use crate::error::{AppError, Result};
use serde_json::Value;
#[cfg(unix)]
use libc;
use std::process::Stdio;
use tokio::{
    io::{AsyncBufReadExt, AsyncWriteExt, BufReader},
    process::Command,
    sync::mpsc::{self, UnboundedReceiver, UnboundedSender},
};

#[derive(Debug)]
pub enum StructuredCommand {
    Input {
        prompt: String,
        default: Option<String>,
        secret: bool,
    },
    Menu {
        prompt: String,
        options: Vec<MenuOption>,
    },
    Confirm {
        prompt: String,
    },
    Message {
        level: MessageLevel,
        text: String,
    },
    Progress {
        /// Some(n) = deterministic bar (0-100).
        /// None    = indeterminate spinner (percent omitted from JSON).
        percent: Option<u8>,
        message: Option<String>,
    },
    /// A list of checkboxes and radio buttons.
    /// Response: space-separated IDs of all checked/selected fields.
    Form {
        prompt: String,
        fields: Vec<FormField>,
    },
    /// Run an interactive program that needs the real terminal.
    Exec {
        shell: String,
    },
}

#[derive(Debug, Clone, PartialEq)]
pub enum FormFieldType {
    Checkbox,
    Radio,
}

#[derive(Debug, Clone)]
pub struct FormField {
    pub id: String,
    pub label: String,
    pub field_type: FormFieldType,
    pub default: bool,
    /// Radio buttons with the same group are mutually exclusive.
    pub group: Option<String>,
}

#[derive(Debug)]
pub struct MenuOption {
    pub id: String,
    pub label: String,
}

#[derive(Debug)]
pub enum MessageLevel {
    Info,
    Warn,
    Error,
}

/// Запускает bash-скрипт в структурированном режиме.
/// Возвращает:
/// - `output_rx` – канал для строк вывода (обычный текст и stderr)
/// - `command_rx` – канал для команд от скрипта
/// - `finished_rx` – одноразовый канал с кодом завершения
/// - `reply_tx` – канал для отправки ответов обратно в stdin скрипта
pub fn spawn(
    script: &str,
) -> Result<(
    UnboundedReceiver<String>,
    UnboundedReceiver<StructuredCommand>,
    tokio::sync::oneshot::Receiver<i32>,
    UnboundedSender<String>,
    tokio::sync::oneshot::Sender<()>, // kill signal
)> {
    let mut child = Command::new("bash")
        .arg("-c")
        .arg(script)
        .stdin(Stdio::piped())
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .spawn()?;

    // Capture the PID before moving child into tasks (needed for kill).
    let pid = child.id();

    let stdin = child.stdin.take().unwrap();
    let stdout = child.stdout.take().unwrap();
    let stderr = child.stderr.take().unwrap();

    let (output_tx, output_rx) = mpsc::unbounded_channel();
    let (cmd_tx, cmd_rx) = mpsc::unbounded_channel();
    let (finished_tx, finished_rx) = tokio::sync::oneshot::channel();
    let (reply_tx, mut reply_rx) = mpsc::unbounded_channel::<String>();
    let (kill_tx, kill_rx) = tokio::sync::oneshot::channel::<()>();

    // Чтение stdout
    let output_tx_clone = output_tx.clone();
    let cmd_tx_stdout = cmd_tx.clone();
    tokio::spawn(async move {
        let mut reader = BufReader::new(stdout).lines();
        while let Ok(Some(line)) = reader.next_line().await {
            if line.starts_with("CMD:") {
                if parse_command(&line[4..], cmd_tx_stdout.clone()).is_err() {
                    let _ = output_tx_clone.send(format!("[PROTOCOL ERROR] {}", line));
                }
            } else {
                let _ = output_tx_clone.send(line);
            }
        }
    });

    // Чтение stderr
    let output_tx_stderr = output_tx.clone();
    let cmd_tx_stderr = cmd_tx.clone();
    tokio::spawn(async move {
        let mut reader = BufReader::new(stderr).lines();
        while let Ok(Some(line)) = reader.next_line().await {
            if line.starts_with("CMD:") {
                if parse_command(&line[4..], cmd_tx_stderr.clone()).is_err() {
                    let _ = output_tx_stderr.send(format!("[PROTOCOL ERROR] {}", line));
                }
            } else {
                let _ = output_tx_stderr.send(format!("stderr: {}", line));
            }
        }
    });

