package api

import (
	"encoding/json"
	"net/http"
	"os/exec"
	"strings"

	"github.com/muyue/muyue/internal/config"
	"github.com/muyue/muyue/internal/lsp"
	"github.com/muyue/muyue/internal/mcp"
	"github.com/muyue/muyue/internal/scanner"
	"github.com/muyue/muyue/internal/skills"
	"github.com/muyue/muyue/internal/updater"
	"github.com/muyue/muyue/internal/version"
)

type Server struct {
	config     *config.MuyueConfig
	scanResult *scanner.ScanResult
	mux        *http.ServeMux
}

func NewServer(cfg *config.MuyueConfig) *Server {
	s := &Server{
		config: cfg,
		mux:    http.NewServeMux(),
	}
	s.scanResult = scanner.ScanSystem()
	s.routes()
	return s
}

func (s *Server) routes() {
	s.mux.HandleFunc("/api/info", s.handleInfo)
	s.mux.HandleFunc("/api/system", s.handleSystem)
	s.mux.HandleFunc("/api/tools", s.handleTools)
	s.mux.HandleFunc("/api/config", s.handleConfig)
	s.mux.HandleFunc("/api/providers", s.handleProviders)
	s.mux.HandleFunc("/api/skills", s.handleSkills)
	s.mux.HandleFunc("/api/lsp", s.handleLSP)
	s.mux.HandleFunc("/api/mcp", s.handleMCP)
	s.mux.HandleFunc("/api/updates", s.handleUpdates)
	s.mux.HandleFunc("/api/install", s.handleInstall)
	s.mux.HandleFunc("/api/scan", s.handleScan)
	s.mux.HandleFunc("/api/terminal", s.handleTerminal)
	s.mux.HandleFunc("/api/mcp/configure", s.handleMCPConfigure)
}

func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	w.Header().Set("Access-Control-Allow-Origin", "*")
	w.Header().Set("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
	w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
	if r.Method == "OPTIONS" {
		w.WriteHeader(http.StatusOK)
		return
	}
	s.mux.ServeHTTP(w, r)
}

func writeJSON(w http.ResponseWriter, data interface{}) {
	json.NewEncoder(w).Encode(data)
}

func writeError(w http.ResponseWriter, msg string, code int) {
	w.WriteHeader(code)
	json.NewEncoder(w).Encode(map[string]string{"error": msg})
}

func (s *Server) handleInfo(w http.ResponseWriter, r *http.Request) {
	writeJSON(w, map[string]interface{}{
		"name":    version.Name,
		"version": version.Version,
		"author":  version.Author,
	})
}

func (s *Server) handleSystem(w http.ResponseWriter, r *http.Request) {
	if s.scanResult == nil {
		s.scanResult = scanner.ScanSystem()
	}
	writeJSON(w, map[string]interface{}{
		"system": s.scanResult.System,
	})
}

type ToolInfo struct {
	Name      string `json:"name"`
	Installed bool   `json:"installed"`
	Version   string `json:"version"`
	Path      string `json:"path"`
}

func (s *Server) handleTools(w http.ResponseWriter, r *http.Request) {
	if s.scanResult == nil {
		s.scanResult = scanner.ScanSystem()
	}
	tools := make([]ToolInfo, len(s.scanResult.Tools))
	for i, t := range s.scanResult.Tools {
		tools[i] = ToolInfo{
			Name:      t.Name,
			Installed: t.Installed,
			Version:   t.Version,
			Path:      t.Path,
		}
	}
	writeJSON(w, map[string]interface{}{
		"tools": tools,
		"total": len(tools),
	})
}

func (s *Server) handleConfig(w http.ResponseWriter, r *http.Request) {
	if s.config == nil {
		writeError(w, "no config", http.StatusNotFound)
		return
	}
	writeJSON(w, map[string]interface{}{
		"profile":   s.config.Profile,
		"terminal":  s.config.Terminal,
		"bmad":      s.config.BMAD,
	})
}

