use std::{path::PathBuf, sync::Arc};

use fuzzy::{StringMatch, StringMatchCandidate};
use gpui::{
    actions, impl_actions, rems, AppContext, DismissEvent, EventEmitter, FocusableView,
    InteractiveElement, Model, ParentElement, Render, SharedString, Styled, Subscription, View,
    ViewContext, VisualContext, WeakView,
};
use picker::{
    highlighted_match_with_paths::{HighlightedMatchWithPaths, HighlightedText},
    Picker, PickerDelegate,
};
use project::{Inventory, ProjectPath, TaskSourceKind};
use task::{oneshot_source::OneshotSource, Task, TaskContext};
use ui::{v_flex, ListItem, ListItemSpacing, RenderOnce, Selectable, WindowContext};
use util::{paths::PathExt, ResultExt};
use workspace::{ModalView, Workspace};

use crate::schedule_task;
use serde::Deserialize;
actions!(task, [Spawn]);

/// Rerun last task
#[derive(PartialEq, Clone, Deserialize, Default)]
pub struct Rerun {
    #[serde(default)]
    /// Controls whether the task context is reevaluated prior to execution of a task.
    /// If it is not, environment variables such as ZED_COLUMN, ZED_FILE are gonna be the same as in the last execution of a task
    /// If it is, these variables will be updated to reflect current state of editor at the time task::Rerun is executed.
    /// default: false
    pub reevaluate_context: bool,
}

impl_actions!(task, [Rerun]);

/// A modal used to spawn new tasks.
pub(crate) struct TasksModalDelegate {
    inventory: Model<Inventory>,
    candidates: Vec<(TaskSourceKind, Arc<dyn Task>)>,
    matches: Vec<StringMatch>,
    selected_index: usize,
    workspace: WeakView<Workspace>,
    prompt: String,
    task_context: TaskContext,
}

impl TasksModalDelegate {
    fn new(
        inventory: Model<Inventory>,
        task_context: TaskContext,
        workspace: WeakView<Workspace>,
    ) -> Self {
        Self {
            inventory,
            workspace,
            candidates: Vec::new(),
            matches: Vec::new(),
            selected_index: 0,
            prompt: String::default(),
            task_context,
        }
    }

    fn spawn_oneshot(&mut self, cx: &mut AppContext) -> Option<Arc<dyn Task>> {
        self.inventory
            .update(cx, |inventory, _| inventory.source::<OneshotSource>())?
            .update(cx, |oneshot_source, _| {
                Some(
                    oneshot_source
                        .as_any()
                        .downcast_mut::<OneshotSource>()?
                        .spawn(self.prompt.clone()),
                )
            })
    }

    fn active_item_path(
        &mut self,
        cx: &mut ViewContext<'_, Picker<Self>>,
    ) -> Option<(PathBuf, ProjectPath)> {
        let workspace = self.workspace.upgrade()?.read(cx);
        let project = workspace.project().read(cx);
        let active_item = workspace.active_item(cx)?;
        active_item.project_path(cx).and_then(|project_path| {
            project
                .worktree_for_id(project_path.worktree_id, cx)
                .map(|worktree| worktree.read(cx).abs_path().join(&project_path.path))
                .zip(Some(project_path))
        })
    }
}

pub(crate) struct TasksModal {
    picker: View<Picker<TasksModalDelegate>>,
    _subscription: Subscription,
}

impl TasksModal {
    pub(crate) fn new(
        inventory: Model<Inventory>,
        task_context: TaskContext,
        workspace: WeakView<Workspace>,
        cx: &mut ViewContext<Self>,
    ) -> Self {
        let picker = cx.new_view(|cx| {
            Picker::uniform_list(
                TasksModalDelegate::new(inventory, task_context, workspace),
                cx,
            )
        });
        let _subscription = cx.subscribe(&picker, |_, _, _, cx| {
            cx.emit(DismissEvent);
        });
        Self {
            picker,
            _subscription,
        }
    }
}

impl Render for TasksModal {
    fn render(&mut self, cx: &mut ViewContext<Self>) -> impl gpui::prelude::IntoElement {
        v_flex()
            .key_context("TasksModal")
            .w(rems(34.))
            .child(self.picker.clone())
            .on_mouse_down_out(cx.listener(|modal, _, cx| {
                modal.picker.update(cx, |picker, cx| {
                    picker.cancel(&Default::default(), cx);
                })
            }))
    }
}

impl EventEmitter<DismissEvent> for TasksModal {}

impl FocusableView for TasksModal {
    fn focus_handle(&self, cx: &gpui::AppContext) -> gpui::FocusHandle {
        self.picker.read(cx).focus_handle(cx)
    }
}

impl ModalView for TasksModal {}

impl PickerDelegate for TasksModalDelegate {
    type ListItem = ListItem;

