use anyhow::anyhow;
use collections::{CommandPaletteFilter, HashMap};
use fuzzy::{StringMatch, StringMatchCandidate};
use gpui::{
    actions, div, Action, AnyElement, AnyWindowHandle, AppContext, BorrowWindow, Div, Element,
    EventEmitter, FocusHandle, Keystroke, ParentElement, Render, Styled, View, ViewContext,
    VisualContext, WeakView,
};
use picker::{Picker, PickerDelegate};
use std::cmp::{self, Reverse};
use ui::modal;
use util::{
    channel::{parse_zed_link, ReleaseChannel, RELEASE_CHANNEL},
    ResultExt,
};
use workspace::{ModalEvent, Workspace};
use zed_actions::OpenZedURL;

actions!(Toggle);

pub fn init(cx: &mut AppContext) {
    dbg!("init");
    cx.set_global(HitCounts::default());

    cx.observe_new_views(
        |workspace: &mut Workspace, _: &mut ViewContext<Workspace>| {
            dbg!("new workspace found");
            workspace
                .modal_layer()
                .register_modal(Toggle, |workspace, cx| {
                    dbg!("hitting cmd-shift-p");
                    let Some(focus_handle) = cx.focused() else {
                        return None;
                    };

                    let available_actions = cx.available_actions();
                    dbg!(&available_actions);

                    Some(cx.build_view(|cx| {
                        let delegate =
                            CommandPaletteDelegate::new(cx.view().downgrade(), focus_handle);
                        CommandPalette::new(delegate, cx)
                    }))
                });
        },
    )
    .detach();
}

pub struct CommandPalette {
    picker: View<Picker<CommandPaletteDelegate>>,
}

impl CommandPalette {
    fn new(delegate: CommandPaletteDelegate, cx: &mut ViewContext<Self>) -> Self {
        let picker = cx.build_view(|cx| Picker::new(delegate, cx));
        Self { picker }
    }
}
impl EventEmitter<ModalEvent> for CommandPalette {}

impl Render for CommandPalette {
    type Element = Div<Self>;

    fn render(&mut self, cx: &mut ViewContext<Self>) -> Self::Element {
        modal(cx).w_96().child(self.picker.clone())
    }
}

pub type CommandPaletteInterceptor =
    Box<dyn Fn(&str, &AppContext) -> Option<CommandInterceptResult>>;

pub struct CommandInterceptResult {
    pub action: Box<dyn Action>,
    pub string: String,
    pub positions: Vec<usize>,
}

pub struct CommandPaletteDelegate {
    command_palette: WeakView<CommandPalette>,
    actions: Vec<Command>,
    matches: Vec<StringMatch>,
    selected_ix: usize,
    focus_handle: FocusHandle,
}

pub enum Event {
    Dismissed,
    Confirmed {
        window: AnyWindowHandle,
        focused_view_id: usize,
        action: Box<dyn Action>,
    },
}

struct Command {
    name: String,
    action: Box<dyn Action>,
    keystrokes: Vec<Keystroke>,
}

impl Clone for Command {
    fn clone(&self) -> Self {
        Self {
            name: self.name.clone(),
            action: self.action.boxed_clone(),
            keystrokes: self.keystrokes.clone(),
        }
    }
}
/// Hit count for each command in the palette.
/// We only account for commands triggered directly via command palette and not by e.g. keystrokes because
/// if an user already knows a keystroke for a command, they are unlikely to use a command palette to look for it.
#[derive(Default)]
struct HitCounts(HashMap<String, usize>);

impl CommandPaletteDelegate {
    pub fn new(command_palette: WeakView<CommandPalette>, focus_handle: FocusHandle) -> Self {
        Self {
            command_palette,
            actions: Default::default(),
            matches: vec![StringMatch {
                candidate_id: 0,
                score: 0.,
                positions: vec![],
                string: "Foo my bar".into(),
            }],
            selected_ix: 0,
            focus_handle,
        }
    }
}

