package engine

// Dream 巩固提示词构建器.
//
// 升华改进(ELEVATED): 早期方案 构建叙事式 4 阶段提示词,
// 让 Dream SubAgent 用真实工具(ls,grep,Edit,Write)自主完成记忆整理.
// 我们的旧版(已删除)用 JSON-ops 格式(让模型输出 [{"op":"update",...}]),
// 存在根本性缺陷:模型无法访问 transcript 文件,Phase 2(Gather)完全失效.
// 新版恢复早期方案设计:叙事式提示词 + SubAgent-with-tools,模型可以自主 grep 历史.
//
// 关键常量:
//   - IndexFile:记忆目录的索引文件名(MEMORY.md),与 memory.Store.UpdateIndex 一致
//   - MaxIndexLines:索引截断上限(与 memory.TruncateIndex 保持一致)

import (
	"fmt"
	"strings"
)

// IndexFile 是记忆目录的入口索引文件名.
// 与 pkg/memory 包的 UpdateIndex 逻辑保持一致(同文件名).
const IndexFile = "MEMORY.md"

// MaxIndexLines 是索引文件的行数上限(超过则截断).
// 与 memory.TruncateIndex 的 maxIndexLines 常量保持一致:200 行 / 25KB.
const MaxIndexLines = 200

// BuildConsolidationPrompt 构建发送给 Dream SubAgent 的四阶段巩固提示词.
//
// 参数:
//   - memoryRoot:记忆目录的绝对路径(SubAgent 的 Edit/Write 限于此目录)
//   - transcriptDir:会话 transcript 文件目录(空 = 跳过 Grep transcript 提示)
//   - sessionIDs:自上次巩固以来的会话 ID 列表(可选,用于提示词 hint;nil = 不提供)
//
// SubAgent 使用的工具:
//   - Bash(只读命令:ls/find/grep/cat/stat/head/tail)
//   - Read,Glob,Grep(探索记忆和 transcript)
//   - Edit,Write(只允许写入 memoryRoot 目录)
func BuildConsolidationPrompt(memoryRoot, transcriptDir string, sessionIDs []string) string {
	var sb strings.Builder

	sb.WriteString("# Dream: Memory Consolidation\n\n")
	sb.WriteString("You are performing a dream — a reflective pass over your memory files. ")
	sb.WriteString("Synthesize what you've learned recently into durable, well-organized memories ")
	sb.WriteString("so that future sessions can orient quickly.\n\n")

	sb.WriteString(fmt.Sprintf("Memory directory: `%s`\n", memoryRoot))
	sb.WriteString(fmt.Sprintf(
		"If the directory does not exist yet, create it with `mkdir -p %s` before writing.\n\n",
		memoryRoot,
	))

	// Transcript 目录(可选)
	if transcriptDir != "" {
		sb.WriteString(fmt.Sprintf("Session transcripts: `%s`\n", transcriptDir))
		sb.WriteString("(Large JSONL files — grep narrowly, **do not** read whole files.)\n\n")
	}

	sb.WriteString("---\n\n")

	// Phase 1 - Orient
	sb.WriteString("## Phase 1 — Orient\n\n")
	sb.WriteString(fmt.Sprintf("- `ls` the memory directory to see what already exists\n"))
	sb.WriteString(fmt.Sprintf("- Read `%s` to understand the current index\n", IndexFile))
	sb.WriteString("- Skim existing topic files so you improve them rather than creating duplicates\n\n")

	// Phase 2 - Gather
	sb.WriteString("## Phase 2 — Gather recent signal\n\n")
	sb.WriteString("Look for new information worth persisting. Sources in rough priority order:\n\n")
	sb.WriteString("1. **Existing memories that drifted** — facts that contradict the current codebase\n")

	if transcriptDir != "" {
		sb.WriteString(fmt.Sprintf(
			"2. **Transcript search** — grep the JSONL transcripts for narrow terms:\n"+
				"   `grep -rn \"<term>\" %s/ --include=\"*.jsonl\" | tail -50`\n"+
				"   Don't exhaustively read transcripts. Look only for things you already suspect matter.\n",
			transcriptDir,
		))
	}

	sb.WriteString("\n")

	// Phase 3 - Consolidate
	sb.WriteString("## Phase 3 — Consolidate\n\n")
	sb.WriteString("For each thing worth remembering, write or update a memory file at the top level of ")
	sb.WriteString("the memory directory. Use the memory file format and type conventions from your ")
	sb.WriteString("system prompt's auto-memory section — it's the source of truth for what to save, ")
	sb.WriteString("how to structure it, and what NOT to save.\n\n")
	sb.WriteString("Focus on:\n")
	sb.WriteString("- Merging new signal into existing topic files rather than creating near-duplicates\n")
	sb.WriteString("- Converting relative dates (\"yesterday\", \"last week\") to absolute dates\n")
	sb.WriteString("- Deleting contradicted facts — if today's investigation disproves an old memory, fix it at the source\n\n")

	// Phase 4 - Prune and index
	sb.WriteString("## Phase 4 — Prune and index\n\n")
	sb.WriteString(fmt.Sprintf(
		"Update `%s` so it stays under %d lines AND under ~25KB. ",
		IndexFile, MaxIndexLines,
	))
	sb.WriteString("It's an **index**, not a dump — each entry should be one line under ~150 characters: ")
	sb.WriteString("`- [Title](file.md) — one-line hook`. Never write memory content directly into it.\n\n")
	sb.WriteString("- Remove pointers to memories that are now stale, wrong, or superseded\n")
	sb.WriteString("- Demote verbose entries: if an index line is over ~200 chars, move the detail to the topic file\n")
	sb.WriteString("- Add pointers to newly important memories\n")
	sb.WriteString("- Resolve contradictions — if two files disagree, fix the wrong one\n\n")

	sb.WriteString("---\n\n")
	sb.WriteString("Return a brief summary of what you consolidated, updated, or pruned. ")
	sb.WriteString("If nothing changed (memories are already tight), say so.")

	// 额外上下文:会话列表 hint
	if len(sessionIDs) > 0 {
		sb.WriteString(fmt.Sprintf(
			"\n\n## Additional context\n\n**Tool constraints for this run:** "+
				"Bash is restricted to read-only commands (`ls`, `find`, `grep`, `cat`, `stat`, "+
				"`wc`, `head`, `tail`, and similar). Anything that writes, redirects to a file, "+
				"or modifies state will be denied.\n\n"+
				"Sessions since last consolidation (%d):\n",
			len(sessionIDs),
		))
		for _, id := range sessionIDs {
			sb.WriteString(fmt.Sprintf("- %s\n", id))
		}
	}

	return sb.String()
}