package gateway

import (
	"fmt"
	"net/http"
	"time"

	"gitea.rutua.cn/kate522/CrossRelay/internal/claudecfg"
	"gitea.rutua.cn/kate522/CrossRelay/internal/codexcfg"
	"gitea.rutua.cn/kate522/CrossRelay/internal/config"
)

// providerInput is the provider payload accepted by the management API.
type providerInput struct {
	Name    string        `json:"name"`
	Preset  string        `json:"preset"`
	BaseURL string        `json:"base_url"`
	APIKey  string        `json:"api_key"`
	Models  config.Models `json:"models"`
}

func (s *Server) handleStatus(w http.ResponseWriter, r *http.Request) {
	cfg := s.store.Config()
	var active any
	if p := s.store.ActiveClaude(); p != nil {
		active = map[string]any{
			"id":       p.ID,
			"name":     p.Name,
			"base_url": p.BaseURL,
			"models":   p.Models,
		}
	}
	var activeCodex any
	if p := s.store.ActiveCodex(); p != nil {
		activeCodex = map[string]any{
			"id":       p.ID,
			"name":     p.Name,
			"base_url": p.BaseURL,
			"models":   p.Models,
		}
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"running":                true,
		"version":                Version,
		"port":                   s.port,
		"uptime_sec":             int(time.Since(s.started).Seconds()),
		"active_claude_provider": active,
		"active_codex_provider":  activeCodex,
		"stats":                  s.snapshotStats(),
		"language":               cfg.Language,
		"port_mode":              cfg.Gateway.PortMode,
		"fixed_port":             cfg.Gateway.FixedPort,
	})
}

func (s *Server) handleListProviders(w http.ResponseWriter, r *http.Request) {
	writeJSON(w, http.StatusOK, map[string]any{"items": s.store.Config().Providers})
}

func (s *Server) handleCreateProvider(w http.ResponseWriter, r *http.Request) {
	var in providerInput
	if err := decodeJSON(r, &in, 1<<20); err != nil {
		writeAPIError(w, http.StatusBadRequest, "invalid request body: "+err.Error())
		return
	}
	p, err := s.store.AddProvider(in.Name, in.Preset, in.BaseURL, in.APIKey, in.Models)
	if err != nil {
		writeAPIError(w, http.StatusBadRequest, err.Error())
		return
	}
	writeJSON(w, http.StatusCreated, p)
}

func (s *Server) handleUpdateProvider(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	var in providerInput
	if err := decodeJSON(r, &in, 1<<20); err != nil {
		writeAPIError(w, http.StatusBadRequest, "invalid request body: "+err.Error())
		return
	}
	p, err := s.store.UpdateProvider(id, in.Name, in.Preset, in.BaseURL, in.APIKey, in.Models)
	if err != nil {
		writeAPIError(w, http.StatusBadRequest, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, p)
}

func (s *Server) handleDeleteProvider(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	if err := s.store.DeleteProvider(id); err != nil {
		writeAPIError(w, http.StatusNotFound, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"deleted": id})
}

// applyInput selects which client configuration receives the provider.
type applyInput struct {
	Target string `json:"target"`
}

// handleApply activates a provider and writes it into the target
// client's configuration. The body is optional; an absent or empty
// target means Claude Code, keeping older clients working.
func (s *Server) handleApply(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	var in applyInput
	if r.Body != nil {
		_ = decodeJSON(r, &in, 1<<20) // an empty body leaves the zero value
	}
	switch in.Target {
	case "", "claude":
		s.applyClaude(w, id)
	case "codex":
		s.applyCodex(w, id)
	default:
		writeAPIError(w, http.StatusBadRequest, `target must be "claude" or "codex"`)
	}
}

// applyClaude activates a provider and writes it into Claude Code's
// settings.json.
func (s *Server) applyClaude(w http.ResponseWriter, id string) {
	p, err := s.store.ActivateClaude(id)
	if err != nil {
		writeAPIError(w, http.StatusNotFound, err.Error())
		return
	}
	mgr, err := s.claudeManager()
	if err != nil {
		writeAPIError(w, http.StatusInternalServerError, err.Error())
		return
	}
	settings, err := mgr.Apply(claudecfg.ApplyOptions{
		BaseURL: fmt.Sprintf("http://127.0.0.1:%d", s.port),
		Token:   s.store.Config().RelayToken,
		Models:  p.Models,
	})
	if err != nil {
		writeAPIError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"provider": p,
		"target":   "claude",
		"env":      settings.Env,
	})
}

// applyCodex activates a provider and writes it into Codex's
// config.toml.
func (s *Server) applyCodex(w http.ResponseWriter, id string) {
	p, err := s.store.ActivateCodex(id)
	if err != nil {
		writeAPIError(w, http.StatusNotFound, err.Error())
		return
	}
	mgr, err := s.codexManager()
	if err != nil {
		writeAPIError(w, http.StatusInternalServerError, err.Error())
		return
	}
	injection, err := mgr.Apply(codexcfg.ApplyOptions{
		BaseURL: fmt.Sprintf("http://127.0.0.1:%d", s.port),
		Token:   s.store.Config().RelayToken,
	})
	if err != nil {
		writeAPIError(w, http.StatusInternalServerError, err.Error())
		return
	}
	// Remember the provider the user had before the first apply so
	// restore can put it back instead of dropping the key.
	if injection.PriorProvider != "" && s.store.Config().CodexPriorProvider == "" {
		if err := s.store.SetCodexPriorProvider(injection.PriorProvider); err != nil {
			writeAPIError(w, http.StatusInternalServerError, err.Error())
			return
		}
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"provider":  p,
		"target":    "codex",
		"injection": injection,
	})
}

