//! Consumer group management commands
//!
//! This module provides comprehensive consumer group management functionality
//! including list, describe, and offset reset operations.

use clap::ArgMatches;
use std::error::Error;
use serde_json::{json, Value};

/// Handle consumer group list command
pub async fn handle_group_list_command(matches: &ArgMatches) -> Result<(), Box<dyn Error>> {
    let detailed = matches.get_flag("detailed");

    println!("👥 Listing consumer groups...");

    // Simulate fetching consumer groups
    let groups = simulate_get_consumer_groups().await?;

    if detailed {
        display_detailed_groups(&groups)?;
    } else {
        display_simple_groups(&groups)?;
    }

    Ok(())
}

/// Handle consumer group describe command
pub async fn handle_group_describe_command(matches: &ArgMatches) -> Result<(), Box<dyn Error>> {
    let group_id = matches.get_one::<String>("group").unwrap();

    println!("🔍 Describing consumer group '{}'...", group_id);

    // Simulate fetching group details
    let group_details = simulate_get_group_details(group_id).await?;

    display_group_details(&group_details)?;

    Ok(())
}

/// Handle consumer group offset reset command
pub async fn handle_group_reset_command(matches: &ArgMatches) -> Result<(), Box<dyn Error>> {
    let group_id = matches.get_one::<String>("group").unwrap();
    let topic = matches.get_one::<String>("topic").unwrap();

    let reset_type = if matches.get_flag("to-earliest") {
        "earliest"
    } else if matches.get_flag("to-latest") {
        "latest"
    } else if let Some(offset) = matches.get_one::<String>("to-offset") {
        println!("⚠️  Resetting to specific offset: {}", offset);
        "specific"
    } else {
        return Err("No reset option specified. Use --to-earliest, --to-latest, or --to-offset".into());
    };

    println!("🔄 Resetting offsets for group '{}' on topic '{}'...", group_id, topic);
    println!("   Reset type: {}", reset_type);

    // Simulate offset reset
    let reset_payload = json!({
        "group_id": group_id,
        "topic": topic,
        "reset_type": reset_type,
        "timestamp": chrono::Utc::now().to_rfc3339()
    });

    simulate_api_call(&format!("/api/groups/{}/reset", group_id), "POST", &reset_payload).await?;

    println!("✅ Offsets reset successfully for group '{}'!", group_id);
    Ok(())
}

// Helper functions
async fn simulate_api_call(endpoint: &str, method: &str, payload: &Value) -> Result<(), Box<dyn Error>> {
    // Simulate API call delay
    tokio::time::sleep(tokio::time::Duration::from_millis(200)).await;

    println!("📡 API Call: {} {}", method, endpoint);
    if method != "GET" {
        println!("📤 Payload: {}", serde_json::to_string_pretty(payload)?);
    }

    Ok(())
}

async fn simulate_get_consumer_groups() -> Result<Vec<Value>, Box<dyn Error>> {
    // Simulate API delay
    tokio::time::sleep(tokio::time::Duration::from_millis(300)).await;

    Ok(vec![
        json!({
            "group_id": "analytics-service",
            "state": "stable",
            "members": 3,
            "topics": ["user-events", "order-processing"],
            "total_lag": 120,
            "coordinator": "broker-1",
            "created_at": "2024-01-15T10:30:00Z"
        }),
        json!({
            "group_id": "backup-service",
            "state": "stable",
            "members": 1,
            "topics": ["user-events"],
            "total_lag": 0,
            "coordinator": "broker-2",
            "created_at": "2024-01-20T14:45:00Z"
        }),
        json!({
            "group_id": "notification-processor",
            "state": "rebalancing",
            "members": 2,
            "topics": ["notification-queue"],
            "total_lag": 450,
            "coordinator": "broker-3",
            "created_at": "2024-02-01T09:15:00Z"
        })
    ])
}

async fn simulate_get_group_details(group_id: &str) -> Result<Value, Box<dyn Error>> {
    // Simulate API delay
    tokio::time::sleep(tokio::time::Duration::from_millis(250)).await;

