package generators

import (
	"context"
	"fmt"
	"path"
	"sort"
	"strconv"
	"strings"
	"time"

	argoprojiov1alpha1 "github.com/argoproj/applicationset/api/v1alpha1"
	"github.com/argoproj/applicationset/pkg/services"
	"github.com/jeremywohl/flatten"
	log "github.com/sirupsen/logrus"
	"sigs.k8s.io/yaml"
)

var _ Generator = (*GitGenerator)(nil)

type GitGenerator struct {
	repos services.Repos
}

func NewGitGenerator(repos services.Repos) Generator {
	g := &GitGenerator{
		repos: repos,
	}
	return g
}

func (g *GitGenerator) GetTemplate(appSetGenerator *argoprojiov1alpha1.ApplicationSetGenerator) *argoprojiov1alpha1.ApplicationSetTemplate {
	return &appSetGenerator.Git.Template
}

func (g *GitGenerator) GetRequeueAfter(appSetGenerator *argoprojiov1alpha1.ApplicationSetGenerator) time.Duration {

	// Return a requeue default of 3 minutes, if no default is specified.

	if appSetGenerator.Git.RequeueAfterSeconds != nil {
		return time.Duration(*appSetGenerator.Git.RequeueAfterSeconds) * time.Second
	}

	return DefaultRequeueAfterSeconds
}

func (g *GitGenerator) GenerateParams(appSetGenerator *argoprojiov1alpha1.ApplicationSetGenerator, _ *argoprojiov1alpha1.ApplicationSet) ([]map[string]string, error) {

	if appSetGenerator == nil {
		return nil, EmptyAppSetGeneratorError
	}

	if appSetGenerator.Git == nil {
		return nil, EmptyAppSetGeneratorError
	}

	var err error
	var res []map[string]string
	if appSetGenerator.Git.Directories != nil {
		res, err = g.generateParamsForGitDirectories(appSetGenerator)
	} else if appSetGenerator.Git.Files != nil {
		res, err = g.generateParamsForGitFiles(appSetGenerator)
	} else {
		return nil, EmptyAppSetGeneratorError
	}
	if err != nil {
		return nil, err
	}

	return res, nil
}

func (g *GitGenerator) generateParamsForGitDirectories(appSetGenerator *argoprojiov1alpha1.ApplicationSetGenerator) ([]map[string]string, error) {

	// Directories, not files
	allPaths, err := g.repos.GetDirectories(context.TODO(), appSetGenerator.Git.RepoURL, appSetGenerator.Git.Revision)
	if err != nil {
		return nil, err
	}

	log.WithFields(log.Fields{
		"allPaths": allPaths,
		"total":    len(allPaths),
		"repoURL":  appSetGenerator.Git.RepoURL,
		"revision": appSetGenerator.Git.Revision,
	}).Info("applications result from the repo service")

	requestedApps := g.filterApps(appSetGenerator.Git.Directories, allPaths)

	res := g.generateParamsFromApps(requestedApps, appSetGenerator)

	return res, nil
}

func (g *GitGenerator) generateParamsForGitFiles(appSetGenerator *argoprojiov1alpha1.ApplicationSetGenerator) ([]map[string]string, error) {

	// Get all files that match the requested path string, removing duplicates
	allFiles := make(map[string][]byte)
	for _, requestedPath := range appSetGenerator.Git.Files {
		files, err := g.repos.GetFiles(context.TODO(), appSetGenerator.Git.RepoURL, appSetGenerator.Git.Revision, requestedPath.Path)
		if err != nil {
			return nil, err
		}
		for filePath, content := range files {
			allFiles[filePath] = content
		}
	}

	// Extract the unduplicated map into a list, and sort by path to ensure a deterministic
	// processing order in the subsequent step
	allPaths := []string{}
	for path := range allFiles {
		allPaths = append(allPaths, path)
	}
	sort.Strings(allPaths)

	// Generate params from each path, and return
	res := []map[string]string{}
	for _, path := range allPaths {

		// A JSON / YAML file path can contain multiple sets of parameters (ie it is an array)
		paramsArray, err := g.generateParamsFromGitFile(path, allFiles[path])
		if err != nil {
			return nil, fmt.Errorf("unable to process file '%s': %v", path, err)
		}

		for index := range paramsArray {
			res = append(res, paramsArray[index])
		}
	}
	return res, nil
}

func (g *GitGenerator) generateParamsFromGitFile(filePath string, fileContent []byte) ([]map[string]string, error) {
	objectsFound := []map[string]interface{}{}

	// First, we attempt to parse as an array
	err := yaml.Unmarshal(fileContent, &objectsFound)
	if err != nil {
		// If unable to parse as an array, attempt to parse as a single object
		singleObj := make(map[string]interface{})
		err = yaml.Unmarshal(fileContent, &singleObj)
		if err != nil {
			return nil, fmt.Errorf("unable to parse file: %v", err)
		}
		objectsFound = append(objectsFound, singleObj)
	}

	res := []map[string]string{}

	// Flatten all objects found, and return them
	for _, objectFound := range objectsFound {

		flat, err := flatten.Flatten(objectFound, "", flatten.DotStyle)
		if err != nil {
			return nil, err
		}
		params := map[string]string{}
		for k, v := range flat {
			params[k] = fmt.Sprintf("%v", v)
		}
		params["path"] = path.Dir(filePath)
		params["path.basename"] = path.Base(params["path"])
		params["path.basenameNormalized"] = sanitizeName(path.Base(params["path"]))
		for k, v := range strings.Split(strings.TrimSuffix(params["path"], params["path.basename"]), "/") {
			if len(v) > 0 {
				params["path["+strconv.Itoa(k)+"]"] = v
			}
		}
		res = append(res, params)
	}

	return res, nil

}

func (g *GitGenerator) filterApps(Directories []argoprojiov1alpha1.GitDirectoryGeneratorItem, allPaths []string) []string {
	res := []string{}
	for _, appPath := range allPaths {
		appInclude := false
		appExclude := false
		// Iterating over each appPath and check whether directories object has requestedPath that matches the appPath
		for _, requestedPath := range Directories {
			match, err := path.Match(requestedPath.Path, appPath)
			if err != nil {
				log.WithError(err).WithField("requestedPath", requestedPath).
					WithField("appPath", appPath).Error("error while matching appPath to requestedPath")
				continue
			}
			if match && !requestedPath.Exclude {
				appInclude = true
			}
			if match && requestedPath.Exclude {
				appExclude = true
			}
		}
		// Whenever there is a path with exclude: true it wont be included, even if it is included in a different path pattern
		if appInclude && !appExclude {
			res = append(res, appPath)
		}
	}
	return res
}

func (g *GitGenerator) generateParamsFromApps(requestedApps []string, _ *argoprojiov1alpha1.ApplicationSetGenerator) []map[string]string {
	// TODO: At some point, the appicationSetGenerator param should be used

	res := make([]map[string]string, len(requestedApps))
	for i, a := range requestedApps {

		params := make(map[string]string, 2)
		params["path"] = a
		params["path.basename"] = path.Base(a)
		params["path.basenameNormalized"] = sanitizeName(path.Base(a))
		for k, v := range strings.Split(strings.TrimSuffix(params["path"], params["path.basename"]), "/") {
			if len(v) > 0 {
				params["path["+strconv.Itoa(k)+"]"] = v
			}
		}
		res[i] = params
	}

	return res
}
