package task

import (
	"context"
	"io"
	"os"
	"path/filepath"
	"sync"
	"time"

	"github.com/puzpuzpuz/xsync/v3"
	"github.com/sajari/fuzzy"

	"github.com/go-task/task/v3/internal/logger"
	"github.com/go-task/task/v3/internal/output"
	"github.com/go-task/task/v3/internal/sort"
	"github.com/go-task/task/v3/taskfile/ast"
)

type (
	// An ExecutorOption is any type that can apply a configuration to an
	// [Executor].
	ExecutorOption interface {
		ApplyToExecutor(*Executor)
	}
	// An Executor is used for processing Taskfile(s) and executing the task(s)
	// within them.
	Executor struct {
		// Flags
		Dir                 string
		Entrypoint          string
		TempDir             TempDir
		Force               bool
		ForceAll            bool
		Insecure            bool
		Download            bool
		Offline             bool
		Timeout             time.Duration
		CacheExpiryDuration time.Duration
		Watch               bool
		Verbose             bool
		Silent              bool
		AssumeYes           bool
		AssumeTerm          bool // Used for testing
		Dry                 bool
		Summary             bool
		Parallel            bool
		Color               bool
		Concurrency         int
		Interval            time.Duration

		// I/O
		Stdin  io.Reader
		Stdout io.Writer
		Stderr io.Writer

		// Internal
		Taskfile           *ast.Taskfile
		Logger             *logger.Logger
		Compiler           *Compiler
		Output             output.Output
		OutputStyle        ast.Output
		TaskSorter         sort.Sorter
		UserWorkingDir     string
		EnableVersionCheck bool

		fuzzyModel *fuzzy.Model

		concurrencySemaphore chan struct{}
		taskCallCount        map[string]*int32
		mkdirMutexMap        map[string]*sync.Mutex
		executionHashes      map[string]context.Context
		executionHashesMutex sync.Mutex
		watchedDirs          *xsync.MapOf[string, bool]
	}
	TempDir struct {
		Remote      string
		Fingerprint string
	}
)

// NewExecutor creates a new [Executor] and applies the given functional options
// to it.
func NewExecutor(opts ...ExecutorOption) *Executor {
	e := &Executor{
		Timeout:              time.Second * 10,
		Stdin:                os.Stdin,
		Stdout:               os.Stdout,
		Stderr:               os.Stderr,
		Logger:               nil,
		Compiler:             nil,
		Output:               nil,
		OutputStyle:          ast.Output{},
		TaskSorter:           sort.AlphaNumericWithRootTasksFirst,
		UserWorkingDir:       "",
		fuzzyModel:           nil,
		concurrencySemaphore: nil,
		taskCallCount:        map[string]*int32{},
		mkdirMutexMap:        map[string]*sync.Mutex{},
		executionHashes:      map[string]context.Context{},
		executionHashesMutex: sync.Mutex{},
	}
	e.Options(opts...)
	return e
}

// Options loops through the given [ExecutorOption] functions and applies them
// to the [Executor].
func (e *Executor) Options(opts ...ExecutorOption) {
	for _, opt := range opts {
		opt.ApplyToExecutor(e)
	}
}

// WithDir sets the working directory of the [Executor]. By default, the
// directory is set to the user's current working directory.
func WithDir(dir string) ExecutorOption {
	return &dirOption{dir}
}

type dirOption struct {
	dir string
}

func (o *dirOption) ApplyToExecutor(e *Executor) {
	e.UserWorkingDir, _ = filepath.Abs(o.dir)
	e.Dir = o.dir
}

// WithEntrypoint sets the entrypoint (main Taskfile) of the [Executor]. By
// default, Task will search for one of the default Taskfiles in the given
// directory.
func WithEntrypoint(entrypoint string) ExecutorOption {
	return &entrypointOption{entrypoint}
}

type entrypointOption struct {
	entrypoint string
}

func (o *entrypointOption) ApplyToExecutor(e *Executor) {
	e.Entrypoint = o.entrypoint
}

