//! Story Bible breakout editor: a dedicated window for editing Story Bible items.
//!
//! Provides a tree view of Story Bible items on the left and an editor on the right.

use super::*;
use std::fs;
use std::path::PathBuf;

/// A tree node for the Story Bible tree view.
#[derive(Debug, Clone)]
pub enum BibleTreeNode {
    /// A directory/folder node with children
    Directory {
        name: String,
        path: String,
        children: Vec<BibleTreeNode>,
    },
    /// A file/node (leaf)
    File {
        name: String,
        path: String,
    },
}

impl BibleTreeNode {
    /// Create a directory node.
    fn dir(name: String, path: String, children: Vec<BibleTreeNode>) -> Self {
        Self::Directory { name, path, children }
    }

    /// Create a file node.
    fn file(name: String, path: String) -> Self {
        Self::File { name, path }
    }
}

impl App {
    /// Build the Story Bible tree structure from the Story Bible directory.
    pub(super) fn build_story_bible_tree(&self) -> Vec<BibleTreeNode> {
        let story_bible_dir = self.find_story_bible_directory();
        let Some(base_dir) = story_bible_dir else {
            return Vec::new();
        };

        let mut root_nodes = Vec::new();

        // Read the directory structure
        if let Ok(entries) = fs::read_dir(&base_dir) {
            let mut entries: Vec<_> = entries.filter_map(Result::ok).collect();
            // Sort entries: directories first, then files, both alphabetically
            entries.sort_by(|a, b| {
                let a_is_dir = a.file_type().map_or(false, |ft| ft.is_dir());
                let b_is_dir = b.file_type().map_or(false, |ft| ft.is_dir());
                if a_is_dir != b_is_dir {
                    b_is_dir.cmp(&a_is_dir) // dirs first
                } else {
                    a.file_name().cmp(&b.file_name())
                }
            });

            for entry in entries {
                let path = entry.path();
                let file_name = entry.file_name().to_string_lossy().to_string();

                // Skip hidden files/directories
                if file_name.starts_with('.') {
                    continue;
                }

                let is_dir = entry.file_type().map_or(false, |ft| ft.is_dir());
                
                if is_dir {
                    // Recursively build subtree
                    let rel_path = path.strip_prefix(&base_dir).unwrap_or(&path).to_string_lossy().to_string();
                    let display_name = if rel_path.is_empty() {
                        base_dir.file_name().unwrap_or_else(|| "Story Bible".as_ref()).to_string_lossy().to_string()
                    } else {
                        path.file_name().unwrap_or_else(|| "".as_ref()).to_string_lossy().to_string()
                    };
                    let children = Self::build_tree_recursive(&path, &base_dir);
                    root_nodes.push(BibleTreeNode::dir(display_name, rel_path, children));
                } else if path.extension().and_then(|s| s.to_str()) == Some("md") {
                    // It's a markdown file
                    let rel_path = path.strip_prefix(&base_dir).unwrap_or(&path).to_string_lossy().to_string();
                    let display_name = path.file_stem().unwrap_or_else(|| "".as_ref()).to_string_lossy().to_string();
                    root_nodes.push(BibleTreeNode::file(display_name, rel_path));
                }
            }
        }

        root_nodes
    }

    /// Recursively build tree from a directory.
    fn build_tree_recursive(dir_path: &PathBuf, base_dir: &PathBuf) -> Vec<BibleTreeNode> {
        let mut children = Vec::new();

        if let Ok(entries) = fs::read_dir(dir_path) {
            let mut entries: Vec<_> = entries.filter_map(Result::ok).collect();
            // Sort entries: directories first, then files, both alphabetically
            entries.sort_by(|a, b| {
                let a_is_dir = a.file_type().map_or(false, |ft| ft.is_dir());
                let b_is_dir = b.file_type().map_or(false, |ft| ft.is_dir());
                if a_is_dir != b_is_dir {
                    b_is_dir.cmp(&a_is_dir) // dirs first
                } else {
                    a.file_name().cmp(&b.file_name())
                }
            });

            for entry in entries {
                let path = entry.path();
                let file_name = entry.file_name().to_string_lossy().to_string();

