// XATTACH command — attach an external DWG/DXF file as an XREF block
// and insert it at a picked point.
//
// Workflow:
//   Step 1 (text input): user types the file path (or the file-picker
//           message has already supplied it).
//   Step 2 (point pick): user clicks the insertion point.
//   Result: BlockRecord + Block entities are created with is_xref=true,
//           then an INSERT entity is committed.

use acadrust::entities::{Block, BlockEnd, Insert};
use acadrust::tables::block_record::{BlockFlags, BlockRecord};
use acadrust::types::Vector3;
use acadrust::EntityType;
use glam::Vec3;

use crate::command::{CadCommand, CmdResult};
use crate::modules::{IconKind, ModuleEvent, ToolDef};
use crate::scene::wire_model::WireModel;
use crate::scene::Scene;

pub fn tool() -> ToolDef {
    ToolDef {
        id: "XATTACH",
        label: "Attach XREF",
        icon: IconKind::Svg(include_bytes!("../../../assets/icons/blocks/insert.svg")),
        event: ModuleEvent::Command("XATTACH".to_string()),
    }
}

#[allow(dead_code)]
enum Step {
    /// Waiting for the user to type (or accept) a file path.
    FilePath,
    /// File path is confirmed; waiting for an insertion point.
    InsertionPoint { path: String, block_name: String },
}

pub struct XAttachCommand {
    step: Step,
    /// Pre-supplied path (from the file-picker message).
    prefilled_path: Option<String>,
}

impl XAttachCommand {
    #[allow(dead_code)]
    pub fn new() -> Self {
        Self {
            step: Step::FilePath,
            prefilled_path: None,
        }
    }

    /// Create an XATTACH command with a path already filled in (from file-picker).
    pub fn with_path(path: String) -> Self {
        let block_name = path_to_block_name(&path);
        Self {
            step: Step::InsertionPoint {
                path: path.clone(),
                block_name,
            },
            prefilled_path: Some(path),
        }
    }
}

impl CadCommand for XAttachCommand {
    fn name(&self) -> &'static str {
        "XATTACH"
    }

    fn prompt(&self) -> String {
        match &self.step {
            Step::FilePath => "XATTACH  Enter path to external DWG/DXF file:".to_string(),
            Step::InsertionPoint { block_name, .. } => {
                format!("XATTACH  Specify insertion point for \"{}\":", block_name)
            }
        }
    }

    fn wants_text_input(&self) -> bool {
        matches!(self.step, Step::FilePath)
    }

    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
        if !matches!(self.step, Step::FilePath) {
            return None;
        }
        let path = text.trim().to_string();
        if path.is_empty() {
            return None;
        }
        let block_name = path_to_block_name(&path);
        self.step = Step::InsertionPoint { path, block_name };
        Some(CmdResult::NeedPoint)
    }

    fn on_point(&mut self, pt: Vec3) -> CmdResult {
        match &self.step {
            Step::FilePath => CmdResult::NeedPoint,
            Step::InsertionPoint {
                path: _,
                block_name,
            } => {
                // We return the INSERT entity; the command handler in
                // commands.rs will call `prepare_xref_block` on the scene
                // before committing.
                CmdResult::CommitAndExit(EntityType::Insert(Insert::new(
                    block_name.clone(),
                    Vector3::new(pt.x as f64, pt.y as f64, pt.z as f64),
                )))
            }
        }
    }

    fn on_enter(&mut self) -> CmdResult {
        CmdResult::Cancel
    }

    fn on_preview_wires(&mut self, _pt: Vec3) -> Vec<WireModel> {
        vec![]
    }

    fn xattach_path(&self) -> Option<String> {
        match &self.step {
            Step::InsertionPoint { path, .. } => Some(path.clone()),
            Step::FilePath => self.prefilled_path.clone(),
        }
    }
}

/// Derive a block name from the file path: take the file stem, uppercase it.
pub fn path_to_block_name(path: &str) -> String {
    let p = std::path::Path::new(path);
    p.file_stem()
        .map(|s| s.to_string_lossy().to_uppercase())
        .unwrap_or_else(|| "XREF".to_string())
}

/// Create the XREF BlockRecord + Block/EndBlock entities in the scene document
/// for a given file path.  Returns the block name.
///
/// This must be called before committing the INSERT so that the block
/// definition exists when the renderer looks it up.
pub fn prepare_xref_block(scene: &mut Scene, path: &str) -> String {
    let block_name = path_to_block_name(path);

    // If a BlockRecord already exists with this name, skip creation.
    if scene.document.block_records.get(&block_name).is_some() {
        return block_name;
    }

    // Create the BlockRecord.
    let mut br = BlockRecord::new(&block_name);
    br.handle = scene.document.allocate_handle();
    br.flags = BlockFlags {
        is_xref: true,
        is_xref_overlay: false,
        anonymous: false,
        has_attributes: false,
        is_external: false,
    };
    br.xref_path = path.to_string();
    let _ = scene.document.block_records.add(br);

    // Create BLOCK entity.
    let b = Block::new(&block_name, Vector3::zero()).with_xref_path(path);
    let _ = scene.document.add_entity(EntityType::Block(b));
    let _ = scene
        .document
        .add_entity(EntityType::BlockEnd(BlockEnd::new()));

    // Resolve the XREF content immediately.
    let path_buf = std::path::PathBuf::from(path);
    if let Some(base_dir) = path_buf.parent() {
        crate::io::xref::resolve_xrefs(&mut scene.document, base_dir);
    }

    block_name
}