package codex

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"sort"
	"strings"
	"sync"

	"github.com/chenhg5/cc-connect/core"
)

func init() {
	core.RegisterAgent("codex", New)
}

// Agent drives OpenAI Codex CLI using `codex exec --json`.
//
// Modes (maps to codex exec flags):
//   - "suggest":   default, no special flags (safe commands only)
//   - "auto-edit": --full-auto (sandbox-protected auto execution)
//   - "full-auto": --full-auto (sandbox-protected auto execution)
//   - "yolo":      --dangerously-bypass-approvals-and-sandbox
type Agent struct {
	workDir    string
	model      string
	mode       string // "suggest" | "auto-edit" | "full-auto" | "yolo"
	providers  []core.ProviderConfig
	activeIdx  int // -1 = no provider set
	sessionEnv []string
	mu         sync.Mutex
}

func New(opts map[string]any) (core.Agent, error) {
	workDir, _ := opts["work_dir"].(string)
	if workDir == "" {
		workDir = "."
	}
	model, _ := opts["model"].(string)
	mode, _ := opts["mode"].(string)
	mode = normalizeMode(mode)

	if _, err := exec.LookPath("codex"); err != nil {
		return nil, fmt.Errorf("codex: 'codex' CLI not found in PATH, install with: npm install -g @openai/codex")
	}

	return &Agent{
		workDir:   workDir,
		model:     model,
		mode:      mode,
		activeIdx: -1,
	}, nil
}

func normalizeMode(raw string) string {
	switch strings.ToLower(strings.TrimSpace(raw)) {
	case "auto-edit", "autoedit", "auto_edit", "edit":
		return "auto-edit"
	case "full-auto", "fullauto", "full_auto", "auto":
		return "full-auto"
	case "yolo", "bypass", "dangerously-bypass":
		return "yolo"
	default:
		return "suggest"
	}
}

func (a *Agent) Name() string { return "codex" }

func (a *Agent) SetModel(model string) {
	a.mu.Lock()
	defer a.mu.Unlock()
	a.model = model
	slog.Info("codex: model changed", "model", model)
}

func (a *Agent) GetModel() string {
	a.mu.Lock()
	defer a.mu.Unlock()
	return a.model
}

func (a *Agent) AvailableModels(ctx context.Context) []core.ModelOption {
	if models := a.fetchModelsFromAPI(ctx); len(models) > 0 {
		return models
	}
	return []core.ModelOption{
		{Name: "o4-mini", Desc: "O4 Mini (fast reasoning)"},
		{Name: "o3", Desc: "O3 (most capable reasoning)"},
		{Name: "gpt-4.1", Desc: "GPT-4.1 (balanced)"},
		{Name: "gpt-4.1-mini", Desc: "GPT-4.1 Mini (fast)"},
		{Name: "gpt-4.1-nano", Desc: "GPT-4.1 Nano (fastest)"},
		{Name: "codex-mini-latest", Desc: "Codex Mini (code-optimized)"},
	}
}

var openaiChatModels = map[string]bool{
	"o4-mini": true, "o3": true, "o3-mini": true, "o1": true, "o1-mini": true,
	"gpt-4.1": true, "gpt-4.1-mini": true, "gpt-4.1-nano": true,
	"gpt-4o": true, "gpt-4o-mini": true,
	"codex-mini-latest": true,
}

func (a *Agent) fetchModelsFromAPI(ctx context.Context) []core.ModelOption {
	a.mu.Lock()
	apiKey := ""
	baseURL := ""
	if a.activeIdx >= 0 && a.activeIdx < len(a.providers) {
		apiKey = a.providers[a.activeIdx].APIKey
		baseURL = a.providers[a.activeIdx].BaseURL
	}
	a.mu.Unlock()

	if apiKey == "" {
		apiKey = os.Getenv("OPENAI_API_KEY")
	}
	if apiKey == "" {
		return nil
	}
	if baseURL == "" {
		baseURL = os.Getenv("OPENAI_BASE_URL")
	}
	if baseURL == "" {
		baseURL = "https://api.openai.com"
	}
	baseURL = strings.TrimRight(baseURL, "/")

	req, err := http.NewRequestWithContext(ctx, "GET", baseURL+"/v1/models", nil)
	if err != nil {
		return nil
	}
	req.Header.Set("Authorization", "Bearer "+apiKey)

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		slog.Debug("codex: failed to fetch models", "error", err)
		return nil
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return nil
	}

	var result struct {
		Data []struct {
			ID string `json:"id"`
		} `json:"data"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil
	}

	var models []core.ModelOption
	for _, m := range result.Data {
		if openaiChatModels[m.ID] {
			models = append(models, core.ModelOption{Name: m.ID})
		}
	}
	sort.Slice(models, func(i, j int) bool { return models[i].Name < models[j].Name })
	return models
}

func (a *Agent) SetSessionEnv(env []string) {
	a.mu.Lock()
	defer a.mu.Unlock()
	a.sessionEnv = env
}

func (a *Agent) StartSession(ctx context.Context, sessionID string) (core.AgentSession, error) {
	a.mu.Lock()
	mode := a.mode
	model := a.model
	extraEnv := a.providerEnvLocked()
	extraEnv = append(extraEnv, a.sessionEnv...)
	if a.activeIdx >= 0 && a.activeIdx < len(a.providers) {
		if m := a.providers[a.activeIdx].Model; m != "" {
			model = m
		}
	}
	a.mu.Unlock()

