package gateway

import (
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	"gopkg.in/yaml.v3"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/auth"
	apperr "git.yeij.top/AskaEth/Cyrene_v2/internal/errors"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/persona/loader"
	personareg "git.yeij.top/AskaEth/Cyrene_v2/internal/persona/registry"
)

// 人格到身份与 API key 的管理写操作（仅 owner，带审计）。人格
// 写操作注册进人格注册表（真实的运行时效果），并持久化
// 一个 YAML 文件使其在重启后存活；API key 在
// auth.APIKey 存储中铸造/吊销。

const personaDir = "configs/personas"

// personaUpsertRequest 是 POST/PUT /api/v1/admin/personas 的请求体。
type personaUpsertRequest struct {
	ID           string   `json:"id"`
	Name         string   `json:"name"`
	CharacterRef string   `json:"characterRef"`
	Role         string   `json:"role"`
	SystemPrompt string   `json:"systemPrompt"`
	Personality  string   `json:"personality"`
	SpeechStyle  string   `json:"speechStyle"`
	Catchphrase  string   `json:"catchphrase"`
	Background   string   `json:"background"`
	Values       []string `json:"values"`
	Modes        []string `json:"modes"`
	Mode         string   `json:"mode"`
	MemoryNS     string   `json:"memoryNamespace"`
	// Thinking 是可选的推理/呈现块（design/01 §2.1）。它
	// 原样持久化进人格 YAML；更新时省略它会保留
	// 已存块（见 adminUpdatePersona）。
	Thinking *personaThinkingRequest `json:"thinking,omitempty"`
}

// personaThinkingRequest 是人格 `thinking` 段的线上形式。
// 其指针/命名与 YAML 一致，使面板能原样往返。
type personaThinkingRequest struct {
	BudgetTokens int    `json:"budgetTokens,omitempty"`
	Effort       string `json:"effort,omitempty"`
	ShowToUser   *bool  `json:"showToUser,omitempty"`
	Mode         string `json:"mode,omitempty"`
}

// adminCreatePersona 在注册表中注册一个新人格（真实的运行时
// 效果），并持久化进人格 YAML 库使其在重启后存活。
func (s *Server) adminCreatePersona(w http.ResponseWriter, r *http.Request) {
	var req personaUpsertRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "invalid request body"))
		return
	}
	if strings.TrimSpace(req.ID) == "" || strings.TrimSpace(req.Name) == "" || strings.TrimSpace(req.Role) == "" {
		s.auditClaims(r, "persona.create", "error")
		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "id, name and role are required"))
		return
	}
	reg, ok := s.personas.(*personareg.Registry)
	if !ok {
		s.auditClaims(r, "persona.create", "error")
		writeError(w, apperr.Wrap(apperr.ErrInternal, "persona_unavailable", "persona registry is not configured"))
		return
	}
	if _, exists := reg.Persona(req.ID); exists {
		s.auditClaims(r, "persona.create", "error")
		writeError(w, &apperr.AppError{Code: "duplicate", Message: "人格已存在，请使用编辑", HTTPCode: http.StatusConflict})
		return
	}
	p := personaFromRequest(req)
	if err := p.ValidateThinking(); err != nil {
		s.auditClaims(r, "persona.create", "error")
		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "invalid thinking config: %v", err))
		return
	}
	if err := savePersonaYAML(p); err != nil {
		s.auditClaims(r, "persona.create", "error")
		s.log.Error("persona persist", "id", req.ID, "err", err)
		writeError(w, apperr.Wrap(apperr.ErrInternal, "persona_persist_failed", "failed to persist persona"))
		return
	}
	if err := reg.RegisterPersona(p); err != nil {
		s.auditClaims(r, "persona.create", "error")
		writeError(w, apperr.Wrap(apperr.ErrInternal, "persona_register_failed", "failed to register persona"))
		return
	}
	if err := reg.RegisterCharacter(characterFromRequest(req)); err != nil {
		s.auditClaims(r, "persona.create", "error")
		writeError(w, apperr.Wrap(apperr.ErrInternal, "persona_register_failed", "failed to register character"))
		return
	}
	s.auditClaims(r, "persona.create", "ok")
	writeJSON(w, http.StatusCreated, s.personaSummaryOf(p, characterFromRequest(req)))
}

