//! Status line configuration view for customizing the TUI status bar.
//!
//! This module provides an interactive picker for selecting which items appear
//! in the status line at the bottom of the terminal. Users can:
//!
//! - **Select items**: Toggle which information is displayed
//! - **Reorder items**: Use left/right arrows to change display order
//! - **Preview changes**: See a live preview of the configured status line
//!
//! # Available Status Line Items
//!
//! - Model information (name, reasoning level)
//! - Directory paths (current dir, project root)
//! - Git information (branch name)
//! - Context usage (remaining %, used %, window size)
//! - Usage limits (5-hour, weekly)
//! - Session info (thread title, ID, tokens used)
//! - Application version

use ratatui::buffer::Buffer;
use ratatui::layout::Rect;
use std::collections::HashSet;
use strum::IntoEnumIterator;
use strum_macros::Display;
use strum_macros::EnumIter;
use strum_macros::EnumString;

use crate::app_event::AppEvent;
use crate::app_event_sender::AppEventSender;
use crate::bottom_pane::CancellationEvent;
use crate::bottom_pane::bottom_pane_view::BottomPaneView;
use crate::bottom_pane::multi_select_picker::MultiSelectItem;
use crate::bottom_pane::multi_select_picker::MultiSelectPicker;
use crate::bottom_pane::status_surface_preview::StatusSurfacePreviewData;
use crate::bottom_pane::status_surface_preview::StatusSurfacePreviewItem;
use crate::render::renderable::Renderable;

/// Available items that can be displayed in the status line.
///
/// Each variant represents a piece of information that can be shown at the
/// bottom of the TUI. Items are serialized to kebab-case for configuration
/// storage (e.g., `ModelWithReasoning` becomes `model-with-reasoning`).
///
/// Some items are conditionally displayed based on availability:
/// - Git-related items only show when in a git repository
/// - Context/limit items only show when data is available from the API
/// - Session ID only shows after a session has started
#[derive(EnumIter, EnumString, Display, Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
#[strum(serialize_all = "kebab_case")]
pub(crate) enum StatusLineItem {
    /// The current model name.
    #[strum(to_string = "model", serialize = "model-name")]
    ModelName,

    /// Model name with reasoning level suffix.
    ModelWithReasoning,

    /// Current working directory path.
    CurrentDir,

    /// Project root directory (if detected).
    #[strum(
        to_string = "project-name",
        serialize = "project",
        serialize = "project-root"
    )]
    ProjectRoot,

    /// Current git branch name (if in a repository).
    GitBranch,

    /// Compact runtime run-state text.
    #[strum(to_string = "run-state", serialize = "status")]
    Status,

    /// Percentage of context window remaining.
    ContextRemaining,

    /// Percentage of context window used.
    ///
    /// Also accepts the legacy `context-usage` config value.
    #[strum(to_string = "context-used", serialize = "context-usage")]
    ContextUsed,

    /// Remaining usage on the 5-hour rate limit.
    FiveHourLimit,

    /// Remaining usage on the weekly rate limit.
    WeeklyLimit,

    /// Codex application version.
    CodexVersion,

    /// Total context window size in tokens.
    ContextWindowSize,

    /// Total tokens used in the current session.
    UsedTokens,

    /// Total input tokens consumed.
    TotalInputTokens,

    /// Total output tokens generated.
    TotalOutputTokens,

    /// Full session UUID.
    SessionId,

    /// Whether Fast mode is currently active.
    FastMode,

    /// Current thread title (if set by user).
    ThreadTitle,

    /// Latest checklist task progress from `update_plan` (if available).
    TaskProgress,
}

impl StatusLineItem {
    /// User-visible description shown in the popup.
    pub(crate) fn description(&self) -> &'static str {
        match self {
            StatusLineItem::ModelName => "Current model name",
            StatusLineItem::ModelWithReasoning => "Current model name with reasoning level",
            StatusLineItem::CurrentDir => "Current working directory",
            StatusLineItem::ProjectRoot => "Project name (omitted when unavailable)",
            StatusLineItem::GitBranch => "Current Git branch (omitted when unavailable)",
            StatusLineItem::Status => "Compact session run-state text (Ready, Working, Thinking)",
            StatusLineItem::ContextRemaining => {
                "Percentage of context window remaining (omitted when unknown)"
            }
            StatusLineItem::ContextUsed => {
                "Percentage of context window used (omitted when unknown)"
            }
            StatusLineItem::FiveHourLimit => {
                "Remaining usage on 5-hour usage limit (omitted when unavailable)"
            }
            StatusLineItem::WeeklyLimit => {
                "Remaining usage on weekly usage limit (omitted when unavailable)"
            }
            StatusLineItem::CodexVersion => "Codex application version",
            StatusLineItem::ContextWindowSize => {
                "Total context window size in tokens (omitted when unknown)"
            }
            StatusLineItem::UsedTokens => "Total tokens used in session (omitted when zero)",
            StatusLineItem::TotalInputTokens => "Total input tokens used in session",
            StatusLineItem::TotalOutputTokens => "Total output tokens used in session",
            StatusLineItem::SessionId => {
                "Current session identifier (omitted until session starts)"
            }
            StatusLineItem::FastMode => "Whether Fast mode is currently active",
            StatusLineItem::ThreadTitle => "Current thread title (omitted when unavailable)",
            StatusLineItem::TaskProgress => {
                "Latest task progress from update_plan (omitted until available)"
            }
        }
    }

