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"
)

// persona-to-identity and API-key admin writes (owner-only, audited). Persona
// writes register into the persona registry (real runtime effect) and persist a
// YAML file so they survive a restart; API keys are minted/revoked in the
// auth.APIKey store.

const personaDir = "configs/personas"

// personaUpsertRequest is the POST/PUT /api/v1/admin/personas body.
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"`
}

// adminCreatePersona registers a new persona in the registry (real runtime
// effect) and persists it to the persona YAML library so it survives a restart.
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 := 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, personaSummaryOf(p, characterFromRequest(req)))
}

// adminUpdatePersona edits an existing persona, persisting the YAML and
// replacing the in-memory persona/character.
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 := 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, personaSummaryOf(p, characterFromRequest(req)))
}

// adminCreateUser answers honestly: there is no persistent user table and no
// user-authenticated login to back one (the deployment is a single admin
// account from .env plus runtime API keys; design/11 is single-user first), so
// user creation would be a row nobody could log in with. It reports the missing
// store instead of fabricating a user.
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 is the POST /api/v1/admin/users/apikey body.
type apiKeyIssueRequest struct {
	Role string `json:"role"`
}

// adminIssueApiKey mints a real API key bound to a role and returns the plaintext
// once (the only time it is visible). The id in the response is the masked form
// the admin list shows, so it can be used to revoke the key later.
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 revokes a key by its masked id (the identifier the admin list
// returns). It reports not-found when no key carries that mask.
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 builds a loader.Persona from the upsert request, filling a
// derived system prompt/characterRef when omitted so a minimal create validates.
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)},
	}
}

// characterFromRequest builds the registry.Character bound to the persona.
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 maps a persona+character to its wire summary.
func 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(),
	}
}

// savePersonaYAML persists p to the persona library as <id>.yaml so it survives
// a restart (wire.go loads this directory). The id is sanitized so user input
// cannot traverse out of the library directory.
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 keeps only URL/path-safe characters so a persona id cannot escape
// the persona directory.
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()
}