impl PickerDelegate for CommandPaletteDelegate {
    type ListItem = Div<Picker<Self>>;

    fn match_count(&self) -> usize {
        self.matches.len()
    }

    fn selected_index(&self) -> usize {
        self.selected_ix
    }

    fn set_selected_index(&mut self, ix: usize, _: &mut ViewContext<Picker<Self>>) {
        self.selected_ix = ix;
    }

    fn update_matches(
        &mut self,
        query: String,
        cx: &mut ViewContext<Picker<Self>>,
    ) -> gpui::Task<()> {
        let view_id = &self.focus_handle;
        let window = cx.window();
        cx.spawn(move |picker, mut cx| async move {
            let mut actions = picker
                .update(&mut cx, |this, _| this.delegate.actions.clone())
                .expect("todo: handle picker no longer being around");
            // _ = window
            //     .available_actions(view_id, &cx)
            //     .into_iter()
            //     .flatten()
            //     .filter_map(|(name, action, bindings)| {
            //         let filtered = cx.read(|cx| {
            //             if cx.has_global::<CommandPaletteFilter>() {
            //                 let filter = cx.global::<CommandPaletteFilter>();
            //                 filter.filtered_namespaces.contains(action.namespace())
            //             } else {
            //                 false
            //             }
            //         });

            //         if filtered {
            //             None
            //         } else {
            //             Some(Command {
            //                 name: humanize_action_name(name),
            //                 action,
            //                 keystrokes: bindings
            //                     .iter()
            //                     .map(|binding| binding.keystrokes())
            //                     .last()
            //                     .map_or(Vec::new(), |keystrokes| keystrokes.to_vec()),
            //             })
            //         }
            //     })
            //     .collect::<Vec<_>>();

            cx.read_global::<HitCounts, _>(|hit_counts, _| {
                actions.sort_by_key(|action| {
                    (
                        Reverse(hit_counts.0.get(&action.name).cloned()),
                        action.name.clone(),
                    )
                });
            })
            .ok();

            let candidates = actions
                .iter()
                .enumerate()
                .map(|(ix, command)| StringMatchCandidate {
                    id: ix,
                    string: command.name.to_string(),
                    char_bag: command.name.chars().collect(),
                })
                .collect::<Vec<_>>();
            let mut matches = if query.is_empty() {
                candidates
                    .into_iter()
                    .enumerate()
                    .map(|(index, candidate)| StringMatch {
                        candidate_id: index,
                        string: candidate.string,
                        positions: Vec::new(),
                        score: 0.0,
                    })
                    .collect()
            } else {
                fuzzy::match_strings(
                    &candidates,
                    &query,
                    true,
                    10000,
                    &Default::default(),
                    cx.background_executor().clone(),
                )
                .await
            };
            let mut intercept_result = None;
            // todo!() for vim mode
            // cx.read(|cx| {
            //     if cx.has_global::<CommandPaletteInterceptor>() {
            //         cx.global::<CommandPaletteInterceptor>()(&query, cx)
            //     } else {
            //         None
            //     }
            // });
            if *RELEASE_CHANNEL == ReleaseChannel::Dev {
                if parse_zed_link(&query).is_some() {
                    intercept_result = Some(CommandInterceptResult {
                        action: OpenZedURL { url: query.clone() }.boxed_clone(),
                        string: query.clone(),
                        positions: vec![],
                    })
                }
            }
            if let Some(CommandInterceptResult {
                action,
                string,
                positions,
            }) = intercept_result
            {
                if let Some(idx) = matches
                    .iter()
                    .position(|m| actions[m.candidate_id].action.type_id() == action.type_id())
                {
                    matches.remove(idx);
                }
                actions.push(Command {
                    name: string.clone(),
                    action,
                    keystrokes: vec![],
                });
                matches.insert(
                    0,
                    StringMatch {
                        candidate_id: actions.len() - 1,
                        string,
                        positions,
                        score: 0.0,
                    },
                )
            }
            picker
                .update(&mut cx, |picker, _| {
                    let delegate = &mut picker.delegate;
                    delegate.actions = actions;
                    delegate.matches = matches;
                    if delegate.matches.is_empty() {
                        delegate.selected_ix = 0;
                    } else {
                        delegate.selected_ix =
                            cmp::min(delegate.selected_ix, delegate.matches.len() - 1);
                    }
                })
                .log_err();
        })
    }