                // Skip hidden files/directories
                if file_name.starts_with('.') {
                    continue;
                }

                let is_dir = entry.file_type().map_or(false, |ft| ft.is_dir());
                
                if is_dir {
                    let rel_path = path.strip_prefix(base_dir).unwrap_or(&path).to_string_lossy().to_string();
                    let display_name = path.file_name().unwrap_or_else(|| "".as_ref()).to_string_lossy().to_string();
                    let grandchildren = Self::build_tree_recursive(&path, base_dir);
                    children.push(BibleTreeNode::dir(display_name, rel_path, grandchildren));
                } else if path.extension().and_then(|s| s.to_str()) == Some("md") {
                    let rel_path = path.strip_prefix(base_dir).unwrap_or(&path).to_string_lossy().to_string();
                    let display_name = path.file_stem().unwrap_or_else(|| "".as_ref()).to_string_lossy().to_string();
                    children.push(BibleTreeNode::file(display_name, rel_path));
                }
            }
        }

        children
    }

    /// Find the Story Bible directory path.
    pub(super) fn find_story_bible_directory(&self) -> Option<PathBuf> {
        use std::path::Path;
        let ws = self.config.workspace.clone();

        // Look for Story Bible directory - common locations
        let story_bible_dirs = [
            "03-Story-Bible",
            "03-Characters",
            "02-Story Bible",
            "Story Bible",
            "Characters",
        ];

        for dir_name in story_bible_dirs.iter() {
            let dir_path = Path::new(&ws).join(dir_name);
            if dir_path.exists() && dir_path.is_dir() {
                return Some(dir_path.to_path_buf());
            }
        }

        None
    }

    /// Render the Story Bible tree recursively.
    fn render_bible_tree(
        &self,
        ui: &mut egui::Ui,
        nodes: &[BibleTreeNode],
        selected_path: &Option<String>,
    ) -> Option<String> {
        let mut clicked_path: Option<String> = None;

        for node in nodes {
            match node {
                BibleTreeNode::Directory { name, path, children } => {
                    let _is_selected = selected_path.as_ref().map_or(false, |p| p == path);
                    
                    egui::CollapsingHeader::new(name)
                        .default_open(true)
                        .show(ui, |ui| {
                            if let Some(child_clicked) = self.render_bible_tree(ui, children, selected_path) {
                                clicked_path = Some(child_clicked);
                            }
                        });
                }
                BibleTreeNode::File { name, path } => {
                    let is_selected = selected_path.as_ref().map_or(false, |p| p == path);
                    
                    if ui
                        .selectable_label(is_selected, name)
                        .clicked()
                    {
                        clicked_path = Some(path.clone());
                    }
                }
            }
        }

        clicked_path
    }

    /// Show the Story Bible breakout editor window.
    pub(super) fn story_bible_editor_window(&mut self, ctx: &egui::Context) {
        // Build tree structure
        let tree = self.build_story_bible_tree();
        
        // Create a window with custom sizing - we want tree on left 1/3, editor on right 2/3
        let mut open = self.show_story_bible_editor;
        
        egui::Window::new("Story Bible Editor")
            .open(&mut open)
            .resizable(true)
            .collapsible(false)
            .default_width(1000.0)
            .default_height(700.0)
            .show(ctx, |ui| {
                self.story_bible_editor_contents(ui, &tree);
            });

        self.show_story_bible_editor = open;
        
        // Clear editor state when window is closed
        if !open {
            self.story_bible_editor_content.clear();
            self.story_bible_editor_path = None;
            self.story_bible_editor_focused = false;
        }
    }
    
    /// Contents of the Story Bible editor window.
    fn story_bible_editor_contents(&mut self, ui: &mut egui::Ui, tree: &[BibleTreeNode]) {
        // Set by the editor's text area below, read back out once the closures
        // that borrow `self` have finished.
        let mut focused = false;
        ui.horizontal(|ui| {
            // Left panel: Tree view (1/3 width). The width must be set on
            // this panel's own child `Ui`, not the shared horizontal one —
            // that had been shrinking the whole row (tree, separator, and
            // the editor panel with it) down to a third of the window,
            // which is why the editor's heading used to wrap one letter at
            // a time.
            let tree_width = ui.available_width() / 3.0;

            ui.vertical(|ui| {
                ui.set_width(tree_width);
                ui.heading("Story Bible");
                ui.separator();
                
