cx.simulate_keystrokes("a .");
        request.next().await;
        cx.condition(|editor, _| editor.context_menu_visible())
            .await;
        cx.simulate_keystrokes("down enter ! escape");

        cx.assert_state(
            indoc! {"
                one.secondˇ!
                two
                three
            "},
            Mode::Normal,
        );
        cx.simulate_keystrokes("j .");
        cx.assert_state(
            indoc! {"
                one.second!
                two.secondˇ!
                three
            "},
            Mode::Normal,
        );
    }

    #[gpui::test]
    async fn test_repeat_visual(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        // single-line (3 columns)
        cx.set_shared_state(indoc! {
            "ˇthe quick brown
            fox jumps over
            the lazy dog"
        })
        .await;
        cx.simulate_shared_keystrokes("v i w s o escape").await;
        cx.shared_state().await.assert_eq(indoc! {
            "ˇo quick brown
            fox jumps over
            the lazy dog"
        });
        cx.simulate_shared_keystrokes("j w .").await;
        cx.shared_state().await.assert_eq(indoc! {
            "o quick brown
            fox ˇops over
            the lazy dog"
        });
        cx.simulate_shared_keystrokes("f r .").await;
        cx.shared_state().await.assert_eq(indoc! {
            "o quick brown
            fox ops oveˇothe lazy dog"
        });

        // visual
        cx.set_shared_state(indoc! {
            "the ˇquick brown
            fox jumps over
            fox jumps over
            fox jumps over
            the lazy dog"
        })
        .await;
        cx.simulate_shared_keystrokes("v j x").await;
        cx.shared_state().await.assert_eq(indoc! {
            "the ˇumps over
            fox jumps over
            fox jumps over
            the lazy dog"
        });
        cx.simulate_shared_keystrokes(".").await;
        cx.shared_state().await.assert_eq(indoc! {
            "the ˇumps over
            fox jumps over
            the lazy dog"
        });
        cx.simulate_shared_keystrokes("w .").await;
        cx.shared_state().await.assert_eq(indoc! {
            "the umps ˇumps over
            the lazy dog"
        });
        cx.simulate_shared_keystrokes("j .").await;
        cx.shared_state().await.assert_eq(indoc! {
            "the umps umps over
            the ˇog"
        });

        // block mode (3 rows)
        cx.set_shared_state(indoc! {
            "ˇthe quick brown
            fox jumps over
            the lazy dog"
        })
        .await;
        cx.simulate_shared_keystrokes("ctrl-v j j shift-i o escape")
            .await;
        cx.shared_state().await.assert_eq(indoc! {
            "ˇothe quick brown
            ofox jumps over
            othe lazy dog"
        });
        cx.simulate_shared_keystrokes("j 4 l .").await;
        cx.shared_state().await.assert_eq(indoc! {
            "othe quick brown
            ofoxˇo jumps over
            otheo lazy dog"
        });

        // line mode
        cx.set_shared_state(indoc! {
            "ˇthe quick brown
            fox jumps over
            the lazy dog"
        })
        .await;
        cx.simulate_shared_keystrokes("shift-v shift-r o escape")
            .await;
        cx.shared_state().await.assert_eq(indoc! {
            "ˇo
            fox jumps over
            the lazy dog"
        });
        cx.simulate_shared_keystrokes("j .").await;
        cx.shared_state().await.assert_eq(indoc! {
            "o
            ˇo
            the lazy dog"
        });
    }

    #[gpui::test]
    async fn test_repeat_motion_counts(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        cx.set_shared_state(indoc! {
            "ˇthe quick brown
            fox jumps over
            the lazy dog"
        })
        .await;
        cx.simulate_shared_keystrokes("3 d 3 l").await;
        cx.shared_state().await.assert_eq(indoc! {
            "ˇ brown
            fox jumps over
            the lazy dog"
        });
        cx.simulate_shared_keystrokes("j .").await;
        cx.shared_state().await.assert_eq(indoc! {
            " brown
            ˇ over
            the lazy dog"
        });
        cx.simulate_shared_keystrokes("j 2 .").await;
        cx.shared_state().await.assert_eq(indoc! {
            " brown
             over
            ˇe lazy dog"
        });
    }