// WithTempDir sets the temporary directory that will be used by [Executor] for
// storing temporary files like checksums and cached remote files. By default,
// the temporary directory is set to the user's temporary directory.
func WithTempDir(tempDir TempDir) ExecutorOption {
	return &tempDirOption{tempDir}
}

type tempDirOption struct {
	tempDir TempDir
}

func (o *tempDirOption) ApplyToExecutor(e *Executor) {
	e.TempDir = o.tempDir
}

// WithForce ensures that the [Executor] always runs a task, even when
// fingerprinting or prompts would normally stop it.
func WithForce(force bool) ExecutorOption {
	return &forceOption{force}
}

type forceOption struct {
	force bool
}

func (o *forceOption) ApplyToExecutor(e *Executor) {
	e.Force = o.force
}

// WithForceAll ensures that the [Executor] always runs all tasks (including
// subtasks), even when fingerprinting or prompts would normally stop them.
func WithForceAll(forceAll bool) ExecutorOption {
	return &forceAllOption{forceAll}
}

type forceAllOption struct {
	forceAll bool
}

func (o *forceAllOption) ApplyToExecutor(e *Executor) {
	e.ForceAll = o.forceAll
}

// WithInsecure allows the [Executor] to make insecure connections when reading
// remote taskfiles. By default, insecure connections are rejected.
func WithInsecure(insecure bool) ExecutorOption {
	return &insecureOption{insecure}
}

type insecureOption struct {
	insecure bool
}

func (o *insecureOption) ApplyToExecutor(e *Executor) {
	e.Insecure = o.insecure
}

// WithDownload forces the [Executor] to download a fresh copy of the taskfile
// from the remote source.
func WithDownload(download bool) ExecutorOption {
	return &downloadOption{download}
}

type downloadOption struct {
	download bool
}

func (o *downloadOption) ApplyToExecutor(e *Executor) {
	e.Download = o.download
}

// WithOffline stops the [Executor] from being able to make network connections.
// It will still be able to read local files and cached copies of remote files.
func WithOffline(offline bool) ExecutorOption {
	return &offlineOption{offline}
}

type offlineOption struct {
	offline bool
}

func (o *offlineOption) ApplyToExecutor(e *Executor) {
	e.Offline = o.offline
}

// WithTimeout sets the [Executor]'s timeout for fetching remote taskfiles. By
// default, the timeout is set to 10 seconds.
func WithTimeout(timeout time.Duration) ExecutorOption {
	return &timeoutOption{timeout}
}

type timeoutOption struct {
	timeout time.Duration
}

func (o *timeoutOption) ApplyToExecutor(e *Executor) {
	e.Timeout = o.timeout
}

// WithCacheExpiryDuration sets the duration after which the cache is considered
// expired. By default, the cache is considered expired after 24 hours.
func WithCacheExpiryDuration(duration time.Duration) ExecutorOption {
	return &cacheExpiryDurationOption{duration: duration}
}

type cacheExpiryDurationOption struct {
	duration time.Duration
}

func (o *cacheExpiryDurationOption) ApplyToExecutor(r *Executor) {
	r.CacheExpiryDuration = o.duration
}

// WithWatch tells the [Executor] to keep running in the background and watch
// for changes to the fingerprint of the tasks that are run. When changes are
// detected, a new task run is triggered.
func WithWatch(watch bool) ExecutorOption {
	return &watchOption{watch}
}

type watchOption struct {
	watch bool
}

func (o *watchOption) ApplyToExecutor(e *Executor) {
	e.Watch = o.watch
}

// WithVerbose tells the [Executor] to output more information about the tasks
// that are run.
func WithVerbose(verbose bool) ExecutorOption {
	return &verboseOption{verbose}
}

type verboseOption struct {
	verbose bool
}

func (o *verboseOption) ApplyToExecutor(e *Executor) {
	e.Verbose = o.verbose
}

// WithSilent tells the [Executor] to suppress all output except for the output
// of the tasks that are run.
func WithSilent(silent bool) ExecutorOption {
	return &silentOption{silent}
}

type silentOption struct {
	silent bool
}

func (o *silentOption) ApplyToExecutor(e *Executor) {
	e.Silent = o.silent
}

// WithAssumeYes tells the [Executor] to assume "yes" for all prompts.
func WithAssumeYes(assumeYes bool) ExecutorOption {
	return &assumeYesOption{assumeYes}
}

type assumeYesOption struct {
	assumeYes bool
}

func (o *assumeYesOption) ApplyToExecutor(e *Executor) {
	e.AssumeYes = o.assumeYes
}

// WithAssumeTerm is used for testing purposes to simulate a terminal.
func WithAssumeTerm(assumeTerm bool) ExecutorOption {
	return &assumeTermOption{assumeTerm}
}

type assumeTermOption struct {
	assumeTerm bool
}

func (o *assumeTermOption) ApplyToExecutor(e *Executor) {
	e.AssumeTerm = o.assumeTerm
}