    fn dismissed(&mut self, cx: &mut ViewContext<Picker<Self>>) {
        dbg!("dismissed");
        self.command_palette
            .update(cx, |command_palette, cx| cx.emit(ModalEvent::Dismissed))
            .log_err();
    }

    fn confirm(&mut self, _: bool, cx: &mut ViewContext<Picker<Self>>) {
        // if !self.matches.is_empty() {
        //     let window = cx.window();
        //     let focused_view_id = self.focused_view_id;
        //     let action_ix = self.matches[self.selected_ix].candidate_id;
        //     let command = self.actions.remove(action_ix);
        //     cx.update_default_global(|hit_counts: &mut HitCounts, _| {
        //         *hit_counts.0.entry(command.name).or_default() += 1;
        //     });
        //     let action = command.action;

        //     cx.app_context()
        //         .spawn(move |mut cx| async move {
        //             window
        //                 .dispatch_action(focused_view_id, action.as_ref(), &mut cx)
        //                 .ok_or_else(|| anyhow!("window was closed"))
        //         })
        //         .detach_and_log_err(cx);
        // }
        self.dismissed(cx)
    }

    fn render_match(
        &self,
        ix: usize,
        selected: bool,
        cx: &mut ViewContext<Picker<Self>>,
    ) -> Self::ListItem {
        div().child("ooh yeah")
    }

    // fn render_match(
    //     &self,
    //     ix: usize,
    //     mouse_state: &mut MouseState,
    //     selected: bool,
    //     cx: &gpui::AppContext,
    // ) -> AnyElement<Picker<Self>> {
    //     let mat = &self.matches[ix];
    //     let command = &self.actions[mat.candidate_id];
    //     let theme = theme::current(cx);
    //     let style = theme.picker.item.in_state(selected).style_for(mouse_state);
    //     let key_style = &theme.command_palette.key.in_state(selected);
    //     let keystroke_spacing = theme.command_palette.keystroke_spacing;

    //     Flex::row()
    //         .with_child(
    //             Label::new(mat.string.clone(), style.label.clone())
    //                 .with_highlights(mat.positions.clone()),
    //         )
    //         .with_children(command.keystrokes.iter().map(|keystroke| {
    //             Flex::row()
    //                 .with_children(
    //                     [
    //                         (keystroke.ctrl, "^"),
    //                         (keystroke.alt, "⌥"),
    //                         (keystroke.cmd, "⌘"),
    //                         (keystroke.shift, "⇧"),
    //                     ]
    //                     .into_iter()
    //                     .filter_map(|(modifier, label)| {
    //                         if modifier {
    //                             Some(
    //                                 Label::new(label, key_style.label.clone())
    //                                     .contained()
    //                                     .with_style(key_style.container),
    //                             )
    //                         } else {
    //                             None
    //                         }
    //                     }),
    //                 )
    //                 .with_child(
    //                     Label::new(keystroke.key.clone(), key_style.label.clone())
    //                         .contained()
    //                         .with_style(key_style.container),
    //                 )
    //                 .contained()
    //                 .with_margin_left(keystroke_spacing)
    //                 .flex_float()
    //         }))
    //         .contained()
    //         .with_style(style.container)
    //         .into_any()
    // }
}

fn humanize_action_name(name: &str) -> String {
    let capacity = name.len() + name.chars().filter(|c| c.is_uppercase()).count();
    let mut result = String::with_capacity(capacity);
    for char in name.chars() {
        if char == ':' {
            if result.ends_with(':') {
                result.push(' ');
            } else {
                result.push(':');
            }
        } else if char == '_' {
            result.push(' ');
        } else if char.is_uppercase() {
            if !result.ends_with(' ') {
                result.push(' ');
            }
            result.extend(char.to_lowercase());
        } else {
            result.push(char);
        }
    }
    result
}

impl std::fmt::Debug for Command {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("Command")
            .field("name", &self.name)
            .field("keystrokes", &self.keystrokes)
            .finish()
    }
}

