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

use serde::{Deserialize, Serialize};

#[derive(Clone, Debug, Serialize)]
pub struct DocumentSnapshot {
    pub id: usize,
    pub revision: u64,
    pub path: Option<String>,
    pub root: String,
    pub text: String,
}

#[derive(Clone, Copy, Debug, Serialize)]
#[serde(rename_all = "snake_case")]
pub enum DocumentEventKind {
    Open,
    Change,
    Save,
    Close,
}

#[derive(Clone, Debug, Serialize)]
pub struct DocumentEvent {
    pub event: DocumentEventKind,
    pub document: DocumentSnapshot,
}

#[derive(Clone, Copy, Debug, Deserialize, Eq, PartialEq)]
#[serde(rename_all = "snake_case")]
pub enum DiagnosticSeverity {
    Error,
    Warning,
    Information,
    Hint,
}

/// Zero-based extended-grapheme positions, independent of any server encoding.
#[derive(Clone, Copy, Debug, Deserialize, Eq, Ord, PartialEq, PartialOrd)]
#[serde(deny_unknown_fields)]
pub struct TextPosition {
    pub row: usize,
    pub column: usize,
}

#[derive(Clone, Debug, Deserialize, Eq, PartialEq)]
#[serde(deny_unknown_fields)]
pub struct Diagnostic {
    pub start: TextPosition,
    pub end: TextPosition,
    pub severity: DiagnosticSeverity,
    pub message: String,
}

/// Standard LSP semantic token categories, independent of frontend colors.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum SemanticTokenKind {
    Namespace,
    Type,
    Class,
    Enum,
    Interface,
    Struct,
    TypeParameter,
    Parameter,
    Variable,
    Property,
    EnumMember,
    Event,
    Function,
    Method,
    Macro,
    Keyword,
    Modifier,
    Comment,
    String,
    Number,
    Regexp,
    Operator,
    Decorator,
}

/// Canonical modifier bits; server legend bit positions are translated by LSP.
#[repr(u16)]
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum SemanticTokenModifier {
    Declaration = 1,
    Definition = 1 << 1,
    Readonly = 1 << 2,
    Static = 1 << 3,
    Deprecated = 1 << 4,
    Abstract = 1 << 5,
    Async = 1 << 6,
    Modification = 1 << 7,
    Documentation = 1 << 8,
    DefaultLibrary = 1 << 9,
}

/// A single-line foreground annotation using whole extended-grapheme positions.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct SemanticToken {
    pub start: TextPosition,
    pub end: TextPosition,
    pub kind: SemanticTokenKind,
    pub modifiers: u16,
}

/// A completion replacement in zero-based, end-exclusive grapheme coordinates.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct CompletionEdit {
    pub start: TextPosition,
    pub end: TextPosition,
    pub text: String,
}

/// Protocol-independent completion text and its atomic document edits.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct CompletionItem {
    pub label: String,
    pub detail: Option<String>,
    /// Index of the primary replacement; other edits never determine caret placement.
    pub primary_edit: usize,
    pub edits: Vec<CompletionEdit>,
}

#[derive(Debug, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case", deny_unknown_fields)]
pub enum UpdateEffect {
    Diagnostics {
        buffer_id: usize,
        revision: u64,
        items: Vec<Diagnostic>,
    },
    #[serde(skip_deserializing)]
    SemanticTokens {
        buffer_id: usize,
        revision: u64,
        /// None clears the overlay. Immutable slices are shared without copying.
        tokens: Option<Arc<[SemanticToken]>>,
    },
    Navigate {
        buffer_id: usize,
        revision: u64,
        path: PathBuf,
        row: usize,
        column: usize,
    },
    Hover {
        buffer_id: usize,
        revision: u64,
        text: String,
    },
    #[serde(skip_deserializing)]
    Completion {
        buffer_id: usize,
        revision: u64,
        items: Vec<CompletionItem>,
    },
    Message {
        text: String,
    },
}

#[derive(Debug)]
pub struct PluginUpdate {
    pub request_id: Option<u64>,
    pub effects: Vec<UpdateEffect>,
}

#[derive(Debug)]
pub enum PluginEvent {
    Response {
        id: u64,
        effects: Vec<crate::editor::Effect>,
    },
    Update(PluginUpdate),
}