package runtime

import (
	"strings"

	"agent-system-backend/internal/vision"
	core "agent-system-core"
)

// SecretLookup 由组合根注入。layer 是 owner 或 system。没有独立密钥时 ok 为 false，调用方用设置里的旧字段。
var SecretLookup func(owner, service string) (value, layer string, ok bool)

// LookupSecret 给组合根以外的调用方使用。owner 为空时用 local。
func LookupSecret(owner, service, fallback string) string {
	value, _ := overlayKey(owner, service, fallback)
	return value
}

func overlayKey(owner, service, fallback string) (string, string) {
	if SecretLookup == nil {
		return fallback, "settings"
	}
	if owner == "" {
		owner = "local"
	}
	if v, layer, ok := SecretLookup(owner, service); ok && strings.TrimSpace(v) != "" {
		if layer == "" {
			layer = "owner"
		}
		return v, layer
	}
	return fallback, "settings"
}

// 模型路由解析（4.7 / 4.9 覆盖链）：设置层 defaults → system → user → project，
// 画像 ModelRoute 为会话内最高层覆盖（kind 为空回落设置层主模型）。
// 端点与密钥按 kind 独立配置，轻量档空则回落主档。

// ContextInjection 是一条条件注入，由 runmgr 从存储读出，组装时再转换成 ctxasm 的形状。
type ContextInjection struct {
	Keys        []string
	Secondary   string
	Logic       string
	Content     string
	Constant    bool
	ScanDepth   int
	BudgetChars int
}

// ResolvedModel 是一次路由解析的结果。
type ResolvedModel struct {
	Kind      string // chat | lightweight
	Model     string
	Base      string
	Key       string
	KeySource string // owner | system | settings
}

// ResolveChatModel 解析主对话模型（画像 route > 设置层）。
func ResolveChatModel(prof core.AgentProfile, eff core.EffectiveSettings) ResolvedModel {
	m := eff.GetString("models.chat.model", "")
	if prof.Model.Chat != "" {
		m = prof.Model.Chat
	}
	key, source := overlayKey(prof.Owner, "models.chat", eff.GetString("models.chat.apiKey", ""))
	return ResolvedModel{Kind: "chat", Model: m,
		Base: eff.GetString("models.chat.baseUrl", ""), Key: key, KeySource: source}
}

// ResolveVisionModel 在当前轮含图片时核对视觉清单。清单内的模型保持原选择；
// 不在清单内则这一轮改用 models.vision.model，端点和密钥仍沿用主模型。
// 没有图片时与 ResolveChatModel 相同。
func ResolveVisionModel(prof core.AgentProfile, eff core.EffectiveSettings, hasImages bool) ResolvedModel {
	chat := ResolveChatModel(prof, eff)
	if !hasImages || modelCapable(chat.Model, VisionCapable(eff)) {
		return chat
	}
	name := strings.TrimSpace(eff.GetString("models.vision.model", ""))
	if name == "" {
		name = vision.DefaultVisionModel
	}
	if name == chat.Model {
		return chat
	}
	chat.Model = name
	return chat
}

// VisionCapable 解析 models.vision.capable。空字符串用内置默认清单。
func VisionCapable(eff core.EffectiveSettings) []string {
	raw := strings.TrimSpace(eff.GetString("models.vision.capable", ""))
	if raw == "" {
		raw = vision.DefaultVisionCapable
	}
	return splitModelList(raw)
}

func modelCapable(name string, capable []string) bool {
	name = strings.TrimSpace(name)
	if name == "" {
		return false
	}
	for _, item := range capable {
		if item == name {
			return true
		}
	}
	return false
}

func splitModelList(raw string) []string {
	var out []string
	seen := map[string]bool{}
	for _, part := range strings.Split(raw, ",") {
		name := strings.TrimSpace(part)
		if name == "" || seen[name] {
			continue
		}
		seen[name] = true
		out = append(out, name)
	}
	return out
}

// ChatFallbacks 解析 models.chat.fallbacks。默认空，不改变现有模型选择。
func ChatFallbacks(eff core.EffectiveSettings) []string {
	return splitModelList(eff.GetString("models.chat.fallbacks", ""))
}

// ChatFallbacksFor 在图片轮只保留视觉清单内的回退模型，避免退到不能看图的模型。
func ChatFallbacksFor(eff core.EffectiveSettings, hasImages bool) []string {
	all := ChatFallbacks(eff)
	if !hasImages {
		return all
	}
	capable := VisionCapable(eff)
	var out []string
	for _, name := range all {
		if modelCapable(name, capable) {
			out = append(out, name)
		}
	}
	return out
}

// ResolveLightweightModel 解析轻量模型：画像 route > 设置层轻量档 > 回落主档。
func ResolveLightweightModel(prof core.AgentProfile, eff core.EffectiveSettings) ResolvedModel {
	m := eff.GetString("models.lightweight.model", "")
	base := eff.GetString("models.lightweight.baseUrl", "")
	key, source := overlayKey(prof.Owner, "models.lightweight", eff.GetString("models.lightweight.apiKey", ""))
	if prof.Model.Lightweight != "" {
		m = prof.Model.Lightweight
	}
	if m == "" || base == "" {
		// 回落主档（模型与端点分别回落，允许轻量仅覆盖模型名）。
		chat := ResolveChatModel(prof, eff)
		if m == "" {
			m = chat.Model
		}
		if base == "" {
			base, key, source = chat.Base, chat.Key, chat.KeySource
		}
	}
	return ResolvedModel{Kind: "lightweight", Model: m, Base: base, Key: key, KeySource: source}
}