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

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

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

    fn placeholder_text(&self, cx: &mut WindowContext) -> Arc<str> {
        Arc::from(format!(
            "{} use task name as prompt, {} spawns a bash-like task from the prompt, {} runs the selected task",
            cx.keystroke_text_for(&menu::UseSelectedQuery),
            cx.keystroke_text_for(&menu::SecondaryConfirm),
            cx.keystroke_text_for(&menu::Confirm),
        ))
    }

    fn update_matches(
        &mut self,
        query: String,
        cx: &mut ViewContext<picker::Picker<Self>>,
    ) -> gpui::Task<()> {
        cx.spawn(move |picker, mut cx| async move {
            let Some(candidates) = picker
                .update(&mut cx, |picker, cx| {
                    let (path, worktree) = match picker.delegate.active_item_path(cx) {
                        Some((abs_path, project_path)) => {
                            (Some(abs_path), Some(project_path.worktree_id))
                        }
                        None => (None, None),
                    };
                    picker.delegate.candidates =
                        picker.delegate.inventory.update(cx, |inventory, cx| {
                            inventory.list_tasks(path.as_deref(), worktree, true, cx)
                        });
                    picker
                        .delegate
                        .candidates
                        .iter()
                        .enumerate()
                        .map(|(index, (_, candidate))| StringMatchCandidate {
                            id: index,
                            char_bag: candidate.name().chars().collect(),
                            string: candidate.name().into(),
                        })
                        .collect::<Vec<_>>()
                })
                .ok()
            else {
                return;
            };
            let matches = fuzzy::match_strings(
                &candidates,
                &query,
                true,
                1000,
                &Default::default(),
                cx.background_executor().clone(),
            )
            .await;
            picker
                .update(&mut cx, |picker, _| {
                    let delegate = &mut picker.delegate;
                    delegate.matches = matches;
                    delegate.prompt = query;

                    if delegate.matches.is_empty() {
                        delegate.selected_index = 0;
                    } else {
                        delegate.selected_index =
                            delegate.selected_index.min(delegate.matches.len() - 1);
                    }
                })
                .log_err();
        })
    }

    fn confirm(&mut self, secondary: bool, cx: &mut ViewContext<picker::Picker<Self>>) {
        let current_match_index = self.selected_index();
        let task = if secondary {
            if !self.prompt.trim().is_empty() {
                self.spawn_oneshot(cx)
            } else {
                None
            }
        } else {
            self.matches.get(current_match_index).map(|current_match| {
                let ix = current_match.candidate_id;
                self.candidates[ix].1.clone()
            })
        };

        let Some(task) = task else {
            return;
        };

        self.workspace
            .update(cx, |workspace, cx| {
                schedule_task(workspace, task.as_ref(), self.task_context.clone(), cx);
            })
            .ok();
        cx.emit(DismissEvent);
    }

    fn dismissed(&mut self, cx: &mut ViewContext<picker::Picker<Self>>) {
        cx.emit(DismissEvent);
    }

    fn render_match(
        &self,
        ix: usize,
        selected: bool,
        cx: &mut ViewContext<picker::Picker<Self>>,
    ) -> Option<Self::ListItem> {
        let hit = &self.matches[ix];
        let (source_kind, _) = &self.candidates[hit.candidate_id];
        let details = match source_kind {
            TaskSourceKind::UserInput => "user input".to_string(),
            TaskSourceKind::Worktree { abs_path, .. } | TaskSourceKind::AbsPath(abs_path) => {
                abs_path.compact().to_string_lossy().to_string()
            }
        };

        let highlighted_location = HighlightedMatchWithPaths {
            match_label: HighlightedText {
                text: hit.string.clone(),
                highlight_positions: hit.positions.clone(),
                char_count: hit.string.chars().count(),
            },
            paths: vec![HighlightedText {
                char_count: details.chars().count(),
                highlight_positions: Vec::new(),
                text: details,
            }],
        };
        Some(
            ListItem::new(SharedString::from(format!("tasks-modal-{ix}")))
                .inset(true)
                .spacing(ListItemSpacing::Sparse)
                .selected(selected)
                .child(highlighted_location.render(cx)),
        )
    }

    fn selected_as_query(&self) -> Option<String> {
        Some(self.matches.get(self.selected_index())?.string.clone())
    }
}