    pub(crate) fn preview_item(self) -> StatusSurfacePreviewItem {
        match self {
            StatusLineItem::ModelName => StatusSurfacePreviewItem::Model,
            StatusLineItem::ModelWithReasoning => StatusSurfacePreviewItem::ModelWithReasoning,
            StatusLineItem::CurrentDir => StatusSurfacePreviewItem::CurrentDir,
            StatusLineItem::ProjectRoot => StatusSurfacePreviewItem::ProjectRoot,
            StatusLineItem::GitBranch => StatusSurfacePreviewItem::GitBranch,
            StatusLineItem::Status => StatusSurfacePreviewItem::Status,
            StatusLineItem::ContextRemaining => StatusSurfacePreviewItem::ContextRemaining,
            StatusLineItem::ContextUsed => StatusSurfacePreviewItem::ContextUsed,
            StatusLineItem::FiveHourLimit => StatusSurfacePreviewItem::FiveHourLimit,
            StatusLineItem::WeeklyLimit => StatusSurfacePreviewItem::WeeklyLimit,
            StatusLineItem::CodexVersion => StatusSurfacePreviewItem::CodexVersion,
            StatusLineItem::ContextWindowSize => StatusSurfacePreviewItem::ContextWindowSize,
            StatusLineItem::UsedTokens => StatusSurfacePreviewItem::UsedTokens,
            StatusLineItem::TotalInputTokens => StatusSurfacePreviewItem::TotalInputTokens,
            StatusLineItem::TotalOutputTokens => StatusSurfacePreviewItem::TotalOutputTokens,
            StatusLineItem::SessionId => StatusSurfacePreviewItem::SessionId,
            StatusLineItem::FastMode => StatusSurfacePreviewItem::FastMode,
            StatusLineItem::ThreadTitle => StatusSurfacePreviewItem::ThreadTitle,
            StatusLineItem::TaskProgress => StatusSurfacePreviewItem::TaskProgress,
        }
    }
}

/// Interactive view for configuring which items appear in the status line.
///
/// Wraps a [`MultiSelectPicker`] with status-line-specific behavior:
/// - Pre-populates items from current configuration
/// - Shows a live preview of the configured status line
/// - Emits [`AppEvent::StatusLineSetup`] on confirmation
/// - Emits [`AppEvent::StatusLineSetupCancelled`] on cancellation
pub(crate) struct StatusLineSetupView {
    /// The underlying multi-select picker widget.
    picker: MultiSelectPicker,
}

impl StatusLineSetupView {
    /// Creates a new status line setup view.
    ///
    /// # Arguments
    ///
    /// * `status_line_items` - Currently configured item IDs (in display order),
    ///   or `None` to start with all items disabled
    /// * `app_event_tx` - Event sender for dispatching configuration changes
    ///
    /// Items from `status_line_items` are shown first (in order) and marked as
    /// enabled. Remaining items are appended and marked as disabled.
    pub(crate) fn new(
        status_line_items: Option<&[String]>,
        preview_data: StatusSurfacePreviewData,
        app_event_tx: AppEventSender,
    ) -> Self {
        let mut used_ids = HashSet::new();
        let mut items = Vec::new();

        if let Some(selected_items) = status_line_items.as_ref() {
            for id in *selected_items {
                let Ok(item) = id.parse::<StatusLineItem>() else {
                    continue;
                };
                let item_id = item.to_string();
                if !used_ids.insert(item_id.clone()) {
                    continue;
                }
                items.push(Self::status_line_select_item(item, /*enabled*/ true));
            }
        }

        for item in StatusLineItem::iter() {
            let item_id = item.to_string();
            if used_ids.contains(&item_id) {
                continue;
            }
            items.push(Self::status_line_select_item(item, /*enabled*/ false));
        }