// adminUpdatePersona 编辑既有人格，持久化 YAML 并
// 替换内存中的人格/角色。
func (s *Server) adminUpdatePersona(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	var req personaUpsertRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "invalid request body"))
		return
	}
	if strings.TrimSpace(req.Name) == "" || strings.TrimSpace(req.Role) == "" {
		s.auditClaims(r, "persona.update", "error")
		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "name and role are required"))
		return
	}
	req.ID = id
	reg, ok := s.personas.(*personareg.Registry)
	if !ok {
		s.auditClaims(r, "persona.update", "error")
		writeError(w, apperr.Wrap(apperr.ErrInternal, "persona_unavailable", "persona registry is not configured"))
		return
	}
	if _, exists := reg.Persona(id); !exists {
		s.auditClaims(r, "persona.update", "error")
		writeError(w, apperr.Wrap(apperr.ErrNotFound, "not_found", "persona %q not found", id))
		return
	}
	p := personaFromRequest(req)
	if err := p.ValidateThinking(); err != nil {
		s.auditClaims(r, "persona.update", "error")
		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "invalid thinking config: %v", err))
		return
	}
	// 不认识可选 `thinking` 块的客户端（旧面板、脚本）会省略它；
	// 应保留已存的那个，而不是静默清掉手工编辑的
	// 配置。发送该对象则替换它，全字段为默认值
	// 时清除它。
	p.Thinking = applyThinkingEdit(req.Thinking, existingPersona(reg, id))
	if err := savePersonaYAML(p); err != nil {
		s.auditClaims(r, "persona.update", "error")
		s.log.Error("persona persist", "id", id, "err", err)
		writeError(w, apperr.Wrap(apperr.ErrInternal, "persona_persist_failed", "failed to persist persona"))
		return
	}
	if err := reg.UpdatePersona(p); err != nil {
		s.auditClaims(r, "persona.update", "error")
		writeError(w, apperr.Wrap(apperr.ErrInternal, "persona_update_failed", "failed to update persona"))
		return
	}
	if err := reg.UpdateCharacter(characterFromRequest(req)); err != nil {
		s.auditClaims(r, "persona.update", "error")
		writeError(w, apperr.Wrap(apperr.ErrInternal, "persona_update_failed", "failed to update character"))
		return
	}
	s.auditClaims(r, "persona.update", "ok")
	writeJSON(w, http.StatusOK, s.personaSummaryOf(p, characterFromRequest(req)))
}

// adminCreateUser 诚实作答：既没有持久化用户表，也没有
// 可供支撑的用户认证登录（部署形态是来自 .env 的单个管理
// 账号加运行时 API key；design/11 是单用户优先），因此
// 创建用户会是一行没人能登录的记录。它报告缺失的
// 存储，而不是编造一个用户。
func (s *Server) adminCreateUser(w http.ResponseWriter, r *http.Request) {
	s.auditClaims(r, "user.create", "error")
	writeError(w, &apperr.AppError{
		Code:     "not_implemented",
		Message:  "新增用户/角色未实现：无用户表，登录仅用 .env 单 admin（ADMIN_USERNAME/PASSWORD），角色为 owner>admin>viewer 常量；多用户存储与登录接入需先设计（design/11 单用户为主）",
		HTTPCode: http.StatusNotImplemented,
	})
}

// apiKeyIssueRequest 是 POST /api/v1/admin/users/apikey 的请求体。
type apiKeyIssueRequest struct {
	Role string `json:"role"`
}

// adminIssueApiKey 铸造一个绑定到某角色的真实 API key，并返回一次
// 明文（唯一可见的一次）。响应中的 id 是管理列表所展示的
// 脱敏形式，因此之后可用它吊销该 key。
func (s *Server) adminIssueApiKey(w http.ResponseWriter, r *http.Request) {
	var req apiKeyIssueRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "invalid request body"))
		return
	}
	role, err := auth.ParseRole(req.Role)
	if err != nil {
		s.auditClaims(r, "apikey.issue", "error")
		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "invalid role"))
		return
	}
	keys, ok := s.users.(*auth.APIKey)
	if !ok {
		s.auditClaims(r, "apikey.issue", "error")
		writeError(w, apperr.Wrap(apperr.ErrInternal, "users_unavailable", "用户服务未配置"))
		return
	}
	key, err := keys.Generate(role)
	if err != nil {
		s.auditClaims(r, "apikey.issue", "error")
		writeError(w, apperr.Wrap(apperr.ErrInternal, "apikey_failed", "failed to issue api key"))
		return
	}
	s.auditClaims(r, "apikey.issue", "ok")
	writeJSON(w, http.StatusCreated, map[string]any{"id": auth.MaskKey(key), "key": key, "role": string(role)})
}

// adminRevokeApiKey 按脱敏 id（管理列表返回的标识）吊销一个
// key。没有 key 携带该掩码时报告 not-found。
func (s *Server) adminRevokeApiKey(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	keys, ok := s.users.(*auth.APIKey)
	if !ok {
		s.auditClaims(r, "apikey.revoke", "error")
		writeError(w, apperr.Wrap(apperr.ErrInternal, "users_unavailable", "用户服务未配置"))
		return
	}
	if !keys.RevokeByMask(id) {
		s.auditClaims(r, "apikey.revoke", "error")
		writeError(w, apperr.Wrap(apperr.ErrNotFound, "not_found", "api key not found"))
		return
	}
	s.auditClaims(r, "apikey.revoke", "ok")
	writeJSON(w, http.StatusOK, map[string]any{"id": id, "revoked": true})
}