#[cfg(test)]
mod tests {
    use gpui::{TestAppContext, VisualTestContext};
    use project::{FakeFs, Project};
    use serde_json::json;

    use super::*;

    #[gpui::test]
    async fn test_spawn_tasks_modal_query_reuse(cx: &mut TestAppContext) {
        crate::tests::init_test(cx);
        let fs = FakeFs::new(cx.executor());
        fs.insert_tree(
            "/dir",
            json!({
                ".zed": {
                    "tasks.json": r#"[
                        {
                            "label": "example task",
                            "command": "echo",
                            "args": ["4"]
                        },
                        {
                            "label": "another one",
                            "command": "echo",
                            "args": ["55"]
                        },
                    ]"#,
                },
                "a.ts": "a"
            }),
        )
        .await;

        let project = Project::test(fs, ["/dir".as_ref()], cx).await;
        project.update(cx, |project, cx| {
            project.task_inventory().update(cx, |inventory, cx| {
                inventory.add_source(TaskSourceKind::UserInput, |cx| OneshotSource::new(cx), cx)
            })
        });

        let (workspace, cx) = cx.add_window_view(|cx| Workspace::test_new(project, cx));

        let tasks_picker = open_spawn_tasks(&workspace, cx);
        assert_eq!(
            query(&tasks_picker, cx),
            "",
            "Initial query should be empty"
        );
        assert_eq!(
            task_names(&tasks_picker, cx),
            vec!["another one", "example task"],
            "Initial tasks should be listed in alphabetical order"
        );

        let query_str = "tas";
        cx.simulate_input(query_str);
        assert_eq!(query(&tasks_picker, cx), query_str);
        assert_eq!(
            task_names(&tasks_picker, cx),
            vec!["example task"],
            "Only one task should match the query {query_str}"
        );

        cx.dispatch_action(menu::UseSelectedQuery);
        assert_eq!(
            query(&tasks_picker, cx),
            "example task",
            "Query should be set to the selected task's name"
        );
        assert_eq!(
            task_names(&tasks_picker, cx),
            vec!["example task"],
            "No other tasks should be listed"
        );
        cx.dispatch_action(menu::Confirm);

        let tasks_picker = open_spawn_tasks(&workspace, cx);
        assert_eq!(
            query(&tasks_picker, cx),
            "",
            "Query should be reset after confirming"
        );
        assert_eq!(
            task_names(&tasks_picker, cx),
            vec!["example task", "another one"],
            "Last recently used task should be listed first"
        );

        let query_str = "echo 4";
        cx.simulate_input(query_str);
        assert_eq!(query(&tasks_picker, cx), query_str);
        assert_eq!(
            task_names(&tasks_picker, cx),
            Vec::<String>::new(),
            "No tasks should match custom command query"
        );

        cx.dispatch_action(menu::SecondaryConfirm);
        let tasks_picker = open_spawn_tasks(&workspace, cx);
        assert_eq!(
            query(&tasks_picker, cx),
            "",
            "Query should be reset after confirming"
        );
        assert_eq!(
            task_names(&tasks_picker, cx),
            vec![query_str, "example task", "another one"],
            "Last recently used one show task should be listed first"
        );

        cx.dispatch_action(menu::UseSelectedQuery);
        assert_eq!(
            query(&tasks_picker, cx),
            query_str,
            "Query should be set to the custom task's name"
        );
        assert_eq!(
            task_names(&tasks_picker, cx),
            vec![query_str],
            "Only custom task should be listed"
        );
    }

    fn open_spawn_tasks(
        workspace: &View<Workspace>,
        cx: &mut VisualTestContext,
    ) -> View<Picker<TasksModalDelegate>> {
        cx.dispatch_action(crate::modal::Spawn);
        workspace.update(cx, |workspace, cx| {
            workspace
                .active_modal::<TasksModal>(cx)
                .unwrap()
                .read(cx)
                .picker
                .clone()
        })
    }

    fn query(spawn_tasks: &View<Picker<TasksModalDelegate>>, cx: &mut VisualTestContext) -> String {
        spawn_tasks.update(cx, |spawn_tasks, cx| spawn_tasks.query(cx))
    }

    fn task_names(
        spawn_tasks: &View<Picker<TasksModalDelegate>>,
        cx: &mut VisualTestContext,
    ) -> Vec<String> {
        spawn_tasks.update(cx, |spawn_tasks, _| {
            spawn_tasks
                .delegate
                .matches
                .iter()
                .map(|hit| hit.string.clone())
                .collect::<Vec<_>>()
        })
    }
}