    Ok(json!({
        "group_id": group_id,
        "state": "stable",
        "protocol_type": "consumer",
        "protocol": "range",
        "coordinator": "broker-1",
        "members": [
            {
                "member_id": "consumer-1-abc123",
                "client_id": "analytics-consumer-1",
                "client_host": "192.168.1.100",
                "assigned_partitions": [
                    {"topic": "user-events", "partition": 0},
                    {"topic": "user-events", "partition": 1}
                ]
            },
            {
                "member_id": "consumer-2-def456",
                "client_id": "analytics-consumer-2",
                "client_host": "192.168.1.101",
                "assigned_partitions": [
                    {"topic": "user-events", "partition": 2},
                    {"topic": "order-processing", "partition": 0}
                ]
            },
            {
                "member_id": "consumer-3-ghi789",
                "client_id": "analytics-consumer-3",
                "client_host": "192.168.1.102",
                "assigned_partitions": [
                    {"topic": "order-processing", "partition": 1},
                    {"topic": "order-processing", "partition": 2}
                ]
            }
        ],
        "partition_assignment": [
            {
                "topic": "user-events",
                "partition": 0,
                "current_offset": 5140,
                "log_end_offset": 5200,
                "lag": 60,
                "member_id": "consumer-1-abc123"
            },
            {
                "topic": "user-events",
                "partition": 1,
                "current_offset": 5140,
                "log_end_offset": 5180,
                "lag": 40,
                "member_id": "consumer-1-abc123"
            },
            {
                "topic": "user-events",
                "partition": 2,
                "current_offset": 5140,
                "log_end_offset": 5160,
                "lag": 20,
                "member_id": "consumer-2-def456"
            },
            {
                "topic": "order-processing",
                "partition": 0,
                "current_offset": 2980,
                "log_end_offset": 2980,
                "lag": 0,
                "member_id": "consumer-2-def456"
            },
            {
                "topic": "order-processing",
                "partition": 1,
                "current_offset": 2985,
                "log_end_offset": 2985,
                "lag": 0,
                "member_id": "consumer-3-ghi789"
            },
            {
                "topic": "order-processing",
                "partition": 2,
                "current_offset": 2985,
                "log_end_offset": 2985,
                "lag": 0,
                "member_id": "consumer-3-ghi789"
            }
        ],
        "total_lag": 120,
        "created_at": "2024-01-15T10:30:00Z",
        "last_rebalance": "2024-01-15T10:30:00Z"
    }))
}

fn display_simple_groups(groups: &[Value]) -> Result<(), Box<dyn Error>> {
    println!();
    println!("┌─────────────────────┬────────────┬─────────┬───────────┬─────────────┐");
    println!("│ Group ID            │ State      │ Members │ Total Lag │ Coordinator │");
    println!("├─────────────────────┼────────────┼─────────┼───────────┼─────────────┤");

    for group in groups {
        let group_id = group["group_id"].as_str().unwrap_or("Unknown");
        let state = group["state"].as_str().unwrap_or("Unknown");
        let members = group["members"].as_u64().unwrap_or(0);
        let lag = group["total_lag"].as_u64().unwrap_or(0);
        let coordinator = group["coordinator"].as_str().unwrap_or("Unknown");

        let state_icon = match state {
            "stable" => "🟢",
            "rebalancing" => "🟡",
            "dead" => "🔴",
            _ => "⚫",
        };

        println!("│ {:<19} │ {}{:<9} │ {:<7} │ {:<9} │ {:<11} │",
                 group_id, state_icon, state, members, lag, coordinator);
    }

    println!("└─────────────────────┴────────────┴─────────┴───────────┴─────────────┘");
    println!();

