use crate::{Context, Error};
use tracing::{debug, error, trace};
use ollama_rs::Ollama;
use std::env;
use std::time::Duration;
use ollama_rs::models::create::CreateModelRequest;
use ollama_rs::generation::completion::request::GenerationRequest;
use chrono::{DateTime, Utc};
use tokio_stream::StreamExt;
use poise::CreateReply;

/// Prompt the super advanced EwiAI
#[poise::command(slash_command, prefix_command)]
pub async fn prompt(
    ctx: Context<'_>,
    #[description = "The prompt to send to EwiAI"]
    prompt: String,
    #[description = "Include recent messages (max 10)"]
    include_messages: Option<u8>,
) -> Result<(), Error> {
    debug!("{} has requested to prompt EwiAI with '{}'", ctx.author().name, prompt);

    let host = match env::var("TG_BOT_OLLAMA_HOST") {
        Ok(h) => h,
        Err(_) => {
            ctx.say("Error: Expected an ollama url in the environment (`TG_BOT_OLLAMA_HOST`).").await?;
            return Ok(());
        }
    };

    let formatted_host = if !host.starts_with("http://") && !host.starts_with("https://") {
        format!("http://{}", host)
    } else {
        host
    };

    let ollama = Ollama::builder()
        .host(&formatted_host)
        .port(11434)
        .build();

    let model_list = match ollama.list_local_models().await {
        Ok(m) => m,
        Err(e) => {
            ctx.say(format!("Error: Failed to connect to Ollama: {}", e)).await?;
            return Ok(());
        }
    };

    let mut needs_create = true;
    let yesterday = Utc::now() - chrono::Duration::days(1);

    for model in &model_list {
        if model.name.starts_with("EwiAI") {
            if let Ok(modified) = DateTime::parse_from_rfc3339(&model.modified_at) {
                if modified.with_timezone(&Utc) > yesterday {
                    needs_create = false;
                }
            }
        }
    }

    if needs_create {
        let system_prompt = system_prompt();
        let _ = ctx.say("EwiAI model is missing or out of date. Creating/updating model (this may take a bit)...").await?;
        if let Err(e) = ollama.create_model(CreateModelRequest::new("EwiAI".into())
            .system(system_prompt.into())
            .from_model("gemma4:e2b-it-qat".into())).await {
            ctx.say(format!("Error creating model: {}", e)).await?;
            return Ok(());
        }
    }

    let mut final_prompt = String::new();
    if let Some(mut limit) = include_messages {
        if limit > 10 {
            limit = 10;
        }
        match ctx.channel_id().messages(ctx.http(), poise::serenity_prelude::GetMessages::new().limit(limit)).await {
            Ok(msgs) => {
                final_prompt.push_str("Recent channel messages:\n");
                for msg in msgs.iter().rev() {
                    let mut content = msg.content.clone();
                    if content.len() > 100 {
                        content.truncate(100);
                        content.push_str("...");
                    }
                    final_prompt.push_str(&format!("{} (ID: {}): {}\n", msg.author.name, msg.author.id, content));
                }
                final_prompt.push_str("\n");
            }
            Err(e) => {
                error!("Failed to get messages: {:?}", e);
            }
        }
    }
    
    final_prompt.push_str(&format!("The user talking to you is {} (ID: {}).\nThat user is telling you the following: {}", ctx.author().name, ctx.author().id, prompt));
    trace!("Final prompt: {}", final_prompt);

    let reply = ctx.say("Thinking...\n-# The hardware this thing runs is really slow, expect a long wait").await?;
    let mut stream = match ollama.generate_stream(GenerationRequest::new("EwiAI".into(), final_prompt).system(system_prompt())).await {
        Ok(s) => s,
        Err(e) => {
            reply.edit(ctx, CreateReply::default().content(format!("Error during generation: {}", e))).await?;
            return Ok(());
        }
    };

    let mut response_text = String::new();
    let mut last_update = std::time::Instant::now();
    let mut final_response = None;

    while let Some(res) = stream.next().await {
        match res {
            Ok(chunks) => {
                for chunk in chunks {
                    response_text.push_str(&chunk.response);
                    if chunk.done {
                        final_response = Some(chunk);
                    }
                }

                if last_update.elapsed() >= Duration::from_secs(1) && !response_text.is_empty() {
                    let _ = reply.edit(ctx, CreateReply::default().content(&response_text)).await;
                    last_update = std::time::Instant::now();
                }
            }
            Err(e) => {
                let _ = reply.edit(ctx, CreateReply::default().content(format!("{} [Stream Error: {}]", response_text, e))).await;
                return Ok(());
            }
        }
    }

    if let Some(stats) = final_response {
        let total_duration = stats.total_duration.unwrap_or(0) as f64 / 1_000_000_000.0;
        let eval_count = stats.eval_count.unwrap_or(0);
        let eval_duration = stats.eval_duration.unwrap_or(0) as f64 / 1_000_000_000.0;
        let tokens_per_sec = if eval_duration > 0.0 { eval_count as f64 / eval_duration } else { 0.0 };

        let stats_text = format!(
            "\n\n*Generated in {:.2}s ({:.2} tok/s)*",
            total_duration, tokens_per_sec
        );
        response_text.push_str(&stats_text);
    }
    
    let _ = reply.edit(ctx, CreateReply::default().content(&response_text)).await;