// WithDry tells the [Executor] to output the commands that would be run without
// actually running them.
func WithDry(dry bool) ExecutorOption {
	return &dryOption{dry}
}

type dryOption struct {
	dry bool
}

func (o *dryOption) ApplyToExecutor(e *Executor) {
	e.Dry = o.dry
}

// WithSummary tells the [Executor] to output a summary of the given tasks
// instead of running them.
func WithSummary(summary bool) ExecutorOption {
	return &summaryOption{summary}
}

type summaryOption struct {
	summary bool
}

func (o *summaryOption) ApplyToExecutor(e *Executor) {
	e.Summary = o.summary
}

// WithParallel tells the [Executor] to run tasks given in the same call in
// parallel.
func WithParallel(parallel bool) ExecutorOption {
	return &parallelOption{parallel}
}

type parallelOption struct {
	parallel bool
}

func (o *parallelOption) ApplyToExecutor(e *Executor) {
	e.Parallel = o.parallel
}

// WithColor tells the [Executor] whether or not to output using colorized
// strings.
func WithColor(color bool) ExecutorOption {
	return &colorOption{color}
}

type colorOption struct {
	color bool
}

func (o *colorOption) ApplyToExecutor(e *Executor) {
	e.Color = o.color
}

// WithConcurrency sets the maximum number of tasks that the [Executor] can run
// in parallel.
func WithConcurrency(concurrency int) ExecutorOption {
	return &concurrencyOption{concurrency}
}

type concurrencyOption struct {
	concurrency int
}

func (o *concurrencyOption) ApplyToExecutor(e *Executor) {
	e.Concurrency = o.concurrency
}

// WithInterval sets the interval at which the [Executor] will wait for
// duplicated events before running a task.
func WithInterval(interval time.Duration) ExecutorOption {
	return &intervalOption{interval}
}

type intervalOption struct {
	interval time.Duration
}

func (o *intervalOption) ApplyToExecutor(e *Executor) {
	e.Interval = o.interval
}

// WithOutputStyle sets the output style of the [Executor]. By default, the
// output style is set to the style defined in the Taskfile.
func WithOutputStyle(outputStyle ast.Output) ExecutorOption {
	return &outputStyleOption{outputStyle}
}

type outputStyleOption struct {
	outputStyle ast.Output
}

func (o *outputStyleOption) ApplyToExecutor(e *Executor) {
	e.OutputStyle = o.outputStyle
}

// WithTaskSorter sets the sorter that the [Executor] will use to sort tasks. By
// default, the sorter is set to sort tasks alphabetically, but with tasks with
// no namespace (in the root Taskfile) first.
func WithTaskSorter(sorter sort.Sorter) ExecutorOption {
	return &taskSorterOption{sorter}
}

type taskSorterOption struct {
	sorter sort.Sorter
}

func (o *taskSorterOption) ApplyToExecutor(e *Executor) {
	e.TaskSorter = o.sorter
}

// WithStdin sets the [Executor]'s standard input [io.Reader].
func WithStdin(stdin io.Reader) ExecutorOption {
	return &stdinOption{stdin}
}

type stdinOption struct {
	stdin io.Reader
}

func (o *stdinOption) ApplyToExecutor(e *Executor) {
	e.Stdin = o.stdin
}

// WithStdout sets the [Executor]'s standard output [io.Writer].
func WithStdout(stdout io.Writer) ExecutorOption {
	return &stdoutOption{stdout}
}

type stdoutOption struct {
	stdout io.Writer
}

func (o *stdoutOption) ApplyToExecutor(e *Executor) {
	e.Stdout = o.stdout
}

// WithStderr sets the [Executor]'s standard error [io.Writer].
func WithStderr(stderr io.Writer) ExecutorOption {
	return &stderrOption{stderr}
}

type stderrOption struct {
	stderr io.Writer
}

func (o *stderrOption) ApplyToExecutor(e *Executor) {
	e.Stderr = o.stderr
}

// WithIO sets the [Executor]'s standard input, output, and error to the same
// [io.ReadWriter].
func WithIO(rw io.ReadWriter) ExecutorOption {
	return &ioOption{rw}
}

type ioOption struct {
	rw io.ReadWriter
}

func (o *ioOption) ApplyToExecutor(e *Executor) {
	e.Stdin = o.rw
	e.Stdout = o.rw
	e.Stderr = o.rw
}

// WithVersionCheck tells the [Executor] whether or not to check the version of
func WithVersionCheck(enableVersionCheck bool) ExecutorOption {
	return &versionCheckOption{enableVersionCheck}
}

type versionCheckOption struct {
	enableVersionCheck bool
}

func (o *versionCheckOption) ApplyToExecutor(e *Executor) {
	e.EnableVersionCheck = o.enableVersionCheck
}