package controller

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"strings"

	"github.com/kandev/kandev/internal/agent/discovery"
	"github.com/kandev/kandev/internal/agent/settings/dto"
	"github.com/kandev/kandev/internal/agent/settings/models"
	"github.com/kandev/kandev/internal/agent/settings/store"
	"github.com/kandev/kandev/internal/common/logger"
	"go.uber.org/zap"
)

var (
	ErrAgentNotFound        = errors.New("agent not found")
	ErrAgentProfileNotFound = errors.New("agent profile not found")
)

type Controller struct {
	repo      store.Repository
	discovery *discovery.Registry
	logger    *logger.Logger
}

func NewController(repo store.Repository, discoveryRegistry *discovery.Registry, log *logger.Logger) *Controller {
	return &Controller{
		repo:      repo,
		discovery: discoveryRegistry,
		logger:    log.WithFields(zap.String("component", "agent-settings-controller")),
	}
}

func (c *Controller) ListDiscovery(ctx context.Context) (*dto.ListDiscoveryResponse, error) {
	results, err := c.discovery.Detect(ctx)
	if err != nil {
		return nil, err
	}
	payload := make([]dto.AgentDiscoveryDTO, 0, len(results))
	for _, result := range results {
		payload = append(payload, dto.AgentDiscoveryDTO{
			Name:              result.Name,
			SupportsMCP:       result.SupportsMCP,
			MCPConfigPath:     result.MCPConfigPath,
			InstallationPaths: result.InstallationPaths,
			Available:         result.Available,
			MatchedPath:       result.MatchedPath,
		})
	}
	return &dto.ListDiscoveryResponse{Agents: payload, Total: len(payload)}, nil
}

func (c *Controller) ListAgents(ctx context.Context) (*dto.ListAgentsResponse, error) {
	agents, err := c.repo.ListAgents(ctx)
	if err != nil {
		return nil, err
	}
	payload := make([]dto.AgentDTO, 0, len(agents))
	for _, agent := range agents {
		profiles, err := c.repo.ListAgentProfiles(ctx, agent.ID)
		if err != nil {
			return nil, err
		}
		payload = append(payload, toAgentDTO(agent, profiles))
	}
	return &dto.ListAgentsResponse{Agents: payload, Total: len(payload)}, nil
}

func (c *Controller) GetAgent(ctx context.Context, id string) (*dto.AgentDTO, error) {
	agent, err := c.repo.GetAgent(ctx, id)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil, ErrAgentNotFound
		}
		return nil, err
	}
	profiles, err := c.repo.ListAgentProfiles(ctx, agent.ID)
	if err != nil {
		return nil, err
	}
	result := toAgentDTO(agent, profiles)
	return &result, nil
}

type CreateAgentRequest struct {
	Name        string
	WorkspaceID *string
	Profiles    []CreateAgentProfileRequest
}

type CreateAgentProfileRequest struct {
	Name                       string
	Model                      string
	AutoApprove                bool
	DangerouslySkipPermissions bool
	Plan                       string
}

func (c *Controller) CreateAgent(ctx context.Context, req CreateAgentRequest) (*dto.AgentDTO, error) {
	if req.Name == "" {
		return nil, fmt.Errorf("name is required")
	}
	existing, err := c.repo.GetAgentByName(ctx, req.Name)
	if err != nil && !errors.Is(err, sql.ErrNoRows) {
		return nil, err
	}
	if err == nil && existing != nil {
		return nil, fmt.Errorf("agent already configured: %s", req.Name)
	}
	discoveryResults, err := c.discovery.Detect(ctx)
	if err != nil {
		return nil, err
	}
	var matched *discovery.Availability
	for _, result := range discoveryResults {
		if result.Name == req.Name {
			matched = &result
			break
		}
	}
	if matched == nil {
		return nil, fmt.Errorf("unknown agent: %s", req.Name)
	}
	if !matched.Available {
		return nil, fmt.Errorf("agent not installed: %s", req.Name)
	}
	agent := &models.Agent{
		Name:          matched.Name,
		WorkspaceID:   req.WorkspaceID,
		SupportsMCP:   matched.SupportsMCP,
		MCPConfigPath: matched.MCPConfigPath,
	}
	if err := c.repo.CreateAgent(ctx, agent); err != nil {
		return nil, err
	}
	profiles := make([]*models.AgentProfile, 0, len(req.Profiles))
	for _, profileReq := range req.Profiles {
		profile := &models.AgentProfile{
			AgentID:                    agent.ID,
			Name:                       profileReq.Name,
			Model:                      profileReq.Model,
			AutoApprove:                profileReq.AutoApprove,
			DangerouslySkipPermissions: profileReq.DangerouslySkipPermissions,
			Plan:                       profileReq.Plan,
		}
		if err := c.repo.CreateAgentProfile(ctx, profile); err != nil {
			return nil, err
		}
		profiles = append(profiles, profile)
	}
	result := toAgentDTO(agent, profiles)
	return &result, nil
}