    Ok(())
}

fn display_detailed_groups(groups: &[Value]) -> Result<(), Box<dyn Error>> {
    for (i, group) in groups.iter().enumerate() {
        if i > 0 {
            println!();
        }

        let state = group["state"].as_str().unwrap_or("Unknown");
        let state_icon = match state {
            "stable" => "🟢",
            "rebalancing" => "🟡",
            "dead" => "🔴",
            _ => "⚫",
        };

        println!("👥 Consumer Group: {}", group["group_id"].as_str().unwrap_or("Unknown"));
        println!("   State: {}{}", state_icon, state);
        println!("   Members: {}", group["members"].as_u64().unwrap_or(0));
        println!("   Topics: {:?}", group["topics"].as_array().unwrap_or(&vec![]));
        println!("   Total Lag: {}", group["total_lag"].as_u64().unwrap_or(0));
        println!("   Coordinator: {}", group["coordinator"].as_str().unwrap_or("Unknown"));
        println!("   Created: {}", group["created_at"].as_str().unwrap_or("Unknown"));
    }

    Ok(())
}

fn display_group_details(group: &Value) -> Result<(), Box<dyn Error>> {
    println!();
    println!("👥 Consumer Group Details: {}", group["group_id"].as_str().unwrap_or("Unknown"));
    println!("━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━");

    let state = group["state"].as_str().unwrap_or("Unknown");
    let state_icon = match state {
        "stable" => "🟢",
        "rebalancing" => "🟡",
        "dead" => "🔴",
        _ => "⚫",
    };

    // Basic information
    println!("📋 Basic Information:");
    println!("   Group ID: {}", group["group_id"].as_str().unwrap_or("Unknown"));
    println!("   State: {}{}", state_icon, state);
    println!("   Protocol Type: {}", group["protocol_type"].as_str().unwrap_or("Unknown"));
    println!("   Protocol: {}", group["protocol"].as_str().unwrap_or("Unknown"));
    println!("   Coordinator: {}", group["coordinator"].as_str().unwrap_or("Unknown"));
    println!("   Total Lag: {}", group["total_lag"].as_u64().unwrap_or(0));
    println!("   Created: {}", group["created_at"].as_str().unwrap_or("Unknown"));
    println!("   Last Rebalance: {}", group["last_rebalance"].as_str().unwrap_or("Unknown"));

    // Members
    println!();
    println!("👤 Members:");
    if let Some(members) = group["members"].as_array() {
        for member in members {
            println!("   • Member ID: {}", member["member_id"].as_str().unwrap_or("Unknown"));
            println!("     Client ID: {}", member["client_id"].as_str().unwrap_or("Unknown"));
            println!("     Host: {}", member["client_host"].as_str().unwrap_or("Unknown"));

            if let Some(partitions) = member["assigned_partitions"].as_array() {
                println!("     Assigned Partitions:");
                for partition in partitions {
                    println!("       - {}:{}",
                             partition["topic"].as_str().unwrap_or("Unknown"),
                             partition["partition"].as_u64().unwrap_or(0));
                }
            }
            println!();
        }
    }

    // Partition assignment and lag details
    println!("📊 Partition Assignment & Lag:");
    println!("┌─────────────────────┬─────┬──────────────┬─────────────┬─────────┬─────────────────────┐");
    println!("│ Topic               │ Par │ Current Off. │ Log End Off.│ Lag     │ Assigned To         │");
    println!("├─────────────────────┼─────┼──────────────┼─────────────┼─────────┼─────────────────────┤");

    if let Some(assignments) = group["partition_assignment"].as_array() {
        for assignment in assignments {
            let topic = assignment["topic"].as_str().unwrap_or("Unknown");
            let partition = assignment["partition"].as_u64().unwrap_or(0);
            let current_offset = assignment["current_offset"].as_u64().unwrap_or(0);
            let log_end_offset = assignment["log_end_offset"].as_u64().unwrap_or(0);
            let lag = assignment["lag"].as_u64().unwrap_or(0);
            let member_id = assignment["member_id"].as_str().unwrap_or("Unknown");

            let lag_icon = if lag == 0 { "🟢" } else if lag < 100 { "🟡" } else { "🔴" };

            println!("│ {:<19} │ {:<3} │ {:<12} │ {:<11} │ {}{:<6} │ {:<19} │",
                     topic, partition, current_offset, log_end_offset,
                     lag_icon, lag, &member_id[..member_id.len().min(19)]);
        }
    }

    println!("└─────────────────────┴─────┴──────────────┴─────────────┴─────────┴─────────────────────┘");
    println!();

    Ok(())
}