    #[gpui::test]
    async fn test_record_interrupted(cx: &mut gpui::TestAppContext) {
        let mut cx = VimTestContext::new(cx, true).await;

        cx.set_state("ˇhello\n", Mode::Normal);
        cx.simulate_keystrokes("4 i j cmd-shift-p escape");
        cx.simulate_keystrokes("escape");
        cx.assert_state("ˇjhello\n", Mode::Normal);
    }

    #[gpui::test]
    async fn test_repeat_over_blur(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        cx.set_shared_state("ˇhello hello hello\n").await;
        cx.simulate_shared_keystrokes("c f o x escape").await;
        cx.shared_state().await.assert_eq("ˇx hello hello\n");
        cx.simulate_shared_keystrokes(": escape").await;
        cx.simulate_shared_keystrokes(".").await;
        cx.shared_state().await.assert_eq("ˇx hello\n");
    }

    #[gpui::test]
    async fn test_undo_repeated_insert(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        cx.set_shared_state("hellˇo").await;
        cx.simulate_shared_keystrokes("3 a . escape").await;
        cx.shared_state().await.assert_eq("hello..ˇ.");
        cx.simulate_shared_keystrokes("u").await;
        cx.shared_state().await.assert_eq("hellˇo");
    }

    #[gpui::test]
    async fn test_record_replay(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        cx.set_shared_state("ˇhello world").await;
        cx.simulate_shared_keystrokes("q w c w j escape q").await;
        cx.shared_state().await.assert_eq("ˇj world");
        cx.simulate_shared_keystrokes("2 l @ w").await;
        cx.shared_state().await.assert_eq("j ˇj");
    }

    #[gpui::test]
    async fn test_record_replay_count(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        cx.set_shared_state("ˇhello world!!").await;
        cx.simulate_shared_keystrokes("q a v 3 l s 0 escape l q")
            .await;
        cx.shared_state().await.assert_eq("0ˇo world!!");
        cx.simulate_shared_keystrokes("2 @ a").await;
        cx.shared_state().await.assert_eq("000ˇ!");
    }

    #[gpui::test]
    async fn test_record_replay_dot(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        cx.set_shared_state("ˇhello world").await;
        cx.simulate_shared_keystrokes("q a r a l r b l q").await;
        cx.shared_state().await.assert_eq("abˇllo world");
        cx.simulate_shared_keystrokes(".").await;
        cx.shared_state().await.assert_eq("abˇblo world");
        cx.simulate_shared_keystrokes("shift-q").await;
        cx.shared_state().await.assert_eq("ababˇo world");
        cx.simulate_shared_keystrokes(".").await;
        cx.shared_state().await.assert_eq("ababˇb world");
    }

    #[gpui::test]
    async fn test_record_replay_of_dot(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        cx.set_shared_state("ˇhello world").await;
        cx.simulate_shared_keystrokes("r o q w . q").await;
        cx.shared_state().await.assert_eq("ˇoello world");
        cx.simulate_shared_keystrokes("d l").await;
        cx.shared_state().await.assert_eq("ˇello world");
        cx.simulate_shared_keystrokes("@ w").await;
        cx.shared_state().await.assert_eq("ˇllo world");
    }

    #[gpui::test]
    async fn test_record_replay_interleaved(cx: &mut gpui::TestAppContext) {
        let mut cx = NeovimBackedTestContext::new(cx).await;

        cx.set_shared_state("ˇhello world").await;
        cx.simulate_shared_keystrokes("q z r a l q").await;
        cx.shared_state().await.assert_eq("aˇello world");
        cx.simulate_shared_keystrokes("q b @ z @ z q").await;
        cx.shared_state().await.assert_eq("aaaˇlo world");
        cx.simulate_shared_keystrokes("@ @").await;
        cx.shared_state().await.assert_eq("aaaaˇo world");
        cx.simulate_shared_keystrokes("@ b").await;
        cx.shared_state().await.assert_eq("aaaaaaˇworld");
        cx.simulate_shared_keystrokes("@ @").await;
        cx.shared_state().await.assert_eq("aaaaaaaˇorld");
        cx.simulate_shared_keystrokes("q z r b l q").await;
        cx.shared_state().await.assert_eq("aaaaaaabˇrld");
        cx.simulate_shared_keystrokes("@ b").await;
        cx.shared_state().await.assert_eq("aaaaaaabbbˇd");
    }
}