// restoreInput selects the client and, optionally, one specific backup
// file to roll back to.
type restoreInput struct {
	Target string `json:"target"`
	Backup string `json:"backup,omitempty"`
}

// handleRestore puts a client's configuration back. Claude restores
// the newest backup (or the named one); Codex removes the managed
// keys, or rolls back to the named backup.
func (s *Server) handleRestore(w http.ResponseWriter, r *http.Request) {
	var in restoreInput
	if r.Body != nil {
		_ = decodeJSON(r, &in, 1<<20)
	}
	switch in.Target {
	case "", "claude":
		s.restoreClaude(w, in.Backup)
	case "codex":
		s.restoreCodex(w, in.Backup)
	default:
		writeAPIError(w, http.StatusBadRequest, `target must be "claude" or "codex"`)
	}
}

func (s *Server) restoreClaude(w http.ResponseWriter, backup string) {
	mgr, err := s.claudeManager()
	if err != nil {
		writeAPIError(w, http.StatusInternalServerError, err.Error())
		return
	}
	var name string
	if backup != "" {
		name, err = mgr.RestoreFrom(backup)
	} else {
		name, err = mgr.Restore()
	}
	if err != nil {
		writeAPIError(w, http.StatusNotFound, err.Error())
		return
	}
	_ = s.store.ClearActiveClaude()
	writeJSON(w, http.StatusOK, map[string]any{"restored_from": name})
}

func (s *Server) restoreCodex(w http.ResponseWriter, backup string) {
	mgr, err := s.codexManager()
	if err != nil {
		writeAPIError(w, http.StatusInternalServerError, err.Error())
		return
	}
	if backup != "" {
		name, err := mgr.RestoreBackup(backup)
		if err != nil {
			writeAPIError(w, http.StatusNotFound, err.Error())
			return
		}
		_ = s.store.ClearActiveCodex()
		writeJSON(w, http.StatusOK, map[string]any{"restored_from": name})
		return
	}
	if err := mgr.RemoveManaged(s.store.Config().CodexPriorProvider); err != nil {
		writeAPIError(w, http.StatusInternalServerError, err.Error())
		return
	}
	_ = s.store.ClearActiveCodex()
	_ = s.store.SetCodexPriorProvider("")
	writeJSON(w, http.StatusOK, map[string]any{"restored_from": ""})
}

func (s *Server) handleBackups(w http.ResponseWriter, r *http.Request) {
	switch target := r.URL.Query().Get("target"); target {
	case "", "claude":
		mgr, err := s.claudeManager()
		if err != nil {
			writeAPIError(w, http.StatusInternalServerError, err.Error())
			return
		}
		items, err := mgr.Backups()
		if err != nil {
			writeAPIError(w, http.StatusInternalServerError, err.Error())
			return
		}
		if items == nil {
			items = []claudecfg.BackupInfo{}
		}
		writeJSON(w, http.StatusOK, map[string]any{"items": items})
	case "codex":
		mgr, err := s.codexManager()
		if err != nil {
			writeAPIError(w, http.StatusInternalServerError, err.Error())
			return
		}
		items, err := mgr.Backups()
		if err != nil {
			writeAPIError(w, http.StatusInternalServerError, err.Error())
			return
		}
		if items == nil {
			items = []codexcfg.BackupInfo{}
		}
		writeJSON(w, http.StatusOK, map[string]any{"items": items})
	default:
		writeAPIError(w, http.StatusBadRequest, `target must be "claude" or "codex"`)
	}
}

func (s *Server) handleGetSettings(w http.ResponseWriter, r *http.Request) {
	cfg := s.store.Config()
	writeJSON(w, http.StatusOK, map[string]any{
		"language":   cfg.Language,
		"port_mode":  cfg.Gateway.PortMode,
		"fixed_port": cfg.Gateway.FixedPort,
	})
}

type settingsInput struct {
	Language  string `json:"language"`
	PortMode  string `json:"port_mode"`
	FixedPort int    `json:"fixed_port"`
}

func (s *Server) handleUpdateSettings(w http.ResponseWriter, r *http.Request) {
	var in settingsInput
	if err := decodeJSON(r, &in, 1<<20); err != nil {
		writeAPIError(w, http.StatusBadRequest, "invalid request body: "+err.Error())
		return
	}
	if in.Language != "" {
		if err := s.store.SetLanguage(in.Language); err != nil {
			writeAPIError(w, http.StatusBadRequest, err.Error())
			return
		}
	}
	if in.PortMode != "" {
		if err := s.store.SetGateway(config.Gateway{
			PortMode:  in.PortMode,
			FixedPort: in.FixedPort,
		}); err != nil {
			writeAPIError(w, http.StatusBadRequest, err.Error())
			return
		}
	}
	cfg := s.store.Config()
	writeJSON(w, http.StatusOK, map[string]any{
		"language":   cfg.Language,
		"port_mode":  cfg.Gateway.PortMode,
		"fixed_port": cfg.Gateway.FixedPort,
	})
}

func (s *Server) handleLogs(w http.ResponseWriter, r *http.Request) {
	writeJSON(w, http.StatusOK, map[string]any{"items": s.logs.list()})
}