                // Scroll area for tree
                egui::ScrollArea::vertical()
                    .id_salt("story_bible_editor_tree")
                    .auto_shrink(false)
                    .show(ui, |ui| {
                        if tree.is_empty() {
                            ui.label("No Story Bible items found");
                        } else {
                            // Render tree
                            if let Some(clicked_path) = self.render_bible_tree(
                                ui, tree, &self.story_bible_editor_path
                            ) {
                                // Load the clicked file
                                self.load_story_bible_item(&clicked_path);
                            }
                        }
                    });
            });
            
            ui.separator();
            
            // Right panel: Editor (2/3 width)
            ui.vertical(|ui| {
                // Show current file info
                if let Some(ref path) = self.story_bible_editor_path {
                    ui.heading(path);
                } else {
                    ui.heading("Select an item to edit");
                }
                ui.separator();
                
                // Editor area
                egui::ScrollArea::vertical()
                    .id_salt("story_bible_editor_content")
                    .auto_shrink(false)
                    .show(ui, |ui| {
                        let text_edit = egui::TextEdit::multiline(&mut self.story_bible_editor_content)
                            .id_salt("story_bible_editor_textedit")
                            .code_editor()
                            .desired_width(f32::INFINITY)
                            .desired_rows(20);
                        
                        let response = ui.add(text_edit);

                        // Recorded rather than acted on: the save needs `&mut
                        // self`, which this closure is already borrowing to
                        // draw with. `App::update` reads the flag next frame and
                        // routes Ctrl+S here instead of to the manuscript.
                        focused = response.has_focus();
                    });
                
                // Save button
                ui.separator();
                ui.horizontal(|ui| {
                    if ui.button("Save (Ctrl+S)").clicked() {
                        if let Some(ref path) = self.story_bible_editor_path {
                            self.save_story_bible_item(path.clone());
                        }
                    }
                    
                    if ui.button("Close").clicked() {
                        self.show_story_bible_editor = false;
                    }
                });
            });
        });
        self.story_bible_editor_focused = focused;
    }

    /// Load a Story Bible item from the workspace.
    pub(super) fn load_story_bible_item(&mut self, workspace_rel_path: &str) {
        let story_bible_dir = self.find_story_bible_directory();
        let Some(base_dir) = story_bible_dir else {
            self.status = "Story Bible directory not found".to_string();
            return;
        };

        let full_path = base_dir.join(workspace_rel_path);
        
        match fs::read_to_string(&full_path) {
            Ok(content) => {
                self.story_bible_editor_content = content;
                self.story_bible_editor_path = Some(workspace_rel_path.to_string());
            }
            Err(e) => {
                self.status = format!("Could not read {}: {}", workspace_rel_path, e);
            }
        }
    }

    /// Save the current Story Bible item.
    pub(super) fn save_story_bible_item(&mut self, workspace_rel_path: String) {
        let story_bible_dir = self.find_story_bible_directory();
        let Some(base_dir) = story_bible_dir else {
            self.status = "Story Bible directory not found".to_string();
            return;
        };

        let full_path = base_dir.join(&workspace_rel_path);
        
        match fs::write(&full_path, &self.story_bible_editor_content) {
            Ok(_) => {
                self.status = format!("Saved: {}", workspace_rel_path);
                // Rebuild the Story Bible index to pick up any changes
                self.build_story_bible_index();
            }
            Err(e) => {
                self.status = format!("Could not save {}: {}", workspace_rel_path, e);
            }
        }
    }

    /// Open the Story Bible editor.
    pub(super) fn open_story_bible_editor(&mut self) {
        self.show_story_bible_editor = true;
        
        // If we have a tree, try to select the first item
        let tree = self.build_story_bible_tree();
        if !tree.is_empty() {
            if let Some(first_file) = Self::find_first_file(&tree) {
                self.load_story_bible_item(&first_file);
            }
        }
    }

    /// Find the first file in the tree (depth-first).
    fn find_first_file(nodes: &[BibleTreeNode]) -> Option<String> {
        for node in nodes {
            match node {
                BibleTreeNode::Directory { children, .. } => {
                    if let Some(file) = Self::find_first_file(children) {
                        return Some(file);
                    }
                }
                BibleTreeNode::File { path, .. } => {
                    return Some(path.clone());
                }
            }
        }
        None
    }
}