    // Запись в stdin
    tokio::spawn(async move {
        let mut stdin = stdin;
        while let Some(response) = reply_rx.recv().await {
            if stdin.write_all(response.as_bytes()).await.is_err() {
                break;
            }
            if stdin.write_all(b"\n").await.is_err() {
                break;
            }
        }
    });

    // Wait for child exit normally.
    tokio::spawn(async move {
        let status = child.wait().await;
        let code = status.map(|s| s.code().unwrap_or(1)).unwrap_or(1);
        let _ = finished_tx.send(code);
    });

    // Kill-watcher: when kill_tx fires, send SIGTERM to the entire process
    // group so bash AND all its children (mysqldump, php, etc.) are killed.
    tokio::spawn(async move {
        if kill_rx.await.is_ok() {
            if let Some(pid) = pid {
                #[cfg(unix)]
                unsafe {
                    libc::kill(-(pid as libc::pid_t), libc::SIGTERM);
                }
            }
        }
    });

    Ok((output_rx, cmd_rx, finished_rx, reply_tx, kill_tx))
}

fn parse_command(json_str: &str, cmd_tx: UnboundedSender<StructuredCommand>) -> Result<()> {
    let v: Value = serde_json::from_str(json_str)?;
    let typ = v["type"].as_str().ok_or_else(|| AppError::Protocol("Missing type".into()))?;

    let cmd = match typ {
        "input" => {
            let prompt = v["prompt"].as_str().unwrap_or("").to_string();
            let default = v["default"].as_str().map(String::from);
            let secret = v["secret"].as_bool().unwrap_or(false);
            StructuredCommand::Input { prompt, default, secret }
        }
        "menu" => {
            let prompt = v["prompt"].as_str().unwrap_or("").to_string();
            let options = v["options"]
                .as_array()
                .map(|arr| {
                    arr.iter()
                        .filter_map(|opt| {
                            Some(MenuOption {
                                id: opt["id"].as_str()?.to_string(),
                                label: opt["label"].as_str()?.to_string(),
                            })
                        })
                    .collect()
                })
            .unwrap_or_default();
            StructuredCommand::Menu { prompt, options }
        }
        "confirm" => {
            let prompt = v["prompt"].as_str().unwrap_or("").to_string();
            StructuredCommand::Confirm { prompt }
        }
        "message" => {
            let level = match v["level"].as_str() {
                Some("warn") => MessageLevel::Warn,
                Some("error") => MessageLevel::Error,
                _ => MessageLevel::Info,
            };
            let text = v["text"].as_str().unwrap_or("").to_string();
            StructuredCommand::Message { level, text }
        }
        "progress" => {
            // percent absent or null → None (indeterminate spinner)
            let percent = v["percent"].as_u64().map(|n| n.min(100) as u8);
            let message = v["message"].as_str().map(String::from);
            StructuredCommand::Progress { percent, message }
        }
        "form" => {
            let prompt = v["prompt"].as_str().unwrap_or("").to_string();
            let fields = v["fields"].as_array()
                .map(|arr| {
                    arr.iter().filter_map(|f| {
                        let id = f["id"].as_str()?.to_string();
                        let label = f["label"].as_str()?.to_string();
                        let field_type = match f["field_type"].as_str().unwrap_or("checkbox") {
                            "radio" => FormFieldType::Radio,
                            _ => FormFieldType::Checkbox,
                        };
                        let default = f["default"].as_bool().unwrap_or(false);
                        let group = f["group"].as_str().map(String::from);
                        Some(FormField { id, label, field_type, default, group })
                    }).collect()
                })
                .unwrap_or_default();
            StructuredCommand::Form { prompt, fields }
        }
        "exec" => {
            let shell = v["shell"].as_str().unwrap_or("").to_string();
            StructuredCommand::Exec { shell }
        }
        _ => return Err(AppError::Protocol(format!("Unknown command type: {}", typ))),
    };

    cmd_tx.send(cmd).map_err(|_| AppError::Protocol("Command channel closed".into()))?;
    Ok(())
}