        Self {
            picker: MultiSelectPicker::builder(
                "Configure Status Line".to_string(),
                Some("Select which items to display in the status line.".to_string()),
                app_event_tx,
            )
            .instructions(vec![
                "Use ↑↓ to navigate, ←→ to move, space to select, enter to confirm, esc to cancel."
                    .into(),
            ])
            .items(items)
            .enable_ordering()
            .on_preview(move |items| {
                preview_data.line_for_items(
                    items
                        .iter()
                        .filter(|item| item.enabled)
                        .filter_map(|item| item.id.parse::<StatusLineItem>().ok())
                        .map(StatusLineItem::preview_item),
                )
            })
            .on_confirm(|ids, app_event| {
                let items = ids
                    .iter()
                    .map(|id| id.parse::<StatusLineItem>())
                    .collect::<Result<Vec<_>, _>>()
                    .unwrap_or_default();
                app_event.send(AppEvent::StatusLineSetup { items });
            })
            .on_cancel(|app_event| {
                app_event.send(AppEvent::StatusLineSetupCancelled);
            })
            .build(),
        }
    }

    /// Converts a [`StatusLineItem`] into a [`MultiSelectItem`] for the picker.
    fn status_line_select_item(item: StatusLineItem, enabled: bool) -> MultiSelectItem {
        MultiSelectItem {
            id: item.to_string(),
            name: item.to_string(),
            description: Some(item.description().to_string()),
            enabled,
        }
    }
}

impl BottomPaneView for StatusLineSetupView {
    fn handle_key_event(&mut self, key_event: crossterm::event::KeyEvent) {
        self.picker.handle_key_event(key_event);
    }

    fn is_complete(&self) -> bool {
        self.picker.complete
    }

    fn on_ctrl_c(&mut self) -> CancellationEvent {
        self.picker.close();
        CancellationEvent::Handled
    }
}

impl Renderable for StatusLineSetupView {
    fn render(&self, area: Rect, buf: &mut Buffer) {
        self.picker.render(area, buf)
    }

    fn desired_height(&self, width: u16) -> u16 {
        self.picker.desired_height(width)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::app_event_sender::AppEventSender;
    use insta::assert_snapshot;
    use pretty_assertions::assert_eq;
    use ratatui::buffer::Buffer;
    use ratatui::layout::Rect;
    use ratatui::text::Line;
    use tokio::sync::mpsc::unbounded_channel;

    use crate::app_event::AppEvent;

    #[test]
    fn context_used_accepts_context_usage_legacy_id() {
        assert_eq!(StatusLineItem::ContextUsed.to_string(), "context-used");
        assert_eq!(
            "context-used".parse::<StatusLineItem>(),
            Ok(StatusLineItem::ContextUsed)
        );
        assert_eq!(
            "context-usage".parse::<StatusLineItem>(),
            Ok(StatusLineItem::ContextUsed)
        );
    }

    #[test]
    fn context_remaining_is_selectable_id() {
        assert_eq!(
            "context-remaining".parse::<StatusLineItem>(),
            Ok(StatusLineItem::ContextRemaining)
        );
        assert_eq!(
            StatusLineItem::ContextRemaining.to_string(),
            "context-remaining"
        );
    }
    #[test]
    fn project_name_is_canonical_and_accepts_legacy_ids() {
        assert_eq!(StatusLineItem::ProjectRoot.to_string(), "project-name");
        assert_eq!(
            "project-name".parse::<StatusLineItem>(),
            Ok(StatusLineItem::ProjectRoot)
        );
        assert_eq!(
            "project".parse::<StatusLineItem>(),
            Ok(StatusLineItem::ProjectRoot)
        );
        assert_eq!(
            "project-root".parse::<StatusLineItem>(),
            Ok(StatusLineItem::ProjectRoot)
        );
    }

    #[test]
    fn model_is_canonical_and_accepts_model_name_legacy_id() {
        assert_eq!(StatusLineItem::ModelName.to_string(), "model");
        assert_eq!(
            "model".parse::<StatusLineItem>(),
            Ok(StatusLineItem::ModelName)
        );
        assert_eq!(
            "model-name".parse::<StatusLineItem>(),
            Ok(StatusLineItem::ModelName)
        );
    }

    #[test]
    fn run_state_is_canonical_and_accepts_status_legacy_id() {
        assert_eq!(StatusLineItem::Status.to_string(), "run-state");
        assert_eq!(
            "run-state".parse::<StatusLineItem>(),
            Ok(StatusLineItem::Status)
        );
        assert_eq!(
            "status".parse::<StatusLineItem>(),
            Ok(StatusLineItem::Status)
        );
    }

    #[test]
    fn parse_status_line_items_accepts_title_only_variants() {
        let items = ["run-state", "task-progress"]
            .into_iter()
            .map(str::parse::<StatusLineItem>)
            .collect::<Result<Vec<_>, _>>();
        assert_eq!(
            items,
            Ok(vec![StatusLineItem::Status, StatusLineItem::TaskProgress,])
        );
    }