    Ok(())
}

/// Ask EwiAI to answer to recent messages
#[poise::command(slash_command, prefix_command)]
pub async fn answer(
    ctx: Context<'_>,
    #[description = "How many messages to include (max 10)"]
    messages_count: Option<u8>,
) -> Result<(), Error> {
    debug!("{} has requested EwiAI to answer", ctx.author().name);

    let host = match env::var("TG_BOT_OLLAMA_HOST") {
        Ok(h) => h,
        Err(_) => {
            ctx.say("Error: Expected an ollama url in the environment (`TG_BOT_OLLAMA_HOST`).").await?;
            return Ok(());
        }
    };

    let formatted_host = if !host.starts_with("http://") && !host.starts_with("https://") {
        format!("http://{}", host)
    } else {
        host
    };

    let ollama = Ollama::builder()
        .host(&formatted_host)
        .port(11434)
        .build();

    let model_list = match ollama.list_local_models().await {
        Ok(m) => m,
        Err(e) => {
            ctx.say(format!("Error: Failed to connect to Ollama: {}", e)).await?;
            return Ok(());
        }
    };

    let mut needs_create = true;
    let yesterday = Utc::now() - chrono::Duration::days(1);

    for model in &model_list {
        if model.name.starts_with("EwiAI") {
            if let Ok(modified) = DateTime::parse_from_rfc3339(&model.modified_at) {
                if modified.with_timezone(&Utc) > yesterday {
                    needs_create = false;
                }
            }
        }
    }

    if needs_create {
        let system_prompt = system_prompt();
        let _ = ctx.say("EwiAI model is missing or out of date. Creating/updating model (this may take a bit)...").await?;
        if let Err(e) = ollama.create_model(CreateModelRequest::new("EwiAI".into())
            .system(system_prompt.into())
            .from_model("gemma4:e2b-it-qat".into())).await {
            ctx.say(format!("Error creating model: {}", e)).await?;
            return Ok(());
        }
    }

    let mut final_prompt = String::new();
    let mut limit = messages_count.unwrap_or(5);
    if limit > 10 {
        limit = 10;
    }
    match ctx.channel_id().messages(ctx.http(), poise::serenity_prelude::GetMessages::new().limit(limit)).await {
        Ok(msgs) => {
            final_prompt.push_str("Recent channel messages:\n");
            for msg in msgs.iter().rev() {
                let mut content = msg.content.clone();
                if content.len() > 100 {
                    content.truncate(100);
                    content.push_str("...");
                }
                final_prompt.push_str(&format!("{} (ID: {}): {}\n", msg.author.name, msg.author.id, content));
            }
            final_prompt.push_str("\n");
        }
        Err(e) => {
            error!("Failed to get messages: {:?}", e);
        }
    }
    
    final_prompt.push_str(&format!("Please respond to the messages above."));
    trace!("Final prompt: {}", final_prompt);

    let reply = ctx.say("Thinking...\n-# The hardware this thing runs is really slow, expect a long wait").await?;
    let mut stream = match ollama.generate_stream(GenerationRequest::new("EwiAI".into(), final_prompt).system(system_prompt())).await {
        Ok(s) => s,
        Err(e) => {
            reply.edit(ctx, CreateReply::default().content(format!("Error during generation: {}", e))).await?;
            return Ok(());
        }
    };

    let mut response_text = String::new();
    let mut last_update = std::time::Instant::now();
    let mut final_response = None;

    while let Some(res) = stream.next().await {
        match res {
            Ok(chunks) => {
                for chunk in chunks {
                    response_text.push_str(&chunk.response);
                    if chunk.done {
                        final_response = Some(chunk);
                    }
                }

                if last_update.elapsed() >= Duration::from_secs(1) && !response_text.is_empty() {
                    let _ = reply.edit(ctx, CreateReply::default().content(&response_text)).await;
                    last_update = std::time::Instant::now();
                }
            }
            Err(e) => {
                let _ = reply.edit(ctx, CreateReply::default().content(format!("{} [Stream Error: {}]", response_text, e))).await;
                return Ok(());
            }
        }
    }

    if let Some(stats) = final_response {
        let total_duration = stats.total_duration.unwrap_or(0) as f64 / 1_000_000_000.0;
        let eval_count = stats.eval_count.unwrap_or(0);
        let eval_duration = stats.eval_duration.unwrap_or(0) as f64 / 1_000_000_000.0;
        let tokens_per_sec = if eval_duration > 0.0 { eval_count as f64 / eval_duration } else { 0.0 };

        let stats_text = format!(
            "\n\n*Generated in {:.2}s ({:.2} tok/s)*",
            total_duration, tokens_per_sec
        );
        response_text.push_str(&stats_text);
    }
    
    let _ = reply.edit(ctx, CreateReply::default().content(&response_text)).await;

    Ok(())
}

fn system_prompt() -> String {
    format!("You are EwiAI, an AI in the TeenGovernment Development Server. Your developer is Ewi/ewenlau (discord user id: 713354021124964422, discord username: ewenlau). Be slightly unhelpful, in a sarcastic way, but still answer the question. The current date is {}", Utc::now().to_string())
}