package model

import (
	"fmt"
	"io"
	"reflect"
	"regexp"
	"strconv"
	"strings"

	"github.com/nektos/act/pkg/common"
	log "github.com/sirupsen/logrus"
	"gopkg.in/yaml.v3"
)

// Workflow is the structure of the files in .github/workflows
type Workflow struct {
	File     string
	Name     string            `yaml:"name"`
	RawOn    yaml.Node         `yaml:"on"`
	Env      map[string]string `yaml:"env"`
	Jobs     map[string]*Job   `yaml:"jobs"`
	Defaults Defaults          `yaml:"defaults"`
}

// CompositeRestrictions is the structure to control what is allowed in composite actions
type CompositeRestrictions struct {
	AllowCompositeUses            bool
	AllowCompositeIf              bool
	AllowCompositeContinueOnError bool
}

func defaultCompositeRestrictions() *CompositeRestrictions {
	return &CompositeRestrictions{
		AllowCompositeUses:            true,
		AllowCompositeIf:              true,
		AllowCompositeContinueOnError: false,
	}
}

// On events for the workflow
func (w *Workflow) On() []string {
	switch w.RawOn.Kind {
	case yaml.ScalarNode:
		var val string
		err := w.RawOn.Decode(&val)
		if err != nil {
			log.Fatal(err)
		}
		return []string{val}
	case yaml.SequenceNode:
		var val []string
		err := w.RawOn.Decode(&val)
		if err != nil {
			log.Fatal(err)
		}
		return val
	case yaml.MappingNode:
		var val map[string]interface{}
		err := w.RawOn.Decode(&val)
		if err != nil {
			log.Fatal(err)
		}
		var keys []string
		for k := range val {
			keys = append(keys, k)
		}
		return keys
	}
	return nil
}

// Job is the structure of one job in a workflow
type Job struct {
	Name           string                    `yaml:"name"`
	RawNeeds       yaml.Node                 `yaml:"needs"`
	RawRunsOn      yaml.Node                 `yaml:"runs-on"`
	Env            yaml.Node                 `yaml:"env"`
	If             yaml.Node                 `yaml:"if"`
	Steps          []*Step                   `yaml:"steps"`
	TimeoutMinutes int64                     `yaml:"timeout-minutes"`
	Services       map[string]*ContainerSpec `yaml:"services"`
	Strategy       *Strategy                 `yaml:"strategy"`
	RawContainer   yaml.Node                 `yaml:"container"`
	Defaults       Defaults                  `yaml:"defaults"`
	Outputs        map[string]string         `yaml:"outputs"`
	Uses           string                    `yaml:"uses"`
	Result         string
}

// Strategy for the job
type Strategy struct {
	FailFast          bool
	MaxParallel       int
	FailFastString    string    `yaml:"fail-fast"`
	MaxParallelString string    `yaml:"max-parallel"`
	RawMatrix         yaml.Node `yaml:"matrix"`
}

// Default settings that will apply to all steps in the job or workflow
type Defaults struct {
	Run RunDefaults `yaml:"run"`
}

// Defaults for all run steps in the job or workflow
type RunDefaults struct {
	Shell            string `yaml:"shell"`
	WorkingDirectory string `yaml:"working-directory"`
}

// GetMaxParallel sets default and returns value for `max-parallel`
func (s Strategy) GetMaxParallel() int {
	// MaxParallel default value is `GitHub will maximize the number of jobs run in parallel depending on the available runners on GitHub-hosted virtual machines`
	// So I take the liberty to hardcode default limit to 4 and this is because:
	// 1: tl;dr: self-hosted does only 1 parallel job - https://github.com/actions/runner/issues/639#issuecomment-825212735
	// 2: GH has 20 parallel job limit (for free tier) - https://github.com/github/docs/blob/3ae84420bd10997bb5f35f629ebb7160fe776eae/content/actions/reference/usage-limits-billing-and-administration.md?plain=1#L45
	// 3: I want to add support for MaxParallel to act and 20! parallel jobs is a bit overkill IMHO
	maxParallel := 4
	if s.MaxParallelString != "" {
		var err error
		if maxParallel, err = strconv.Atoi(s.MaxParallelString); err != nil {
			log.Errorf("Failed to parse 'max-parallel' option: %v", err)
		}
	}
	return maxParallel
}

// GetFailFast sets default and returns value for `fail-fast`
func (s Strategy) GetFailFast() bool {
	// FailFast option is true by default: https://github.com/github/docs/blob/3ae84420bd10997bb5f35f629ebb7160fe776eae/content/actions/reference/workflow-syntax-for-github-actions.md?plain=1#L1107
	failFast := true
	log.Debug(s.FailFastString)
	if s.FailFastString != "" {
		var err error
		if failFast, err = strconv.ParseBool(s.FailFastString); err != nil {
			log.Errorf("Failed to parse 'fail-fast' option: %v", err)
		}
	}
	return failFast
}