    #[test]
    fn preview_uses_runtime_values() {
        let preview_data = StatusSurfacePreviewData::from_iter([
            (
                StatusLineItem::ModelName.preview_item(),
                "gpt-5".to_string(),
            ),
            (
                StatusLineItem::CurrentDir.preview_item(),
                "/repo".to_string(),
            ),
        ]);
        let items = [
            MultiSelectItem {
                id: StatusLineItem::ModelName.to_string(),
                name: String::new(),
                description: None,
                enabled: true,
            },
            MultiSelectItem {
                id: StatusLineItem::CurrentDir.to_string(),
                name: String::new(),
                description: None,
                enabled: true,
            },
        ];

        assert_eq!(
            preview_data.line_for_items(
                items
                    .iter()
                    .filter_map(|item| item.id.parse::<StatusLineItem>().ok())
                    .map(StatusLineItem::preview_item),
            ),
            Some(Line::from("gpt-5 · /repo"))
        );
    }

    #[test]
    fn preview_uses_placeholders_when_runtime_values_are_missing() {
        let preview_data = StatusSurfacePreviewData::from_iter([(
            StatusSurfacePreviewItem::Model,
            "gpt-5".to_string(),
        )]);
        let items = [
            MultiSelectItem {
                id: StatusLineItem::ModelName.to_string(),
                name: String::new(),
                description: None,
                enabled: true,
            },
            MultiSelectItem {
                id: StatusLineItem::GitBranch.to_string(),
                name: String::new(),
                description: None,
                enabled: true,
            },
        ];

        assert_eq!(
            preview_data.line_for_items(
                items
                    .iter()
                    .filter_map(|item| item.id.parse::<StatusLineItem>().ok())
                    .map(StatusLineItem::preview_item),
            ),
            Some(Line::from("gpt-5 · feat/awesome-feature"))
        );
    }

    #[test]
    fn preview_includes_thread_title() {
        let preview_data = StatusSurfacePreviewData::from_iter([
            (
                StatusLineItem::ModelName.preview_item(),
                "gpt-5".to_string(),
            ),
            (
                StatusLineItem::ThreadTitle.preview_item(),
                "Roadmap cleanup".to_string(),
            ),
        ]);
        let items = [
            MultiSelectItem {
                id: StatusLineItem::ModelName.to_string(),
                name: String::new(),
                description: None,
                enabled: true,
            },
            MultiSelectItem {
                id: StatusLineItem::ThreadTitle.to_string(),
                name: String::new(),
                description: None,
                enabled: true,
            },
        ];

        assert_eq!(
            preview_data.line_for_items(
                items
                    .iter()
                    .filter_map(|item| item.id.parse::<StatusLineItem>().ok())
                    .map(StatusLineItem::preview_item),
            ),
            Some(Line::from("gpt-5 · Roadmap cleanup"))
        );
    }

    #[test]
    fn setup_view_snapshot_uses_runtime_preview_values() {
        let (tx_raw, _rx) = unbounded_channel::<AppEvent>();
        let view = StatusLineSetupView::new(
            Some(&[
                StatusLineItem::ModelName.to_string(),
                StatusLineItem::CurrentDir.to_string(),
                StatusLineItem::GitBranch.to_string(),
            ]),
            StatusSurfacePreviewData::from_iter([
                (
                    StatusLineItem::ModelName.preview_item(),
                    "gpt-5-codex".to_string(),
                ),
                (
                    StatusLineItem::CurrentDir.preview_item(),
                    "~/codex-rs".to_string(),
                ),
                (
                    StatusLineItem::GitBranch.preview_item(),
                    "jif/statusline-preview".to_string(),
                ),
                (
                    StatusLineItem::WeeklyLimit.preview_item(),
                    "weekly 82%".to_string(),
                ),
            ]),
            AppEventSender::new(tx_raw),
        );

        assert_snapshot!(render_lines(&view, /*width*/ 72));
    }

    fn render_lines(view: &StatusLineSetupView, width: u16) -> String {
        let height = view.desired_height(width);
        let area = Rect::new(0, 0, width, height);
        let mut buf = Buffer::empty(area);
        view.render(area, &mut buf);

        (0..area.height)
            .map(|row| {
                let mut line = String::new();
                for col in 0..area.width {
                    let symbol = buf[(area.x + col, area.y + row)].symbol();
                    if symbol.is_empty() {
                        line.push(' ');
                    } else {
                        line.push_str(symbol);
                    }
                }
                line
            })
            .collect::<Vec<_>>()
            .join("\n")
    }
}