type UpdateAgentRequest struct {
	ID            string
	WorkspaceID   *string
	SupportsMCP   *bool
	MCPConfigPath *string
}

func (c *Controller) UpdateAgent(ctx context.Context, req UpdateAgentRequest) (*dto.AgentDTO, error) {
	agent, err := c.repo.GetAgent(ctx, req.ID)
	if err != nil {
		return nil, ErrAgentNotFound
	}
	if req.WorkspaceID != nil {
		agent.WorkspaceID = req.WorkspaceID
	}
	if req.SupportsMCP != nil {
		agent.SupportsMCP = *req.SupportsMCP
	}
	if req.MCPConfigPath != nil {
		agent.MCPConfigPath = *req.MCPConfigPath
	}
	if err := c.repo.UpdateAgent(ctx, agent); err != nil {
		return nil, err
	}
	profiles, err := c.repo.ListAgentProfiles(ctx, agent.ID)
	if err != nil {
		return nil, err
	}
	result := toAgentDTO(agent, profiles)
	return &result, nil
}

func (c *Controller) DeleteAgent(ctx context.Context, id string) error {
	if err := c.repo.DeleteAgent(ctx, id); err != nil {
		if strings.Contains(err.Error(), "agent not found") {
			return ErrAgentNotFound
		}
		return err
	}
	return nil
}

type CreateProfileRequest struct {
	AgentID                    string
	Name                       string
	Model                      string
	AutoApprove                bool
	DangerouslySkipPermissions bool
	Plan                       string
}

func (c *Controller) CreateProfile(ctx context.Context, req CreateProfileRequest) (*dto.AgentProfileDTO, error) {
	profile := &models.AgentProfile{
		AgentID:                    req.AgentID,
		Name:                       req.Name,
		Model:                      req.Model,
		AutoApprove:                req.AutoApprove,
		DangerouslySkipPermissions: req.DangerouslySkipPermissions,
		Plan:                       req.Plan,
	}
	if err := c.repo.CreateAgentProfile(ctx, profile); err != nil {
		return nil, err
	}
	result := toProfileDTO(profile)
	return &result, nil
}

type UpdateProfileRequest struct {
	ID                         string
	Name                       *string
	Model                      *string
	AutoApprove                *bool
	DangerouslySkipPermissions *bool
	Plan                       *string
}

func (c *Controller) UpdateProfile(ctx context.Context, req UpdateProfileRequest) (*dto.AgentProfileDTO, error) {
	profile, err := c.repo.GetAgentProfile(ctx, req.ID)
	if err != nil {
		return nil, ErrAgentProfileNotFound
	}
	if req.Name != nil {
		profile.Name = *req.Name
	}
	if req.Model != nil {
		profile.Model = *req.Model
	}
	if req.AutoApprove != nil {
		profile.AutoApprove = *req.AutoApprove
	}
	if req.DangerouslySkipPermissions != nil {
		profile.DangerouslySkipPermissions = *req.DangerouslySkipPermissions
	}
	if req.Plan != nil {
		profile.Plan = *req.Plan
	}
	if err := c.repo.UpdateAgentProfile(ctx, profile); err != nil {
		return nil, err
	}
	result := toProfileDTO(profile)
	return &result, nil
}

func (c *Controller) DeleteProfile(ctx context.Context, id string) error {
	if err := c.repo.DeleteAgentProfile(ctx, id); err != nil {
		if strings.Contains(err.Error(), "agent profile not found") {
			return ErrAgentProfileNotFound
		}
		return err
	}
	return nil
}

func toAgentDTO(agent *models.Agent, profiles []*models.AgentProfile) dto.AgentDTO {
	profileDTOs := make([]dto.AgentProfileDTO, 0, len(profiles))
	for _, profile := range profiles {
		profileDTOs = append(profileDTOs, toProfileDTO(profile))
	}
	return dto.AgentDTO{
		ID:            agent.ID,
		Name:          agent.Name,
		WorkspaceID:   agent.WorkspaceID,
		SupportsMCP:   agent.SupportsMCP,
		MCPConfigPath: agent.MCPConfigPath,
		Profiles:      profileDTOs,
		CreatedAt:     agent.CreatedAt,
		UpdatedAt:     agent.UpdatedAt,
	}
}

func toProfileDTO(profile *models.AgentProfile) dto.AgentProfileDTO {
	return dto.AgentProfileDTO{
		ID:                         profile.ID,
		AgentID:                    profile.AgentID,
		Name:                       profile.Name,
		Model:                      profile.Model,
		AutoApprove:                profile.AutoApprove,
		DangerouslySkipPermissions: profile.DangerouslySkipPermissions,
		Plan:                       profile.Plan,
		CreatedAt:                  profile.CreatedAt,
		UpdatedAt:                  profile.UpdatedAt,
	}
}