package daemon

import (
	"fmt"
	"strings"

	"github.com/multica-ai/multica/server/internal/daemon/execenv"
)

// BuildPrompt constructs the task prompt for an agent CLI.
// Keep this minimal — detailed instructions live in CLAUDE.md / AGENTS.md
// injected by execenv.InjectRuntimeConfig.
func BuildPrompt(task Task) string {
	if task.ChatSessionID != "" {
		return buildChatPrompt(task)
	}
	if task.TriggerCommentID != "" {
		return buildCommentPrompt(task)
	}
	if task.AutopilotRunID != "" {
		return buildAutopilotPrompt(task)
	}
	if task.QuickCreatePrompt != "" {
		return buildQuickCreatePrompt(task)
	}
	var b strings.Builder
	b.WriteString("You are running as a local coding agent for a Multica workspace.\n\n")
	fmt.Fprintf(&b, "Your assigned issue ID is: %s\n\n", task.IssueID)
	fmt.Fprintf(&b, "Start by running `multica issue get %s --output json` to understand your task, then complete it.\n", task.IssueID)
	fmt.Fprintf(&b, "If you need comment history, `multica issue comment list %s` returns the latest 50 by default — pass --limit or --since to scope older windows. Long issues can have thousands of comments; do not fetch everything blindly.\n", task.IssueID)
	return b.String()
}

// buildQuickCreatePrompt constructs a prompt for quick-create tasks. The
// user typed a single natural-language sentence in the create-issue modal;
// the agent's job is to translate it into one `multica issue create` CLI
// invocation, using its judgment to decide whether fetching referenced URLs
// would produce a better issue. No issue exists yet, so the agent must NOT
// call `multica issue get` or attempt to comment — there's nothing to read
// or reply to.
func buildQuickCreatePrompt(task Task) string {
	var b strings.Builder
	b.WriteString("You are running as a quick-create assistant for a Multica workspace.\n\n")
	b.WriteString("A user captured the following input via the quick-create modal. There is NO existing issue. Your job is to create a well-formed issue from this input with a single `multica issue create` command.\n\n")
	fmt.Fprintf(&b, "User input:\n> %s\n\n", task.QuickCreatePrompt)

	b.WriteString("Field rules:\n\n")

	// title
	b.WriteString("- **title**: required. A concise but semantically rich summary. If the input references external resources (PRs, issues, URLs), use your judgment on whether fetching the resource would produce a meaningfully better title — e.g. \"review PR #123\" → \"Review PR #123: Refactor auth module to OAuth2\". Strip filler words but preserve key semantic information.\n\n")

	// description — the core optimization
	b.WriteString("- **description**: The description is the executing agent's primary context. Aim for high fidelity — they should grasp the user's intent as if they had read the raw input themselves. Use a two-section structure:\n\n")
	b.WriteString("  1. **User request** — Faithfully restate what the user wants in their own words. Preserve specific names, identifiers, file paths, code snippets, and technical terms verbatim. Strip non-spec material before writing it (this is removal, not paraphrasing): verbal routing wrappers about creating the issue (e.g. \"create an issue\", \"分配给 X\") and pure conversational fillers (e.g. \"对吧？\"). When in doubt, keep it.\n\n")
	b.WriteString("     CC exception: `multica issue create` has no `--subscriber` flag, and the platform auto-subscribes members whose `[@Name](mention://member/<uuid>)` link appears in the description. When the user wrote \"cc @Y\", strip the verbal \"cc\" wrapper from the User request body and append a final `CC: <mention link(s)>` line to the description so the cc routing still fires.\n\n")
	b.WriteString("  2. **Context** — include ONLY when the input cited external resources AND you successfully fetched them AND they produced verifiable facts worth recording. Summarize facts only (e.g. \"PR #45 changes auth to JWT\"), not interpretation or unsolicited reference implementations. If you have nothing factual to add, omit the section entirely — never use it as an apology log for resources you could not fetch.\n\n")
	b.WriteString("  Hard rules: never invent requirements, implementation details, or acceptance criteria the user did not express; never reduce multi-sentence input to a single vague sentence; never echo the title.\n\n")