func (s *Server) handleProviders(w http.ResponseWriter, r *http.Request) {
	if s.config == nil {
		writeError(w, "no config", http.StatusNotFound)
		return
	}
	writeJSON(w, map[string]interface{}{
		"providers": s.config.AI.Providers,
	})
}

func (s *Server) handleSkills(w http.ResponseWriter, r *http.Request) {
	list, err := skills.List()
	if err != nil {
		writeError(w, err.Error(), http.StatusInternalServerError)
		return
	}
	writeJSON(w, map[string]interface{}{
		"skills": list,
		"count":  len(list),
	})
}

func (s *Server) handleLSP(w http.ResponseWriter, r *http.Request) {
	servers := lsp.ScanServers()
	writeJSON(w, map[string]interface{}{
		"servers": servers,
	})
}

func (s *Server) handleMCP(w http.ResponseWriter, r *http.Request) {
	servers := mcp.ScanServers()
	writeJSON(w, map[string]interface{}{
		"servers":   servers,
		"configured": true,
	})
}

func (s *Server) handleMCPConfigure(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		writeError(w, "POST only", http.StatusMethodNotAllowed)
		return
	}
	err := mcp.ConfigureAll(s.config)
	if err != nil {
		writeError(w, err.Error(), http.StatusInternalServerError)
		return
	}
	writeJSON(w, map[string]string{"status": "ok"})
}

func (s *Server) handleUpdates(w http.ResponseWriter, r *http.Request) {
	result := scanner.ScanSystem()
	statuses := updater.CheckUpdates(result)
	type updateInfo struct {
		Tool        string `json:"tool"`
		Current     string `json:"current"`
		Latest      string `json:"latest"`
		NeedsUpdate bool   `json:"needsUpdate"`
		Error       string `json:"error,omitempty"`
	}
	updates := make([]updateInfo, len(statuses))
	for i, u := range statuses {
		updates[i] = updateInfo{
			Tool:        u.Tool,
			Current:     u.Current,
			Latest:      u.Latest,
			NeedsUpdate: u.NeedsUpdate,
			Error:       u.Error,
		}
	}
	writeJSON(w, map[string]interface{}{
		"updates": updates,
	})
}

func (s *Server) handleInstall(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		writeError(w, "POST only", http.StatusMethodNotAllowed)
		return
	}
	var body struct {
		Tools []string `json:"tools"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		writeError(w, err.Error(), http.StatusBadRequest)
		return
	}
	if len(body.Tools) == 0 {
		writeError(w, "no tools specified", http.StatusBadRequest)
		return
	}
	writeJSON(w, map[string]string{"status": "installing"})
}

func (s *Server) handleScan(w http.ResponseWriter, r *http.Request) {
	s.scanResult = scanner.ScanSystem()
	writeJSON(w, map[string]string{"status": "ok"})
}

type TermResult struct {
	Output string `json:"output"`
	Error  string `json:"error,omitempty"`
}

func (s *Server) handleTerminal(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		writeError(w, "POST only", http.StatusMethodNotAllowed)
		return
	}
	var body struct {
		Command string `json:"command"`
		Cwd     string `json:"cwd"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		writeError(w, err.Error(), http.StatusBadRequest)
		return
	}

	if body.Command == "" {
		writeError(w, "no command", http.StatusBadRequest)
		return
	}

	shell := "/bin/sh"
	if sh := strings.TrimSpace(body.Command); sh != "" {
		if s, err := exec.LookPath("bash"); err == nil {
			shell = s
		}
	}

	cmd := exec.Command(shell, "-c", body.Command)
	if body.Cwd != "" {
		cmd.Dir = body.Cwd
	}
	out, err := cmd.CombinedOutput()
	result := TermResult{Output: string(out)}
	if err != nil {
		result.Error = err.Error()
	}
	writeJSON(w, result)
}