// Container details for the job
func (j *Job) Container() *ContainerSpec {
	var val *ContainerSpec
	switch j.RawContainer.Kind {
	case yaml.ScalarNode:
		val = new(ContainerSpec)
		err := j.RawContainer.Decode(&val.Image)
		if err != nil {
			log.Fatal(err)
		}
	case yaml.MappingNode:
		val = new(ContainerSpec)
		err := j.RawContainer.Decode(val)
		if err != nil {
			log.Fatal(err)
		}
	}
	return val
}

// Needs list for Job
func (j *Job) Needs() []string {
	switch j.RawNeeds.Kind {
	case yaml.ScalarNode:
		var val string
		err := j.RawNeeds.Decode(&val)
		if err != nil {
			log.Fatal(err)
		}
		return []string{val}
	case yaml.SequenceNode:
		var val []string
		err := j.RawNeeds.Decode(&val)
		if err != nil {
			log.Fatal(err)
		}
		return val
	}
	return nil
}

// RunsOn list for Job
func (j *Job) RunsOn() []string {
	switch j.RawRunsOn.Kind {
	case yaml.ScalarNode:
		var val string
		err := j.RawRunsOn.Decode(&val)
		if err != nil {
			log.Fatal(err)
		}
		return []string{val}
	case yaml.SequenceNode:
		var val []string
		err := j.RawRunsOn.Decode(&val)
		if err != nil {
			log.Fatal(err)
		}
		return val
	}
	return nil
}

func environment(yml yaml.Node) map[string]string {
	env := make(map[string]string)
	if yml.Kind == yaml.MappingNode {
		if err := yml.Decode(&env); err != nil {
			log.Fatal(err)
		}
	}
	return env
}

// Environments returns string-based key=value map for a job
func (j *Job) Environment() map[string]string {
	return environment(j.Env)
}

// Matrix decodes RawMatrix YAML node
func (j *Job) Matrix() map[string][]interface{} {
	if j.Strategy.RawMatrix.Kind == yaml.MappingNode {
		var val map[string][]interface{}
		if err := j.Strategy.RawMatrix.Decode(&val); err != nil {
			log.Fatal(err)
		}
		return val
	}
	return nil
}

// GetMatrixes returns the matrix cross product
// It skips includes and hard fails excludes for non-existing keys
// nolint:gocyclo
func (j *Job) GetMatrixes() []map[string]interface{} {
	matrixes := make([]map[string]interface{}, 0)
	if j.Strategy != nil {
		j.Strategy.FailFast = j.Strategy.GetFailFast()
		j.Strategy.MaxParallel = j.Strategy.GetMaxParallel()

		if m := j.Matrix(); m != nil {
			includes := make([]map[string]interface{}, 0)
			for _, v := range m["include"] {
				switch t := v.(type) {
				case []interface{}:
					for _, i := range t {
						i := i.(map[string]interface{})
						for k := range i {
							if _, ok := m[k]; ok {
								includes = append(includes, i)
								break
							}
						}
					}
				case interface{}:
					v := v.(map[string]interface{})
					for k := range v {
						if _, ok := m[k]; ok {
							includes = append(includes, v)
							break
						}
					}
				}
			}
			delete(m, "include")

			excludes := make([]map[string]interface{}, 0)
			for _, e := range m["exclude"] {
				e := e.(map[string]interface{})
				for k := range e {
					if _, ok := m[k]; ok {
						excludes = append(excludes, e)
					} else {
						// We fail completely here because that's what GitHub does for non-existing matrix keys, fail on exclude, silent skip on include
						log.Fatalf("The workflow is not valid. Matrix exclude key '%s' does not match any key within the matrix", k)
					}
				}
			}
			delete(m, "exclude")

			matrixProduct := common.CartesianProduct(m)
		MATRIX:
			for _, matrix := range matrixProduct {
				for _, exclude := range excludes {
					if commonKeysMatch(matrix, exclude) {
						log.Debugf("Skipping matrix '%v' due to exclude '%v'", matrix, exclude)
						continue MATRIX
					}
				}
				matrixes = append(matrixes, matrix)
			}
			for _, include := range includes {
				log.Debugf("Adding include '%v'", include)
				matrixes = append(matrixes, include)
			}
		} else {
			matrixes = append(matrixes, make(map[string]interface{}))
		}
	} else {
		matrixes = append(matrixes, make(map[string]interface{}))
	}
	return matrixes
}

func commonKeysMatch(a map[string]interface{}, b map[string]interface{}) bool {
	for aKey, aVal := range a {
		if bVal, ok := b[aKey]; ok && !reflect.DeepEqual(aVal, bVal) {
			return false
		}
	}
	return true
}

// ContainerSpec is the specification of the container to use for the job
type ContainerSpec struct {
	Image       string            `yaml:"image"`
	Env         map[string]string `yaml:"env"`
	Ports       []string          `yaml:"ports"`
	Volumes     []string          `yaml:"volumes"`
	Options     string            `yaml:"options"`
	Credentials map[string]string `yaml:"credentials"`
	Entrypoint  string
	Args        string
	Name        string
	Reuse       bool
}