	// priority
	b.WriteString("- **priority**: one of `urgent`, `high`, `medium`, `low`, or omit. Map P0/P1 → urgent/high; \"asap\" → urgent. If unspecified, omit.\n\n")

	// assignee
	b.WriteString("- **assignee**:\n")
	b.WriteString("    - When the user names someone (\"assign to X\" / \"@X\"), call `multica workspace members --output json` (and `multica agent list --output json` if it might be an agent) and find the matching entity by display name. On a clean unambiguous match, prefer `--assignee-id <uuid>` using the `user_id` (member) or `id` (agent) from that JSON — UUID matching is exact and robust to name collisions in workspaces with overlapping names. `--assignee <name>` (fuzzy) is acceptable as a fallback when names are unambiguous. On no match or ambiguous match, do NOT pass either flag — instead append a final line to the description: `Unrecognized assignee: X`.\n")
	agentID := ""
	agentName := ""
	if task.Agent != nil {
		agentID = task.Agent.ID
		agentName = task.Agent.Name
	}
	if agentID != "" {
		fmt.Fprintf(&b, "    - When the user did NOT name an assignee, default to YOURSELF: pass `--assignee-id %q` (your agent UUID). The picker agent is the expected owner because the user opened quick-create with you selected — never leave the issue unassigned. Use the UUID flag, not `--assignee <name>`, so the assignment is unambiguous even when other agents share part of your name.\n\n", agentID)
	} else if agentName != "" {
		fmt.Fprintf(&b, "    - When the user did NOT name an assignee, default to YOURSELF: pass `--assignee %q`. The picker agent is the expected owner because the user opened quick-create with you selected — never leave the issue unassigned.\n\n", agentName)
	} else {
		b.WriteString("    - When the user did NOT name an assignee, default to YOURSELF (the picker agent): pass `--assignee-id <your agent UUID>` (preferred) or `--assignee <your agent name>`. Never leave the issue unassigned.\n\n")
	}

	// fields to omit
	b.WriteString("- **project**: omit. The platform will route the issue to the workspace default.\n")
	b.WriteString("- **status**: omit (defaults to `todo`).\n")
	b.WriteString("- **attachments**: do NOT pass `--attachment`. The flag only accepts LOCAL file paths. Any image URL in the user input is already markdown — keep it inline in `--description` instead.\n\n")

	// output format
	b.WriteString("Output format:\n")
	b.WriteString("- Run exactly one `multica issue create` invocation. Do not retry for any reason — even on non-zero exit. The issue may already exist; another attempt would create a duplicate.\n")
	b.WriteString("- After success, print exactly one line: `Created MUL-<n>: <title>` and exit. No commentary, no follow-up tool calls.\n")
	b.WriteString("- Do NOT call `multica issue get` or `multica issue comment add` — there is no issue to query or comment on.\n")
	b.WriteString("- On CLI error, exit with the error as the only output. The platform writes a failure notification automatically.\n")
	return b.String()
}

