use std::path::PathBuf;

use clap::Parser;

/// Default system prompt, compiled into the binary as a fallback.
const DEFAULT_SYSTEM_PROMPT: &str = include_str!("../prompts/normalize.txt");

const DEFAULT_MERGE_PROMPT: &str = include_str!("../prompts/merge.txt");

#[derive(Parser, Debug)]
#[command(version, about = "Furumi Agent: music metadata ingest and normalization")]
pub struct Args {
    /// IP address and port for the admin web UI
    #[arg(long, env = "FURUMI_AGENT_BIND", default_value = "0.0.0.0:8090")]
    pub bind: String,

    /// Directory to watch for new music files
    #[arg(long, env = "FURUMI_AGENT_INBOX_DIR")]
    pub inbox_dir: PathBuf,

    /// Directory for permanently stored and organized music files
    #[arg(long, env = "FURUMI_AGENT_STORAGE_DIR")]
    pub storage_dir: PathBuf,

    /// PostgreSQL connection URL
    #[arg(long, env = "FURUMI_AGENT_DATABASE_URL")]
    pub database_url: String,

    /// Ollama API base URL
    #[arg(long, env = "FURUMI_AGENT_OLLAMA_URL", default_value = "http://localhost:11434")]
    pub ollama_url: String,

    /// Ollama model name
    #[arg(long, env = "FURUMI_AGENT_OLLAMA_MODEL", default_value = "qwen3:14b")]
    pub ollama_model: String,

    /// Authorization header value for Ollama API (e.g. "Bearer <token>" or "Basic <base64>")
    #[arg(long, env = "FURUMI_AGENT_OLLAMA_AUTH")]
    pub ollama_auth: Option<String>,

    /// Inbox scan interval in seconds
    #[arg(long, env = "FURUMI_AGENT_POLL_INTERVAL_SECS", default_value_t = 30)]
    pub poll_interval_secs: u64,

    /// Confidence threshold for auto-approval (0.0 - 1.0)
    #[arg(long, env = "FURUMI_AGENT_CONFIDENCE_THRESHOLD", default_value_t = 0.85)]
    pub confidence_threshold: f64,

    /// Path to a custom system prompt file (overrides the built-in default)
    #[arg(long, env = "FURUMI_AGENT_SYSTEM_PROMPT_FILE")]
    pub system_prompt_file: Option<PathBuf>,

    /// Path to a custom merge prompt file (overrides the built-in default)
    #[arg(long, env = "FURUMI_AGENT_MERGE_PROMPT_FILE")]
    pub merge_prompt_file: Option<PathBuf>,
}

impl Args {
    pub fn validate(&self) -> Result<(), Box<dyn std::error::Error>> {
        if !self.inbox_dir.exists() || !self.inbox_dir.is_dir() {
            return Err(format!("Inbox directory {:?} does not exist or is not a directory", self.inbox_dir).into());
        }
        if !self.storage_dir.exists() || !self.storage_dir.is_dir() {
            return Err(format!("Storage directory {:?} does not exist or is not a directory", self.storage_dir).into());
        }
        if !(0.0..=1.0).contains(&self.confidence_threshold) {
            return Err("Confidence threshold must be between 0.0 and 1.0".into());
        }
        Ok(())
    }

    /// Load the system prompt from a custom file or use the built-in default.
    pub fn load_system_prompt(&self) -> Result<String, Box<dyn std::error::Error>> {
        match &self.system_prompt_file {
            Some(path) => {
                tracing::info!("Loading system prompt from {:?}", path);
                Ok(std::fs::read_to_string(path)?)
            }
            None => {
                tracing::info!("Using built-in default system prompt");
                Ok(DEFAULT_SYSTEM_PROMPT.to_owned())
            }
        }
    }

    pub fn load_merge_prompt(&self) -> Result<String, Box<dyn std::error::Error>> {
        match &self.merge_prompt_file {
            Some(path) => {
                tracing::info!("Loading merge prompt from {:?}", path);
                Ok(std::fs::read_to_string(path)?)
            }
            None => Ok(DEFAULT_MERGE_PROMPT.to_owned()),
        }
    }
}