package ansible

import (
	"bytes"
	"context"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"sync"
)

// ErrUnknownDeployType is returned when an unsupported deployment type is specified
var ErrUnknownDeployType = fmt.Errorf("unknown deploy type, expected 'docker' or 'binary'")

// Executor handles running Ansible playbooks
type Executor struct {
	workDir          string
	grpcServerHost   string
	grpcServerPort   string
	backendURL       string
	giteaReleasesURL string
}

// ExecutorConfig holds configuration for the Executor
type ExecutorConfig struct {
	WorkDir          string
	GRPCServerHost   string
	GRPCServerPort   string
	BackendURL       string
	GiteaReleasesURL string
}

// NewExecutor creates a new Ansible executor
func NewExecutor(cfg ExecutorConfig) *Executor {
	return &Executor{
		workDir:          cfg.WorkDir,
		grpcServerHost:   cfg.GRPCServerHost,
		grpcServerPort:   cfg.GRPCServerPort,
		backendURL:       cfg.BackendURL,
		giteaReleasesURL: cfg.GiteaReleasesURL,
	}
}

// DeployResult holds the result of a deployment
type DeployResult struct {
	Host    string
	Success bool
	Stdout  string
	Stderr  string
	Err     error
}

// WorkDir returns the work directory path
func (e *Executor) WorkDir() string {
	return e.workDir
}

// GRPCURL returns the gRPC server URL (host:port)
func (e *Executor) GRPCURL() string {
	return e.grpcServerHost + ":" + e.grpcServerPort
}

// CheckDockerCollection verifies that the community.docker Ansible collection is installed.
// Returns an error if the collection is not found.
func (e *Executor) CheckDockerCollection() error {
	cmd := exec.Command("ansible-galaxy", "collection", "list", "community.docker")
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	if err := cmd.Run(); err != nil {
		return fmt.Errorf("community.docker collection not found: %s", stderr.String())
	}

	// ansible-galaxy collection list returns output like:
	// # /usr/share/ansible/collections/ansible_collections
	// Collection       Version
	// ---------------- -------
	// community.docker 3.10.0
	//
	// If the collection is not installed, it won't appear in the output.
	if !strings.Contains(stdout.String(), "community.docker") {
		return fmt.Errorf("community.docker collection is not installed. Run: ansible-galaxy collection install community.docker")
	}

	return nil
}

// Deploy runs Ansible playbook for the given inventory
func (e *Executor) Deploy(
	ctx context.Context,
	inventoryPath string,
	deployType string,
) ([]DeployResult, error) {
	if deployType != "docker" && deployType != "binary" {
		return nil, fmt.Errorf("invalid deploy type %q: %w", deployType, ErrUnknownDeployType)
	}

	playbookName := "binary_deploy.yml"
	if deployType == "docker" {
		playbookName = "docker_deploy.yml"
	}

	playbookPath := filepath.Join(e.workDir, playbookName)

	cmd := exec.CommandContext(ctx, "ansible-playbook",
		"-i", inventoryPath,
		"-e", fmt.Sprintf("backend_url=%s", e.backendURL),
		"-e", fmt.Sprintf("grpc_url=%s", e.grpcServerHost+":"+e.grpcServerPort),
		"-e", fmt.Sprintf("gitea_releases_url=%s", e.giteaReleasesURL),
		playbookPath,
	)

	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	runErr := cmd.Run()

	// Parse results per host (simplified - returns single result for all)
	return []DeployResult{
		{
			Host:    "all",
			Success: runErr == nil,
			Stdout:  stdout.String(),
			Stderr:  stderr.String(),
			Err:     runErr,
		},
	}, nil
}

// DeployParallel runs Ansible playbook for multiple inventories in parallel
func (e *Executor) DeployParallel(
	ctx context.Context,
	inventoryPaths []string,
	deployType string,
) (map[string][]DeployResult, error) {
	var wg sync.WaitGroup
	var mu sync.Mutex
	results := make(map[string][]DeployResult)
	errCh := make(chan error, len(inventoryPaths))

	for _, path := range inventoryPaths {
		wg.Add(1)
		go func(p string) {
			defer wg.Done()
			res, err := e.Deploy(ctx, p, deployType)
			if err != nil {
				errCh <- err
			}
			mu.Lock()
			results[p] = res
			mu.Unlock()
		}(path)
	}

	wg.Wait()
	close(errCh)

	// Collect errors
	var errs []error
	for err := range errCh {
		errs = append(errs, err)
	}

	if len(errs) > 0 {
		return results, fmt.Errorf("some deployments failed: %v", errs)
	}

	return results, nil
}

// WritePlaybook writes a playbook to the work directory
func (e *Executor) WritePlaybook(name string, content string) error {
	path := filepath.Join(e.workDir, name)
	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
		return err
	}
	return os.WriteFile(path, []byte(content), 0644)
}

// WriteAllPlaybooks writes all playbooks to the work directory
func (e *Executor) WriteAllPlaybooks() error {
	if err := e.WritePlaybook("binary_deploy.yml", BinaryDeployPlaybook); err != nil {
		return err
	}
	return e.WritePlaybook("docker_deploy.yml", DockerDeployPlaybook)
}