// personaFromRequest 从 upsert 请求构建 loader.Persona，在省略时
// 填入派生的 system prompt/characterRef，使最小创建也能通过校验。
func personaFromRequest(req personaUpsertRequest) *loader.Persona {
	systemPrompt := strings.TrimSpace(req.SystemPrompt)
	if systemPrompt == "" {
		systemPrompt = fmt.Sprintf("你是 %s，按角色人设 %q 与主人交流。", req.Name, req.Role)
	}
	characterRef := strings.TrimSpace(req.CharacterRef)
	if characterRef == "" {
		characterRef = req.ID
	}
	return &loader.Persona{
		ID:           req.ID,
		Name:         req.Name,
		CharacterRef: characterRef,
		Identity:     loader.Identity{Role: req.Role, SystemPrompt: systemPrompt},
		Personality:  req.Personality,
		SpeechStyle:  req.SpeechStyle,
		Catchphrase:  req.Catchphrase,
		Background:   req.Background,
		Values:       req.Values,
		Emotion:      loader.EmotionParams{MemoryNamespace: strings.TrimSpace(req.MemoryNS)},
		Thinking:     thinkingFromRequest(req.Thinking),
	}
}

// thinkingFromRequest 把线上 `thinking` 块映射到人格字段；
// 块缺失得到零值，yaml.Marshal 会完全省略它。
func thinkingFromRequest(req *personaThinkingRequest) loader.ThinkingParams {
	if req == nil {
		return loader.ThinkingParams{}
	}
	return loader.ThinkingParams{
		BudgetTokens: req.BudgetTokens,
		Effort:       strings.TrimSpace(req.Effort),
		ShowToUser:   req.ShowToUser,
		Mode:         strings.TrimSpace(req.Mode),
	}
}

// existingPersona 返回 id 对应的已存人格，不存在时为 nil。
func existingPersona(reg *personareg.Registry, id string) *loader.Persona {
	if p, ok := reg.Persona(id); ok {
		return p
	}
	return nil
}

// applyThinkingEdit 返回更新应持久化的 `thinking` 块：请求自带
// 块时用请求的，否则用已存人格的块 ——
// 因此不认识该可选字段的客户端绝不可能清掉它。发送
// 该对象的更新会直接替换整块（全默认字段则清除它）。
func applyThinkingEdit(req *personaThinkingRequest, existing *loader.Persona) loader.ThinkingParams {
	if req != nil {
		return thinkingFromRequest(req)
	}
	if existing != nil {
		return existing.Thinking
	}
	return loader.ThinkingParams{}
}

// characterFromRequest 构建绑定到该人格的 registry.Character。
func characterFromRequest(req personaUpsertRequest) *personareg.Character {
	modes := append([]string(nil), req.Modes...)
	if len(modes) == 0 && req.Mode != "" {
		modes = []string{req.Mode}
	}
	return &personareg.Character{ID: req.ID, Name: req.Name, PersonaID: req.ID, Modes: modes}
}

// personaSummaryOf 把人格+角色映射为其线上摘要。它与
// 管理列表返回的形状相同 —— 角色级 mood 加上 `thinking` 块 ——
// 因此写响应与随后的读对人格的描述完全一致
// （客户端可信任任一方用于回填）。
func (s *Server) personaSummaryOf(p *loader.Persona, c *personareg.Character) PersonaSummary {
	return PersonaSummary{
		ID:        p.ID,
		Name:      c.Name,
		Character: c.Name,
		IsDefault: c.Default,
		Mode:      firstMode(c.Modes),
		MemoryNS:  p.MemoryNamespace(),
		Mood:      s.moodOf(p.ID),
		Thinking:  thinkingSummaryOf(p.Thinking, true),
	}
}

// savePersonaYAML 把 p 以 <id>.yaml 持久化进人格库，使其在
// 重启后存活（wire.go 加载该目录）。id 会被净化，使用户
// 输入无法穿越出库目录。
func savePersonaYAML(p *loader.Persona) error {
	data, err := yaml.Marshal(p)
	if err != nil {
		return fmt.Errorf("persona: marshal %q: %w", p.ID, err)
	}
	if err := os.MkdirAll(personaDir, 0o755); err != nil {
		return fmt.Errorf("persona: mkdir: %w", err)
	}
	path := filepath.Join(personaDir, sanitizeID(p.ID)+".yaml")
	if err := os.WriteFile(path, data, 0o644); err != nil {
		return fmt.Errorf("persona: write %s: %w", path, err)
	}
	return nil
}

// sanitizeID 只保留 URL/路径安全字符，使人格 id 不能
// 逃出人格目录。
func sanitizeID(id string) string {
	var b strings.Builder
	for _, r := range id {
		switch {
		case r >= 'a' && r <= 'z', r >= 'A' && r <= 'Z', r >= '0' && r <= '9', r == '-', r == '_':
			b.WriteRune(r)
		default:
			b.WriteByte('_')
		}
	}
	return b.String()
}