package mcp

import (
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"

	"github.com/muyue/muyue/internal/config"
)

type MCPServer struct {
	Name      string            `json:"name"`
	Command   string            `json:"command"`
	Args      []string          `json:"args"`
	Env       map[string]string `json:"env,omitempty"`
	Installed bool              `json:"installed"`
	Category  string            `json:"category"`
}

type mcpEntry struct {
	name string
	cmd  string
	args []string
	env  map[string]string
}

var knownMCPServers = []MCPServer{
	{Name: "filesystem", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-filesystem"}, Category: "core"},
	{Name: "github", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-github"}, Env: map[string]string{"GITHUB_PERSONAL_ACCESS_TOKEN": ""}, Category: "vcs"},
	{Name: "git", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-git"}, Category: "vcs"},
	{Name: "fetch", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-fetch"}, Category: "web"},
	{Name: "memory", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-memory"}, Category: "core"},
	{Name: "sequential-thinking", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-sequential-thinking"}, Category: "ai"},
	{Name: "brave-search", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-brave-search"}, Env: map[string]string{"BRAVE_API_KEY": ""}, Category: "web"},
	{Name: "sqlite", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-sqlite"}, Category: "database"},
	{Name: "postgres", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-postgres"}, Category: "database"},
	{Name: "docker", Command: "npx", Args: []string{"-y", "@modelcontextprotocol/server-docker"}, Category: "devops"},
	{Name: "minimax-web-search", Command: "npx", Args: []string{"-y", "@minimax/mcp-web-search"}, Env: map[string]string{"MINIMAX_API_KEY": ""}, Category: "ai"},
	{Name: "minimax-image", Command: "npx", Args: []string{"-y", "@minimax/mcp-image-understanding"}, Env: map[string]string{"MINIMAX_API_KEY": ""}, Category: "ai"},
}

func ScanServers() []MCPServer {
	servers := make([]MCPServer, len(knownMCPServers))
	for i, s := range knownMCPServers {
		servers[i] = s
		_, err := exec.LookPath(s.Command)
		servers[i].Installed = err == nil
	}
	return servers
}

func getCoreEntries(homeDir string) []mcpEntry {
	return []mcpEntry{
		{"filesystem", "npx", []string{"-y", "@modelcontextprotocol/server-filesystem", filepath.Join(homeDir, "projects")}, nil},
		{"fetch", "npx", []string{"-y", "@modelcontextprotocol/server-fetch"}, nil},
		{"memory", "npx", []string{"-y", "@modelcontextprotocol/server-memory"}, nil},
	}
}

func withProviderEntries(base []mcpEntry, cfg *config.MuyueConfig, extraEntries []mcpEntry) []mcpEntry {
	entries := make([]mcpEntry, len(base))
	copy(entries, base)
	entries = append(entries, extraEntries...)

	if cfg != nil {
		for _, p := range cfg.AI.Providers {
			if p.Name == "minimax" && p.APIKey != "" {
				entries = append(entries,
					mcpEntry{"minimax-web-search", "npx", []string{"-y", "@minimax/mcp-web-search"}, map[string]string{"MINIMAX_API_KEY": p.APIKey}},
					mcpEntry{"minimax-image", "npx", []string{"-y", "@minimax/mcp-image-understanding"}, map[string]string{"MINIMAX_API_KEY": p.APIKey}},
				)
			}
		}
	}
	return entries
}

func writeMCPConfig(configPath string, mcpKey string, entries []mcpEntry) error {
	configDir := filepath.Dir(configPath)
	if err := os.MkdirAll(configDir, 0700); err != nil {
		return fmt.Errorf("create config dir: %w", err)
	}

	existing := map[string]interface{}{}
	data, err := os.ReadFile(configPath)
	if err == nil {
		if err := json.Unmarshal(data, &existing); err != nil {
			return fmt.Errorf("parse existing config: %w", err)
		}
	}

	mcpMap := map[string]interface{}{}
	for _, e := range entries {
		entry := map[string]interface{}{
			"command": e.cmd,
			"args":    e.args,
		}
		if len(e.env) > 0 {
			entry["env"] = e.env
		}
		mcpMap[e.name] = entry
	}

	existing[mcpKey] = mcpMap

	out, err := json.MarshalIndent(existing, "", "  ")
	if err != nil {
		return err
	}

	return os.WriteFile(configPath, out, 0600)
}

func GenerateCrushMCPConfig(cfg *config.MuyueConfig, homeDir string) error {
	if homeDir == "" {
		home, _ := os.UserHomeDir()
		homeDir = home
	}

	core := getCoreEntries(homeDir)
	entries := withProviderEntries(core, cfg, nil)
	configPath := filepath.Join(homeDir, ".config", "crush", "crush.json")
	return writeMCPConfig(configPath, "mcps", entries)
}

func GenerateClaudeMCPConfig(cfg *config.MuyueConfig, homeDir string) error {
	if homeDir == "" {
		home, _ := os.UserHomeDir()
		homeDir = home
	}

	core := getCoreEntries(homeDir)
	extra := []mcpEntry{
		{"sequential-thinking", "npx", []string{"-y", "@modelcontextprotocol/server-sequential-thinking"}, nil},
	}
	entries := withProviderEntries(core, cfg, extra)
	configPath := filepath.Join(homeDir, ".claude.json")
	return writeMCPConfig(configPath, "mcpServers", entries)
}

func ConfigureAll(cfg *config.MuyueConfig) error {
	home, err := os.UserHomeDir()
	if err != nil {
		return fmt.Errorf("get home dir: %w", err)
	}

	if err := GenerateCrushMCPConfig(cfg, home); err != nil {
		return fmt.Errorf("crush MCP config: %w", err)
	}

	if err := GenerateClaudeMCPConfig(cfg, home); err != nil {
		return fmt.Errorf("claude MCP config: %w", err)
	}

	return nil
}