#[cfg(test)]
mod tests {
    use std::sync::Arc;

    use super::*;
    use editor::Editor;
    use gpui::{executor::Deterministic, TestAppContext};
    use project::Project;
    use workspace::{AppState, Workspace};

    #[test]
    fn test_humanize_action_name() {
        assert_eq!(
            humanize_action_name("editor::GoToDefinition"),
            "editor: go to definition"
        );
        assert_eq!(
            humanize_action_name("editor::Backspace"),
            "editor: backspace"
        );
        assert_eq!(
            humanize_action_name("go_to_line::Deploy"),
            "go to line: deploy"
        );
    }

    #[gpui::test]
    async fn test_command_palette(deterministic: Arc<Deterministic>, cx: &mut TestAppContext) {
        let app_state = init_test(cx);

        let project = Project::test(app_state.fs.clone(), [], cx).await;
        let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
        let workspace = window.root(cx);
        let editor = window.add_view(cx, |cx| {
            let mut editor = Editor::single_line(None, cx);
            editor.set_text("abc", cx);
            editor
        });

        workspace.update(cx, |workspace, cx| {
            cx.focus(&editor);
            workspace.add_item(Box::new(editor.clone()), cx)
        });

        workspace.update(cx, |workspace, cx| {
            toggle_command_palette(workspace, &Toggle, cx);
        });

        let palette = workspace.read_with(cx, |workspace, _| {
            workspace.modal::<CommandPalette>().unwrap()
        });

        palette
            .update(cx, |palette, cx| {
                // Fill up palette's command list by running an empty query;
                // we only need it to subsequently assert that the palette is initially
                // sorted by command's name.
                palette.delegate_mut().update_matches("".to_string(), cx)
            })
            .await;

        palette.update(cx, |palette, _| {
            let is_sorted =
                |actions: &[Command]| actions.windows(2).all(|pair| pair[0].name <= pair[1].name);
            assert!(is_sorted(&palette.delegate().actions));
        });

        palette
            .update(cx, |palette, cx| {
                palette
                    .delegate_mut()
                    .update_matches("bcksp".to_string(), cx)
            })
            .await;

        palette.update(cx, |palette, cx| {
            assert_eq!(palette.delegate().matches[0].string, "editor: backspace");
            palette.confirm(&Default::default(), cx);
        });
        deterministic.run_until_parked();
        editor.read_with(cx, |editor, cx| {
            assert_eq!(editor.text(cx), "ab");
        });

        // Add namespace filter, and redeploy the palette
        cx.update(|cx| {
            cx.update_default_global::<CommandPaletteFilter, _, _>(|filter, _| {
                filter.filtered_namespaces.insert("editor");
            })
        });

        workspace.update(cx, |workspace, cx| {
            toggle_command_palette(workspace, &Toggle, cx);
        });

        // Assert editor command not present
        let palette = workspace.read_with(cx, |workspace, _| {
            workspace.modal::<CommandPalette>().unwrap()
        });

        palette
            .update(cx, |palette, cx| {
                palette
                    .delegate_mut()
                    .update_matches("bcksp".to_string(), cx)
            })
            .await;

        palette.update(cx, |palette, _| {
            assert!(palette.delegate().matches.is_empty())
        });
    }

    fn init_test(cx: &mut TestAppContext) -> Arc<AppState> {
        cx.update(|cx| {
            let app_state = AppState::test(cx);
            theme::init(cx);
            language::init(cx);
            editor::init(cx);
            workspace::init(app_state.clone(), cx);
            init(cx);
            Project::init_settings(cx);
            app_state
        })
    }
}