	return newCodexSession(ctx, a.workDir, model, mode, sessionID, extraEnv)
}

func (a *Agent) ListSessions(_ context.Context) ([]core.AgentSessionInfo, error) {
	return listCodexSessions(a.workDir)
}

func (a *Agent) GetSessionHistory(_ context.Context, sessionID string, limit int) ([]core.HistoryEntry, error) {
	return getSessionHistory(sessionID, limit)
}

func (a *Agent) DeleteSession(_ context.Context, sessionID string) error {
	path := findSessionFile(sessionID)
	if path == "" {
		return fmt.Errorf("session file not found: %s", sessionID)
	}
	return os.Remove(path)
}

func (a *Agent) Stop() error { return nil }

// SetMode changes the approval mode for future sessions.
func (a *Agent) SetMode(mode string) {
	a.mu.Lock()
	defer a.mu.Unlock()
	a.mode = normalizeMode(mode)
	slog.Info("codex: approval mode changed", "mode", a.mode)
}

func (a *Agent) GetMode() string {
	a.mu.Lock()
	defer a.mu.Unlock()
	return a.mode
}

// ── SkillProvider implementation ──────────────────────────────

func (a *Agent) SkillDirs() []string {
	absDir, err := filepath.Abs(a.workDir)
	if err != nil {
		absDir = a.workDir
	}
	dirs := []string{
		filepath.Join(absDir, ".codex", "skills"),
		filepath.Join(absDir, ".claude", "skills"),
	}
	codexHome := os.Getenv("CODEX_HOME")
	if codexHome == "" {
		if home, err := os.UserHomeDir(); err == nil {
			codexHome = filepath.Join(home, ".codex")
		}
	}
	if codexHome != "" {
		dirs = append(dirs, filepath.Join(codexHome, "skills"))
	}
	if home, err := os.UserHomeDir(); err == nil {
		dirs = append(dirs, filepath.Join(home, ".claude", "skills"))
	}
	return dirs
}

// ── ContextCompressor implementation ──────────────────────────

func (a *Agent) CompressCommand() string { return "/compact" }

// ── MemoryFileProvider implementation ─────────────────────────

func (a *Agent) ProjectMemoryFile() string {
	absDir, err := filepath.Abs(a.workDir)
	if err != nil {
		absDir = a.workDir
	}
	return filepath.Join(absDir, "AGENTS.md")
}

func (a *Agent) GlobalMemoryFile() string {
	homeDir, err := os.UserHomeDir()
	if err != nil {
		return ""
	}
	codexHome := os.Getenv("CODEX_HOME")
	if codexHome == "" {
		codexHome = filepath.Join(homeDir, ".codex")
	}
	return filepath.Join(codexHome, "AGENTS.md")
}

// ── ProviderSwitcher implementation ──────────────────────────

func (a *Agent) SetProviders(providers []core.ProviderConfig) {
	a.mu.Lock()
	defer a.mu.Unlock()
	a.providers = providers
}

func (a *Agent) SetActiveProvider(name string) bool {
	a.mu.Lock()
	defer a.mu.Unlock()
	if name == "" {
		a.activeIdx = -1
		slog.Info("codex: provider cleared")
		return true
	}
	for i, p := range a.providers {
		if p.Name == name {
			a.activeIdx = i
			slog.Info("codex: provider switched", "provider", name)
			return true
		}
	}
	return false
}

func (a *Agent) GetActiveProvider() *core.ProviderConfig {
	a.mu.Lock()
	defer a.mu.Unlock()
	if a.activeIdx < 0 || a.activeIdx >= len(a.providers) {
		return nil
	}
	p := a.providers[a.activeIdx]
	return &p
}

func (a *Agent) ListProviders() []core.ProviderConfig {
	a.mu.Lock()
	defer a.mu.Unlock()
	result := make([]core.ProviderConfig, len(a.providers))
	copy(result, a.providers)
	return result
}

func (a *Agent) providerEnvLocked() []string {
	if a.activeIdx < 0 || a.activeIdx >= len(a.providers) {
		return nil
	}
	p := a.providers[a.activeIdx]
	var env []string
	if p.APIKey != "" {
		env = append(env, "OPENAI_API_KEY="+p.APIKey)
	}
	if p.BaseURL != "" {
		env = append(env, "OPENAI_BASE_URL="+p.BaseURL)
	}
	for k, v := range p.Env {
		env = append(env, k+"="+v)
	}
	return env
}

func (a *Agent) PermissionModes() []core.PermissionModeInfo {
	return []core.PermissionModeInfo{
		{Key: "suggest", Name: "Suggest", NameZh: "建议", Desc: "Ask permission for every tool call", DescZh: "每次工具调用都需确认"},
		{Key: "auto-edit", Name: "Auto Edit", NameZh: "自动编辑", Desc: "Auto-approve file edits, ask for shell commands", DescZh: "自动允许文件编辑，Shell 命令需确认"},
		{Key: "full-auto", Name: "Full Auto", NameZh: "全自动", Desc: "Auto-approve with workspace sandbox", DescZh: "自动通过（工作区沙箱）"},
		{Key: "yolo", Name: "YOLO", NameZh: "YOLO 模式", Desc: "Bypass all approvals and sandbox", DescZh: "跳过所有审批和沙箱"},
	}
}