//! Renaming the open file in its folder (MARK-01).

use std::{io, path::PathBuf};

use ely_files::SaveState;
use ely_gpui_component::{forms::TextInput, overlays::PromptDialog, primitives::Severity};
use ely_office::{Host as _, files::file_name, prelude::*};
use ely_ui::{commands, i18n::text};
use gpui::{AnyElement, AppContext as _, Context, IntoElement as _, Window};

use crate::desk::Desk;

/// The text key saying why `name` is refused.
fn refused(name: &str) -> Option<&'static str> {
    let name = name.trim();
    if name.is_empty() || name == "." || name == ".." || name.contains(['/', '\\', '\0']) {
        return Some("mark.rename.bad");
    }
    let extension = std::path::Path::new(name)
        .extension()
        .and_then(|ext| ext.to_str())
        .unwrap_or_default()
        .to_lowercase();
    (!Desk::KIND.kept.contains(&extension.as_str())).then_some("mark.rename.format")
}

impl Desk {
    /// Asks a new name for the active file.
    pub fn on_rename(&mut self, _: &commands::Rename, window: &mut Window, cx: &mut Context<Self>) {
        let Some(tab) = self.active_tab() else {
            return;
        };
        let (id, name) = (tab.id, tab.name.clone());
        let field = cx.new(|cx| {
            let mut field = TextInput::new(window, cx);
            field.set_text(name, cx);
            field
        });
        self.naming = Some((id, field));
        cx.notify();
    }

    pub fn naming_element(&self, cx: &mut Context<Self>) -> Option<AnyElement> {
        let (id, field) = self.naming.as_ref()?;
        let (closed, sent, id) = (cx.entity(), cx.entity(), *id);
        let formats = Desk::KIND.kept.join(", .");
        let bad = text(cx, "mark.rename.bad", &[]);
        let format = text(cx, "mark.rename.format", &[("formats", &formats)]);
        let prompt = PromptDialog::new(
            "mark-rename",
            text(cx, "mark.rename", &[]),
            field,
            move |_, cx| {
                closed.update(cx, |desk, cx| {
                    desk.naming = None;
                    cx.notify();
                })
            },
        )
        .label(text(cx, "mark.rename.name", &[]))
        .submit(text(cx, "mark.rename.apply", &[]))
        .check(move |name| match refused(name) {
            None => Ok(()),
            Some("mark.rename.bad") => Err(bad.clone()),
            Some(_) => Err(format.clone()),
        })
        .on_submit(move |name, _, cx| {
            sent.update(cx, |desk, cx| {
                desk.naming = None;
                desk.rename(id, name, cx);
            })
        });
        Some(prompt.into_any_element())
    }

    /// Renames tab `id`'s file; an existing name is refused.
    fn rename(&mut self, id: u64, name: &str, cx: &mut Context<Self>) {
        let Some(tab) = self.tab(id) else {
            return;
        };
        let Some(from) = tab.session.path().map(|path| path.to_path_buf()) else {
            return self.toast(text(cx, "mark.rename.untitled", &[]), Severity::Warning, cx);
        };
        if tab.exporting || tab.session.state() == SaveState::Saving {
            return self.toast(text(cx, "mark.rename.saving", &[]), Severity::Warning, cx);
        }
        let to = from.with_file_name(name.trim());
        let (source, target) = (from.clone(), to.clone());
        cx.spawn(async move |this, cx| {
            let done = cx
                .background_executor()
                .spawn(async move { ely_files::rename_new(&source, &target) })
                .await;
            this.update(cx, |desk, cx| desk.renamed(id, from, to, done, cx))
                .ok();
        })
        .detach();
    }

    /// The tab follows only if it holds the old path.
    fn renamed(
        &mut self,
        id: u64,
        from: PathBuf,
        to: PathBuf,
        done: io::Result<()>,
        cx: &mut Context<Self>,
    ) {
        if let Err(error) = done {
            log::error!("mark: {} did not rename: {error}", from.display());
            let (name, error) = (file_name(&from), error.to_string());
            let said = text(
                cx,
                "mark.rename.failed",
                &[("name", &name), ("error", &error)],
            );
            return self.toast(said, Severity::Danger, cx);
        }
        log::info!("mark: renamed {} to {}", from.display(), to.display());
        match self.tab(id).and_then(|tab| tab.session.path()) {
            Some(path) if path == from => self.follow(id, to, cx),
            // The watcher saw the rename first.
            Some(path) if path == to => log::info!("mark: the tab already follows"),
            _ => log::info!("mark: the renamed file's tab is gone"),
        }
    }

    /// Tab `id`'s file now lives at `to`.
    pub fn follow(&mut self, id: u64, to: PathBuf, cx: &mut Context<Self>) {
        let Some(registry) = self.tab(id).map(|tab| tab.registry) else {
            return;
        };
        // One session moves: an open in the gap focused it.
        if let Some(registry) = registry
            && let Err(error) = self.core_mut().sessions.track(registry, &to)
        {
            log::error!("mark: the renamed file did not register: {error}");
            let said = text(cx, "office.error.engine", &[("error", &error.to_string())]);
            self.toast(said, Severity::Danger, cx);
        }
        if let Some(tab) = self.tab_mut(id) {
            tab.session.renamed(to.clone());
            tab.name = file_name(&to);
        }
        if let Some(view) = self.tab(id).map(|tab| tab.view.clone()) {
            self.observed(id, &view, cx);
        }
        // The tree and folder search see the new name.
        self.relist(cx);
        cx.notify();
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn names_need_no_slashes_and_a_markdown_end() {
        for bad in ["", " ", "..", "a/b.md", "a\\b.md"] {
            assert_eq!(super::refused(bad), Some("mark.rename.bad"), "{bad:?}");
        }
        assert_eq!(super::refused("notes.txt"), Some("mark.rename.format"));
        assert_eq!(super::refused("Notes.MD"), None);
        assert_eq!(super::refused("a.markdown"), None);
    }
}