// buildCommentPrompt constructs a prompt for comment-triggered tasks.
// The triggering comment content is embedded directly so the agent cannot
// miss it, even when stale output files exist in a reused workdir.
// The reply instructions (including the current TriggerCommentID as --parent)
// are re-emitted on every turn so resumed sessions cannot carry forward a
// previous turn's --parent UUID.
func buildCommentPrompt(task Task) string {
	var b strings.Builder
	b.WriteString("You are running as a local coding agent for a Multica workspace.\n\n")
	fmt.Fprintf(&b, "Your assigned issue ID is: %s\n\n", task.IssueID)
	if task.TriggerCommentContent != "" {
		authorLabel := "A user"
		if task.TriggerAuthorType == "agent" {
			name := task.TriggerAuthorName
			if name == "" {
				name = "another agent"
			}
			authorLabel = fmt.Sprintf("Another agent (%s)", name)
		}
		fmt.Fprintf(&b, "[NEW COMMENT] %s just left a new comment. Focus on THIS comment — do not confuse it with previous ones:\n\n", authorLabel)
		fmt.Fprintf(&b, "> %s\n\n", task.TriggerCommentContent)
		if task.TriggerAuthorType == "agent" {
			b.WriteString("⚠️ The triggering comment was posted by another agent. Decide whether a reply is warranted. If you produced actual work this turn (investigated, fixed something, answered a real question), post the result as a normal reply — that is NOT a noise comment, and the standard rule that final results must be delivered via comment still applies. If the triggering comment was a pure acknowledgment, thanks, or sign-off AND you produced no work this turn, do NOT reply — and do NOT post a comment saying 'No reply needed' or similar. Simply exit with no output. Silence is the preferred way to end agent-to-agent threads. If you do reply, do not @mention the other agent as a sign-off (that re-triggers them and starts a loop).\n\n")
		}
	}
	fmt.Fprintf(&b, "Start by running `multica issue get %s --output json` to understand your task, then decide how to proceed.\n\n", task.IssueID)
	fmt.Fprintf(&b, "If you need comment history, `multica issue comment list %s` returns the latest 50 by default — pass --limit or --since to scope older windows. Long issues can have thousands of comments; do not fetch everything blindly.\n\n", task.IssueID)
	b.WriteString(execenv.BuildCommentReplyInstructions(task.IssueID, task.TriggerCommentID))
	return b.String()
}

// buildChatPrompt constructs a prompt for interactive chat tasks.
func buildChatPrompt(task Task) string {
	var b strings.Builder
	b.WriteString("You are running as a chat assistant for a Multica workspace.\n")
	b.WriteString("A user is chatting with you directly. Respond to their message.\n\n")
	fmt.Fprintf(&b, "User message:\n%s\n", task.ChatMessage)
	return b.String()
}

// buildAutopilotPrompt constructs a prompt for run_only autopilot tasks.
func buildAutopilotPrompt(task Task) string {
	var b strings.Builder
	b.WriteString("You are running as a local coding agent for a Multica workspace.\n\n")
	b.WriteString("This task was triggered by an Autopilot in run-only mode. There is no assigned Multica issue for this run.\n\n")
	fmt.Fprintf(&b, "Autopilot run ID: %s\n", task.AutopilotRunID)
	if task.AutopilotID != "" {
		fmt.Fprintf(&b, "Autopilot ID: %s\n", task.AutopilotID)
	}
	if task.AutopilotTitle != "" {
		fmt.Fprintf(&b, "Autopilot title: %s\n", task.AutopilotTitle)
	}
	if task.AutopilotSource != "" {
		fmt.Fprintf(&b, "Trigger source: %s\n", task.AutopilotSource)
	}
	if strings.TrimSpace(string(task.AutopilotTriggerPayload)) != "" {
		fmt.Fprintf(&b, "Trigger payload:\n%s\n", strings.TrimSpace(string(task.AutopilotTriggerPayload)))
	}
	b.WriteString("\nAutopilot instructions:\n")
	if strings.TrimSpace(task.AutopilotDescription) != "" {
		b.WriteString(task.AutopilotDescription)
		b.WriteString("\n\n")
	} else if task.AutopilotTitle != "" {
		fmt.Fprintf(&b, "%s\n\n", task.AutopilotTitle)
	} else {
		b.WriteString("No additional autopilot instructions were provided. Inspect the autopilot configuration before proceeding.\n\n")
	}
	if task.AutopilotID != "" {
		fmt.Fprintf(&b, "Start by running `multica autopilot get %s --output json` if you need the full autopilot configuration, then complete the instructions above.\n", task.AutopilotID)
	} else {
		b.WriteString("Complete the instructions above.\n")
	}
	b.WriteString("Do not run `multica issue get`; this run does not have an issue ID.\n")
	return b.String()
}