// 記憶、技能、範本 (the original: user bot memories, agent skills and template skills/bots).
// - Memories belong to a bot: facts it was asked to keep across chats.
// - Skills are shared, named procedures; the bot sees their names and loads one when it needs it.
// - Templates start a new bot with a ready role and instructions.

use serde::{Deserialize, Serialize};

/// Most memories a bot keeps; the oldest go first (estimated).
pub const MAX_MEMORIES: usize = 200;
/// Longest memory (estimated).
pub const MAX_MEMORY_CHARS: usize = 500;

#[derive(Clone, Serialize, Deserialize, Debug, PartialEq)]
pub struct Skill {
    pub name: String,
    pub description: String,
    pub instructions: String,
}

pub struct Template {
    pub name: &'static str,
    pub description: &'static str,
    pub instructions: &'static str,
    pub shape: &'static str,
    pub color: &'static str,
}

pub const TEMPLATES: [Template; 5] = [
    Template { name: "研究助理", description: "上網找資料、整理重點、附上來源", instructions: "先釐清問題，再用 web_fetch 或瀏覽器找至少兩個可靠來源。回答先給結論，再列重點，每個重點附來源網址。不確定的地方直接說不確定。", shape: "circle", color: "green" },
    Template { name: "寫作夥伴", description: "幫你構思、改寫和潤稿", instructions: "先問清楚讀者和語氣。改稿時保留作者的意思，列出改了什麼和為什麼。用繁體中文、台灣用語。", shape: "cloud", color: "purple" },
    Template { name: "電腦助手", description: "在 Bot 的電腦上跑指令、整理檔案、操作網頁", instructions: "預設在「Bot 的電腦」上做事。動手前先看清楚（list_dir、read_file、截圖），每一步確認結果。要動到使用者的 Mac 時先說明要做什麼。", shape: "gem", color: "blue" },
    Template { name: "客服助理", description: "在 Slack、Discord、Telegram 或 Teams 回覆客人", instructions: "回答簡短、有禮貌。不確定的事不要編，說會請同事確認。不要透露內部資料或使用者的私人資訊。", shape: "pill", color: "orange" },
    Template { name: "開發助手", description: "看程式、跑測試、追 GitHub 上的事", instructions: "改程式前先讀相關檔案和測試。每次修改後跑測試，回報結果。PR 或 CI 的事件來時，先看紀錄再下結論。", shape: "hexagon", color: "black" },
];

/// Add a memory (no duplicates; the oldest drop off past the limit).
pub fn remember(list: &mut Vec<String>, fact: &str) -> Result<String, String> {
    let f: String = fact.trim().chars().take(MAX_MEMORY_CHARS).collect();
    if f.is_empty() {
        return Err("要記住什麼？".into());
    }
    if list.iter().any(|m| m == &f) {
        return Ok(format!("已經記得：{f}"));
    }
    list.push(f.clone());
    let n = list.len();
    if n > MAX_MEMORIES {
        list.drain(..n - MAX_MEMORIES);
    }
    Ok(format!("記住了：{f}"))
}

/// Forget by number (1-based) or by text it contains.
pub fn forget(list: &mut Vec<String>, what: &str) -> Result<String, String> {
    let w = what.trim();
    let idx = match w.parse::<usize>() {
        Ok(n) if n >= 1 && n <= list.len() => Some(n - 1),
        _ => list.iter().position(|m| !w.is_empty() && m.contains(w)),
    };
    match idx {
        Some(i) => Ok(format!("忘記了：{}", list.remove(i))),
        None => Err(format!("沒有記得「{w}」這件事")),
    }
}

pub fn prompt_section(memories: &[String], skills: &[Skill]) -> String {
    let mut s = String::new();
    if !memories.is_empty() {
        s.push_str("\n\n你記得的事（使用者要你記住的；用 remember 新增、forget 刪除）：\n");
        for (i, m) in memories.iter().enumerate() {
            s.push_str(&format!("{}. {m}\n", i + 1));
        }
    } else {
        s.push_str("\n\n使用者說「記住…」「以後都…」時，用 remember 記下來；說「忘記…」時用 forget。");
    }
    if !skills.is_empty() {
        s.push_str("\n\n可用的技能（做法說明；需要時先用 use_skill 讀取完整內容再照做）：\n");
        for k in skills {
            s.push_str(&format!("- {}：{}\n", k.name, k.description));
        }
    }
    s.push_str("\n使用者教你一套可以重複用的做法時，可以用 save_skill 存成技能，所有 Bot 都能用。");
    s
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn remember_and_forget() {
        let mut m = vec![];
        assert!(remember(&mut m, "我喜歡靠窗的座位").unwrap().starts_with("記住了"));
        assert!(remember(&mut m, "我喜歡靠窗的座位").unwrap().starts_with("已經記得"));
        remember(&mut m, "週五不開會").unwrap();
        assert_eq!(forget(&mut m, "1").unwrap(), "忘記了：我喜歡靠窗的座位");
        assert!(forget(&mut m, "不存在").is_err());
        assert_eq!(forget(&mut m, "週五").unwrap(), "忘記了：週五不開會");
        for i in 0..(MAX_MEMORIES + 5) {
            remember(&mut m, &format!("事 {i}")).unwrap();
        }
        assert_eq!(m.len(), MAX_MEMORIES);
        assert_eq!(m[0], "事 5");
        let p = prompt_section(&m[..1], &[Skill { name: "週報".into(), description: "整理每週進度".into(), instructions: "…".into() }]);
        assert!(p.contains("1. 事 5") && p.contains("- 週報：整理每週進度"));
    }
}