// Step is the structure of one step in a job
type Step struct {
	ID               string            `yaml:"id"`
	If               yaml.Node         `yaml:"if"`
	Name             string            `yaml:"name"`
	Uses             string            `yaml:"uses"`
	Run              string            `yaml:"run"`
	WorkingDirectory string            `yaml:"working-directory"`
	Shell            string            `yaml:"shell"`
	Env              yaml.Node         `yaml:"env"`
	With             map[string]string `yaml:"with"`
	ContinueOnError  bool              `yaml:"continue-on-error"`
	TimeoutMinutes   int64             `yaml:"timeout-minutes"`
}

// String gets the name of step
func (s *Step) String() string {
	if s.Name != "" {
		return s.Name
	} else if s.Uses != "" {
		return s.Uses
	} else if s.Run != "" {
		return s.Run
	}
	return s.ID
}

// Environments returns string-based key=value map for a step
func (s *Step) Environment() map[string]string {
	return environment(s.Env)
}

// GetEnv gets the env for a step
func (s *Step) GetEnv() map[string]string {
	env := s.Environment()

	for k, v := range s.With {
		envKey := regexp.MustCompile("[^A-Z0-9-]").ReplaceAllString(strings.ToUpper(k), "_")
		envKey = fmt.Sprintf("INPUT_%s", strings.ToUpper(envKey))
		env[envKey] = v
	}
	return env
}

// ShellCommand returns the command for the shell
func (s *Step) ShellCommand() string {
	shellCommand := ""

	//Reference: https://github.com/actions/runner/blob/8109c962f09d9acc473d92c595ff43afceddb347/src/Runner.Worker/Handlers/ScriptHandlerHelpers.cs#L9-L17
	switch s.Shell {
	case "", "bash":
		shellCommand = "bash --noprofile --norc -e -o pipefail {0}"
	case "pwsh":
		shellCommand = "pwsh -command . '{0}'"
	case "python":
		shellCommand = "python {0}"
	case "sh":
		shellCommand = "sh -e -c {0}"
	case "cmd":
		shellCommand = "%ComSpec% /D /E:ON /V:OFF /S /C \"CALL \"{0}\"\""
	case "powershell":
		shellCommand = "powershell -command . '{0}'"
	default:
		shellCommand = s.Shell
	}
	return shellCommand
}

// StepType describes what type of step we are about to run
type StepType int

const (
	// StepTypeRun is all steps that have a `run` attribute
	StepTypeRun StepType = iota

	// StepTypeUsesDockerURL is all steps that have a `uses` that is of the form `docker://...`
	StepTypeUsesDockerURL

	// StepTypeUsesActionLocal is all steps that have a `uses` that is a local action in a subdirectory
	StepTypeUsesActionLocal

	// StepTypeUsesActionRemote is all steps that have a `uses` that is a reference to a github repo
	StepTypeUsesActionRemote

	// StepTypeInvalid is for steps that have invalid step action
	StepTypeInvalid
)

// Type returns the type of the step
func (s *Step) Type() StepType {
	if s.Run == "" && s.Uses == "" {
		return StepTypeInvalid
	}

	if s.Run != "" {
		if s.Uses != "" {
			return StepTypeInvalid
		}
		return StepTypeRun
	} else if strings.HasPrefix(s.Uses, "docker://") {
		return StepTypeUsesDockerURL
	} else if strings.HasPrefix(s.Uses, "./") {
		return StepTypeUsesActionLocal
	}
	return StepTypeUsesActionRemote
}

func (s *Step) Validate(config *CompositeRestrictions) error {
	if config == nil {
		config = defaultCompositeRestrictions()
	}
	if s.Type() != StepTypeRun && !config.AllowCompositeUses {
		return fmt.Errorf("(StepID: %s): Unexpected value 'uses'", s.String())
	} else if s.Type() == StepTypeRun && s.Shell == "" {
		return fmt.Errorf("(StepID: %s): Required property is missing: 'shell'", s.String())
	} else if !s.If.IsZero() && !config.AllowCompositeIf {
		return fmt.Errorf("(StepID: %s): Property is not available: 'if'", s.String())
	} else if s.ContinueOnError && !config.AllowCompositeContinueOnError {
		return fmt.Errorf("(StepID: %s): Property is not available: 'continue-on-error'", s.String())
	}
	return nil
}

// ReadWorkflow returns a list of jobs for a given workflow file reader
func ReadWorkflow(in io.Reader) (*Workflow, error) {
	w := new(Workflow)
	err := yaml.NewDecoder(in).Decode(w)
	return w, err
}

// GetJob will get a job by name in the workflow
func (w *Workflow) GetJob(jobID string) *Job {
	for id, j := range w.Jobs {
		if jobID == id {
			if j.Name == "" {
				j.Name = id
			}
			if j.If.Value == "" {
				j.If.Value = "success()"
			}
			return j
		}
	}
	return nil
}

// GetJobIDs will get all the job names in the workflow
func (w *Workflow) GetJobIDs() []string {
	ids := make([]string, 0)
	for id := range w.Jobs {
		ids = append(ids, id)
	}
	return ids
}